big valve heads on seibenrockr80/1000cc conversion, will they work?

pack · 01-16-2007, 09:31 AM

a good question was raised in a previous posting, will RS 44mm/42mm heads work in conjunction with my recently installed seibenrock 1000cc-r80rt conversion? any mods i need to do first or is it just bolt on and go?
Thanks, Pack

Bernd Bauer · 01-16-2007, 11:09 AM

Quote:

Originally Posted by pack

a good question was raised in a previous posting, will RS 44mm/42mm heads work in conjunction with my recently installed seibenrock 1000cc-r80rt conversion?

It is just bolt on. (If the other parts are stock, read no hot camshafts etc.)

Regards

Bernd

R-dubb · 01-16-2007, 01:03 PM

Agreed.

You can use the Siebenrock asymmetrical cam, but can not use the BMW 336 without substantially modifying the heads. I would not use big heads unless you are also putting on big carbs.

Expect a somewhat fussier idle, a slight mid-range flat spot and stronger top-end. Throttle response with the big valves may not be as snappy but should pull harder overall if the intake and exhaust are opened up to match.

pack · 01-16-2007, 02:01 PM

carb and exhaust changes will coincide with the head swap........then camshaft. just want to see what the old girl has to give.

01-16-2007, 09:31 AM	#1
pack ^OP Banned Joined: Oct 2006 Location: OFallon, Mo. Oddometer: 225	big valve heads on seibenrockr80/1000cc conversion, will they work? a good question was raised in a previous posting, will RS 44mm/42mm heads work in conjunction with my recently installed seibenrock 1000cc-r80rt conversion? any mods i need to do first or is it just bolt on and go? Thanks, Pack

01-16-2007, 01:03 PM	#3
R-dubb Dubbious Adventurer Joined: Aug 2001 Location: San Francisco Oddometer: 4,695	Agreed. You can use the Siebenrock asymmetrical cam, but can not use the BMW 336 without substantially modifying the heads. I would not use big heads unless you are also putting on big carbs. Expect a somewhat fussier idle, a slight mid-range flat spot and stronger top-end. Throttle response with the big valves may not be as snappy but should pull harder overall if the intake and exhaust are opened up to match. __________________ MINIMOUNT Hard Shell Netbook Case & Mounts

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01-16-2007, 02:01 PM	#4
pack ^OP Banned Joined: Oct 2006 Location: OFallon, Mo. Oddometer: 225	carb and exhaust changes will coincide with the head swap........then camshaft. just want to see what the old girl has to give.