Motor Turns Over Very Slow!

[kta]

New bike! It's been sitting for a few years but seems to be in pretty good shape all around. I'm developing an obsession with these old Yamahas!

Anyway. When I put power to the bike and hit the start button it turns over VERY slowly, and thus can not start. It isn't corrosion related because I jumped the starter directly and it does the same thing. Next I pulled out the spark plugs, with the plugs out it turns over nice and fast as it should. I squirted some WD40 into the cylinders and cranked it over for a few minutes hoping to free up the motor a bit. Put the plugs back in, no change. Occasionally it'll crank a couple quick revs and I'll get a little puff of smoke, but outside of that it just turns too slow.

What could be causing this? Is the starter just too weak and worn out? Is the motor all gummed up from sitting? I jumped the bike off my truck to make sure the battery was putting out enough juice and it had the same effect. I'm not sure what the problem could be.

Ideas?

[prometheus578]

with the plugs out it turns over nice and fast as it should.

I would run the bike with the plugs out, then.

well, it sounds like starter to me, but then again, I wasn't there watching your jumping and testing proceedure, either.
Cranking nicely with plugs out means the engine is not gummed up. I trust you can tell the difference between a bad starter and a slipping starter clutch.
I hate telling people how to bypass things to check other things, as I don't know their level of understanding, and if they do it wrong, they'll draw the wrong conclusions, etc.
disconnect the bike's battery totally. Hook up jumpers from the truck(engine off). One for the ground(Use a large bolt on the engine of the bike), and the other, the positive, to the starter side of the starter relay.
The starter should spin strong and fast. If it doesn't, it's the starter(but it still could be a bad connection/corrosion, where the battery cable connects to the starter.
remove all battery cables anyway, and clean and tighten them up.
write back with your results.

[mason79]

i would take the plugs out and turn it by hand

[prometheus578]

A weak battery, or bad connections can spin the heck out of an engine with the plugs out. With the plugs in and the starter fighting compression is a different story. I suspect a bad battery, but he stated that he jumped it... but, I don't know just HOW he jumped it.
I never mean to imply that people don't know what they're doing, but often, simple mistakes can screw up testing proceedures.

[Ken Talbot]

I would have a real good look at the negative battery lead - both where it attaches to the battery and where it attaches to the frame. Even if you jump with another battery or vehicle direct to the starter, the juice still has to make a full circuit, and that will probably mean trying to go through that lead. All it takes is one really badly corroded connection and you will have problems. The only way you can really say it is not corrosion is if you actually took the connections apart and cleaned them off.

[kta]

I tried jumping it a few different ways to try and find the problem. However, I did the following and had the same slow turning results. I removed the battery. Then connected jumper cables from my truck. I put the negative on a nice clean bolt on the motor, and put the positive directly to the starter. Full juice, right on the starter with a good solid ground, still turns slow. There were a couple times today while I was playing with it where the motor did actually turn over a few times real quick, but it was very erratic and I didn't see any direct cause for it. So I guess I've got a starter replacement to do! Excellent .

[DiverRay]

The starter can be repaired. It does have brushes, and they can be almost worn out. If you can't find a starter for a reasonable price, try a quick home rebuild with a new set of brushes, and clean the armature with some emery cloth.

[shutchis]

KTA, You might try this...run a ground wire directly from the battery (negative post) to one of the starter bolts. I used some stranded #6 wire and crimped on some ring connectors.

It took me 3 months to figure this out. I added the cable and the starter turned over as expected.

[wingnut]

Starter is easy to get off and apart. Sounds like brushes to me. If it looks like this inside you have found your problem






I've seen complete rebuild kits on Ebay or you can buy just brushes from Parts & More ect. One word of caution if you decide to replace it. The 1100 starter turns in the other direction from the rest of Yamaha's starters so it must be from a 1100. DAMHIKT.

[prometheus578]

"Rare compliments..."

(That's odd...me actually saying nice things to people)
Good tip there, Shutchis.
Nice photo, too Wingnut. That's right where the trouble usually is.

Ok... don't whine...
Ken and Ray are correct, too.

Everybody happy, now?

(This compliment stuff takes too much out of me. A lot easier just to remain my usual crabby self)

[kta]

Awesome guys! Thanks for the help and esp for the pictures! I'll Get to work on this in the next day or so and keep you all updated on my progress.

[xs11bobber]

no update... lol

So was it the brushes? I have this problem along with spark on 1&4 only.

[CatatonicBug]

I just read thought this whole thread and didn't realize how old it was until the last post. Kta hasn't posted ANYTHING for the last 2 years, so I doubt we're gonna get an update any time soon.

[kta]

@ CatatonicBug - I'm still here! haha.

The problem actually wasn't the starter at all. It was the main grounding cable from the battery to the frame. The connections looked nice and clean, but when I cut back the sheath the cable itself was all corroded and worn. I swapped on a different cable and the bike roared to life.

Since then I've had the same problem on another bike - so it's fairly common.

[CatatonicBug]

@ CatatonicBug - I'm still here! haha.

Well, I'll be! Good to see you back on the board!