Engine Jammed!-xr600r

Hi everyone,

Tried to start my bike yesterday. I pulled the decompression lever in and kicked it over. Then I heard a clunking sound in the engine and the engine jammed to a stop and wouldn’t turn over anymore. I can turn it over in reverse 1 revolution then it clunks to a stop. It sounds to me like the valves or valve is hitting the piston. I pulled off the top cover cap to check parts. The camshaft, rockers, cam sprocket, etc. seem fine. With the cover off, I turned the engine over and it has compression. Also, the valves aren’t sticking.

I don’t know much about this engine but I think it could be a problem with the decompressor system??? Anyone have any ideas????

I never had any problem with any XRs I've had but if the timing chain is tight it shouldn't have jumped time, I would pull the Spark Plug and and the left crankcase access plug and turn it both ways (with a socket wrench)to make sure the kickstart and decompressor have dissengaged and if it seems ok then kick it over slow and see if it happens when the kickstarter is accuated might be in the kickstart or decompressor unless something got sucked into the combustion chamber like a choke plate flapper.

(that's assuming it what running ok the last time it ran) good luck!

Hi everyone,

Tried to start my bike yesterday. I pulled the decompression lever in and kicked it over. Then I heard a clunking sound in the engine and the engine jammed to a stop and wouldn’t turn over anymore. I can turn it over in reverse 1 revolution then it clunks to a stop. It sounds to me like the valves or valve is hitting the piston. I pulled off the top cover cap to check parts. The camshaft, rockers, cam sprocket, etc. seem fine. With the cover off, I turned the engine over and it has compression. Also, the valves aren’t sticking.

I don’t know much about this engine but I think it could be a problem with the decompressor system??? Anyone have any ideas????

I am guessing you have a problem somewhere with your valves, maybe the exhaust valves.......

I'm thinkin what your thinkin, Valve's possibly hitting piston :)

Possible jumped time when it last shut off..........

Keep us informed........sorry about the break down :)

This might be long shot, but I had my XR lock up when the cam chain sprocket bolts weren't tightened properly (oops). The bolts backed out, and one of them wedged itself against the head, locking everything up solid. I was lucky, heard it begin to happen, shut the engine off, and suffered no major damage; hope you have the same luck.

DONT TRY TO START THE BIKE AGAIN! Most likely the cam chain has jumped but this only happens when it is extremely loose from being out of adjustment (rattling) for a long time. If it has jumped theres a good chance a valve could be hitting the piston. Was the engine rattling? You'll just have to whip the rocker-cover off and cross ur fingers! Good luck!

sounds like it time for a valve job and timing chain and tensioner

The Cam Chain Jumped Timing And The Piston Shot Up And Hit A Valve Most Likely Bending It If You Tried To Kick It Against Its Will. Looks Like You Are Going To Have Some Serious Top End Work To Take Care Of. Good Luck And Keep Us Posted.

I pulled the flywheel cover and checked the valve timing... its out by one tooth. everything else seems fine, the timing chain seems tight, the valves open and close freely and the engine has good compression. My question now is, how do I know if I need a new tensioner, how do I de-activate the tensioner and move the cam sprocket back one tooth on the chain, and if I do need to replace the tensioner, is that hard to do?

Thanks Guys!

with the tensioner out you can check it so go ahead and pull it i got one when i was doing my motor job because one of those little p;astic pieces on the inside of it was broke and binding my tensioner up its only about 38.00 bucks from honda i did the chain too, held the new chain up to old one and i could see the difference in length by about 1/4 inch thats alot got new chain from ebay 18.00 bucks what a deal

you can move the sprocket back need 2 people almost take bolts loose on sprocket and have someone push the tensioner down to take pressure off the chain then move your sprocket down and rotate the chain around put the sprocket back on quickly i done it by myself once not to easy another helper would be better

Can the tensioner and timing chain be replaced without taking the motor apart?

Thanks

clutch cover must come off and a few gears so you can get chain off of lower spocket it is pretty easy get your tensioner on and in time is the fun part they make a tool to hold the tensioner almost useful just play with the spring and you should be able to do it

Guys,

I checked my valve timing, and it's way off, that's

probably the problem, EH!

yep mate. If you take the inspection caps off the left-hand crankcase cover and align the T on the rotor with the notch on the cover the 2 marks 180 degrees to each other on the cam sprocket should align with the gasket surface on the head. This is when the timing is spot on, where are yours at TDC?

if you order a new tensioner make sure they get you a tensioner and not the guide i think they call it something else besides a tensioner tell them its the small thing with a hook on the end unless the guy your ordering from knows what your talking about

i went threw that just told them a tensioner and they got me the guide because that is what it said on the picture of the parts

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