430/500 base gaskets

I was down to my last new 430 base gasket, and noticed that it was stamped with the Cometic name. So I called them. They were super helpful and said they still make that gasket... in MANY thicknesses!! They guy listed off at least a dozen thicknesses. I ordered .020, .031, .039" to get started.

The Cometic part number is B0299(thickness in thou)F, so a .031" gasket has the part number B0299031F.
Price was $7.20 plus shipping. Quality is excellent. If you call them they'll tell you what thicknesses are available.

This gasket fits the air cooled 81-up 430, and 82-up 250/430/500.

Now we can set our squish distance wherever we want, and these old motors need that badly. Factory deck height was all over the map and it affects the way they run. Get it right and they clean up nicely.

Good news, eh?

Nice find!

Thanks

with my sqish at .090-.100 on both my cylinders this is a God send!

Dave you are the man.
Did you find out what all they have as far as thicknesses so i can machine my base to the mean of what they have to offer.
beers are on me.

You know, I wrote it down as we talked and now guess what? Yup, can't find it. But I remember this:

Thinnest we talked about was .011", and he said he could go thinner.
Then there was .020, .031, .039, .047 (stock), and thicker stuff I didn't pay attention to. There might have been a .015 as well. Ask for Chris


Chris Workman
Technical Sales
Cometic Gasket
8090 Auburn Road
Concord, OH 44077
Phone: 440-354-0777 Ext. 133
Fax: 440-354-0350

Nice, so that is like .010 increments.

So what is the optimum sqiuish?

I will machine off some material from the base of my cylinder to get me down to around.040
so i can adjust my squish height from there.
Good job on the gasket find!

Just watch the compression ratio as it gets higher you'll have to run race gas

I love the smell of VP in the morning, and Blenzall

I'm glad to see you guys are "into" this like I am.
About that "optimum squish" question: I don't think there is an "optimum" for a couple reasons.

1. It's a tuning element. Different settings do different things. Just like timing or main jets or tires.

2. I've seen a couple different 430 heads, and that has to work with the squish distance to affect the squish velocity, which is a large part of what squish is all about. It also affects the compression ratio as lefty suggests. And the different cylinders have different porting, and so on. Husky either did a poor job with quality control, or they tried lots of different combo's, because the motors were all over the map. Two stock 430's did not run the same.

So what do you do? I don't know!! But here's what I do...

I've been pretty happy with stock 430's once they're normalized to about .045-.055" squish. I've gone tighter but it seems to be for vanishing returns so that's what I target now. It seems the bikes have better detonation resistance in this range than either tighter (maybe due to too much compression) or looser (probably due to poor flame and heat control).

Anyway, I won't claim to be an expert but this is my experience. Hope it helps! Enjoy those 430's.

Picklito's right, HVA tried a lot of changes on the fly and QC was poor. I have 2 430 heads, each are different! One has a "band" cast in while the other doesn't so measuring squish is very important.