Starter issue

[Sibgyp]

Hi guys!

This is Sibgyp's other half, mentioned in the 'We are so lucky' thread. Sib and I are just going to use the same account to make things easier.

We got the bike running after solving the electrical issue (other electrical tests still need to be done to make sure every thing electrical is in proper working order, as we were told by the obvious hack who 'worked' on it that the alternator is not putting out the required voltage to charge the battery that doesn't seem to be draining), but now, when we start the bike, it's running like it has a load on the engine. When we kill the ignition, we can hear the starter clutch freewheeling to a stop, as it does when you go to start a bike (or car, for that matter) but it doesn't quite fire, and the compression that's built up spins the engine and hence the starter (most notable on older Chrysler products... I'm sure many of you know what I mean... lol).

Since I do not hear this on my bike (or any other vehicle), and the bike's running like it has a load on it (as well, it won't idle at all with the choke off, even after plenty of warm up time in relatively warm weather), I'm assuming the starter clutch remains engaged after the bike fires.

That's where we are at this point. Any ideas?

Lots and lots of thanks in advance!

[AlanB]

Hi Guys,

I have not heard of a starter clutch not disengaging before; hard to see how it could do it?

If it was stuck "on" when the engine was running, I would guess that it would get pretty hot, pretty quick; try dapping a hand on it after a few moments.

It is possible that a wiring problem is allowing it to spin along with the engine, but if the clutch works, it souldn't giv a load on the engine...... Don't know really....... probably should have thought harder before I started typing!

AlanB

[Sibgyp]

Hi Alan... thanks for your response.

Originally posted by AlanB
Hi Guys,

I have not heard of a starter clutch not disengaging before; hard to see how it could do it?

Well, when it's happened on some of my cars though the years, it's been a solenoid issue. But the starter motor and clutch assembly are separate entities in this application, hence my confusion as to the nature of this issue.

If it was stuck "on" when the engine was running, I would guess that it would get pretty hot, pretty quick;

I would think so too, but, according to the repair manual, the clutch freewheels while the engine is running on this application, meaning, I assume, that the clutch assembly is constantly rotating anyway. I can imagine how I could be misunderstanding how this particular system works, but it seems to me that while there may be some extra heat produced by the clutch not disengaging, it wouldn't be anything that would be that conspicuous as the clutch assembly isn't that big a load.

And when I say it sounds like it's running with a load on it, it's not a huge load. Just enough to keep the bike from idling after warming up.

[AlanB]

Hi Guys,

Starter clutch is a "sprag clutch" not a "friction clutch". It is totally unrelated to the sort of mechanism which seperates the engine from the gearbox. I have never seen a car with this sort of arrangement (But happy to learn!).

If it was to stick, the engine would attempt to turn the starter motor at engine speed, which would give a major amount of drag, and impart a HUGE amount of heat into the starter motor.

I suspect you need to look at some diagrams of the starter motor/ starter clutch arrangement, and start again....

Idling problems (unless ccompanied by clouds of smoke from the starter motor!) probably mean that the pilot circuit on the carbs needs some attention; either adjusting, or (probably!) cleaning!

There have been a few interesting posts recently about the advantages of chemically cleaning the carbs (Seafoam?) rather than stripping and rebuilding. Try a search, and some reading.

Apologies for the poor spelling in my last post; the Kids were fighting in the background, and I was not concentrating.

AlanB

[TopCatGr58]

Hey there Sibgyp,

You can find and see exploded views of our machines on the Official Yamaha online parts fiche site, listed in the LINKS section!

The clutch being mentioned is the starter clutch, not the engine tranny clutch. It is made up of 3 sliding pinch rollers fitted into slots that when the starter motor is engaged, the rollers slide down the slots, pinch and grab the cushdrive mainshaft with is connected directly to the crank shaft via the primary chain. Once the engine starts, that shaft is spinning faster than the starter clutch, and the rollers are supposed to slide away from that shaft allowing it to spin freely, and the starter motor to STOP!

BUT...if the pinch rollers have somehow gotten binded around the starter shaft, then they won't release, and the starter motor is directly connected to the starter clutch assembly via the gear teeth, so it will constantly spin the starter motor, and damage it in no time! You can pull the starter motor out, and then push start the bike, and check to see if that starter clutch housing is still spinning or not!? IF so...then you will probably be in for a bit of a job, because you can't access the starter clutch without splitting the engine!?

Report back what you find, and hopefully others can provide more troubleshooting steps depending on what you find!?
T.C.

[AlanB]

Well put, T.C.!

AlanB

[Sibgyp]

That gives us a good starting point... we already have the motor out... we will try to kick start it/push start it and see what we get...

Thank you both VERY much and thank you, TC for looking out for the 'newbies' and moving this to the right forum.

We will report back when we give that a shot...

Safe rides...