clutch slip, tire spin, misfire?

[damnpoor]

Today I was cruising through town and went to get on the freeway. The onramps are short and uphill, which is a great place to really lay on the gas. I had it in 2nd and wound her up, but I felt some slipping or something. I went to the next exit, gassed it up the ramp again, and the same thing happened. Then again a third time. As the bike was accelerating there was a random series of tiny "jumps", if you will. It felt like I was either missing a cylinder every once in a while or was hitting tar snakes and was getting some spin. I didn't see any, but it was dark. It happened at full throttle in 2nd powering up a hill. The bike drives fine otherwise.

Everything I know tells me it could be one of three things; clutch slip, tire slip, or misfire. I don't think it was a misfire because the check engine light didn't come on. How could I tell if the clutch was slipping? Since it did the same thing on three different ramps I doubt it was from loose material on the road. Could it be that the colder days of fall simply keep my tires cool enough to slip?

Does anyone have some experience or insight into this? If something is wrong in the motor I want to check it out before I drive it further.

 

[scottsst]

before you get to alarmed how check your chain and sprokets! when they get loose the can jump teeth and feel alot like that

 

[allaboutatv]

if a chain was jumping teeth it would be a pretty rough feeling and noisy, if it was tire slip then most likely you would feel your back end get light or move around a little bit, i would bet its the clutch. how many miles?

 

[RJ2112]

How close to redline were you? That misfire sounds a lot like the ECU shutting off a cylinder or two to prevent you over revving the engine.

In 1st, that happens to me on stock gearing at about 52 MPH... I'd guess 2nd would do the same at around 75 or 80 MPH indicated.

 

[damnpoor]

I know it wasn't the ECU because I was in 2nd between 40 and 60 mph. I am due for a new chain. I should stop putting that off, get a new one, and then see it's gone away. The only reason this bothers me is because I had never felt that before, then all of a sudden it did it three times in a row.

Is there a way to check the wear on the clutch or do you have to just replace it?

 

[TownsendsFJR1300]

I know it wasn't the ECU because I was in 2nd between 40 and 60 mph. I am due for a new chain. I should stop putting that off, get a new one, and then see it's gone away. The only reason this bothers me is because I had never felt that before, then all of a sudden it did it three times in a row.

Is there a way to check the wear on the clutch or do you have to just replace it?

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If the clutch is slipping, it won't "skip" the engine will rev up but the bike won't accelerate. (tach will go up easily without accelerating). As stated previously, if you were near the upper limits of the rev range, the rev limiter maybe kicking in....

Check the sprockets (pull the front cover) and make sure its not skipping up there (if severly worn it can skip on the ft sprocket). If there's a bunch of miles on it, it might me a good idea to replace the chain AND sprockets (steel sprockets last longer). I'd do the chain (and/or sprockets) first if you know their bad.

You can check the clutch wear, you have to pull the right side clutch cover off, remove the screws and main pressure plate. Then remove the steel plates and friction plates. You'll need a micrometer to measure the friction plates (if not badly worn), the steels should not look burnt and be flat (NOT WARPED).

A miss-firing spark plug under load or crap in the gas can cause your symptoms. New plugs are cheap enough. My KLR likes a new plug every 10,000 miles or so as it'll start misfiring under load (plug looks fine BTW)

"Chevron techtron" fuel cleaner works very well cleaning the fuel system.....

Scott

 

[RJ2112]

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Check the sprockets (pull the front cover) and make sure its not skipping up there (if severly worn it can skip on the ft sprocket). If there's a bunch of miles on it, it might me a good idea to replace the chain AND sprockets (steel sprockets last longer). I'd do the chain (and/or sprockets) first if you know their bad.

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A miss-firing spark plug under load or crap in the gas can cause your symptoms. New plugs are cheap enough. My KLR likes a new plug every 10,000 miles or so as it'll start misfiring under load (plug looks fine BTW)

"Chevron techtron" fuel cleaner works very well cleaning the fuel system.....

Scott

+1.... chains usually last about as long as the sprockets.... if a previous owner did the -1 +2 thing, and used aluminum sprockets, it's a good bet the issues are all involved in the chain and sprockets.