87sheerips Posted September 1, 2004 Report Share Posted September 1, 2004 ok, im having some work done on my engine, any the guy claims that ive been running my 100 over motor (66.5mm) with a stock head (64mm) and it is impossible that it even ran. It has run great for about a year now! he suggested there was thicker gaskets, but there wasnt. Is this just a really lucky case or what?? im sending the head to get shaved to accomodate for my 66.5mm pistons for the proper fit. What do u think is going on here, it has ran great forever like this.. I did notice the piston had some very slight markings on the top from hitting the head. what should I do!!!?!?!? thanks for the help. ohh, any cheap ways to solve this would be great! Quote Link to comment Share on other sites More sharing options...
97redshee Posted September 1, 2004 Report Share Posted September 1, 2004 get a noss,cool head or what ever and have a set of domes cut for your motor. Quote Link to comment Share on other sites More sharing options...
kenr74 Posted September 1, 2004 Report Share Posted September 1, 2004 I could be completely wrong here but I thought the bore size was only the diameter of the piston and had nothing to do with the height. I wouldn't think the head would matter as long as the piston wasn't taller. I know that I have had to go up in bore sizes and the head was never touched. No problems here either. Does this shop normally work on bicycles or something. Like I said though, it's possible I have no idea what I'm talking about. Quote Link to comment Share on other sites More sharing options...
Brianshee Posted September 1, 2004 Report Share Posted September 1, 2004 I'm having the exact same problem. I'm wondering if it is because I have over reved it a couple of times and may have strectched the rods. I'm putting a cool head on mine. Does anyone know if I will have to have the domes machined? My bore is also .100 over. Quote Link to comment Share on other sites More sharing options...
duneslinger Posted September 1, 2004 Report Share Posted September 1, 2004 if you placed a stock head gskt on the 66.5 cylinders you would find they over hang but the one that come with the .100 piston don't a cool head dome for a big bore has a thinner lip betwen the o,ring and the inside of the cylinder to clear the larger piston the squish band would be very close on the outside of the piston becouse of the dome size on the piston. you could run 2 base gskts for a little more clearance. Quote Link to comment Share on other sites More sharing options...
Brianshee Posted September 2, 2004 Report Share Posted September 2, 2004 So I need to get some big bore domes? Quote Link to comment Share on other sites More sharing options...
duneslinger Posted September 2, 2004 Report Share Posted September 2, 2004 i have 2 bikes that are 66.5 one has a choozen cool head with std 21cc domes 170 psi and the other has a pro design cool head 19cc std domes 170 psi. i have noticed that most std aftermarket domes work up to 66.5 big bore domes are more for you 409+ big bore motors Quote Link to comment Share on other sites More sharing options...
87sheerips Posted September 5, 2004 Author Report Share Posted September 5, 2004 thanks for all the advice. I cant afford a cool head right now, so my head is getting cut to the right dimentions. I could run another base gasket, but im guna do it right, considering i cant afford anything else. Quote Link to comment Share on other sites More sharing options...
87sheerips Posted September 8, 2004 Author Report Share Posted September 8, 2004 anyone else that knows whats goin on here?? i couldnt understand the reply about running another base gasket. Quote Link to comment Share on other sites More sharing options...
itsaripper Posted September 9, 2004 Report Share Posted September 9, 2004 Running another base gasket will raise the head away from the top of the piston. It will also lower the compresson so maybe you will have to go to a smaller dome size to make up for the loss. If you are useing the stock head you should be able to buy a thicker head gasket too. Duneslinger I also have a choozen head, and was told by a mechanic who put one on a 66 mm banshee, that it leaked water. So for my 66.25 jugs I would need a stock head or pro design with big bore domes. You haven't had any trouble? Quote Link to comment Share on other sites More sharing options...
duneslinger Posted September 10, 2004 Report Share Posted September 10, 2004 i've had a small leak on the left cylinder external from a stud that pulled threads when intalled,repaired threads and that was almost a year ago. this bike has 66.5 pistons with 21cc domes dune port work and pumps approx 175 psi. i really like chozen's three piece{counting domes} head design also cool flames Quote Link to comment Share on other sites More sharing options...
87sheerips Posted September 12, 2004 Author Report Share Posted September 12, 2004 well, my head just got back. its now milled to 66.5 for my 100 over jugs. do u think I will notice more performance now that my squish area is correct. or maybe more compression?? Quote Link to comment Share on other sites More sharing options...
pimpeinkc Posted September 14, 2004 Report Share Posted September 14, 2004 if your bore gets above 65 you should look at getting big bore domes, and if you have a stock head, you will have to have it machined. an after market head is the way to go, keep an eye on ebay, i see them going for around 150 all the time. and the domes are around 60bucks. all my friends have after market heads. i think the noss for the money is the best. i have a cool head and the water chamber on the noss looks like it has a lot more flow. and the domes are all interchangable. 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.