Hulio-mv

as far as I can tell it is not the same place and it is a modquad head if it makes any difference I amnot sure if I put the same dome back on the same side either but both times I took it apart it has been the right dome ring -kickstart side

I am having a bit of the same problem the way to tell if it is the compression doing it is when you first start it put your fingher over the end of the overflow tube and see how big the bubbles get with the engine cold my bubbles get big and the coolant keeps coming

right just o-rings popping out all the other stuss has ben in reply to questions and trying togive more info so the good guys can help me.

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.

pipes didnt last long

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

340 I think stock carbs

340 I think stock carbs

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?

I have had t-5s and curently run pc imo I like the pcs better but i mainly ride tracks and feilds and a little sand. never had fatties but from what i hear good on a stock or lightly modded motor. the biggest difference in any of them shows up after several mods imo. I think almost all shees will be modded at some point in time so its a tough choice. for me I like pcs best of the 3 you are looking at

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

The gum if on the left side by the petcock is mostlikely the rubber nuckle pads on his riding gloves it will clean up but it will probably happen again. Swap em and check your plugs there will probably need to be a little change

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?

Good to know i will check it tonight at work if I have thr correct adapter in the kit I have.

What should I look at next?

.05 and .06 there are washers under the acorn nuts and the washers have rubber in them

Ok just measured them and one side is .005 and one is .006. tha is with the old o-rings and one o-ring is split. The caliper i used is pretty cheap digital and claims to be within .001. Is that too much? and if it is what should I check next? The machine shop told me my head was not warped. Just a thought could it be a stud hole in one of the cylinders not the same depth or maybe a streched stud not letting the acorn nuts not draw down tighe enough?

Ok I have the head off right now so I will do that after i get it checked at the shop. Is there a standard measurement that is right or is it dependant on mods and different heads? Thanks for the quick reply I have to get some sleep working overnight is a crappy thing to have to do but someone has to do the crap right

it was all flushed and clean when I put it back together. Is there a easy way to check squish? The o-rings sometimes have a little hump in them when i remove the head but I cant tell if it happened before I took it loose or not

Last year I blew a hole in a piston and seized it up. I think it either over heated or the o-ring failed and let coolant in not sure which. The cylinders were on the last bore so I bought new factory yammaha cylinders. Now after about 2 hours of riding it starts pushing coolant out the over flow tube. I have a prodesign impellar and a vapor computer temps do not get high untill the coolant starts coming out. I have tried 2 different new sets of domes 19 and 20 both new and all new o-rings every time and the same result. I run 92 or 93 octane and maxima at 32:1 It is a modquad head. Is it possible i warped the head by heat? I am taking it to a machine shop to see if they can measure it better than I can. Is it possible the new cylinders are fouled up somehow? the o-ring doesent puhsout in the same spot every time. I took the cylinders back off and all the little dowells were there. I am lost and tired of throwing away a 30 dollar set of o-rings every day. Any info or advice you can give would be great. any info I left out that is needed ask and I will fill in the blanks. :wallbash: :wallbash: :wallbash:

A sharpie and some beer is all you need mine are in my pic but i just wiped my puter clean so i dont have bigger pics

I run them and I like them but I had to use a floor jack and pry bar to get them to fit. Mine have a plate versus the webbing on the heel section.

The modquad head if new comes with acorn nuts and copper washers with rubber in them I have nevet had trouble with coolant coming through the stud holes with the modquad o-ring kit which comes with new washers in every kit. I have only found tha actual modquad kit in motosport outlet catalog or directly from modquad.

where in MO i have the one in pic and a couple others

you still have the rockets if so are you looking for anything. trade