dlnoss

Fatties aren't bad pipes for low/mid. I'm not just saying this because I makes heads and domes but, like was said earlier, a head with domes that would get your compression around 155 - 165 would help a lot. If you have the stock air filter setup, upgrading that would complement the pipes, reeds, and head. These things would be fairly inexpensive and would provide an improvement that you would definitely feel. -David

The one on the left looks like it may have been intended for alcohol with the wide area. That wouldn't change the compression. If you are running gas, I'd probably use the one on the right, I know that's not what you are asking. -David

The oring sizes are: 2-011 2-026 2-039 Viton 2-046 The largest one isn't a standard size. I have them custom molded. I buy all of these in quantities of 1,000 to 10,000 to try to get good enough prices to make a little profit on them. -David

If you are riding at that elevation or higher, you should be fine with 20cc domes running premium pump gas. If you go to Little Sahara, I'm pretty sure it's a couple hundred feet higher. The exception would be if you advanced your timing very much. The 20cc domes should raise the compression by 20 to 25 psi and you should feel a noticeable increase in power. You shouldn't need to re-jet but I would do some plug chops to be sure. -David

The solder should get thicker further away from the cylinder wall because the squish angle is slightly more than the angle (it's not really an angle) of the piston crown. I does seem you are detonating. -David

Brad, It really would be best to talk to Jeff. He would know best what domes would be best with his porting. I would need to know deck height (probably around 0.070" to 0.075"), and piston style (probably Banshee style). I would guess a 19cc or 20cc stroker dome would get you close to 170 but it's a guess without knowing the port specs or at least what size the other domes were and the compression they yielded. -David

Do your domes have numbers engraved on them? If so, and if I made them, I can tell you if they were special alky domes or not. -David

I'd be glad to cc the domes if you want. If you check them, put a spark plug in them fill them with a fluid with low surface tension. I use rubbing alcohol.

I'm certainly 'good enough' to stand behind my products. What was your compression before the 19cc domes. What size domes were they and who made them? How much, if any, were the ports raised when the porting was done? Did the compression gauge thread in as far as a spark plug does?

Black Anodized Noss Heads I haven't had these in a while since my previous plating shop went belly up. I should have some available late next week. There have been a lot of requests. Check with me or one of the dealers if you want one. -David

There were no signs of detonation or running lean?

You can give me a call and I'll talk to you about dome selection. -David

Are you going to mount the 50 gallon tank on your Banshee? :biggrin:

That is certainly odd looking, at least the way it looks to me from the photos. Is it a stock head that has been modified to accept domes?

If the squish clearance wasn't checked during assembly, check it. If there is too much clearance it can hurt the low rpm throttle response. -David

Definitely not a Noss head. There are similarities to the Mod Quad but it's not like their current design. -David

What timing plate are you using?

Is it possible the timing plate, key, dyna isn't working or calibrated correctly? I would set it back to stock and try it. Maybe the +5 is really +10. Just a thought... -David

This is the first I've heard of Fireball Banshee heads. There's been a bunch of Banshee heads come and go over the years. I don't know if their head uses a proprietary dome size or something standard. If you will be running pump gas, the 20cc may be too small. -David

Probably 175 to 185

Guessing you aren't much above sea level, I'd say 19cc domes. That's usually my recommendation for a stock crank at or around sea level. The difference you will notice between 19cc and 18cc wouldn't be worth the increased risk,,,,,,to me anyway. -David

2003LimitedBanshee has the spacers in stock, made of 7075 PM him -David

The stock head was designed to be very forgiving on the type and quality of gas. Yamaha couldn't really sell a product that would detonate and grenade on regular pump gas in a 'stock' configuration. These were sold in countries where the fuel quality is even less than it is in the U.S. (I know it't hard to believe fuel quality is worse anywhere else) Anyway,,,,I design my domes to provide a performance increase even if the compression remains the same. Not 5 horsepower on the same compression,,,,I wish,,,but a better powerband that you can feel. -David

I think you are mistaken,,,,Actually, I'm sure of it. -David

Don't get me wrong,,,,I'll help you figure out the best domes but builders usually know best what works with their porting. -David