- Joined
- Feb 18, 2018
- Messages
- 1,229
After getting my 850 Fastback mongrel running again after 21 years ( it was running pretty well then, 4,500 miles after full rebuild), it now has the following symptoms: Runs on RH cylinder only at idle. LH joins in , but hesitantly, as it is revved out of gear. While riding, same thing happens, and once above 50mph in top gear, it runs consistently on both cylinders, and seems to go well.
The LH plug was changed while doing 550 miles on the trip to Normandy, with no change in symptoms. It has a long timing case breather pipe going to rear , with a one way valve. That is discharging quite a lot more oil than I remember from 2003. There is also oil on inside of Fairing on LHS, opposite the barrels, and oil showing on top two fins at central rear and rear left of barrels. Oil also ends up down lower LHS of bike. The LH plug was oily when checked on the trip. It is using oil too fast , according to tank refilling.
I couldn’t see state of inlet oil seals when checking tappets before trip. The end of the LH silencer, internally , looks basically dry, but maybe not as clean as RHS.
I suspect excessive oil in the combustion chamber as most likely. I can remove LH exhaust for more evidence in downpipe?
I cleaned both concentrics before starting it, but it is possible there is still some pilot passage debris, as I only inserted thin wire from top, rear and pilot adjuster entry points.
Ideas for useful checks to gather more evidence, before head removal please?
The LH plug was changed while doing 550 miles on the trip to Normandy, with no change in symptoms. It has a long timing case breather pipe going to rear , with a one way valve. That is discharging quite a lot more oil than I remember from 2003. There is also oil on inside of Fairing on LHS, opposite the barrels, and oil showing on top two fins at central rear and rear left of barrels. Oil also ends up down lower LHS of bike. The LH plug was oily when checked on the trip. It is using oil too fast , according to tank refilling.
I couldn’t see state of inlet oil seals when checking tappets before trip. The end of the LH silencer, internally , looks basically dry, but maybe not as clean as RHS.
I suspect excessive oil in the combustion chamber as most likely. I can remove LH exhaust for more evidence in downpipe?
I cleaned both concentrics before starting it, but it is possible there is still some pilot passage debris, as I only inserted thin wire from top, rear and pilot adjuster entry points.
Ideas for useful checks to gather more evidence, before head removal please?
