dlnoss

I' also in Oklahoma. If you run good fresh 93 octane, your timing isn't advanced, and you are riding at 1500' (plus or minus a couple hundred), 20cc domes will be okay. If there is doubt about any of the above, I'd say 21cc domes.

I thought I had emailed the instructions to you early in July when I got your PM. Sorry. Here are the instructions I send with the head. Call if you have questions. Stock Stud Banshee Head Installation Thank you for purchasing the Noss Performance Head. You will see a dramatic drop in engine temperatures after installing this head. Performance gains will also be substantial and will vary based on the size domes selected. 1. Remove fuel tank and associated plastic. 2. Drain coolant. Remove plugs in sides of cylinders to be sure coolant is drained low enough so as not to run into cylinders when head is removed. 3. Remove hoses from stock head. 4. Remove nuts from head studs. 5. Remove stock head. 6. Place rags down in cylinders to prevent dirt and hardware from falling down into cylinder. 7. Clean top of cylinders using a razor blade, scotchbrite, or fine sandpaper. 8. Using grease to hold them in place, install the orings into the domes and into the grooves of the head that go against the cylinders. 9. Remove the rags from the cylinders then lay the domes down on cylinders making sure the notches are positioned towards the front of the cylinder. 10. Slide (don

You won't use a head gasket with the new head, only the orings. Is there just carbon peeling off? Can you get a picture of what you're talking about?

I don't do that mod. It might be something simple like the clutch needs adjusting. If it isn't disengaging all the way, neutral is harder to find.

What web site was it where you read that review? I'd like to read it.

I'm trying to remember the differences between the RZ and the Banshee heads. The thermostat and coolant inlet/outlet....I think I remember the water jackets being different. What are the differences?

It's difficult to modify a regular dome into a stroker dome. The reason is that if you cut .078" to .080 out of an existing dome, the remaining TDC volume is reduced by about 6cc's. You can't raise the bowl portion enough to regain the 6cc's back without the spark plug protruding down into the bowl quite a bit which isn't real cool. You can also regain some dome volume by narrowing the squish area but that changes the power characteristics. I'm not just trying to sell a set of domes. Cameron and other builders also sell stroker domes. They are usually just better if they are designed as stroker domes instead of modified to work. Just my opinion.... :shrug:

I make a lot of domes for the 795 kits. Cutting the total step .114" (adding 2mm) is usually a safe way to go but can give you too much squish clearance robbing you of low rpm power. Getting a deck height measurement after assembling everything except the head will let you get the domes exactly right. I've had many of them end up with .010" to .015" less than a true 2mm deck height. I think the kits come with two head gaskets and a top spacer plate so you can use your stock head if you want.

A lot of people get away with 18cc domes and a stock crank but some don't. I wouldn't drop the clutch with it rev'ed way up, with really good traction until the crank is welded. Run the highest octane race gas you can get if you have that Dyna cranked up. -David

I don't remember.....You are going to run race gas aren't you? Is your crank welded? -David

Yea, the PD orings are the same sizes. You might save some shipping costs if you get it all from the same place.

I have oring sets....$16.20 per set + shipping.

I worry a little about 21cc domes with advanced timing at sea level with premium pump gas. I don't really trust pump gas to be fresh and have the octane that is stated. I would run 93 octane at least or mix a little 100LL or race gas in with it to be on the safe side. With 20cc domes 50/50 should be fine.

The smoke could be a dome oring messed up. Was it white smoke smelling like coolant? Is the coolant low after running like that?

I have a few 250R heads left but no domes. Pro Design domes will work with the head.

There is quite a difference between a 4-stroke and a 2-stroke engine,,,paricularly when the 4-stroke is fuel injected and computer controlled. Some engines can survive a lot of detonation. A 70's era pickup truck can knock all it's life without necessarily damaging the engine. A Banshee engine doesn't live long when it's detonating. Some two strokes can do fine on 93 octane with and 180 psi. It depends on the timing, the RPM, the combustion chamber design, and other factors. I run 104 to 110 octane and only have 175 psi. but that's just me..

Make sure the compression tester threads into the spark plug hole the same depth as the spark plug. If not, you will get a false reading. Some of the testers only thread in 3/8" to 1/2" which displaces less volume in the combustion chamber giving false (low) readings.

Was the squish clearance checked when assembled? With the decking, 'standard' Cub dome clearance might not be right for that engine. It could effect the lower RPM power.

Also, if the system is topped off with coolant and if there some some air pockets, it can spew some coolant when it is first warmed up.

Like the other guys said, that's way too much for premium pump gas. It shouldn't make it get hot after 20 seconds but it will probably make it grenade if it's run much. I'd look at the impeller if it's getting hot real quick. It does have coolant,,,,right? Is it getting hot that quick or just spitting coolant? The advanced timing also increases the need for higher octane.

19's would need more octane. I would try to run 93 octane with the 20cc domes since your timing is advanced. If you get the 20cc domes and take a trip to lower elevations, remember to up the octane for the trip.

Sounds like the problem is elsewhere. Carb(s), tors if you still have them,,,

If you haven't removed the head yet, do a compression check first. A coolant leak to the outside doesn't mean there is a compression leak. If you have already taken the head off, see if the pistons or domes look like they have been worked over with an ice pick (detonation). If you put in the higher compression pistons you may need more octane if you don't already.

I've never seen a ModQuad head but if it is a one-piece head, the domes for the 68mm pistons probably wouldn't work because there would be no 'outside' of the oring groove. 68mm domes have the oring groove on the outside edge using the head shell or body as the outside support for the oring. The 66mm domes have the entire oring groove as part of the dome, not needing part of the head shell to be part of the oring groove. The 68mm domes work in the Noss and Pro Design heads and other heads that surround the entire circumference of the base of the dome.

Have you removed the head and seen the domes? 15cc domes would be pretty unusual. Unless the porting was pretty crazy or the Banshee came from a pretty high elevation, 15cc domes would yield too much compression for good performance and would probably trash a stock crank in a short period of time. I would check and be sure they are really 15cc domes. Larger domes would be a quicker and cheaper resolution if they are that small.