dlnoss

Wiseco can provide you with the piston crown geometry, it may even be somewhere on their web site. TSR software is very helpful in designing combustion chambers if you or a friend has a copy. If not it is reasonably priced. -David

I was talking about trying leaving off the stud orings and using stat-o-seals under the nuts. My Super Cub heads don't use any stud orings, only copper washers and acorn nuts, and there haven't been any problem with them. I don't have any of my prototypes. And I do appreciate your support. I just hate that it didn't work for you.

I've made a few prototype one-piece shells but have never been happy with them. A one-piece design is actually easier and less expensive to manufacture but I have to like it before I can sell it. I do have some ideas for a new design but haven't had time to prototype it. A one-piece head is not immune to the issue of coolant leaking past the studs. The nut and washer is still the barrier to that. I guess you had some sealing problems with one of my heads and would have liked to help resolve the problem. I haven't had any other unresolved problems (that I know of). I've also thought about not even using the stud orings and using Parker stat-o-seals in place of the copper washers. If someone wants to try it, let me know. Hope it works well for you. -David

dajogejr, They are making domes now? They, or someone from there, called a while back asking me to make domes for them. :laugh:

Those orings go over the stud between the two main head pieces. You can see the recesses in the base plate where the orings fit. Call if you have any questions during the installation. -David

Check if the throttle cables are in a bind from working around them.

Guessing MD is close to sea level, running premium pump gas with advanced timing, I'd say 21cc domes. Give me a call if you want and we can discuss all the variables, even if you are looking at other heads. -David

Wow csrmel, I must have gotton ripped off back when I had to buy head gaskets,,,,I paid more than $4 for them. And not to be pissy but a stock head can't be cut to 'match' good domes. You can mill them to raise compression but not to have the same chamber characteristics with proper spark plug height. I don't want to start anything but just want information to be accurate. -David

Stroker domes (or any custom domes) are $75 minus the 10% BHQ discount making them $67.50 + shipping. I make them from scratch instead of modifying stock stroke domes. My opinion is that they work out better that way. -David

If you don't do the trade and/or need stroker domes made, give me a call. -David

If you need to get more of the washers with the oring in them, they are called Parker Stat-O-Seals. Seal companies usually have them or can get them. 5/16" or 8mm sizes will work.

If Kevin is doing your porting, he could best recommend domes. He is a Noss dealer and a really nice (and smart) guy. -David

I will be sending another set tomorrow (if the ice storms don't stop UPS). That is pretty high for those domes. -David

Those domes shipped out today. Let me know where the squish clearance and compression come in.

Yes, check to be sure they are tight. If so and it still leaks, remove the bolts and put RTV or gasket sealer on the threads then put it back on. If you do the bolts one at a time, with the other bolt tight to hold the fitting in place, it will be much easier. Call me if that doesn't fix it. -David

I have a few Super Cub heads left if that's the cylinders you have.

25cc is a fairly high compression dome for a Super Cub, more so a 10mm with advanced timing. That is going to vary, of course, with the porting and stuff. I've made quite a few SC domes and most of them are 25cc to 28cc. My guess is that your compression is 220 to 240 but I don't know how it's ported.

I agree with these guys. You probably have something causing the plug to back out. Your mods aren't listed but try mixing up some race gas and see if it still happens. The plugs backing out might be saving you from trashing the engine because of detonation.

I'd use the high-temp Permatex stuff from the auto parts store. It's not really a high-temp application but it makes me feel better...

I think it's easier to hear for someone about 20 feet away. I've heard it on Banshees running short track races and the riders didn't hear it. It could have been due to their adrenaline level also....

If the cylinders have been bored or the studs have been removed for some other reason, they may not have threaded back down in the cylinders all the way. Otherwise, it may be a longer stud from the factory. I don't know how tight the tolerance is on factory studs. Try putting some silicone on the threads of the leaking stud. It should seal even with the stock nut. Give me a call if you need another acorn nut or some copper washers to stack on that one stud. -David

Actually, K&S Racing in Kuwait carries Noss heads if it's very easy to get stuff from there. They should have some in stock. We also ship to Dubai, but shipping isn't real cheap, $40.00 to $55.00 depending on how quick you want to get it. -David

That's kind of the response I was thinking when I first saw the topic.

zach45, I didn't know you were an HQ member. Did you tell my wife you were? robert.b.west, You are probably okay if your timing isn't advanced but check your compression to be sure. Like Bansh-eman said, a little extra octane is cheap insurance if in doubt. You can call to order or order on the web site. If you order on the web site, enter BHQ as the coupon code during checkout for the member discount. -David

Can I vote? :cool: