[Rotaxrob]

Hi All, OOPS posted this in Repair and Maint, maybe Admin can fix that. Looks like a good site here. I have a 2004 450es foreman,2500 miles on it, cam chain tensioner spring broke, jumped time,valves ok. Has anyone ever tried jumping chain back to proper position? Does anyone currently have a running 450 with top end or valve cover off that can measure piston vs push rod height? That front engine cover can kiss my you know what.

 

[shadetree]

ummm..you won't get the cam chain changed..until the front cover is off. with that many miles on it ?, it needs a new cam chain !. also, the cylinder has to come off, in order to replace the cam chain adjuster.

 

[Rotaxrob]

Shadetree, Im thinking 2500 miles is low and the chain jumped with the cover on it will jump again with the cover on, the head and cylinder are off.

 

[retro]

2500 miles on the cam chain is not a bad thing by itself, but parts have obviously failed... so you'll need to yank the front cover off and replace the chain and tensioner and anything else that is worn or broken. There aren't any shortcuts. Welcome to the forums!

 

[shadetree]

Shadetree, Im thinking 2500 miles is low and the chain jumped with the cover on it will jump again with the cover on, the head and cylinder are off.

once you get the front cover off, you can see real quickly if the cam chain is bad or not ?. if it were me ?, and I had to pull the front cover to inspect the cam chain ?, I would go ahead and replace the cam chain while I was in there. its your call, I just know what I would do .

 

[Rotaxrob]

Rebent cam chain tensioner spring,til new one gets here. Jumped chain back what felt like 4 teeth, now I got both valves closed at TDC. Put dial indicator on intake rocker, push rod side, set crank at TDC, set dial to 0, back engine up to .070 on dial indicator. My caliper has a bar style depth rod its .150 x .050 thick, with the heel of caliper resting on valve cover surface, keeping strait as possible measure down through sp plug to top of piston I get 4.980. Looks like the 2 unmarked marks on flywheel are when the decompressor starts to close, I may be closer than I think. Hopefully I will catch someone doing a rebuild or adjusting the valves.

 

[Rotaxrob]

Decompressor is on ex valve, and is in operation almost all the way to TDC, if Im timed right. I wonder what the book says about testing compression, a few thou could change it alot. Anybody know head nut torque.

 

[misterclean59]

Decompressor is on ex valve, and is in operation almost all the way to TDC, if Im timed right. I wonder what the book says about testing compression, a few thou could change it alot. Anybody know head nut torque.

Loosen the exhaust valve to about 30 thousanths. This should disable the automatic compression release. I doubt the starter can turn it over fast enough for a good reading tho.

 

[retro]

You can get a copy of the service manual HERE. Torque specs are found listed near the front of it if I remember right.

 

[Rotaxrob]

retro Thanks for posting that link to the manual with all the torque specs, now I can torque the bolts to the proper spec.

 

[Rotaxrob]

Just looked at the Manual, with a degree wheel, valve timing can be checked, the specs for opening and closing of valves is given. 10mm head nuts are 29 ft lbs with lube on threads and flange.