BMWR850RT question - engine breaking down @4500 rpm

[cruising]

Hi all - hoping for help and I am new to the site. I just purchased a 1997 R850RT with 74000km on the clock. First non Japanese bike - I liked the full fairing for daily all weather commuting. There is not a lot of info around on this model as they were primarily produced for police departments. It is identical in all aspects to the 1100 except has a smaller motor.

I have an issue in that it breaks down at 4500-5000rpm in all gears - it pulls smoothly to this point. Had bike serviced and replaced fuel filter. No improvement. I suppose it could be the fuel pump but I don't want to go to this expense if it does not solve the problem. I am not mechanically minded so any work will be done by a mechanic. All I can say about the bike so far is that it has great suspension, is comfortable and adjustable screen works well. Not so impressive is that in 5th gear and travelling at 60km/phr, the motor labours - prefers 4th gear at this speed. Disappointing because most articles rate the BMWs torque. May be that the 5th gear is long legged for touring and economy. Does anyone know a site where I can I can read more about this model? I have only managed to find spec. sheets on the bike. Thanks

[Meromorph]

On your problem at 4,500 - 5,000 rpm:

It could be a lot of things -

Fuel pressure regulator,

Ignition coils,

Spark plugs,

Plug wires,

ECU, etc.

I would lean to something electrical, but you need diagnostics, or start replacing stuff '''

 

That rev range is where you should be any time you're not just bimbling along in traffic...

At 60 kph on my '98 R1100RT, I'd be in 3rd. On bendy roads 1'm usually in 3rd or 4th, I'm only in 5th on freeways or dual carriageways. Yes, the boxer has lots of torque, but it only gets useful over 3,000 rpm, and only gets good at 4,000 rpm and above.

The 850 is a great bike, but it's just as heavy as the 1100, as everything else is the same.

[Hookman]

I found this on the web during a quick search, hope this works out for you.

 

BMW R850 SERVICE MANUAL REPAIR MANUAL 1994-2005 DOWNLOAD

 

http://tbit.ws/6483454

[Danny caddyshack Noonan]

Info: 60 kph is 37 mph. 3rd gear, maybe 2nd, country. Most 11, 1150 and 1200 riders keep it in the 3500rpm and higher range. I usually shoot for 3500 to 4500. No experience on the 850 so, can't speak to that.

The first thing I'd look into are the plugs and wires. Fuel grade?

[cruising]

Thanks for the feedback. Will book it in at BMW dealer next week and hopefully get the bike sorted - hopefully it can be resolved at a reasonable price. I was surprised at the reply that at 60 kph, I should be in 3rd or 4th gear. My 81 Suzuki GSX 750 was quite happy to idle along at 60kph in 5th and I thought the same should apply to the BMW. Will advise outcome of service.

[kmac]

I have a 1996 R1100RT and 5th gear is ONLY used on the freeway or REALLY fast roads.

Under 60mph {roughly 96 kph} and I am never in 5th gear. These bikes are geared VERY long. They lug taking off in first gear which I hate.

 

Torque does not mean it likes to run at low rpm. Torque means it will pull thru that low rpm fairly easily. But a 2 cylinder motorcycle will always feel lopy or lug at low rpms compared to a 4/6/8....motor.

[Trullion]

I had an 850GS for 11 years, for several years together with an 1100RS which I still own. The 850 always felt way under-geared to me. Top gear was equivalent to 4th on the 1100. On the plus side I could change into top at a low speed but the engine always seemed busy at cruising speeds. It was thirsty too. I don't know if the 850RT has the same gearing as the GS (the 1100RT is higher-geared than the 1100GS), but if it is the same it should have no trouble taking top at 40mph on the level.

[cruising]

The reason for the delay in feedback is that I have no good news yet - starter motor packed up before I could take the bike to the mechanic so now it is standing at the mechanic while I try and find a starter motor at a reasonable price. Cost in Aus. is $600 for a Valeo starter motor or $900 for the genuine article. The part that broke is the starter motor case - the armature is seized inside the case BUT the armature is not available as a spare part even though you can purchase the case with the magnets as a spare.

