Any experience with the Siebenrock 1000cc kit on a G/S?
 

Hi,

Has anyone out there tried the Siebenrock 1000cc upgrade kit on a R80 G/S? If so, what do you think now? Did you/Do you need to add an oil cooler with that modification?

Thanks,

David

Do a search on "Siebenrock" - this has come up before, with a number of thoughts on the whole process.

Oil cooler is a wise option. BMW put it on the R100Gs (in a stupid place) for a reason...

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Grant Johnson

Seek, and ye shall find.
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One world, Two wheels.
www.HorizonsUnlimited.com

Here is the link to the main discussion that I recall....

http://www.horizonsunlimited.com/ubb...ML/000504.html

I did the conversion that Timos link refers to, but I also ported the tops and changed the cam (296 °).
After the rebuild I have used the bike for 8500 kms and it runs great!

Someday I will take a dyno-test and get it properly adjusted and then I will get back with the results.
When it comes to oil-cooler I will wait and see, I have a thermometer on the bike and haven’t had to high temperatures problems this summer.

Hi Ali Baba,

That was a great discussion that Timo referred me to. However, I am not clear about which course of action you decided to take. Are you saying that you added the Siebenrock kit? If so, what has become of the compression issue with lower octane fuel? Have you had a chance to try it with low octane fuel? I am taking this issue seriously as this would be an around the world bike that I am making.

Thanks,
David

Personal opinion / question only fwiw etc:

First are you two or solo?

EITHER way, I'd keep it stock. Simple, inexpensive, reliable, plenty of power, great gas mileage, simple, inexpensive, did I say reliable?

If two up and you're riding in Europe, Australia North America then I'd consider the Siebenrock kit, otherwise it's overkill.

kiss principle...

------------------
Grant Johnson

Seek, and ye shall find.
------------------------

One world, Two wheels.
www.HorizonsUnlimited.com

Yes I have added the Siebenrock-kit (and a different cam and ported the tops).

The bike is running great and personally I don’t think it is overkill. I have also used bikes with the Siebenrock-kit and stock cam and top, and to be honest that was not was I was looking for. It gives you lots of power, but on higher RPM. It boils down to what you are looking for. I like power on low RPM, speed is not that important (as long as I can get 150 km/h).

I also have a standard R80GS and with a friend we drove side by side in 50 km/h. The standard GS was in fourth gear and the modified in fifth, we then gave max throttle and the standard GS disappeared quickly – in the mirror.

The main reason I changed the cylinders was because my pistons had worn out and I had broken some of the cooling-fins on the cylinders. The Siebenrock parts are cheaper then the BMW-parts (you even have to struggle to find used parts in good condition which is cheaper then Siebenrock).

How it works on low octane petrol is hard to say, I have read both good and bad reports. It might be smart to use a low-comp 1040-kit, but that costs…

The fuel consumption improved a bit even if I run the bike a bit rich and my ridingstyle got “worse”.

Good luck!

by the way, why siebenrock and not wunderlich or wudo or touratech or ... kit ?
they are all +/- same same maybe even coming from the same factory.
is one of those kits better ?

for a long trip, i d rather improve the oil cooling system, the brakes, the forks, the suspension than the engine, personnally.

and the gearbox (how ? i don t know!)of course, which is the "disease" of those old bmw gs



[This message has been edited by vincent danna (edited 28 June 2005).]

There are several kits; most of them have some kind of Mahle-pistons and Nicasil-coated cylinders. Most of the 1000ccm is Siebenrock.

You can get more or less what you want (up to 1070ccm, different compression ++). In the end I found Siebenrock kit is cheaper and easiest to install (no modifications of the head, engine block, carbs..)

When it comes to cooling I wouldn’t necessary say that an oil-cooler is a must. It depends on the use of the bike. Up here a lot of people have removed oil-coolers and covered radiators on various bikes to INCREASE engine-life. My bike has 180kkm on the clock (including crossing Sahara in summertime) without an oil-cooler. Maybe I will fit a cooler – with thermostat.
The cooler doesn’t work well when you need it most (at standstill, low speed or when everything is covered in mud).

Yes there is a lot of modification you can do on a G/S (or GS) but in the end it boils down to what you will achieve.

Just to revisit this...

When I contacted Sibenrock, they did not recommend running their kit with less then 94 octane, or 92 octane with a dual plug setup.

YRMV

I have "replacement kit 1000cc" from Siebenrock in my R100Gs, same consept as in those wich are meant to R80-engines.

For some reason my bike didn`t have oil cooler and I drove last season without it. I have temp measurement in oil stick and temp went at hot days to 130C and even over. I think thats a bit too much..

Last winter I added distance ring to oil pan and cooler, now oil temp stays in 95-100C degrees. And oil doesen`t get dark as soon as it used.

Antti,

Have you tried running lower Octane (<92) fuel in your bike?

I have no info on Siebienrock, what I do know is of a dealer that fitted a set of aftermarket cylinders and pistons.
When the cylinders were pulled into the crank case the base of the cylinders craked because the diameter was incorect. They were replaced, and if they were from siebenrock or not I do not know.
What I can say though is that Mahle, the German manufacturer for Porche and the like's make a 1043cc kit producing the max reliable hp possable for the air cooled boxer.
You can get this from HPN at www.hpn.de, they also supply oil coolers, cams and lots of other nice goodies to upgrade your motor.

This one is for Vincent Danna.
I want to differ with you on the reliability of the gearbox.
The proplem with most boxes is that they are being abused, not serviced and water find their way into them and on top of that BMW decided in 1982 to omit a small but very crucial circlip that causes most of the destroyed boxes.
I think I should start a new topic to discuss this in beter detail, there is lots of solutions for these problems.

If you use the 1043ccm or 1070ccm kit you have to modify the block..