Hulio-mv Posted March 16, 2008 Author Report Share Posted March 16, 2008 (edited) i didnt read all of the other posts made , so this is just picking up where my last post was at. Discrd if not needed your squish could be a little tighter. you want idealy .040 of squish, but with yours messuring out farther this isnt the cause of your o rings popping out. timing is advanced with the small key I belive 4. Compression is 165-170 or it was in early winter when everything was new. Gas is 91 some times 93 if I can find it 32 to 1 maxima 927. And I didnt have the correct size adapter to test my cap so I am going to find a shop this week to check it. I know I have read on this site somewhere what pound the cap is and where to find replacements but I cant seem to get the search function to work for me. If the cap could be a cause. How would I go about making the squish tighter? Edited March 16, 2008 by Hulio-mv Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 17, 2008 Author Report Share Posted March 17, 2008 I think I will chec cylinder studs tomorow and maybe try regular nuts instead of the acorn nuts I am just guessing it may be one of those I dont know Quote Link to comment Share on other sites More sharing options...
bink98xcab Posted March 17, 2008 Report Share Posted March 17, 2008 well im not sure if this is the same thing, but my rm had a prob with the engine putting pressure in the radiator and making it overflow when it wasnt even very hot, and i was thinkn a blowed head gasket but , its an o ring head as well, so,,, im thinkn its either got hot and warped or blowed a o ring, so i had the head planed and put new orings a and it fixed it like new Quote Link to comment Share on other sites More sharing options...
shee rips Posted March 17, 2008 Report Share Posted March 17, 2008 you may have too much compression for pump gas. what domes do you have? sorry if youve already answered and i forgot lol. that could explain the hole in the piston before too. i would go back to a stock flywheel key and maybe decrease the compression a little. then if you want to advance the timing, use a stator plate. Quote Link to comment Share on other sites More sharing options...
skeletor15 Posted March 17, 2008 Report Share Posted March 17, 2008 you may have too much compression for pump gas. what domes do you have? sorry if youve already answered and i forgot lol. that could explain the hole in the piston before too. i would go back to a stock flywheel key and maybe decrease the compression a little. then if you want to advance the timing, use a stator plate. i had the same problem. hole in piston and after rebuild it had bubbles in the radiator. took it back apart and had head checked it wasnt warped but had a slot fire across it. a small one but was missed the first time . maybe not your problem here since you have o ring head ,it would be easy to tell with it . but might have a cylinder problem. Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 17, 2008 Report Share Posted March 17, 2008 timing is advanced with the small key I belive 4. Compression is 165-170 or it was in early winter when everything was new. Gas is 91 some times 93 if I can find it 32 to 1 maxima 927. And I didnt have the correct size adapter to test my cap so I am going to find a shop this week to check it. I know I have read on this site somewhere what pound the cap is and where to find replacements but I cant seem to get the search function to work for me. If the cap could be a cause. How would I go about making the squish tighter? i would ditch the key, if you wish to advance your timing do it right by using a plate. as far as your compression at 170 you are well over pump gas with advanced timing. you need to be running at least 50/50 for your squish you would need to get differant domes. or use a thinner base gasket. and if your saying your adaptor was too short your comp will be even higher. Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 17, 2008 Author Report Share Posted March 17, 2008 So I should go back to 20 domes? Or run half half? I meant my rad cap, my pressure tester didnt have the correct adapter to test my rad cap sorry I went back and read that post and I kinda confused my self. As far as the fuel all I have easy acess to is mach115 or blue diamond not sure of the octane rating on it though. but that is not the same as a good race fuel is it? Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 17, 2008 Report Share Posted March 17, 2008 im assuming that is AV gas? if so then no its not the same as race gas. if you cant get good race gas then i would backoff the compression. Quote Link to comment Share on other sites More sharing options...
Screaming Yellow Zonker Posted March 17, 2008 Report Share Posted March 17, 2008 the av gas will work you just have to re jet because the fuel is oxygenated. What size jet are you running? it sounds like you are running it lean. Detonation and running hot are a sign of a lean condition. Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 17, 2008 Author Report Share Posted March 17, 2008 the av gas will work you just have to re jet because the fuel is oxygenated. What size jet are you running? it sounds like you are running it lean. Detonation and running hot are a sign of a lean condition. 340 I think stock carbs Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 17, 2008 Author Report Share Posted March 17, 2008 340 I think stock carbs Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 17, 2008 Report Share Posted March 17, 2008 i dont recall if av gas is oxygenated or not but i know that the octane rating is not the same as fuel used for automotives due to the altitudes and a few other things. there was a chemical engineer guy that came on here a few months ago and explained the differances. Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 17, 2008 Author Report Share Posted March 17, 2008 Here is why I am so confused I changed nothing with my set up other than new cylinders and pistons the bike was fine for 2 years prior Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 17, 2008 Report Share Posted March 17, 2008 the jugs you got could have been milled??? what pistons did you get? there are alot of possibilities. but burning a hole in the piston is due to running lean, so you got a leak some where along the way Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 17, 2008 Author Report Share Posted March 17, 2008 the jugs you got could have been milled??? what pistons did you get? there are alot of possibilities. but burning a hole in the piston is due to running lean, so you got a leak some where along the way the cylinders are new yamaha with wiesco pistons The burnt piston was woth the other jugs that were on last over size. Bought new jugs and pistons and put it all back together cleaned out the bottom end and re-installed I should say. Quote Link to comment Share on other sites More sharing options...
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