Spoke to the previous owner who told me that when he purchased the bike 2nd hand 10 years ago, he was informed that this model was imported to Aus with the view of obtaining the tender to supply bikes for the Olympic games and the motor was limited to provide good fuel consumption and tank range. He has been happy to drive it this way and always changed gear at the 4000 rpm range. When I purchased the bike I had not owned a bike for 5 years and noticed the rpm problem within travelling 5kms - unfortunately I thought that it just required a service as he was not doing much mileage on the bike. I don't know whether the above story is plausible - I have my doubts but maybe it is the case in which case one has to try and figure out what was done and whether it can be undone! So now I am the owner of machine which has spent half of its short life in my possession on its stand, and even when it is on its wheels delivers limited performance.

Am I being unreasonable in wanting the bike to rev through the rpm range or is a BMW boxer motor supposed to be driven gently??

Look forward to responses - hopefully some clever individual can offer a possible solution.

All very frustrating as I have only done about 600 kilometers since I purchased it 4 weeks ago.

[tallman]

Info: 60 kph is 37 mph. 3rd gear, maybe 2nd, country. Most 11, 1150 and 1200 riders keep it in the 3500rpm and higher range. I usually shoot for 3500 to 4500. No experience on the 850 so, can't speak to that.

The first thing I'd look into are the plugs and wires. Fuel grade?

 

Good advice on gear selection for rpm.

 

The boxer isn't one to coddle and short shift, IMO.

 

My GT will pull from low rpm and gear.

 

My boxers were a different animal altogether.

60 KM was 2nd (R1100) in town 3rd in rural.

[Galactic Greyhound]

Evening cruising,

 

Re your problem with the bike not performing at 4500 rpm. It may be that there is insufficient fuel flow at the higher revs. You can check this by running the bike at the problem revs (4500) in a lower gear. If the fuel supply cannot keep up with the engine demand when you do this check then it may be that there is a split hose or connection leakage on the Fuel Pump Plate inside the tank - this is a common problem.

 

You can check for a correct fuel supply by disconnecting the rubber return hose from the black nylon Regulator return pipe (RH side at the rear of the tank - top pipe I think). Connect a hose from the Regulator return pipe and direct it into a clean, clear 2 litre bottle. Start the engine and run it at idle for 1 minute - the return pipe should deliver 2 litres in 1 minute at idle. This also checks the fuel pump pressure as the Regulator has to operate at the required pressure in order to give a return flow i.e. no/low pressure = no fuel return flow.

 

If you replace any hoses inside the tank they MUST be of continual submersion grade - if you buy the genuine BMW spares you will be OK.

 

Here's a couple of links which might help with your Starter Motor spares problem:

 

http://www.ukgser.com/forums/showthread.php?s=0ab19a9a7c26199162cd4b05641d1972&t=301738

 

http://www.woodauto.com/default.aspx

 

http://bmwmotorcycletech.info/boschvaleostarter.htm This is mainly an Airhead's article but some good info to be found.

 

PS. The Boxer will rev throughout it's rev range with very good torque at the lower revs. You can rev the nuts off it if you want but it's basically a touring bike capable of sustained speed over long distances. I love my R1100RT for its low-speed hill-climbing ability two-up on single-track Scottish hill roads.

[cruising]

Thanks for the advise so far - any thoughts regarding the theory that BMW restricted the motor and is causing my frustration - If this is the case could it be in the electronics of the bike?

Cheers for now

[Trullion]

Well, I know that in Europe there were some 850 oilheads that were restricted to 33bhp, or thereabouts, on account of learner licensing laws. Some were imported privately to the UK. Whether or not any went to Australia in RT form I don't know, but I suppose it is plausible that bikes intended for low speed fleet use could have been restricted. In the UK the vehicle registration document would show this.

