R1100RT difficult to start

[BMW_pingvinen]

My BMW R1100RT is difficult to start. Must use full choke when cold, give full throttle once and then hit the start button. It then starts just when I let go of the start button. Often it refuses to start and then there are loud explosions in the exhaust. If I try rolling downhill it starts fine. It is worse if half-warm, then it will not start whatsoever, choke or not. If warm it usually starts ok, but just when I let go of the starter button. Could the starter motor be the problem, using too much current? It turns the engine fine, at good speed. I have just put in a new Odyssey P680 battery, that made it a little better. It runs without problems once it starts.

I have struggled with this for some weeks now, and appreciate any tip from you guys!

[4wheeldog]

First off, these bikes do not have a choke......That is just a fast idle lever. Second, giving full throttle with a fuel injected motor only does something constructive while starting if the motor is flooded......Which is unlikely, in your case.

 

Given your description, (Bike starts when button is released, muffler afterburn, etc), I would start by replacing your spark plug leads. Given the age of you bike, if they have not been replaced they should be. Beemer Boneyard is a good source. Good luck!

[AndyS]

Good afternoon BMW_pingvinen,

When was the bike last serviced?

Check through the following:

 

Spark plug condition - replace if in doubt.

Valve gaps

Ignition timing (has the HES been replaced).

How old is the fuel?

State of the air filter.

 

Andy

[BMW_pingvinen]

Thanks 4wheeldog, I will look at those. They have not been replaced before, and I have now run nearly 80K km.

(I only turn throttle to full and release it again before starting. Does possibly nothing in this scenario, but that was what I did the first time I managed to start, so now I feel I must do it to be sure Giving throttle during start only makes engine turn faster (less suction resistance?), does not help).

[BMW_pingvinen]

Hi AndyS,

thanks for caring.

I got the bike from winter storage and full service at the authorized BMW shop in April. Was OK then, this started suddenly a few weeks ago.

I have tried 2 different spark plug types (both single and dual tip), no difference.

HES has not been replaced. I checked that a couple of years ago, when I had a similar problem that vanished without doing anything (!).

Fuel is new, I have run 5000 km this summer.

Air filter is cleaned and oiled.

[AndyS]

It doesn't sound like a starter motor problem as the bike cranks freely (and for some time by the sound of it)!

 

CAUTION HT VOLTAGE CAN BE FATAL

Using some suitable insulation, you could try hanging a spark plug (connected to the HT lead)against a good ground point. See if you are getting a GOOD consistent spark on both sides of the bike while cranking.

 

Andy

[BMW_pingvinen]

I tried, and there is as spark. Difficult to know how good it is thou...

[NonComp]

I would suggest that you remove the two big brass screws from the two throttle bodies and clean the carbon out of the ports with a good quality carburetor cleaner and a bunch of cotton tipped swabs. You may need to feed a small solid core wire (with plastic insulation on) down through the end of the port to open it up.

 

These screws control the amount of air at idle and are used to tune the idle speed and smoothness. I think that the reference point is to turn them all the way and seat them (gently) then back them out 1.5 to 2 turns and start from there.

 

I'll bet yours (like mine were) are all carboned up. Probably one or both no longer do anything (meaning that the idle doesn't change no matter what position that they are in). The mixture is probably too rich at startup. Try opening the throttle part way (or all the way) while cranking. Also, consider putting some injector cleaner / fuel additive in your fuel.

[BMW_pingvinen]

Thanks NonComp, couple of good tips there. I'll check on the throttle bodies maybe next week, when I have to remove the tupperware anyway to mount new light brackets behind the mirror holding screws (Kind of like the EMP's that are not available any more).

But alas, opening the throttle part or full while cranking makes no difference. Only makes the engine crank faster.

But I'll try some cleaner/additive, can't hurt.

[oldyam]

Following on along Andy's line of thought ...

 

Have you tried removing the plugs after trying to start the bike ?

