A Question Of Timing
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Cam timing or spark timing?
Your cams should have some witness marks on them that should line up with a witness mark on the crank lining up with a mark on the block. you'd have to consult the manual/bike specific forums to know exactly.
Caution: 4cylinders can be timed at what's called "180 out"
Spark timing will be done by an ignition plate. Stock should have no adjustment. If a PO installed an aftermarket unit, and its loose it could cause problems.
Your cams should have some witness marks on them that should line up with a witness mark on the crank lining up with a mark on the block. you'd have to consult the manual/bike specific forums to know exactly.
Caution: 4cylinders can be timed at what's called "180 out"
Spark timing will be done by an ignition plate. Stock should have no adjustment. If a PO installed an aftermarket unit, and its loose it could cause problems.
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740 Posts
Unless you have an ancient bike with points ignition, the timing cannot be adjusted, it's a pre-programmed advance curve in the ignition box. For carb bikes you can have anywhere from 1 to 4 trigger coils that tell the box when to fire the coils, on EFI the computer figures it out from the crank position signal. Older bikes, namely Yamaha's, had crappy analog TCI boxes that are now dropping like flies. As they're dying they can cause all sorts of weird issues, hard starting, runs good cold but not warm, random misfires, ect. By the late 80's almost everything was digital and those problems had mostly been eliminated.
Cam timing can only be set with the engine off....I'd like to see someone try setting it with the engine running.....typically on DOHC engines there's dots/marks on each cam gear that should align with one of the cylinders at TDC, usually whichever is called #1, which is usually the left-most. Sometimes there's a special tool for locating this spot on the crank, sometimes an access port you unscrew to see a mark align with a notch in the case, it varies. Look in the service manual. Cam timing can jump a tooth if the tensioner fails, but that's not very common. Usually if it's a tooth off the engine will seem to still run OK, though overall power will be noticeably lacking.
Cam timing can only be set with the engine off....I'd like to see someone try setting it with the engine running.....typically on DOHC engines there's dots/marks on each cam gear that should align with one of the cylinders at TDC, usually whichever is called #1, which is usually the left-most. Sometimes there's a special tool for locating this spot on the crank, sometimes an access port you unscrew to see a mark align with a notch in the case, it varies. Look in the service manual. Cam timing can jump a tooth if the tensioner fails, but that's not very common. Usually if it's a tooth off the engine will seem to still run OK, though overall power will be noticeably lacking.
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Thanks a lot guys! I found out how to do the timing adjusting but I need a special tool to hold the tension on the cam chain (or something like that) which I don't have. I'm just going to take a bow and send the girl in for tuning and what not - let the pro's get her running properly before I really fuck something up. I am pretty stubborn when it comes to fixing things myself, especially when I have the chance to prove the nay sayer's wrong, but I do believe that sometimes you just have to swallow your pride and ask for a bit of guidance - as much as it sucks!
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3,825 Posts
have you had the engine apart mate? only time your cam timing will change is if you move the cams in relation to their position in the cam chain! so unless you have moved one of the cams out of position it shouldnt change. have you turned the motor over with the CCT removed/loosened?
to check cam timing, your engine needs to be turned until piston one is at TDC (top dead centre) the end of the crank will have a "T" mark on the timing rotor, there is a "I" mark to the right of the "T" mark, this should line up with the timing line that is cast into the ignition cover opening.
There are marks on the cam sprockets, when you look from the end of the cams (right side of engine) the marks should be...
inlet cam = mark (small line with "IN" marked next to it) at 9 oclock position level with top of head casting.
Exhaust cam = mark (small line with "EX") at 3 oclock position level with top of head casting.
if any of the marks dont line up with all the others correctly positioned then your cam timing is out!!
it is easily done, the marks need to be checked for correct alignment very carefully, they can be out without looking bad. :thumbsup:
to check cam timing, your engine needs to be turned until piston one is at TDC (top dead centre) the end of the crank will have a "T" mark on the timing rotor, there is a "I" mark to the right of the "T" mark, this should line up with the timing line that is cast into the ignition cover opening.
There are marks on the cam sprockets, when you look from the end of the cams (right side of engine) the marks should be...
inlet cam = mark (small line with "IN" marked next to it) at 9 oclock position level with top of head casting.
Exhaust cam = mark (small line with "EX") at 3 oclock position level with top of head casting.
if any of the marks dont line up with all the others correctly positioned then your cam timing is out!!
it is easily done, the marks need to be checked for correct alignment very carefully, they can be out without looking bad. :thumbsup:
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