 

I don't know whether the 33bhp bikes were restricted by limiting the throttle opening, or by reprogramming the Motronic, but you should be able to prove the former by removing one of the air intake tubes from a throttle body and look to see if the butterfly valve opens fully with the htrottle wide open.

 

I would have thought that even a restricted bike should pull more than 4,500 rpm; my friend's Triumph Legend certainly did and would just about do the ton.

 

I feel it is more likely that there is something wrong with the fuel supply. Certainly a full power (70bhp) 850 will fly past 4,500rpm in any gear.

 

 

[Danny caddyshack Noonan]

You might learn something from a plug reading. The EFI might preclude this if it is programmed to restrict the HP.

 

There might not be enough "mights" in the above two sentences.

[Galactic Greyhound]

Thanks for the advise so far - any thoughts regarding the theory that BMW restricted the motor and is causing my frustration - If this is the case could it be in the electronics of the bike?

Cheers for now

 

I doubt it as the bike would eventually end up in the open marketplace and be regarded as a lemon - BMW would not market such a machine without there being some clear indication that the bike was not to standard specification.

 

To put your mind at rest about this, email BMW Customer Services with the VIN number of the bike.

 

Check the fuel supply as per previous post or, you can check if the fuel supply is working OK by taking the bike out for a sustained full-throttle top speed blast preferably up a long incline. If the bike manages to do this the fuel supply is OK, if it can't - look at the fuel plate inside hoses/connections for leakage or rupture cos you ain't getting enough fuel flow.

[Galactic Greyhound]

More info on R850RT:

 

 

Performance data:

 

Max Power

70 hp (52 KW) at 7,000 rpm (performance reduction 34 hp (25 Kw) at 5,000 rpm possible)

Max Torque

77 Nm / 56 ft lb at 5,600 rpm (performance reduction: 60 Nm / 44 ft lb at 3,000 rpm)

Top Speed

Approx. 187 Kph / 116 mph. This is the speed you should be able to sustain for a period on a full-throttle top speed blast. If you can't get this either the engine is restricted or there is a fuel supply problem.

 

If the bike has not been restricted -

 

I believe your bike may be fitted with the MA2.4 Motronic system - this system is an adaptive system and learns various engine parameters. If the battery is ever disconnected the Motronic will lose its learned values and revert to a default mapping.

 

In case this has happened, it may be worthwhile making the Motronic relearn the fully open and fully closed Throttle Position Settings (TPS) - this is done as follows (copied from a previous Dirtrider post):

 

"First remove the #5 fuse for at least 30 seconds, then make sure the choke is fully OFF, then turn the key on (do not start engine), then FULLY open & close the throttle twice. That is all there is to it.

 

The above should be in your riders manual under battery replacement."

 

Have you got a catalytic converter fitted? If so, you might also try disconnecting the O2 sensor see if a faulty sensor is causing the problem - this will cause the Motronic to revert to Open Loop default operation and it will fuel the bike according to the default fuel mapping rather than what is being fed back from the sensor.

_________________________

[dirtrider]

Evening cruising

 

Difficult to tell what you have going on there.

 

You would think that if your problem was fuel related like low fuel pressure or low flow it wouldn't have a defined cutoff of 4500-5000 RPMs but more engine load related like cut off at 3K under heavy loading & easily go to 6K at light throttle light engine loading.

 

Ignition issues are more likely to have defined RPM cutoff limits but can still be load (combustion pressure) sensitive.

 

Maybe you can give us some more details-- like what it does climbing a long hill in 4th or 5th gears. How it does revving to 6K in neutral. Can it easily reach 6K in first gear at moderate throttle opening & again at wide open throttle.

 

Maybe try running for a short run with the air cleaner element removed as a test. Those can get wet & the paper swells up therefore impeding air flow but they will still look clean & new when visually looking at them.

