Vintage BMW Motorcycle Owners

Just happy to hear the engine start again. There was something I noticed though, the oily piston still exists… no smoke, so I’m thinking is it the type of mineral oil I’m using in the crankcase?? It just leaves a sheen on the pistons… It is 20w50 mineral oil… wonder if it’s a problem. The oil filter...

So ended up doing 2 rookie mistakes this time around: 1. After I put the last top end together and installed the exhaust. 2 screws left to tighten before firing her up. I look towards the parts box and lo and behold, I see a piston circlip… forgot to install the circlip to hold the pin in… reversing...

Andey; The compression test should tell you if your rings are seating or not. My Haynes manual says the compression ratio on an R 100/7 is 9.0:1. 9X14.7=132.3. You should get +/- 130 psi on your compression check. If you have less than 120 psi something is leaking, either rings or valves. But if yo...

Ok bad news. Ring gaps are perfect… 0.03mm 0.03mm 0.25mm spent close to an hour filing 1 set by hand and measuring with a feeler gauge… But still failed the leak down test. I’m thinking am I doing the test wrong… but referenced online guides and seems pretty straightforward. The only variable is the...

So oversized rings arrived for my rebore to the cylinder-piston limit…

The rings were too big, so like brook reams’ /5 project, I had to grind them down.

Pressure test on the bench tomorrow to see if it works. Fingers crossed…

If it doesn’t work, plan B would be a long wait for oversized pistons.

Yup, that sounds about right. Was thinking along those lines too. The biggest give away was the lack of power when pulling away. There was a noticeable difference after a few rides. It’s a little strange, no smoke, but when I had the jugs off, the pistons were a little oily and there was build up of...

An update on the bike. I managed to do a leak down test about a week ago and both cylinders failed miserably. 80% leak, through the piston rings. I could hear it through the crankcase. Probably explains the heat in the crankcase. Surprisingly the side with the most pitting actually held out better… ...

Hi everyone! Anyone know if you installing a pre 75 cylinder with 16mm pushrod tubes, on an existing18mm pushrod tube setup, would work? Are the pushrods compatible? Would I need to swap the pushrods for another part if I install the 16mm cylinder on? The current cylinder completely failed a leak do...

I’m a little surprised nothing much has “moved” for about 18months… I thought I’d be resetting a few things especially the points gap. I follow the steps for setting up the ignition and carbs religiously… I believe it’s the only way to have the bike working reliably. There’s no lazy steps. If so, wh...

Thanks gents for the replies! So I had the front cover off as it’s been about a year and a half since I was last in there. Thought I might as well have a look at the condition of things… everything’s held up well, but I should really change the 3color stator wire as it had brake fluid drip down it f...