Fair weather rider
Does anybody have the factory information on valve timing for an FXR. I had to take the head off mine this week (bit of a problem with a spark plug that broke off in the head!)
Anyway, I thought I had documented the vavle timing correctly but when I put it back together I just got a whole lot of back firing etc. Can't get it to run at all and I'm tearing my hair out. Now we're gonna miss the fun day tomorrow and probably Taupo as well......
Help!!!!!
Forum whore
Valve timing "RULE of THUMB" valve timing is almost always symmetrical about top dead center.Originally Posted by Sideways Sam
I.e., if the exhaust closes say 30 degrees ATDC (after top dead center) then the inlet will start to open 30 degrees BTDC (before top dead center).
You can quickly check the valve timing by rocking the motor by hand backwards and forwards past TDC (top dead center) and the valves will rock equally with the Exhaust closing/opening and the Inlet opening/closing the same amount.
If your careful you can find that crossover point by eye very accurately and it should occur right on TDC.
It is the method I use to check that I have got the timing right when I change cam belts.
It is easy to see if your one tooth out and so it should be easy to quickly check your bike.
If your getting backfiring I suspect your more than a tooth out and/or most likely the ignition is way out.
Check your ignition timing!!!!!!
Fair weather rider
Thanks,
I'll check it like that in the morning. I had a quick run through and everything is openeing and closing on the correct strokes etc. But what you suggest is a bit more helpful.
I'd really like to get the correct pin count from the '2' marking to the '3' marking which is how Suzuki do it. I know I've got the exhaust correct but I've got a feeling the Inlet may be out.
Ignition timing isn't adjustable on these babies, or is it? That was my first suspician.
Another note compression seems to be way down and everything is OK inside the chamber so that would suggest valve timing???????
Forum whore
Its very possible, but more likely a valve clash resulting in a bent valve by getting one cam out of time with the other. Or valve timing far enough out to go banging a valve into the top of the piston.
If you have bent a valve, the tappet clearance will have become enormous on the bent valve.
No radically increased tappet clearances = no bent valve's.:
Fair weather rider
Clearances are all OK so I'm picking we're OK there. Hopefully just a timing issue
Registered User
Sam have you taken any of the bottom end cases off the engine at all? I'm referring to mainly the left engine cover as generally the ignition pickup is located behind this cover and is factory preset. So if you didn't touch it you can eliminate ignition timing as your problem. Edit: Do check that all the wiring connectors that come from the engine are connected properly, these can be quite problematic on Suzuki's as I've found out recently.
Like you said you'll need that pin count and possibly a diagram to get it spot on. This is critcal in a twin cam engine and easy to get wrong without the correct info.
I checked www.fxr150.co.nz but couldn't find a diagram, maybe you could contact one of the guys on that site they're bound to have a workshop manual, A couple of those guys are on here too I'm just not sure, Buddha#81 would be someone to ask.
Good luck.
Fair weather rider
If anybody is interested I now have the appropriate pages from the Suzuki service manual that relate to this.
I would kill for the rest of the manual but this was all I could coax out of my local Suzuki dealer...
Who You Calling a Pig
Yes, please. Maybe you can drop it off at the same time as my brake disck
For the record Qkkid was in my bed, not the other way round
Fair weather rider
You're on, I'll bring some beer as well.........Yes, please. Maybe you can drop it off at the same time as my brake disck
Have to be next week now, in Chch for the weekend
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