ecoboost12
New member
I recently rebuilt my 1980 440ss engine and now im having troubles. I put new crank seals and replace all gaskets. I also shaved my heads 20 thou. I honed my cylinders and put new wiseco pistons in it. Im running a 102c comet clutch and the original keihn carb which has been cleaned thouroughly.. It starts and idles beautifully. When I rev it up a couple times it gets a mid to high range bog. Could it be jetting? Timing? I have 125pounds of compression. Please help, im pulling my hair out.
did you clean out the primary clutch? could be binding with belt dust or in need of an overhaul.
ecoboost12
New member
I did clean the clutch and rebuilt it it. Put a silver spring and f 2 weights in it.
Yamaha Nutz
New member
how did you test compression ...do it with the throttle wide open what gaskets did you use ..if you cut your heads .020'' with Yamaha gaskets you should be in the 145 -150lbs range sounds like a clutching issue to me ....is the offset and center to center set right is the belt deflection good .....did you go through the secondary ....best for these sleds is a phazer secondary as the helix works way better than the 8K4 helix of the 80 ss
ecoboost12
New member
I used winderosa gaskets. I did the comression test with the throttle open. I was hoping for more compression too, But I cheaped out and put new standard pistons in with a light hone, should have bored it out...next time. What should my belt deflection be? What should my center to center be? Im also on my way to pick up a new belt. As for the secondary im in search of a phazer helix !
Thankyou for your suggestions!
Thankyou for your suggestions!