 

Might also be something like a plugging exhaust system especially if it has a cat.

 

Or even heavily carboned valves under the valve heads restricting intake flow or exhaust flow.

 

But, things like plugging exhaust usually doesn't give a defined RPM cut off but can limit power output at or close to air flow capabilities.

 

More than likely you will either have to start testing things like ignition coil, plug wire resistance, & fuel flow/pressure or maybe give us lots more info & more riding feedback under different riding loads, speeds & in what gears the engine does what.

 

[cruising]

Thanks - at least I can try this and it wont cost me anything!

[cruising]

Forgot to mention that it has a After market exhaust - Statune and I dont think that it has a converter.

[Galactic Greyhound]

Found this while searching for how R850's can be restricted - not a lot of use but perhaps some confirmation? Will keep searching.

 

http://www.horizonsunlimited.com/hubb/bmw-tech/de-restricting-an-r850-gs-65043

[cruising]

Bike hesitates and will only go past the rpm range if you roll back the throttle and ever so gently feed in the fuel to a higher rpm but is still hesitant so if you want to speed things up it is better to change gear. In 5th will do around 155kph and then you are back in the range where it does not want to pull through. It is absolutely constant in its performance whether two up, on hills and acceleration. Today the mechanic checked fuel flow as recommended in one of these posts and also checked the injectors. He was of the opinion that it felt like fuel starvation and is now thinking that maybe the motor has been restricted.

[Galactic Greyhound]

If it is restricted, this may be how it is done - see Throttle Restriction Kit F:

 

http://www.fiinternational.com/FiResKitA42.pdf This would be in line with Trullion's post of 12/09.

 

See Homepage here: http://www.fiinternational.com/default.asp

[roger 04 rt]

This from a French document I found while researching Coding Plugs under the Pin 86 function.

 

Limitation puissance moteur et réduction émission et consommation carburant (Versions 25KW et Suisse)

Si non connecté pas de bridage de la puissance.

 

Which Google Translates to:

 

Limiting engine power and fuel consumption reduction emission and (Versions 25KW and Switzerland)

If not connect non clamping power.

 

I would try removing the Coding Plug (or maybe removing it but grounding 87 with a jumper, needs more research) and also seeing if that pin is hard wired to ground.

 

What coding plug do you have now?

 

4500 RPM would limit your engine to about 25KW or 33 HP assuming 40 lbs.-ft torque at 4500 which sounds about right for an 850.

 

I have a BMW NA document with the same reference and here is another link: Coding Plug colors .

[roger 04 rt]

Here is how Max BMW parts fiche lists the Motronic:

 

 

 

Adding new item to cart:

Part Number   Description lb Qty Each Total

 13611342214  CONTROL UNIT MOTRONIC - 25/KW - 51/KW 1.43 

Total Weight:lbs Sub Total:

 

[Galactic Greyhound]

Aha! So the Coding Plug could be significant in restricting the fuelling then?

[roger 04 rt]

Aha! So the Coding Plug could be significant in restricting the fuelling then?

 

It could be that! But they might have hardwired the pins of the motronic in the cable harness to the same effect. The OP needs to look into it.

 

But the Max BMW parts list makes it pretty clear that one Motronic does both. And RPM limiting would be a simple way to cut the power.

[Galactic Greyhound]

Some interesting pics of the Fi BMW 850 Restrictor Kit:

 

http://www.ukgser.com/forums/showthread.php?t=254473

[roger 04 rt]

R850RT Specs

[roger 04 rt]

Here's another data point: Intake Tubes. This same intake tube info is on the Max BMW parts site.

 

Maybe a new Coding Plug and modified intake tubes would reconfigure it.

[Galactic Greyhound]

Here's another data point: Intake Tubes. This same intake tube info is on the Max BMW parts site.

 

Maybe a new Coding Plug and modified intake tubes would reconfigure it.

