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Engine Dead...
Posted: Fri 28. Dec 2007, 19:56
by Michael Steinmann
Hello everybody. First, I wish you all a happy new year.
I have a problem with my R51/3 and will be grateful for any idea of what to try or do: After standing still for 1 year, I started the bike with 2nd kick (!). I rode it for 2 days, last one was yesterday. Every time it started without hesitating. Today morning, I tried to start the engine and it won't. There are fat sparks on each plug and fuel is reaching the carbs. As far as I know, the ignition is automatically and I also checked valve clearance. Where can the problem be? Any ideas what to look for?
Thanks a lot! Micha.
Re: Engine Dead...
Posted: Tue 1. Jan 2008, 13:50
by 92pmg
Hi Michael,
Because the bike has evidently stood for a lengthy period (dry or damp?)I would immediately want to check the coil and capacitor performance. What colour is the "fat spark"? Blue is good, red is suspect. The plugs may spark outside the cylinder, but not under compression, particularly of the coil is fading.
What is the compression like? The piston rings may be gummed up. What colour were the spark plugs after those two days? They will indicate the overall health of the engine. You won't get anywhere with sooted or oiled plugs. Use Bosch W4AC plugs.
Are the points arcing or is there evidence of a powdery look to the points and evidence of burning? If you have any doubts, fit a new capacitor, they are cheap enough. Best make sure the points are thoroughly clean too as they might have attracted a film of corrosion over the past year.
Is the advance/retard bob-weights returning fully to retard when stationary? It is possible hidden rust is preventing the cam moving freely, thereby preventing the unit operating properly. Weak or broken fly springs might cause the same effect.The cam stuck on advance will cause difficult starting and "popping back" in the carbs when kicking over the engine. Check with a multimeter or timing light.
Are you sure the floats are sound? One or both may have cracked during their idleness and partly filled with fuel during your recent rides. Make sure there is no crud in the jets - corrosion through condensation may have occurred that has shaken loose.
Basically,make sure everything is working according to the book. Mechanical and electrical components don't respond well to lying around idle.
Happy tinkering,
Gerry