Hi

I think I am starting to have issues with the dreaded sprag clutch
I was riding my bike tried to restart the bike unsuccessfully

Placed the bike in second gear let the clutch out and the bike started immediately

I was thinking if I can access the sprag clutchthru the started motor opening
Perhaps use an extended nozzle to spray wd40 thru the hole where the starter is positioned

Any thoughts

Regards

Gabriel

I don't think you have the holes in the sprag clutch. You could try running a high detergent oil for a few hundred or so K's. Until cleaned it will mean picking places to stop where you can roll start. Quite a few inmates have cleaned their sprags this way.
Regards Martin.

I used a mix of half and half 20w50 and dex atf fluid. Ran the bike on stand for 20 mins at 3000rpm. drained and refilled with fresh 20w50. It really does clean everything out. Don’t ride with this mix though.

Gabriel

to access the sprag clutch its not through the starter motor its through the crank cover

carbi cleaner might help ….just a squirt or two

the easiest way to keep it clean is not to let it sit for too long without running the motor at least

good luck

A member here came up with his own version of your idea and posted about it:
https://www.k100-forum.com/t8416-sprag-sprague-clutch-easy-fix-diy

Hi

Today’s experience made me realise how I sometimes jump to conclusions and make false assumptions.
I decided to replace the battery with a known good battery from my K75s and I realised it was my battery that was causing my issues with the bike.
I suppose if we try hard enough, we can convince ourselves of almost anything and I wonder how much of the sprague clutch issues we Experience is actually a faulty battery.
It’s so easy to underestimate the importance of a properly functioning battery, especially when we have electronic fuel injection.
I have once  again learned a valuable lesson.
Hope this advice helps others.
I am currently disassembling my K75s and checking my splines. I have a notchy gearbox.
Final drive and driveshaft splines are in excellent condition. I’m hoping the gearbox input shaft splin is in excellent condition.
Is it ok for me to use Castrol optimal paste for ALL the splines?


Regards

Gabriel

On sprag clutches its important to note early ones do NOT have the three holes that you can access through the right hand engine cover. My K100RT is a 32/84 engine build and does not have the holes in it. The first 4 digit part of the engine number is week/year it was built.

I am curious as to how a weak battery could cause the sprag not to engage.

Hi
Fair point.
Not certain if a starter motor requires a certain amount of current and voltage to operate properly?

The reason I ask is that the classic sprag problem is failure to engage which results in the starter spinning merrily away whilst the engine just sits there.  I've never heard of a new battery correcting that problem.

I was wrong about the sprague clutch..........

Is it ok for me to use Castrol optimal paste for ALL the splines?
Gabriel

Optimal is good stuff, and if you can mix it with Honda lube it's even better!

I use Optimol and found that it really didn't need replacing after two years and about 25,000 miles, but I did it anyway