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Higher compression head, no? Too much so, maybe? Has anyone tried it?

Also, can a 200 head be squish-moded by Ron to be used on a 220?

Anyone know?

The 200 head fits a 200 piston. The 220 piston will smack the 200 head. Ron could, most likely, mill a 200 head to a 220.

You may be right, but I wonder if anyone has actually checked it out. The bore difference is miniscule, and a 220 head gasket above the piston would provide some clearance for that outer diameter difference as the piston does not protrude above the bore at the edges...so there might not be contact...a bit of putty and a slow rotation could tell the tale I guess. Anyone want to loan me their bike so I can try it?

I used to own both a 200 and a 220 at the same time, and the pistons looked identical unless you measured them - kinda makes you think the occasional 220 piston breaking is somewhat more related to power characteristics and heat rather than piston quality, as some others have surmised.

The reason I ask part one is just curiosity, I mean, the increased compression may be interesting, power-wise; the reason for part two is the greater availability of used 200 heads that could be sent to Ron as an option to also keeping the stock 220 head (which I would like to do).

Another question; are the 220 and 200 head gaskets the same thickness? Anyone know?

Just send the 220 head to Ron

tim wrote:Just send the 220 head to Ron

Oh heck, where's the fun in that? LOL
But that's probably what I will do....

Maybe this should be moved to the RB section. I'm sure Ron would be the best person to ask..

That's interesting....I thought the only difference was the bore. Is the 220 a stroker?

It's only the bore.
But, he's suggesting putting the 200 head onto a 220 barrel. The domed piston is going to hit on the edges. Or so I would think. Well, actually I know. I inadvertently bid and won an eBay auction for a 200 head gasket and stuck it on my 220. The piston hit that gasket! If the gasket would have been backed up with the extra metal on a 200 head, I don't think it would have gone past TDC. Luckily I discovered it as I was kicking the bike and before it started. I guess I have a guardian angel.

My thought is that the 200 head could be slightly modified to work with some light machining...as well as a 220 head for Ron's squish mod purposes for a 220 machine. The 200 heads are more readily available.

The 220 and 200 have different compression ratios but that may be due to the porting differences, the combustion chamber differences, or a combination of both combustion chamber volumes and porting - I dunno. Mebbe if I can get a 200 head cheapo I'll do some sleuthing rather than speculate like a ninny.

OK,

Sorry that I have not chimed in sooner on this topic, but I have been down and out with the flu all week (needless to say that I am behind on my work)

A stock 200 head has a head volume of about 19 cc's

A stock 220 head has a head volume of about 24 cc's

A 200 has a 66 mm bore.

A 220 has a 69 mm bore.

As you can see, there is a 3 mm (almost 1/8") difference in bore sizes. You can also see that there is a large difference in head volumes. There is also a difference in port timings between the two.

There is more to a head mod than just bumping up compression. It has more to do with the configuration of the squish area and the combustion chamber volume.

Lets say you could put a 200 head on a 220 without crashing the piston into the head, you would be bumping the static compression over 50 Lbs.

Now did you say race gas and special blends and what are we doing about the detonation features that are now a problem without a proper squish configuration?

YES, I can modify a 200 head to work on the 220, it would be expensive $80.00 to $90.00 to re-cut and re-shape the 200 head and get the head volume right and still run pump gas. Oh and one more thing, a spacer maybe required under the spark plug as the bowl area that needs to be removed to get the proper volume, would have the spark plug threads sticking through into the combustion chamber.

Ron

Ron,
Thanks for clearing that up. Sorry 'bout the flu! Hope you feel better soon...
Sounds like a modded 200 head would be a last choice scenario after all.
If luck is with us, I'll be sending some work your way this spring.

Tom from Hollister