Motorcycle sold

[cb650]

side roads are way more interesting. More friendly too

[Lejaun79]

I filled my second tank of petrol yesterday and worked out thet I get 17.5km/l with my 79 model. I also checked and i drove 220km without having to switch to res. You have to convert this to m/gallon sorry. So basicly i drove 220 km on 14liters. Reserve on my tank is at 15.5liters so i could easilly do 240km before swithing to res.

[Volker_P]

I So basicly i drove 220 km on 14liters.

This would be all right if you ride at 85mph however it is very much for cruising speed.

[Lejaun79]

If I did 85mph my bike would be revving high. I try to keep revs lower than 7k. I think my speedometer is buggered. My wife was driving next to me on the highway the other day and she said that she was doing 75mph and then I just kept on picking up speed, but when I got home I told her my speedo said I was just doing 70mph and slowly picking up.
I also think that the 1979 model with piston carbs are heavier on fuel.

[Volker_P]

I also think that the 1979 model with piston carbs are heavier on fuel.

Well, piston carbs are more sensitive to the rider. So one may use more here, however with a good feeling, one can also save a bit.

CV carbs are made to compensate nervous wrists.

[cb650]

My 80 had 79 carbs on it and always gets 50+ mpg. 60 sometimes.
Same as my 81 and 82 with cv's.

[Lejaun79]

Ok, I did the conversion like a true nerd, I get 41.4mpg. My 4th cylinder do have a small amount of smoke, not sure if it rings, hope it's just valves.
Could valves be a reason why I don't get 60mpg?

[Volker_P]

First check out your plugs. I can imagine it does not run on all four all the time. On the road, you could also feel your header pipes for being equally hot.

To your question: If a valve does not close due to misadjustment or bending, a cylinder may fail due to lack of compression. The engine may still run and pull quite reasonably on three but this will mean a power loss together with a much lower mpg.

[bubbachicken]

OK, I'll bite..

Adjusting the valves.. I seem to recall the adjustment is just loosening the nut on the front of the crankcase, and turning the engine a few times manually, then tightening the nut again... Is this right? Maybe that is part of my problem, because I do hear a little chain rattle now and then when the bike is cold....??

[Volker_P]

Basically all right.
The cam chain tension may be verified directly at the camshaft sprocket with a screwdriver after removal of the central valve cover. Sometimes it requires a few efforts of loosening the tensioner and turning the engine until tension is fine.