Chevy4life32 Posted July 31, 2011 Report Share Posted July 31, 2011 So i just got my motor Back and put together. It has a 4 mil long rod in it and the domes are cut for the 4 mil crank. When I put the noss head on and tightened all the bolts down. When I turned the flywheel to move the pistons i could hear a slight click noise as the hit top dead center. Im wondering y and took the top end apart and checked the domes for any types of marks and the piston clear them just fine. So i put it back together again and still i hear a slight click noise when the piston gets to the top. My question is this just cause there is no compression to keep the pistons from moving or what. I dont have the engine in the bike just on the work bench. I have rebuilt the top end before and I guess i never paid attention to the noise. The pistons move freely and everything. Any info would be good. I may just be crazy and hearing something. Any info could help put my mind at ease. Thanks Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted July 31, 2011 Report Share Posted July 31, 2011 check the squish with some solder, is there any resistance when the click sounds ?, if you cant find anything you may have to pull the clutch cover off and see if there is something in there clicking. is it at the same place in crank rotation, every time ? does it click with the head removed ? Quote Link to comment Share on other sites More sharing options...
Chevy4life32 Posted July 31, 2011 Author Report Share Posted July 31, 2011 check the squish with some solder, is there any resistance when the click sounds ?, if you cant find anything you may have to pull the clutch cover off and see if there is something in there clicking. is it at the same place in crank rotation, every time ? The clutch was just put together and no sound coming from that. the sound is coming from right where piston would go into the head but i pulled it apart and nothing it hitting and wierd but i hold my finger over the spark plug holes and add a little bit of compression and there is no clicking sound. so is it just cause there needs to be compression to make the click go away. I have checked it twice and the pistons dont hit the head at all. Is that sound normal on a 4 mil with cut domes or are the domes just off a little bit. Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted July 31, 2011 Report Share Posted July 31, 2011 should be no click. Quote Link to comment Share on other sites More sharing options...
Zwiser Posted July 31, 2011 Report Share Posted July 31, 2011 did you check for up and down play in the rod? if theres not check the wrist pin bearing and wrist pin for wear and up and down play. can you get a video of the clicking sound? Quote Link to comment Share on other sites More sharing options...
Chevy4life32 Posted July 31, 2011 Author Report Share Posted July 31, 2011 did you check for up and down play in the rod? if theres not check the wrist pin bearing and wrist pin for wear and up and down play. can you get a video of the clicking sound? There is no play the motor was just build and last week and put together today. Its a brand new 4 mil crank. I took the cylinders off and looked inside with the domes and head on and there it just a tiny little lip where the domes meet the cylinders and when i say small like just can barely see it. so i put it back together and didnt bolt the head down and the pistons just barely hits the domes. So now im wondering what to do about it. I just got the domes custom cut for the pistons. so gay. well I will try to get new domes im guessing. Or it there any way i could jently sand the domes. cause like i said its a tiny bit that the piston touches. Quote Link to comment Share on other sites More sharing options...
Zwiser Posted July 31, 2011 Report Share Posted July 31, 2011 get in contact with Jeff at F.A.S.T racing he'll hook you up Quote Link to comment Share on other sites More sharing options...
Titan up Posted July 31, 2011 Report Share Posted July 31, 2011 So the dome diamater is smaller than the cylinder dia? What's the ring gap and squish measurment? Both cylinders make that sound? Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted July 31, 2011 Report Share Posted July 31, 2011 Get in touch with builder.....tell him the domes are just barely hitting...possibly cut them wrong. Who cut your domes? Quote Link to comment Share on other sites More sharing options...
Chevy4life32 Posted August 1, 2011 Author Report Share Posted August 1, 2011 Get in touch with builder.....tell him the domes are just barely hitting...possibly cut them wrong. Who cut your domes? I got it taken care of, the domes need to be cut to 66.5mm for the cylinders instead of 66mm for the pistons. Its all good thanks guys for the advice. Quote Link to comment Share on other sites More sharing options...
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