 

Are the plugs getting wet ? ( possible indication of fuel & no / weak spark )

 

If the plugs are dry ...... possible fuel fault ( ie non injection ).

 

Some thing to try before next weekend, might provide more usefull info for when the tupperware is off.

 

 

 

[BMW_pingvinen]

Thanks oldyam.

I have removed the plugs once, when I had no downhill nearby and I had entertained the area with muffler bangs for a long time. (At that occasion the engine was half-warm, that is the worst. It started after half an hour cooling totally down.) The plugs did not seem wet, but all the bangs are signs of fresh gas in the system, don't you think?

Also, often when it finally start after lengthy trials, there is much exhaust smoke for the first few seconds, before it is running clean.

So I figure there is a problem with the sparks/plugs/coils... but I cannot understand why this is so _only_ when the starter is running. Is the starter draining too much current/voltage, or is the ignition system weak somehow so it doesn't produce a strong enough spark when I'm cranking the engine?

Downhill roll - starts like a dream.

[AndyS]

When did these problems start?

Have they gradually come on, or is it after some event.

ie, maintenance (of any sort), component replacement (of any sort). extreme riding. extreme weather conditions.

 

Have you checked your throttle linkage at the TBs to see if one cable has become derailed off the cam, or a piece of debris jamming either the cable or the cam open?

 

Andy

[BMW_pingvinen]

It started suddenly a few weeks ago, without anything special happening.

I can check the linkage when I remove the tupperware (in a cople of weeks I hope).

Today it has been easiest to start with no "choke" and just a little throttle while cranking. I am starting to believe this is a fuel/injection/adjustment issue.

[AndyS]

How does the bike (engine) perform, once the engine is running (in comparison to before these issues started)?

 

Andy

[NonComp]

My 1100 sat for 8 months while I sorted out some wiring problems. When I finally got it back together last month, I had a brand new battery and fresh fuel. But it failed to start. I cranked and cranked. Finally I held the throttle wide open and it eventually coughed and then started up, running ragged and smoking. I had flooded it. Since then, it starts fine.

 

I think something similar is happening with your bike. The mixture may be too rich for some reason during cold start. Cleaning out the Big Brass Screw ports may help. It might be an injector issue. Any aftermarket fuel computers or changes from stock on the fueling jumper module (CCP)? Bad batch of fuel? High ethanol content? Try starting with no air filter in place?

 

What is idling like when it fully warmed up? Smooth? Does it backfire (after-burn) a lot during deceleration in gear?

[David R]

A symptom from the old days.

 

The crank button does NOT shut off the spark, but If it only starts when you let go of the button and the exhaust pops and bangs, you are getting fuel but no or not enough spark. It could be a pinched wire, It could be plug wires or something related to spark like coil leakage.

 

 

While cranking not enough spark due to lower voltage. You let go of the button, voltage goes up and BANG! you get one spark. It happens where ever the piston is on both sides. Fuel has been discharged but not burnt,so the bang and smoke when it does start which is by pure luck.

 

Pull the plugs and see if you can get the spark to jump 1/2" while cranking.

 

David

[oldyam]

Just going to throw in a wild idea here ....... is the load shed relay working ?

 

A coil failure could happen suddenly, without any other issues

 

If I understand this correctly the load shed relay not opening could well cause exactly this sort of fault ie low voltage ( first small relay from the LHS of the bike along the front line )

 

I seem to remember someone saying its a STD relay ? maybe swapping it with another relay may improve things?

 

[BMW_pingvinen]

Yeah, I guess we are closing in on something here, but I don't know what yet.

- Only standard components, no mods in fuel or other systems

- I have run a couple of thousand kilometers since this started, tried different fuel stations/brands, all are alike. No ethanol as I know.

- The idle is smooth once it starts, both warm and cold. No backfiring whatsoever.

 

Last two days I have started it without the 'choke', and just a hint of throttle while cranking. Best method so far - but I have tried cranking with no choke and full throttle at times I suspected it was flooded, and it didn't help-

[BMW_pingvinen]

Hmm, I'll check on that.

