1043cc engine kits 97mm - Page 2

chasbmw · 07-16-2012, 03:13 AM

I have taken some rough and ready measurements of the outside of the cylinder of my R90/6 and of the 1070 bike.

R90/6. Is 118.6 mm

1070. Is. 122.4 mm

These are rough and ready measurements just measuring the diameter of the cylinder between the fins.

mattcfish · 07-16-2012, 01:06 PM

Quote:

Originally Posted by chasbmw

Back in the old days if you wanted a larger than stock engine, you had to take a BMW steel lined cylinder and bore it out, im not sure if special liners were fitted, but in any event the liner would be thinner than standard as the operation was constrianed by the size of the existing BMW cylinders, these were often fitted with venolia pistons. These are the setups that according to SS have developed corrugation.
Nowadays we have the luxury of the kits coming out of Germany mainly sold under the brand name Seibenrock which feature new aluminum cylinders faced with nikilsil and no steel liners.

Yeah, the Seibenrock barrels are cast in Italy if I remember correctly.
I thought the pistons were Wossner not Mahle though.

Airhead Wrangler · 07-16-2012, 01:26 PM

Quote:

Originally Posted by mattcfish

Yeah, the Seibenrock barrels are cast in Italy

Gilardoni? At some point didn't they cast OEM BMW barrels? Didn't Mahle at some point also?

chasbmw · 07-16-2012, 02:07 PM

I don't know who makes the pistons for the 1070 kits, the modern lightweight pistons I fitted to my R90/6 were made. Y wossner.
Charles

RGregor · 07-16-2012, 03:10 PM

Quote:

Originally Posted by chasbmw

I don't know who makes the pistons for the 1070 kits, the modern lightweight pistons I fitted to my R90/6 were made. Y wossner.
Charles

The first (small) series 1070cc kits came from Gilardoni. They also had other conrods then and a slightly different piston shape.
Now (at least for the last three years) pistons and barrels come from Mahle.

bernardofeio · 07-16-2012, 04:09 PM

hello

what is the weight of the original bmw r100 pistons? "Mahle sport kit standard" have 604g that seems to me a bit heavy. Moorespeed 12,5:1 are 415g

97mm, 10,5:1 compression and some light pistons would be near to perfect!

one more question. these 1043cc kitks need altering the heads of are they prepared to be used without this mod?

07-16-2012, 03:13 AM	#16
chasbmw Beastly Adventurer Joined: Feb 2006 Location: Bath Uk Oddometer: 1,009	I have taken some rough and ready measurements of the outside of the cylinder of my R90/6 and of the 1070 bike. R90/6. Is 118.6 mm 1070. Is. 122.4 mm These are rough and ready measurements just measuring the diameter of the cylinder between the fins. __________________ Charles http://i46.photobucket.com/albums/f1...ps6e61ae2e.jpg R90s 1070 replica, R90/6 1971 Commando Fastback

07-16-2012, 02:07 PM	#19
chasbmw Beastly Adventurer Joined: Feb 2006 Location: Bath Uk Oddometer: 1,009	I don't know who makes the pistons for the 1070 kits, the modern lightweight pistons I fitted to my R90/6 were made. Y wossner. Charles __________________ Charles http://i46.photobucket.com/albums/f1...ps6e61ae2e.jpg R90s 1070 replica, R90/6 1971 Commando Fastback

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07-16-2012, 04:09 PM	#21
bernardofeio ^OP Bernardo Feio Joined: Feb 2011 Location: Portugal Oddometer: 17	hello what is the weight of the original bmw r100 pistons? "Mahle sport kit standard" have 604g that seems to me a bit heavy. Moorespeed 12,5:1 are 415g 97mm, 10,5:1 compression and some light pistons would be near to perfect! one more question. these 1043cc kitks need altering the heads of are they prepared to be used without this mod?