yz426 worries

10 replies to this topic
  • phil2k

Posted January 04, 2014 - 09:30 AM


I stripped and rebuilt the top end on my bike as I was getting water in the transmission and found there to be a small leak in the head gasket, the rings were just out of spec so they were replaced. i cleaned the head and replaced head and base gaskets then started to rebuild the engine. the problem i have is that i can now turn the engine over by hand without the decomp lever, the valve clearances are all in spec and the timing is set. would the compression increase when i fill it with oil? i really don't understand why its gone like this. Before i couldn't even turn the engine over by putting all my weight on the kick start lever.

  • Arizo

Posted January 04, 2014 - 09:38 AM


Do you got your cams installed good at TDC?

  • phil2k

Posted January 04, 2014 - 09:45 AM


i think so, the dots are about 1/3 of a tooth from the top of the case when i allign it all, this is the closest i can get them. it may need a new cam chain soon but i have spent too much already on this dog 

  • Arizo

Posted January 04, 2014 - 10:12 AM


And are you sure it is at TDC? Maybe a stupid question but did you put your spark plug in while trying to kick it over?

  • phil2k

Posted January 04, 2014 - 10:21 AM


ha ha not stupid i have seen it done myself yes i did put the plug in, i have not kicked it yet just turned the engine over by hand. its not finished yet so i have no oil in it and don't really want to kick it till i get it full of fluids, but i don't want to fill it if im just going to have to empty it again. im sure its at tdc, the I mark ligns up in the hole in the timing cover

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • RocketRoss57

Posted January 04, 2014 - 11:05 AM


Make sure you are using the right marks on your cams to align with. There should be three marks on each cam. It needs to be set to where each cam has one mark pointing up and the others out to the sides with farthest outside ones aligned with the headImageUploadedByThumper Talk1388862319.054318.jpg

  • phil2k

Posted January 04, 2014 - 12:19 PM


right just taken some pictures the 1st 2 pics are with the bike at tdc and where the marks actually are and the 3rd picture is with the bike just off tdc and the marks in the right place, I noticed you have 13 pins in the chain between the marks and I only have 12 though 018372d0-99f3-446c-8e1e-9c7fbb4cf82f.jpg c95b3f07-1011-4861-a0f4-b51cad2d8c22.jpg 44ce63cf-c6c1-471c-b156-00952d94a55f.jpg

  • phil2k

Posted January 04, 2014 - 12:21 PM





  • grayracer513

Posted January 04, 2014 - 01:09 PM


Pin count between cams in not meaningful in most cases.  Only the alignment of the "E" and "I" marks. 


Recheck your valve clearance while you are there.

  • phil2k

Posted January 04, 2014 - 01:14 PM


valve clearances are right in the middle of spec, so does this timing look ok or should I turn the exhaust one more anti clockwise

  • phil2k

Posted January 04, 2014 - 02:24 PM


Sorted it, I removed cams so all valves were closed and turned it over and still had no compression so removed the decomp shaft problem solved ha ha I checked the clearances before I put the decomp shaft back in. That will teach me to try the obvious first

Related Content


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.