Thanks Nigel.

[BMW_pingvinen]

Runs like an angel...

[BMW_pingvinen]

You are thinking along my lines David. But why does it run so fine once it starts.

I'll check what distance I can get the spark jump.

[BMW_pingvinen]

I checked the load relief relay just now. When I crank, the headlight goes dark, so I guess the relay is working. But the last day or two it has been easier to start - maybe that relay has an intermittent fault.

I have also noticed earlier that once the engine starts (with headlight switch to "off") the headlight lights for a second or so.. but that might be normal.

[David R]

No that should not be normal for the head light to come on if its shut off. This could be showing what is sucking your voltage down?

 

you need a voltmeter to check cranking voltage at the battery and next at the coil. It should never go below 9.6 with the engine cranking.

 

Can you draw a 1/2" spark? Did you get bit (zapped) trying?

 

Perhaps you could try to start it with the headlight unplugged.

 

David

 

Edit: I did just order a set of wires for mine. 121,000 miles and 11 years on the original ones. $75.00 each..... I went to napa and autozone with the old one. We opened a lot of boxes, but no joy.

 

I knew they were bad because If I washed the bike it would misfire under load on one cylinder until it dried out. They measured 5.7k ohms and 6.4K ohms.

[BMW_pingvinen]

Hi everybody,

I just wanted to apologise for my disappearance last fall. I appreciate your effort and suggestions, and I will continue to work on this when the snow and cold is gone (minus 10 celcius this morning...). Several things happened last fall that stopped me from both riding and working on the bike, less follow up on the forum.

So, I wish you all a nice spring time, and soon a very good season on 2 wheels!

 

[AndyS]

.....I have also noticed earlier that once the engine starts (with headlight switch to "off") the headlight lights for a second or so.. but that might be normal.

 

You have a problem there that may be directly related to you starting issues. You need to investigate which lamp comes on (main or dip), and work out where it could be getting a voltage from.

 

Andy

[BMW_pingvinen]

Status update:

Took the bike to bvz.de at Karlshof, and "my" mechanic Torsten concluded that the HES was unreliable. It was changed, and the bike serviced (80K km) and adjusted. Had a great ride home to Oslo, starts every time and runs like a clock.

Thanks to Torsten, and to you folks.

Happy ending

[AndyS]

Confused......

How does the HES decide not to run normally while cranking, and then perform faultlessly the rest of the time????

[philbytx]

Hi Andy

 

Well, you aren't the first one mate

 

The HES failure on my R happened in stages!

It cut out on me on the road, stopped and restarted it just fine. Then a couple of days later it wouldn't start at all. I went into the whole battery/system check. Then, after a frustrating hour or so, it "miraculously" started. Then I rode it 7 miles to my friends house, it crapped out on me on the road. Wouldn't start so I started pushing it. Just for kicks, I tried to restart it and Voila! it did. Rode to my friends house, then, when we were heading out for our ride, it wouldn't start at all......had to trailer it home. R&R'd the HES with a new unit from John and Euromotoelectrics and it has run perfectly ever since.

 

This was 3 years ago on a low mileage bike (a 2000 with 7500 miles!) but it was stored in an aircraft hangar (no heat/cooling) for 6 years. Although the wiring LOOKED good, believe it was deterioration of plastic sheathing.

[BMW_pingvinen]

Confused......

How does the HES decide not to run normally while cranking, and then perform faultlessly the rest of the time????

Beats me... Should mention that I had a couple of incidents where the motor suddenly stopped while riding at 80 km/h, then started again, stopped, started... I felt like on a cangaroo for a couple of km, then it suddenly ran normal...

 

Cannot explain it, but I am glad it works now.

[BMW_pingvinen]

Seems I forgot an update on this.

Was able to go to Bert von Zitzewitz last summer, and had the HES replaced. No starting problems after that.

My favourite shop (bvz.de) even if it is quite a distance from Oslo.