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Buell - Clunk when clutch released quickly

Sportster Motorcycle Transmission, Clutch, Primary & Secondary Drive - The Sportster and Buell Motorcycle Forum -
Okay, something's may or may not be wrong with my tranny, clutch or transmission, so I've decided to share it with you guys ...

I hear pretty noticeable and sometimes pretty loud clunk on the bottom left side of engine when I quickly release the clutch AFTER TWISTING THE THROTTLE WHILE THE CLUTCH WAS PULLED. I know this ain't the healthiest shifting method, but it happens sometimes, especially while crawling through the heavy city traffic in 1st gear, and something force you to heavily brake and slow down... In that situation you pull the brake heavily but due to rapid slow-down, you have to pull the clutch too to avoid jerky low-rpm movements, but the danger is suddenly gone and you want to catch up by twisting the throttle and quickly releasing clutch. In that situation, if I accidentally twist the throttle too much and release the clutch pretty quick, I clearly hear loud clunk in a tranny area. Its clear and loud enough to be heard under the full-face helmet and I also feel the impact/stroke in my feet (through the foot pegs).

After closely examining and isolating the situation, this is what I've concluded:

1. It happens ONLY IF I QUICKLY release the clutch after I previously twisted the throttle to 2k rpm or higher (higher RPMs > louder clunk)

2. It happens ONLY WHILE THE BIKE IS MOVING, so it can't be invoked while getting off from standing still. BUT if bike is moving really slow (walking speed) in 1st gear, and I pull the clutch, twist the throttle and release the clutch quickly, it results in the loudest version of clunk.

3. It happens in ALL GEARS. The loudest is in 1st, less in 2nd, and so on (higher ratio > louder clunk). So the higher the gear, the less is the chance to happen.

4. At higher gears/speed it gets almost impossible to invoke, no matter how fast I release the clutch/twist the throttle.

Few days ago, I've perfectly adjusted the primary chain tension (by sound) and clutch screw (released 1/4 of a turn when feeling the first resistance), but this clunk is still there.

I guess this happens on all evo sportsters, due to lack of sprocket compensator (big twins & ironhead have it), but the reason why I'm worried is that it feels like its happening more often then it was before. Like it requires a less RPMs to happen then before. I've noticed this while trying to immediately start riding with totally cold engine, without waiting for warm up. Very rare situation, but it happens sometimes when your bike is your only vehicle... So I've cranked the bike with choke fully open, shifted into 1st and start moving. Then, while moving slowly in 1st gear, I've pulled the clutch but released it immediately, which resulted in clunk, without even touching the throttle (opened choke raised the RPMs enough to cause it). Then I've tried to pull/release the clutch several times, invoking multiple clunks (sounded scary as hell ). Since then I'm testing, examining, searching and freaking out, so it isn't included that I'm imaging things

What do you think?
Date: Oct 13, 2017    Labels: Buell

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