Been a while since I reported last on my sprag clutch woes as I've been given the task by my good lady to build her a CB250, but the weather has been nice so I've dragged the K100 out for a bit of a spin.

The story so far, done all of the things that I can think of and that most of the generous community here has suggested but still have the occasional failure of the sprag clutch kind.

Done the strip and clean so many times I can do a sprag replacement in under 4 hours.
Done the crank case off and spray sprag with cleaner, useful because it's quicker then above
Done the change to 10w40 thing.
I've added a little SeaFoam to the oil, although I'm not really sure what to do with the stuff.

The last few days I've been using it for work it's only about 20miles each way, but if I keep the engine below 4K rpm the bike will start with no problem the next time I use it, in fact I'm finding myself hitting the starter as soon as my ride is over just to see if it will start.

4K is about 58 mph so fine around where I live if I stay away from the dual carriage ways. anything over 4k and I can pretty guarantee it will fail.

There are higher detergent oils that are available that have been used by other Brick owners. These have provided an easy fix Risolene is one used by US inmates. I'm not sure what's available in the UK. Probably need to run it for a least 100 miles before changing back to normal oil. Never use moly based oil or products  in your oil these are a known source of problems.
Regards Martin.

Have you done an engine flush?  Drain the old oil, refill with cheap oil and a whole bottle of Seafoam, run about 50 miles and change the oil and filter.

I have been running heavy duty Rotella T6 synthetic 15w40 in a bike that had sprag issues with good results.

JonnyHonda wrote:Done the strip and clean so many times I can do a sprag replacement in under 4 hours.
Done the crank case off and spray sprag with cleaner, useful because it's quicker then above
Done the change to 10w40 thing.

If it is still happening then firstly is the clutch a 3 roller type and if so replace it with the later type which is a multi sprag. If it is the multi sprag type they will respond well to a clean up to a point but they cant be fixed and will need to be replaced.
It seems to me that yours is beyond repair if as you say it has been cleaned many times. No amount of any type of oil will solve that problem.

I have done engine flushes and the sprag is the later tpye, i have in fact swapped it out from another later  bike a K1200RS i think, but I suppose you don't know how much wear that one had on it.

I think I'm going to have to get a new one, it's the only way to be sure.

Cheers guys.

just my 2 cents
nothing like a good long ride to heat and free things up and splash around that oil into places that it doesn't settle in ..
I have found what makes the sprag clutch more likely to fail is ...big time lags between rides and short rides at that

just sayin

good luck