BMW R45 - an older look

[luca.stere]

Electrics:

[Mammagoose]

I have a R45 1984 with a post production kick start installed. It’s an art to be able kick start it. Only succeeded once. It’s important to position the piston at the correct point by slowly pressing the kick starter repeatedly until you can feel the compression point. Then give it a kick.

[Mammagoose]

I have an issue with my R45 1984 45.000km
It’s been used very little in the years preceding my “barn yard” discovery. Mint condition. The last year the left cylinder has started smoking whitish blue very badly only after riding 15km and the engine is hot. Sometimes it stops smoking. Very odd behavior. If I am descending a hill and use the engine to break it will cause it to start smoking. I’ve had different mechanics tell me different things. From old valve stem seals to pushrod seals to consumed piston rings to dirty carburetor. Possible cause leaving it on the side stand all winter causing the oil to stay in the left cylinder base.

Before I go dismantling the engine I would like to hear from other people’s experience. Having so few kilometers it is odd that it is already smoking.

[schrader7032]

Welcome to the forum! Sounds like you should do a compression test as well as a leak-down test. If you have oil getting into the exhaust, could be a valve seal or the rings.

[cwf]

Hello, it's a strange thing but motors often go wrong/wear out quicker when not used than when used regularly. I used to do 700 miles a week, 50 weeks a year for 30 years on BM twins and would replace piston rings at 150,000 miles (average).

I would check the rings, a fairly simple job BUT, before you remove the exhaust clamps, they are a known weak spot. It is safer to cut them off and save the cost of renewing the threads on the heads.

Best wishes, Charlie.