Cheap upgrade ?

[flytoolow]

Hi All, Hope you're keeping well through all this.

After looking through eBay.de for high front mudguards for a R80GSPD I noticed the barrel & Piston set for an R100GS and CS for sale at about 450Euros.

Given that a Siebenrock 1000cc upgrade is about twice that ( 900 quidish) would this make a cheap power upgrade with a set of new piston rings and stuff ?

Just wondering and trying to save the pennies...

Cheers

F2L

 

[mikeyboy]

Won’t be a cheap upgrade if the pistons are worn or the bores need replating,just sayin like

 

[rossi]

The Siebenrock kit pistons are designed to work with the 800 heads. Ideally you would also want to fit 1000 heads or have the 800 heads machined to match the 1000 pistons.

 

[mikeyboy]

The Siebenrock kit pistons are designed to work with the 800 heads. Ideally you would also want to fit 1000 heads or have the 800 heads machined to match the 1000 pistons.

The siebenrock 800 to 1000 kit simply has a step machined into the piston crown ,to provide clearance for the piston with the smaller 800 combustion chamber.
Not an ideal engineering solution really,
A far better solution is to use the proper 1000cc piston or upgrade kit and get the squish clearance machined correctly to match the piston.

 

[Sylvester]

The Siebenrock kit pistons are designed to work with the 800 heads. Ideally you would also want to fit 1000 heads or have the 800 heads machined to match the 1000 pistons.

Been there, had the heads/ pistons machined to match. I’ve had both 80s and 100s and the Siebenrock Kit as it came was half way between the two I felt. I bunged a midrange cam in when the time chain was replaced which made a difference as I don’t wring it’s neck anyway so didn’t miss the top end operation. Still running the 80 carbs though, can’t be arsed to change. Runs nice now. Not sure I’d pay top wack though. I bought mine from a guy that changed back to standard when he sold his bike.

 

[flytoolow]

Thanks all for the knowledge,

What Im reading here is that it is not just a case of a simple swap. Either I get the barrels, pistons and heads, or I do some machining, or I just go with the Siebenrock Kit?

Given my non-existent machining knowledge my best option is the Siebenrock kit - Less hassle, minimal room for errors.

Again, Thanks for sharing your knowledge.

Cheers

F2L

 

[rossi]

If you are looking for a cheap upgrade have you though about a set of pulse-jet spark plugs from Steve Scriminger?

www.pulse-jetignition.co.uk.

Just put a set in today and they definitely made an improvement. They're worthy of their own thread which I am about to start.

I also have another cheap upgrade in the pipeline. I'll let you know how it goes once I complete it.

 

[DrFarkoff]

Given my non-existent machining knowledge my best option is the Siebenrock kit - Less hassle, minimal room for errors

The Seibenrock kit works well I have fitted about 6 in my time and its pretty much plug and play Big improvement in Torque and rideability and MPG

If I recall the whole 1000cc Piston assembly for the Seibenrock is 6 grammes lighter than the whole 800 piston assembly PLUS it has those sexy Teflon coated Skirts

More expensive but will work well I tend to pull the big ends and conrods and balance the conrods as close as possible I think BMW spec is within 6 grammes

6 grammes difference at 3000rpm is interesting enough

Iusually fire in new shells and big end bolts with a dollop of graphogen on the bearings

Enjoy

They used to do 3 kits If I recall the top one had all the gaskets and Stainless pushrod tubes etc etc