 

Evening Roger,

I think you have nailed it - well done. If the bike was factory modified to be restricted and supplied by BMW from new this would likely be the way BMW would do it. It doesn't appear to need any mechanical restriction to the throttle body pulleys.

 

It's not clear from your link which Connecting Plug (Coding Plug) is the Restricted one. My data shows it is likely to be:

R850 GS non-cat 25Kw Olive yellow 30 86, 61 36 8 366 621 2.2 [RESTRICTED 33HP]. The de-Restriction kit doesn't seem to include a Connecting (Coding) Plug - is it removed or rewired?

 

If the BMW Part Number on the Intake Tubes and colour/Part Number of Coding Plug was checked it would confirm restriction (25KW) or otherwise.

 

I had a look on the RealOEM Fiche as below to see if it made things any clearer about the parts fitted:

 

Intake Manifolds: http://www.realoem.com/bmw/showparts.do?model=0412&mospid=51681&btnr=13_0525&hg=13&fg=71 Item 7. Clear enough and agrees with yours.

 

Connection Plug (Coding Plug): http://www.realoem.com/bmw/showparts.do?model=0412&mospid=51681&btnr=61_0267&hg=61&fg=36 Item 6. Not clear what the 'Restricted' Part Number/Colour is.

 

 

[roger 04 rt]

For the Coding Plugs, from a BMW Service Memo I found,

 

Unrestricted Power R850R(T)

No Plug: No Cat

Golden Yellow 30-87: With Cat

 

25 KW

Olive Yellow 30-86: No Cat

Light Grey 30-86-87: With Cat

 

Since it might be hard to know whether you had an Olive Yellow or a Golden Yellow plug I would check the connections.

 

Looked at Cylinder Heads and Cams, no difference.

[Galactic Greyhound]

Thanks Roger!

[cruising]

Too much technical stuff for me so I will Take this latest info to the mechanic. Any idea as to whether the coding plug and intake tubes is an expensive procedure?

Thanks again to everyone for the time they have put into this.

The seller has offered me a refund - starting to think that this may be the best option. Will make up my mind this weekend. If I knew that I could resolve the issue at no great expense I would keep it. May be time to go back to Japanese but as I said in the beginning the bike is very comfortable and the fairing is great.

 

[Galactic Greyhound]

Too much technical stuff for me so I will Take this latest info to the mechanic. Any idea as to whether the coding plug and intake tubes is an expensive procedure?

Thanks again to everyone for the time they have put into this.

The seller has offered me a refund - starting to think that this may be the best option. Will make up my mind this weekend. If I knew that I could resolve the issue at no great expense I would keep it. May be time to go back to Japanese but as I said in the beginning the bike is very comfortable and the fairing is great.

 

Evening Cruising,

 

First you need to check that the bike has indeed been restricted.

 

To do this, and assuming you have no catalytic converter, check if you have an Olive-Yellow coloured Connection (Coding CCP) Plug fitted in the Fusebox under the Rider Seat.

 

Next, check if you have 'Restricted' Inlet Manifolds fitted between the Air Filter Box and the Throttle Bodies. These Inlet Manifolds should be marked with the BMW Part Numbers 13 71 1 342 175 (for LH side) and 13 71 1 342 176 (for RH side) - you only need to check one side.

 

If you find that the bike is fitted with the 'Restricted' parts above, then it would appear to be easily converted back at little cost to the 'Un-Restricted' Full Power mode.

 

To convert back to 'Un-restricted' mode, do the following:

 

1. Unplug the Olive-Yellow coloured Connection (Coding CCP) Plug in the Fusebox and leave it out. No cost!

 

2. Replace the existing 'Restricted' Inlet Manifolds BMW Part Numbers 13 71 1 342 175 (for LH side) and 13 71 1 342 176 (for RH side) with the 'Un-Restricted' Inlet Manifolds BMW Part Numbers 13 71 1 341 405 (for LH side) and 13 71 1 341 406 (for RH side). Cost of each Manifold is $US 38.10 each = Total $US 76.20.

