Cylinder head/ camshaft cover problems

[Dan Padgett]

afrernoon all, I’m working with an xs250 not a 400 but understand they’re the same pretty much anyway so some help would be great!

I had to replace the rings and I’m at the point now of rebuilding but have run in to a few issues/ questions...

Firstly the bike is fitted with an electronic ignition. My question is, does this omit the need to follow the instructions ref the timing of the valves when rebuilding the camshaft/ valves?

It was rebuilt using the instructions for the manual prior to me getting it and once the camshaft cover was reinstalled and tightened the bike would not kick over at all but upon loseening the bolts allowing the camshaft to freely spin it would kick over fine.

Any help would be appreciated

Thanks, Dan

 

[NewHavenMike]

Forget about the ignition timing for now. The camshaft and valves need to be in time with the crank shaft. Its been a while, but I think you need to get cyl 1 to TDC and theres a notch on the cam gear that need to be pointing straight up. If youre not able to turn the crank, you may have a valve hitting the piston or something else is jammed up. The cam should rest where its supposed to and should operate everything as normal even without the cam cover.

Make sure to give the engine a couple turns to make sure nothing crashes.

I cant imagine that the cam cover would actually clamp on the cam enough to stop it from turning, but I guess it possible.

 

[Dan Padgett]

Thanks Mike,

You’re exactly right that’s what it states in the Hayes manual. I’ve done all of that, aligned everything as per the manual. It turns nicely!

I’ve gone ahead and tried to refit the camshaft cover.... firstly I assume it’s supposed to sit uneven on the cam? Depending on where the shaft is in it’s turn? I.e one side is raised slightly? the exact same thing is happening, I’ve tightened the bolts down and the whole thing gets stuck! Cannot shift the kick start at all! It’s like the cam doesn’t have room to spin...

Could it be the valves are stuck so not depressing the springs and so not being able to spin freely?

 

[NewHavenMike]

The cover will sit uneven at first. Its weird how theres no official sequence to getting the cover back on. Just start in the middle and focus on the bolts close to the cam. Tighten each bolt evenly, about one turn each at a time. That way the cover will settle evenly and wont create too much pressure on the cover or anything else and the valve springs will compress slowly and smoothly.

I cant remember if the cover bolts had torque values, but i think i stopped around 12-14lbs.

 

[xschris]

Torque specs are in the manual. When I remove covers to replace seals I remove the spark plugs and turn the motor over to where most of the rockers are loose. This will make putting it back on easy. Also make sure the tach drive is in line and not cross threaded with the drive on the cam. This will cause issues with turning the motor over and the cover going on correctly.