More Compression

Reply Subscribe

Thread Tools

Search this Thread

Dec 4, 2007 | 08:41 AM

btmoye

Thread Starter

Stage I

Joined: Dec 2007

Posts: 1

Likes: 0

More Compression

I have a 2006 883C. Stock compression ratio is 8.9 to 1. I want to bump that up to somewhere between 9.5 and 10 to 1, but there are no higher compression pistons available for an 883 that I have been able to find. There are several for a 1200. The problem is I do not want to punch the engine up to a 1200. I want to leave it an 883. Does anyone know of a manufacturer that makes a 9.5 or 10 to 1 piston for an 883? If not, is it possible to mill the head enough to reach the desired compression, and if so, how much does it need to be milled?

I changed the primary gear over to the world gear ratio lastwinter to help lower the revs on the highway since that is where I spend most of my time, and it has worked out well. The only noticable flaw with the gear change is that on long steep climbs in the mountains I can not alwaysmaintain highway speedall the way up if I am riding into a stiff headwind (OK, maybe I'm going a little over the posted speed limit). I'll lose about 5 mph before I get all the way up.I need just alittle more oomph to fix it.

Thanks

Dec 4, 2007 | 08:50 AM

Kingofcubes

Road Master

Joined: May 2007

Posts: 851

Likes: 5

From: Mitchellville, Ia.

RE: More Compression

Yes you can shave the heads and cylinders to up the compression and tighten up the quench, can not tell you the shave factor for that combustion chamber so will have to be done the shave and check and shave way. Probably -.040" would be about a point of compression. I would set the quench at .030" to. 035" which in itself will give you 3-4 foot pounds of torque and help it to not ping with the higher compression.