There will be labour costs of around 2 - 3 hours if you don't do the work yourself.

 

See picture/parts here [item No. 07]:

http://www.realoem.com/bmw/showparts.do?model=0412&mospid=51681&btnr=13_0525&hg=13&fg=71

 

Good of the seller to offer you a refund but if this is what is causing your problem then it is easily fixed and will make a huge difference to the bike. Worth checking out as you could change from 33 HP (25 KW) to 70 HP [52 KW].

[cruising]

Thanks for this infomation - looks like this is the possible solution. I send the vin no. of the bike to a BMW dealer in Brisbane.The vin no. is WB 10412 F9TTZA 00025. The dealer gave me a call yesterday and said that according to a website in USA this bike was restricted and the solution is exactly as you outlined. The only additional info. he requires is the no. on the computer box underneath the tank as this may have to be replaced as well. I hope not as it sounds like it could be an expensive item. Anyway, I will check this out over the weekend and keep this thread posted.

Cheers for now

[roger 04 rt]

Sounds like this will work out for you.

 

The computer box part number in the US is the same for both the restricted and unrestricted power. It is:

 

BMW Part #: 13 61 1 342 214

BMW Description: CONTROL UNIT MOTRONIC - 25/KW - 51/KW

BMW List Price: $1265.05

[Galactic Greyhound]

Evening cruising,

 

Well that's good news about it being restricted but just verify it yourself by looking for a Coding Plug as posted previously.

 

There is a BMW Parts Fiche called 'RealOEM.com'. This is a good resource for you to use as it enables you to put the last 7 digits of your VIN (ZA00025 without spaces) into the Serial No. search Box and derive a VIN match for your bike. This match is specific to your bike and it correctly identifies any spare parts you may require using the Fiche. Any parts which are not specific to your bike will therefore not be shown in the Parts List under the diagrams.

 

See VIN match here: http://www.realoem.com/bmw/select.do?vin=ZA00025

 

Using the above VIN match for your bike, if you then click the 'Browse Parts' box, you will be shown the Parts Groups either in Picture or Text format [using Switch to Text/Images Drill Down box] depending on what format you have selected.

 

If you then select 'Fuel Preparation and Control' and then scroll down and select 'Electronic Control Unit' [computer box], you will see when this is displayed that Item 1 is shown in the Parts List below the diagram as 'Control Unit Motronic'.

 

Under 'Supplement' in the Parts List it shows '25/KW - 51/KW' and Part Number '13611342214'. This means that the Motronic unit is capable of running Restricted 25/KW or Un-restricted 51/KW power modes and does NOT need to be replaced.

 

[if you have used the Parts Fiche correctly as above you should end up here at the 'Control Unit Motronic':

http://www.realoem.com/bmw/showparts.do?model=0412&mospid=51681&btnr=13_0528&hg=13&fg=61 ]

 

Sorry for the post being a bit long-winded but I wouldn't like to see you being taken for the $US 1,651.92 for a new Motronic - and now you know how to use the Parts Fiche correctly for other bits too!

 

PS: Hi roger! Just seen your post - our posts have crossed! Thanks.

 

 

[cruising]

I checked the fuse box yesterday - there is a yellowish square fuse approx. 1 inch square in the first row on the left hand side, but there is no coding ccp.

I noticed that in the middle row of fuses there is a space for a fuse which is slightly larger than the one above - There are 2 block fuses in the middle row and the absent space is between these 2. I am wandering whether it is possible that this absent fuse is the one referred to as the fuse marked ccp - or is it the yellowish one described above.Just checked the bike manual - The middle one I am talking about is in place but is black(manual is in black and white). In the manual, the one on the left of this appears to be similar in colour to the yellowish one in the first row as they are both light in appearance - the same one on my bike is black.Hopefully you can make sense of what I have described.

