Cam timing question

[Bob East]

Hi Guys,

One of my buddies has an XR600R that appears to have slipped timing.

He said that the bike tipped over on him and he had some difficulty in

shutting it down while it was on its side. Afterward, he couldn't get it

to start again. So, I'm wondering if something like a defective cam

chain tensioner could allow this to happen? I plan to get my hands

on his bike to see if I can troubleshoot this problem rather than depend

on his accounting of the facts. However, I just want to know if there

is any problem with the cam chain tensioners that might allow the

cam to jump timing?

Rgds,

Bob East

[creeky]

I have seen XR cam chains that were REALLY loose and clattering like the hammers of hell, and did not jump time. It's pretty normal for a 600 to start hard after a fall because when the bike is tipped over, a crap load of gas runs into the intake. I'd be really surprised if a tipover would cause the chain to jump time.

[frankstr]

I agree with creeky, could not believe that a tip over would cause the bike to jump time,probably flooded real bad.... ?

Pull the spark plug and kick it over with plug out and install a new plug, tmo

[creeky]

When restarting after a fall, hold the throttle open, pull in the compression release and kick the engine over 8-10 times to clear the combustion chamber of gas and dead air, then do the normal starting drill. If the flooding is severe, you might have to repeat this drill 2-3 times.

[Blade Man]

If he just dumped the bike he could probly use the rest and waiting to start a flooded engine can only help both of them.

[Bob East]

Hi Guys,

Thank you for the input. I thought that sounded a bit odd, too. I'll have

to get my hands on his bike and see if I can get it started. I have a new

spare sparkplug I can put into it along with a can of starting fluid to help

the process along.

I think the bike I just bought is in much better shape than my friend's

bike. It looks much cleaner and it seems to run like a Swiss watch.

However, when it's cold, it's a real bear to start. It's already kicked

back on me and tried to launch me over the handlebars. My knee was

sore for a week.

One thing I'm curious about. Has anyone ever tried to power the ignition

with an external battery when starting one of these beasts? I would

think that would provide a much stronger spark and make starting a

bit easier. Anyway, I'll look into it and if I come-up with anything

that seems to work, I'll post it to this forum.

Rgds,

Bob East

[creeky]

Bob East............be very careful with starting fluid. Too much of this stuff in the combustion chamber can cause piston damage due to the extremely rapid expansion of gasses this stuff causes when it goes off.

[oldturtle]

Hi Guys,

I think the bike I just bought is in much better shape than my friend's

bike. It looks much cleaner and it seems to run like a Swiss watch.

However, when it's cold, it's a real bear to start. It's already kicked

back on me and tried to launch me over the handlebars. My knee was

sore for a week.

I have never had mine kick back because of the automatic decompression system that opens right exhaust valve whenever motor tries to go backwards. I suspect that previous owner replaced cam with aftermarket cam that did not have provision for decompression feature.