Barrel's, gaskets and ring pieces.

[Redboots]

I need some info from them that are in the know please.

On removing my head and barrels, there was no base gasket, but there was the 2 O-rings on the studs and the stringy bit that I presume passes for and O-ring on the cylinder wall protrusion.

I was sent spares that included a fairly thick base gasket and the stud O-rings.
I queried the gaskets and was told they are better and will make the motor run better/smoother and with a bit more torque at low revs.

Its a 100GS of '95 vintage and this is its first strip... as far as I'm aware.

Opinions/experiences please, before your subs expire

John

 

[Rob Farmer]

The gasket will reduce compression slightly. I presume this is where the "smoother/more torque" comment comes from.

Motobins sell this. BMW specified silicone goo to do the same job

 

[Kenny]

I'd stick with the original O rings and if prefered BWM 'goo' ( just a smidge mind ) especially if not originally leaking
Plenty of beemers still out there on original parts without any trouble...just glad I got that answer in before me subs expired

 

[Beemerboff]

There are some folks who reckon the purpose of the hard setting goo is to stop the barrels from moving around as much as a sealant.

Not certain how a lower compression ratio alone can make more power anywhere in the rev range, unless you make major changes to the rest of the bike, or your engine is pinking slightly without you noticing it.

FWIW when I bored my R75/7 out to 900cc I also had the head machined to to get it closer to piston and give a squish band, and a higher compression ratio.

Result is a motor with that distinctive crack of a hi comp motor, a big increase in torque right through the rev range, and sufficient power to outrun any 1000cc bike I've come across, though the lower gearing probably helps a bit here.

The R75 has the heavy flywheel, so smoothness hasn't been affected much, but I can see how it might be more noticeable on a later light clutch bike.

I will find out some time - I have a set oF 9.5 pistons to go into the R100GS - just got to wait until the machinist has time to do the squish bands, deglaze the bores, equalize the chamber volumes, balance the pistons and rods, check the valves and guides, clean up the ports and all the other little things which will give me a more powerful and smoother engine than I have now

He is booked out months ahead, as he usually builds air cooled Porsche engines which incidentally also have nicasil bores, and he seems to be the only guy around here with the inclination, knowledge and gear to do them right.

 

[Redboots]

OK, ta for the replies... I don't like the idea of the goo.

I will give these base gaskets a whirl 'cos I can always revert to O-rings in a short period of time.

I was just wondering if someone had "hands-on" experience of them.

John