Starter clutch or starter motor.?

Guys,
Maybe I'm barking up the wrong tree here..
What are the symptoms of a dodgy starter motor.?
Thanks all.
Morg

 

Let's do this the other way round before we talk you into fixing something that aint broke


What's your symptoms?

 

It will make you think you have a problem with the starter clutch (as will old oil, or the wrong oil.)

If the starter doesn't spin fast enough and with enough torque, it won't cause the sprag clutch to engage as it should.

 

Ah this is the one with the slipping sprag clutch even after oil change isn't it?

In that case I retract what I said about fixing stuff that aint broken, I'd rather rebuild 50 good starter motors than replace one dead sprag clutch lol

If you're still having trouble with slippage, it's a lot easier route to pull the starter & ensure everything is in order (brushes long enough & free to move, windings Ohm-out good, commutator clean & segments deep enough etc) than it would be to split the cases, and I'd say even if the sprag does turn out to be at fault in the end, it's worth having the rest of the system in tip-top shape first...

 

Guys, What would I do without ye lol.
Symptoms are.. Usually first thing from cold when I press the start button I just get a sound like gas escaping ( hard to describe but sounds like ptt...cheew, If that makes sense). The bikes fires up and then the starter disengages, doesn't stay engaged long enough to get her running.. Then when I try again no movement at all from the starter. Just what sounds like ptt cheew again but no rotating. Then sometimes when turning the engine the starter makes a groaning noise and disengages. So I come back after a while and try again..She starts...Once she is warm it doesn't seem to be a problem.. When warmed up she starts with the slightest push of the starter button.
I am aware of the starter clutch oil issues and with the recent sticky float allowing the gas into the crank I have already changed the oil once. No 20w40 left though.. Is 20w50 ok instead.? I intend to keep changing the oil until the gas smell has gone.
Hopefully its just a lazy starter and not the clutch...

 

Assuming your battery is known to be good, have you checked the wiring (including the earth lead and the small wires to the solenoid) and done the solenoid/screwdriver short out test?

It does seem likely you have a duff starter (although hard to be 100% when diag'ing based on typed noises not hearing them myself lol) but you could prove out the solenoid by shorting the 2 large nuts with an old screwdriver (lots of sparks, mind eyes, no flammable liquids open!)

This has the effect of bypassing the internal contacts of the solenoid (really just a heavy relay on these bikes) and allowing current to flow through the screwdriver instead of through the contacts.

I would imagine 20w50 would be OK as it's only 10 weight heavier when hot, I can't see it increasing the oil pressure enough to do any damage but I'm NOT recommending it all the same... I have 15w40 in mine, not recommending that either because I'm not Yamaha & have no business recommending lubricants for an engine I didn't design! lol

 

Thanks again, The battery is only six months old but is the old acid type which I believe doesn't like the crappy freezing weather we have been having for months.. Probably affecting you too in Cheshire.
So if I short out the solenoid what will this show me.?
And I assume the ignition has to be on at the time.?
It wont fry the loom I hope...
And...is it a big job to take the starter apart and clean her out.?
As always thanks.
Morg.

 

Shorting the 2 bolts on the solenoid will prove whether or not the solenoid is the problem (if it spins over like a gooden then you have your culprit).

That said, if you're not 100% on exactly how I mean to do the test I'd say leave that & just check the wiring & starter instead since it's more likely to be the starter itself.

It's not a big job to pull the starter no, couple of bolts hold it on & another holds the wire, pull it out & then 2 more bolts hold it together. It's fairly well covered in the manual and there's some threads with pics on here showing starter rebuilds. Only "trap" that gets some people is making sure to get the brush holder back in the right spot else it turns backwards! Easy enough to test before refitting though.

Oh, and lead/acid batteries are just fine at sub-zero temps as long as they're fully charged. If they're left to sit discharged they can freeze (and even in warmer temps they sulphate up fast if left discharged for any length of time, so always recharge your batteries whenever you've run them down a bit. And ALWAYS put a new battery on charge after filling the acid, even though they come dry charged it affects the overall power & lifespan of the battery if it isn't fully wet charged before it's used...)

Weather's been bloody well arctic lately yeah. It's lovely now, bit cold in the mornings still (-6 yesterday) but spring seems to have finally sprung