i have an 04 636 with 17k on it and was doin wheelie in 3rd on way home from work stock sprockets and heard a bang. bike knocks hard as hell. fairly cofident it was cam chain tensioner so i got a new one. put it in and bike still knocks hard as hell. sounds like 3rd or 4th valve. could it have skipped a tooth causing a bent valve or piston slapping? help please! thank you

 

Your cam chain tensioner could have had a problem or you snapped your cam chain but either way riding hard on it while either on happens I can almost assure your your timing fell out. When this happens your cams are opening and closing your valves at the wrong time. You possibly could have bent a valve from it hitting the piston. I would start by pulliung out the service manuel. Relieve the tension off your cam chain tensioner. Pull the valve cover off and re-time your chain. Then see how it runs. If it is still knocking your probably bent a valve.


Ps...dont run it too much like this as you dont want to damage the top of the piston or thats going to get expensive...


PS...there is no way for you to hear what valve it could be. There is like 16 of them running so fast.....eight for intake and eight for exhaust.......a leak down test will tell you exactly where it is coming from if a valve is bent. (at least narrow it down to intake or exhaust....)

 

put bike in 6th and roll backwards 10'.

try it!

 

k ill check that thanks zride. y2kmk i dont know what thats supposed to mean lol

 

That'll fix the cam chain chatter. If your bikes knocking I don't think its a cam chain problem

 

ha! i didn't even read the whole post.

bent a rod or some **** huh? that sucks.

 

dont think i bent a rod lol. cam chain tensioner i have heard can cause bent valves and if it skips a tooth can jump timing. surely more people have had this problem? i heard its common on 636s. my case might be different cus it happened during wheelie with load on engine

 

did you get any smoke after the wheelie

 

yeah, sounds like a spun bearing to me

 

he may have hydrolock it from oil getting in the air box and bent a rod

 

true.

 

thats what i was thinking. kleen air mod done on the bike? what makes you think it's the cct.. just the noise?

cct sounds like a can of bb's at higher rpm's... "knocking hard as hell" isnt a cct issue.. at least not anymore. LOL!

 

mmm hmmm

 

no smoke. and no i didnt do the kleen air mod? im guessing that might be where i went wrong? hydrolock basically mean i need new motor?

 

if you hydrolocked it and bent a rod.. you'll need at least a rebuild...

 

usually there will be a bunch of smoke when you hydrolock a motor so that may be good news that there wasn't any

 

i have a motor 1200 bucks but its only like 500 miles on it.. i know its high but its not "mine" its my parts guy but its there if you can't find anything else

 

im done with streetbikes i have been ridin a drz 400 sm lately and it the **** and has dry sump motor. how much would you say is a fair price for a 100% clean minty blue 636 without motor? haha i dont think its hydrolocked there was no smoke and it still starts. i think valve is hitting head or piston slapping. something like that. i heard initial bang when it happened

 

i have a spare motor and would love to buy it but your too far away

 

what year is it? i'm in joliet for work for a few weeks and if the price is right... i got cash.