The Faster Cracker Posted July 3, 2009 Report Share Posted July 3, 2009 wouldn't 160 mains be to small or am i thinking of that being to small for stock carbs? Quote Link to comment Share on other sites More sharing options...
Ieat4strokes Posted July 3, 2009 Author Report Share Posted July 3, 2009 pull the head just to be safe and to make sure no ring lands are broken.don't base your octane requirements on static compression alone(i had a 115 lb# compression motor that would detonate without race gas)i would bet detonation is backing out your plugs......peace Does detonation make a noise? Thats audible, that you can hear? I hear some ticking...... Did you originally check the compression with the motor warmed up, and the throttle wide open while kicking? Yea the motor was warm, i checked it after the trip down the street and back, approx, 1/4 mile after i noticed plugs were backing out, i wanted to check compression to see if i needed to drain tank and put in straight race gas.....I had one plug out, and throttle wide open.... But my question is, were the squish numbers good? was solder too thick to get accurate reading and bending them at a 90 degree angle and touching cylinder wall the proper way? Ive never done it before......and will detonation cause the noise im hearing? Its like a hollow tick coming through the pipe....hell i dont know Quote Link to comment Share on other sites More sharing options...
Ieat4strokes Posted July 3, 2009 Author Report Share Posted July 3, 2009 wouldn't 160 mains be to small or am i thinking of that being to small for stock carbs? 160 mains on keihin's are waaaaaaaaaaay bigger than a 160 on stock carbs.....Im running 162's if i posted 160's that was a typo...... Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted July 3, 2009 Report Share Posted July 3, 2009 Motor warm, Pull both plugs, and kick it repeatedly very fast with the trottle wide open the whole time. As long as you measure the squish at the side of the rod pins, then use your lowest number (.045") it should be ok. Now, the key is to see if your compression is actually what the gauge says it is. If its detonating, you can back off timing, or up the octane to get rid of it. If the plugs back out on their own, thats a sure sign that it is detonating. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted July 3, 2009 Report Share Posted July 3, 2009 Im running the same motor as you with 20cc domes and I kick 175 both sides,you bought that piece from kubitza rite,did you buy the 19s from jeff also.What size base gasket are you running,those domes didnt come with the motor because he ran alky,just wondering,with 20s I run straight c-12,c-16 VP fuels Quote Link to comment Share on other sites More sharing options...
dlnoss Posted July 3, 2009 Report Share Posted July 3, 2009 The solder should get thicker further away from the cylinder wall because the squish angle is slightly more than the angle (it's not really an angle) of the piston crown. I does seem you are detonating. -David Quote Link to comment Share on other sites More sharing options...
Ieat4strokes Posted July 3, 2009 Author Report Share Posted July 3, 2009 Motor warm, Pull both plugs, and kick it repeatedly very fast with the trottle wide open the whole time. As long as you measure the squish at the side of the rod pins, then use your lowest number (.045") it should be ok. Now, the key is to see if your compression is actually what the gauge says it is. If its detonating, you can back off timing, or up the octane to get rid of it. If the plugs back out on their own, thats a sure sign that it is detonating. I did measure both sides of each cylinder, as close to the pin as I could get it, kinda hard to get it dead on at the pin bbut i se whre your going, plugs backed out last night on a wot run, havent ran it since, but i cant be 100% that i tightened em down, with putting the motor togther and installing the motor, cutting old brackets off frame, rerouting and cleaning up harness I had alot going on yesterday,, may have been a oversite, Im going to empty tank, put in some 115 i have here and try again, then look at plugs to see whats going on. thanks for all your help snop. You aint half bad of a guy, i dont care what they say hahahahahah j/k Im running the same motor as you with 20cc domes and I kick 175 both sides,you bought that piece from kubitza rite,did you buy the 19s from jeff also.What size base gasket are you running,those domes didnt come with the motor because he ran alky,just wondering,with 20s I run straight c-12,c-16 VP fuels So now i know my tester is off, p.o.s. cost me 40 bucks too, looks like its made well but inaccurate all the same, I got some 19cc gas domes cut by mr. Noss, kubitza's ( Mark) were 20cc alky's your correct... and the c12 is awesome stuff, ran it in my streetbike for years, this quad stuff is still all new to me, as far as the gasket its just the blk ones that come in the wiseco top end kit...Im gonna try straight race fuel and see if that noise stops, i hate any kind of noise, it might have always done it just never paid so close attention until you build your very first motor from the crank up. The solder should get thicker further away from the cylinder wall because the squish angle is slightly more than the angle (it's not really an angle) of the piston crown. I does seem you are detonating. -David David, yea the solder tapers off slightly from the actually squish imprint, so i should measure closest to the tip right? Once again thanks from the domes, quick shipping, i had em the next day! Quote Link to comment Share on other sites More sharing options...
Ieat4strokes Posted July 3, 2009 Author Report Share Posted July 3, 2009 (edited) ok well i put straight 115 race gas in, new plugs and its missing, not reving out clean and that knocking sound is still there, almost sounds like piston slap or the crank, what could I have done wrong......i talked to jeff for a hour earlier and he said the knocking noise concerns him, but he didnt know what it was, also i need to mention i caught h3ll trying to get the piston pin out of the pistons when i got them, had to beat them out and back in, should the pin be that tight? could that be the noise im hearing? Help please edit: there is quite a bit of vibration coming from the motor, more than before, are there c-clips on both sides of the crank? or just on output side? I only seen a c-clip on the output side and nothing on flywheel side.... sorry for the dumb questions but ive never been in case before Edited July 3, 2009 by Ieat4strokes Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.