Iam putting together a big cat triple and want it to run on race fuel.
Lots of compression and timing.
I need to know how important the chamber shape is. I will be taking 0.100" off for starters then cutting the squish area for 0.050" piston to head clearance.
The area of concern is the bowl area by the spark plug it just will not be the same shape as my other engine with race inserts. These will be alot deeper but also alot smaller around then the race inserts. Is this going to be ok? Will this create a hot spot? Or is it just mainly the cc's that count? Maybe I should weld the chamber first then retap the plug hole and just copy a race insert head?

Thanks

Get a hold of Augie in Maple Grove, MN. Do a search, he is on HCS. He bought a head from me about 2 months ago to do cutting on for exactly what you are talking about. He seemed top know a lot about combustion chamber shaping. He has been running big Cat motors a long time.

[quote name='zr900dude' date='Feb 5 2008, 10:32 PM' post='3611003']
Iam putting together a big cat triple and want it to run on race fuel.
Lots of compression and timing.
I need to know how important the chamber shape is. I will be taking 0.100" off for starters then cutting the squish area for 0.050" piston to head clearance.
The area of concern is the bowl area by the spark plug it just will not be the same shape as my other engine with race inserts. These will be alot deeper but also alot smaller around then the race inserts. Is this going to be ok? Will this create a hot spot? Or is it just mainly the cc's that count? Maybe I should weld the chamber first then retap the plug hole and just copy a race insert head?

Thanks

Hello,
If you are going to get your squish real tight, probaby want to get the domes reshaped. I have had work done by Bikeman and Dakota Sports for T-Cats, and I was very saticfied with the work and the cost with both. I used Dakota more than once, but heard a rumor later that they were just sending the heads to Bikeman anyway.
Good luck!

Actually I will be cutting the heads myself...I will not be sending them out to be done.
Thanks for the replies...I kind of figured this would be a top secret area. I'll figure it out (trial&error)!