Is it reasonable to assume from your article that the control unit motronic will not have to be changed? Definitely not prepared to spend that sort of money.

At the point where I am thinking that I should replace the manifolds and hope for the best!

Thanks for all the input - you guys have all been very helpful.

Cheers for now.

 

[cruising]

Hi all - Unfortunately I am back to the beginning - just got back from the mechanic. Checked right side manifold and it is not restricted - removed pipes and checked the inside visually. The part no. is 13407701-R. Also, the mechanic is of the opinion that the fuse referred to in these links is the one at the back of the fuse box which is a flattish fuse - mine is green.

Just when I thought that the problem was about to be solved.

Cheers for now - will have to change from Cruising to Frustrated.

[roger 04 rt]

The underseat electrical box has mostly relays in row 1, nearest the tank, and row 2, middle row. The Coding Plug is square and goes in the center of the box, middle row. It sounds as if that position is empty on your machine. Can you post a photo of the inside of your electrical box to confirm?

[cruising]

you are correct - middle row and centre = no plug! I really thought that this issue had been resolved and not sure whether this latest development is good or bad news - I suspect the latter!

[Galactic Greyhound]

Morning cruising,

 

Hi all - Unfortunately I am back to the beginning - just got back from the mechanic. Checked right side manifold and it is not restricted - removed pipes and checked the inside visually. The part no. is 13407701-R.

 

The designation 13407701-R is NOT a BMW Part Number. The BMW Part Numbers comprise of 11 digits e.g. 13 71 1 342 175. The old system used 7 digits which is still recognised but should not be applicable to any parts on your bike. Re-check the Intake Manifold - the Part Number should be marked on it somewhere. When you find it post it here for verification.

 

Also, the mechanic is of the opinion that the fuse referred to in these links is the one at the back of the fuse box which is a flattish fuse - mine is green.

 

If you've got a workshop manual (Haynes or Clymer) with the bike, look in the index under Fusebox, Fuses, Relays and you should see the layout and what fuse/relay is what. If you don't have a workshop manual, then this link for the R1100GS Fusebox layout should be similar for your bike. (Print, Cut out, Laminate and keep under lid of fusebox]:

http://micapeak.com/bmw/gs/gs11fuse.htm

 

If you can post a pic of your Fusebox as Roger said it will help us identify what you have fitted.

 

Just when I thought that the problem was about to be solved.

Cheers for now - will have to change from Cruising to Frustrated.

 

Roger and I both believe that you do NOT have to change your existing Motronic unit as it is capable of dual-mode power operation 25KW - 52KW. The unit is programmed by the Coding Plug to give reduced power AND by the use of 'Restricted -type' Intake Manifolds.

 

IF the bike is found to be 'Restricted', you need to remove the Coding Plug AND fit the 'Un-Restricted' Inlet Manifolds. That is all that appears to be required to restore the bike to full power mode.

 

HOWEVER, we have still not physically proven that your bike us still in 'Restricted' mode and this needs to be verified before you go spending any money!!!

[roger 04 rt]

Repeating an earlier question, can you reach and sustain 6000 rpm in neutral?

 

That might tell us if there is an rpm limitation by the motronic.

[cruising]

Bike revs freely in neutral- However, on the road, two up, on hills - up and down, it is always constant in that it hesitates at the 4500-5000 rpm range. The mechanic visually inspected the manifolds by removing the hose and says it is not restricted. Fuse box = middle row and middle plug definitely missing. Have foto but have to work out how to attach it to this post.

[roger 04 rt]

If it revs on the stand, then it doesn't seem like it has a rev limiter and you're pretty sure the tubes aren't blocked.

 

It's sounding like you may have something going wrong on the fuel side. You should get 43.5 pai on the high pressure side at idle or a bit above PLUS a return line flow of roughly 2 liters per minute. It may be time to check that out.

