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Bike only running on 1 cylinder need help


Just_wanna_Ride

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Just_wanna_Ride

I have a problem with my 03 RT I need help with before I take it to the dealer.

 

The other day I was riding in 6th gear down the highway. Nothing out of the ordinary until I couldn't accelerate above 65 mph. The bike refused to idle after coming to a stop after that. After doing a little troubleshooting I found out the left cylinder is not working. I am getting spark and gas but no power from the left cylinder. I also noticed (may not be related but too coincidental not to mention) the clock reset like the power went out.

 

Any help anyone can provide will help. It's about 40 miles to the nearest dealer and I don't want to nurse it that far.

 

Thanks

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When you have spark and gas, the only thing left is compression and timing. Compression is not likely a problem as you will soon confirm. That leaves timing. If your ignition is like my older one, you actually get a spart every time the cylinder rises to the top. There are two sensors on the Hall Effect Sensor 180 apart and they send a spark every time. If one fails, you still get spark from the other one but it will be on the exhaust stroke rather than the compression stroke. I would suspect this. Yes, it happened to me.

 

--jerry

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Sorry, can't agree. If there is a spark timing issue, on a single-coil, wasted-spark system both cylinders will be effected. This in itself cannot cause an issue on just one side.

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Sorry, can't agree. If there is a spark timing issue, on a single-coil, wasted-spark system both cylinders will be effected. This in itself cannot cause an issue on just one side.

 

Ken,

I could be wrong but I'm not talking about the coil but about the HES sensor. I believe that if one goes out then you'll lose half your spark. You'll lose the good one on one cylinder and the wasted one on the other. When my HES went out I checked the spark a dozen times. It was good. In the end I realized I was looking at the wasted spark. I'll admit I haven't been through the drawings to confirm this. --Jerry

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A long shot maybe, but i had the same some time ago: after finishing up having done some work on a cylinder, it would not run anymore (exhaust pipe/downpipe for that cylinder stayed cool). Did not run the bike because I could HEAR something was wrong (very rough idle). Turned out that I messed up the throttle cable to that cylinder big time. Re-arranged the cable and it worked again.

 

Good luck troubleshooting and finding a solution!

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180° won't get you to an exhaust stroke but it would be a time that the fule pump could operate and allow the computer to send a signal for injector to spray. That charge of fuel isn't actually used yet. It is drawn into the combustion chamber the next time around.]

 

Crankshaft position with two sensors 180°apart gives you top-dead-center and bottom-dead-center of the piston location.

 

 

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Yup, gotta be a burned valve.

You should find a way to trailer it, rather than ride it. It'll only get worse, & if it makes the trip, it's not worth the stress.

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Nothing out of the ordinary until I couldn't accelerate above 65 mph. The bike refused to idle after coming to a stop after that. After doing a little troubleshooting I found out the left cylinder is not working.

Can a 2-cylinder bike even run on 1-cylinder? I thought it would vibrate itself to death.

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Can a 2-cylinder bike even run on 1-cylinder? I thought it would vibrate itself to death.

Mine did. When my right jug exhaust valve went bye-bye, I was forced to ride it about 6 miles home (BFE and no help available). At about 4k rpm it was smooth enough and made enough power to limp home. I suspect that it was still firing on the right but just loosing all the compression pretty much instantaneously, but it may have been enough to keep it from killing itself.

 

When I finally got home and was coasting down the driveway, I let the rpm come down below 2k and it died immediately.

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You say you have spark. BUT! How are you checking the spark? I have seen it more than a couple of times before where you check the spark with the plug grounded to the side of the head and see spark. Or where you check it with the spark plug wire slipped over the end of a large Phillips head screw driver. HOWEVER, what we have here is a very high compression engine and that, in itself, makes the spark plug's job much harder. Before I go to the dealer (and I wouldn't ride it on one cylinder either) the first thing I'd do is invest in a new set of spark plugs first. I've run Autolite with much success, but right now any good quality brand plug should work for troubleshooting right now. Try that first!!!

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Just_wanna_Ride
You say you have spark. BUT! How are you checking the spark?

