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1990 Yamaha Big Bear 350 4X4 Timing Chain

WIJBIRD

By WIJBIRD
in Yamaha ATV Forum

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WIJBIRD Apprentice

WIJBIRD

Posted
Posted

Looking for a guru to help me get the top end back together. I'm stumped!! There seems to be an issue with the removable chain guide on the left hand side. In its current position (which is probably incorrect) there's not enough clearance to get the chain on the sprocket and be able to line up the timing. Does the guide rest on the side or is it supposed to be in the notch underneath? I have a manual, but it doesn't show the correct positioning on that guide. I tried to fit it in the notch, but then the cylinder head doesn't seem to seat properly. Let me know if you need pictures. Any help (and pictures) you able to provide will be greatly appreciated.

Thanks in advance!!

Jay in WI

MarkinAR Experienced

MarkinAR

Posted
Posted

If it's like the 93 Kodiak I had apart recently, there is a valley at the bottom of the front (not adjusting) the timing chain guide goes in to.  The top of that adjuster just kind of "sticks up" into the rocker cover.  It seems that I got the front guide in a bind and noticed that it touched the chain so it sounds like you've done that also.  Just have to get it seated right, may have to lift and lower the head a dozen times and then it just magically sits down cleanly.

WIJBIRD Apprentice

WIJBIRD

Posted
  • Author
Posted

Here are two pictures. If you look at the lower left corner of the sprocket (I know that circles don't have corners), you'll see the top of the black chain guide. Is it suppose to tuck into that little "pocket" in the cylinder head? I tried that once, but then the cylinder head wouldn't seat. What do you all think?

Thanks!

IMG_2030.jpg

IMG_2029.jpg

MarkinAR Experienced

MarkinAR

Posted
Posted

Looks fairly normal to me. As long as the bottom sits in its groove the top is just suspended. The kodiak I had apart you could flick the forward guide forward and backward a bit with the chain tensioner out. 

WIJBIRD Apprentice

WIJBIRD

Posted
  • Author
Posted

I got it! It did go in that pocket in the cylinder head. MarkinAR commented that you just need to keep lifting the cylinder head up and down until that guide sits in the correct position and then everything fits together. Wow, what a relief!!

Thanks to everyone for their input,

Jay

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