I just had my transmission redone by FBG (impressive work) and the engine had to be removed from the chassis and cases split to get to the main and countershaft.

Upon putting the engine back together, I gave the mechanic new bottles of Mobil-1 Red Cap. I thought they looked a little strange but didn’t investigate further – MISTAKE.

Upon startup, the mechanic stated that the starter clutch just spun and recommended replacement.

I then theorized that the new oil I gave him may be the culprit. The new Red Cap oil has an API rating of SN. IIRC, the bike should use SG or SJ, however API website says those rating scales have been discontinued.
What should be the new API rating used for our bikes?

Can I simply drain and fill and (hopefully) bring my starter clutch back to operation (no previous issues)?

 

If the original API grade is SG or SJ, anything higher than that (SN) is perfectly fine. Redcap 15w-50 should work just fine.... any oil that isn't labeled as 'energy conserving'

And the oil has absolutely nothing whatsoever to do with your starter clutch, so that's not the reason and you'll just be wasting $$ draining it out and putting new stuff in

 

What kinda bike?

 

The F4i that is in my sig is the bike.

SN oil is a 'resource conserving' oil. The theory is that the starter clutch doesn't have sufficient friction to engage, as the friction modifiers that may be present in the oil is preventing.

The bike was simply disassembled to get the transmission parts out and then reassembled with the new red cap oil.

 

The starter clutch is nothing more than a one way sprag clutch, the same used in automatic transmissions.... it's not a fiber clutch like the transmission clutch is, which is the one affected by moly in energy conserving oils. Any kind of oil you put in isn't going to affect a sprag clutch

I mean you can do what you want, but changing the oil isn't going to fix it..... I call complete BS on that theory. I'm more than willing to bet they left the little transmission gear between the starter and the flywheel out, or didn't put it in correctly, since the problem wasn't there before. Of course the clutch itself could have gone bad too, but again being that it didn't do it before it's not likely. They would have had all that stuff apart since you have to take both covers off to split the cases

This is the sprag clutch (on the right)



And this is the little gear that is likely not in right or left out



Believe me I'm not trying to sound rude or anything here, but as a professional tech myself I'm just trying to save you a lil time and $$ by not doing stuff that I know isn't going to fix it. Pop the left side cover off and see what you find.... it'll be easy to tell right away what's going on with it

 

DIY it or pay $150 in labor?

 

Well if it is actually the starter clutch itself that needs to be replaced, there's a puller tool that you'd need to get the flywheel off. After that it's cake, but you gotta get the flywheel off first before you can do anything. I think it was around $50 or so for the tool. Or you "might" be able to rig something up to make your own.... it's been awhile since I've been in there I forget exactly. So that's up to you if you want to buy the tool or just have somebody else do it

That is "IF" it's actually the starter clutch itself that's gone bad.... If you do have somebody else do it I would at least pull the cover off first and look for yourself and see what's actually wrong with it, see if they're being honest or just trying to cover up their screw up by saying it needs something else. If the gear on the back of the flywheel spins freely in both directions then the clutch is shot. If not, there's only the starter and the gear between the starter and flywheel left....

 

Does the motor need to come back out to fix?

 

Nope.... just pull the left side case cover off. Might want to lean the bike towards the right side though to keep oil from possibly spilling out

 

Okay, I got a 2nd opinion:
Said that the starter motor went bad because its spinning the wrong way! Never heard that before but they say the polarity on it is correct....just what they do sometimes when the motor goes bad.

Again, I never had starter issues before disassembly.

Thoughts?