Boxerworks.com

Thinking about this for my 90S and wondering if anyone has installed and any feed back.

High quality pistons for R90/6 and R90S produced with recent technical expertise.
MADE IN GERMANY!
Forged piston Modern threepart oilring for less oil consumption
Less weight improved the balancing and realise a smoother engine running
516 gram than original 712 gram
Reduction in weight of over 190 gr per piston
3. oversize in 91.50mm (part number 112952) available, one more than BMW!
Excellent cost/performance ratio.
With immediate effect, the new piston will be available in the sizes 90.50mm, 91.00mm and
91.50mm.

My main question, which oversize? Don't think, but not sure if my engine's been bored
so order the first oversize? Or...?

Thanks for any thoughts,

pSquared

that question could be answered with your ownership if the motor was used only by you but as you asked I think you have many many owers behind you

a 1970 to 1990 could have been rebuilt a few times especally the early ones

the comany does make or sell quality parts

and getting those parts in the USA a long time

BUT the best idea is plan and take it apart and buy what you need if you find your cylinders are over bored the Company does sell kits that fit all airheads

I am using these pistons in my R90/6, they are fairly high compression 9.5, and so are run in a dual plugged engine. The engine works well, it has been balanced so is smoother than stock.

You will need to get the cylinders measured to see if they have already been bored. You will also need to find someone who knows what they are doing to bore the cylinders.

This is the German Company I bought my Seibenrock 1000cc powerkit from, very high quality
components, the kit costing $AU 1,008.

I considered buying this kit for my small spiget 1975 R90/6. I opted for the 1000cc kit with Nikasil barrels.
Very nice, barrels already match, everything is lighter, cools better, fits my block, fits my heads and lasts longer.
If your barrels aren't perfect, boring them properly isn't cheap. The 1000cc kit will be much less hassle and not much more expensive.