 

I checked the spark with the sparkplug grounded to the case. The plugs were changed about 1,000 miles ago with autolites. As an added precausion against a bad plug I switched the plugs Left with right. No change in problem. I haven't been able to do a compression check yet but I think it is good. Without a plug in the laft cylinder the engine is surprisingly smooth and actually idles.

 

 

 

Can a 2-cylinder bike even run on 1-cylinder? I thought it would vibrate itself to death.

 

At idle it does not run well, except with the left plug removed. At RPMs over 2,500 it runs OK and starts to vibrate over 4,500 RPMs. In answer to your vibration question, it will run. Badly, but it will run. Most of the vibration is taken away by engine design. It is not a single crankpin motor (like HD). The pistons are set 180 degrees from each other on the crank. This makes the pistons move in and out cancelling the vibration, instead of all of the mass moving in the same direction which would increase vibration.

 

As soon as I can I will test the compression and look at the condition of the valves. Probably this weekend.

 

Thanks,

I'm looking at everything.

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  • 2 months later...
Just_wanna_Ride

Just FYI and thanks to all of you that responded.

 

The final verdict was a burned valve. I did a compression check before I took it to BMW of Orlando. I borrowed a compression tester from a friend and both cylinders tested good. After the mechanic did the same thing he found the left cylinder was dead. I re-visited the compression tester and blew into it and got the same compression as the bike. Result very bad compression tester.

 

BMW of Orlando was very helpful and took care of the problem quickly and I was back on the road in a couple of weeks. Their customer service was excellent.

 

Again, Thank You all for responding.

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I re-visited the compression tester and blew into it and got the same compression as the bike. Result very bad compression tester.
Or very good lungs! grin.gif
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Can a 2-cylinder bike even run on 1-cylinder? I thought it would vibrate itself to death.

Mine did. When my right jug exhaust valve went bye-bye, I was forced to ride it about 6 miles home (BFE and no help available). At about 4k rpm it was smooth enough and made enough power to limp home. I suspect that it was still firing on the right but just loosing all the compression pretty much instantaneously, but it may have been enough to keep it from killing itself.

 

When I finally got home and was coasting down the driveway, I let the rpm come down below 2k and it died immediately.

 

On a a cross country trip from Oregon to Maine (1980) I burned an exhaust valve on my R90/6. I continued to ride it from New York to Maine two-up and fully loaded. It wouldn't idle, but had enough power to travel easily at highway speeds AND gave me 60+ mpg. I don't remember it being particularly rough; it was just a big single with a really big counter balancer. With a carbureted engine no gas gets pulled into the engine when there's a hole in the valve since a carburetor won't draw any fuel without a vacuum (unlike fuel injection which just keeps spraying away).

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When the dealer fixed your valve did he mention anything about you having put in the AutoLite plugs. I am interested in using the autolites from what I've read, but don't want to risk damaging the valves. Any comments about the plugs???

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Just_wanna_Ride
When the dealer fixed your valve did he mention anything about you having put in the AutoLite plugs.

 

No he didn't and I did ask about possible causes. With about 35,000 on the clock it seems a bit premature.

 

As long as the plug is the correct heat range and size I don't see a problem with the autolites. I'm not going to stop using the autolites because of the performance changes I noticed after switching to them. I got rid of the NGK plugs (why a German company is using Japenese plugs baffles me, but that is a conversation for another day) and noticed immediately the lack of knocking under heavy load. Before the plug change it was occasional but noticeable and kept me off the throttle most of the time. Also note, I changed the air filter to a K&N at the same time.

 

Good luck on your decision

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ShovelStrokeEd

Doubtful that a spark plug would have any influence on a burnt exhaust valve. Most frequent cause is a chunk of carbon, from the combustion chamber of piston top, lodging on the seat of the valve. 1300 degree C combustion gases do the rest. The combination of the heat of the gas, the fact that the valve has no opportunity to transfer heat to the seat, and the small gap contributing to gas velocity will cut a notch in the valve in very short order. You really create a plasma cutter under these conditions and the poor valve has no chance. Takes only a couple of seconds for the cut to start and once started, only a few minutes, even if the carbon chunk departs the scene of the crime, for the valve to be cut past the seat.

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I am interested in using the autolites from what I've read, but don't want to risk damaging the valves. Any comments about the plugs???

I've used Autolites for about 100,000 miles with no problems so far.

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