[cruising]

The fuel flow and the injectors have been checked; The mechanic checked the fuel flow as recommended in these threads and confirmed the 2 litres per minute.

[roger 04 rt]

Evening cruising

 

Difficult to tell what you have going on there.

 

You would think that if your problem was fuel related like low fuel pressure or low flow it wouldn't have a defined cutoff of 4500-5000 RPMs but more engine load related like cut off at 3K under heavy loading & easily go to 6K at light throttle light engine loading.

 

Ignition issues are more likely to have defined RPM cutoff limits but can still be load (combustion pressure) sensitive.

 

Maybe you can give us some more details-- like what it does climbing a long hill in 4th or 5th gears. How it does revving to 6K in neutral. Can it easily reach 6K in first gear at moderate throttle opening & again at wide open throttle.

 

Maybe try running for a short run with the air cleaner element removed as a test. Those can get wet & the paper swells up therefore impeding air flow but they will still look clean & new when visually looking at them.

 

Might also be something like a plugging exhaust system especially if it has a cat.

 

Or even heavily carboned valves under the valve heads restricting intake flow or exhaust flow.

 

But, things like plugging exhaust usually doesn't give a defined RPM cut off but can limit power output at or close to air flow capabilities.

 

More than likely you will either have to start testing things like ignition coil, plug wire resistance, & fuel flow/pressure or maybe give us lots more info & more riding feedback under different riding loads, speeds & in what gears the engine does what.

 

I've gone back earlier in the thread, as first exposure to your problems was when you wondered if you had a power restricted motorcycle. After going back to the beginning and reading through your earlier posts, I think you'll need to take a systematic approach to figuring this out. If you search the forum, you'll find a lot of posts under the general topic of "surging" and even though there aren't as many R850 posts the R1100 or R1150 posts on surging will give you an idea of how to go at this.

 

You should be able to get to where you have a great running motorcycle but it will take some patience and probably several trial-and-error steps.

[cruising]

When I mentioned previously that a dealer who I found on the internet told me the bike was restricted - well, I phoned him and he is actually a BMW mechanic and only looks after BMW bikes.His own business. He said that I have to get the part no. of the motronic. Only then can he trace back with the vin no. the component options as to what may be the case with the bike. He has never worked on a restricted bike in his 20 years of experience and is not convinced that it is restricted. He also deals in 2nd hand spares and mentioned that there could be more than one motronic that fits the bike.

My biggest problem is that I dont have a workshop/garage at home and every time I have to go to the mechanic and strip the fairing etc. I know that it would be a lot easier to strip the bike and do the various tests etc. I reckon I have to make the decision - ride it as is or see whether the seller will still offer a refund.

 

[cruising]

I dont think the problem is surging. Still think that it may be an ex police bike as the original colour was white. Maybe that had some restriction for fuel economy?

[roger 04 rt]

If you had a hard RPM curt-off I'd buy the restricted power idea, but lacking that, or a Coding Plug, or restricted intake tubes, I'd say if you want to keep the bike you'll have to go step by step.

 

Have you satisfied yourself that the HES, coil, plugs and plug wires are all working properly?

 

Next, put the correct Coding Plug in for your bike (Golden Yellow, jumpers 30 to 87) and see how that compares, assuming that your O2 sensor is there and functioning.

[cruising]

Thats a plan - obtain the coding plug and see what that does. I phoned BMW Australia and they told me that BMW would not restrict the motor - it would have been standard. They confirmed that it went to a Government authority. Got the telephone no for the police dept. in NSW

and they put me onto a guy who was on the police force for many years. He said that they used 800 and 900cc models but cant recall any 850's.

Also they dont have a Government Garage who would tinker with the bikes and they certainly would not have the motor restricted. All servicing etc. would be done via a dealer. He said that the computer should be checked as it is possible that the original motronic failed and that it may have been replaced with an incorrect one at some stage in its life.

Looks like the Motronic may provide some answers.

Will make a few more calls today.