Bike won't turn over with plugs in place... Suggestions?

[Dave_A]

In the midst of doing some work, I left my 850 sit for about a month with no oil, and the valve cover off...

I finally got it finished today, sealed up & re-installed the VC, and tried to start it...

Result: The bike turns over fine with the plugs out, but it binds up if you put the plugs in place.

It ran fine before, and I didn't do anything to the cams, so there's no way for the chain to have skipped... The throttle is still operable, I haven't taken the carbs off yet...

Could it be stuck carb floats? Some other simple problem?

[Anonymous]

stuck

If it was hydro lock, then you would see and smell the gas pumping out of the cylinders when cranking with the plugs, if you let it sit with out the plugs in it, you may have rusted the cylinder walls, could also be Battery, ign. timing, starter brushs, starter solinoid or any one of a number of connections

[Dave_A]

Re: stuck

If it was hydro lock, then you would see and smell the gas pumping out of the cylinders when cranking with the plugs, if you let it sit with out the plugs in it, you may have rusted the cylinder walls, could also be Battery, ign. timing, starter brushs, starter solinoid or any one of a number of connections

It's not hydro lock - works with the plugs out, nothing but air coming out the plug holes when it cycles, the bike was totally drained of oil & gas...

Battery was dead, and I was cranking the bike jumped off my car.

The only idea I can come up with is that it's some sort of 'compression lock' - eg no air is getting past the carbs on the intake stroke, or similar....

I don't know if the carbs with floats down can seal it up that tight, though...

The only other thing I can think of is that the oil pump is not getting oil back into the system for some reason???

[SqDancerLynn1]

First thing to do is charge the battery!!!!

[Dave_A]

[quote="SqDancerLynn1"]First thing to do is charge the battery!!!![/quote

Could the battery be the problem, even if it still does this running off a large car batt?

I've been trying to do the tests running off my Camaro's battery, both with and without the engine (V8) running on the car...

[Anonymous]

Jump-strating the bike from the car battery with the car's engine gunning is a bad idea. The car's voltage regulator will allow more alternator output to compensate for the extra load of your weak battery. Your bike's elecrical system isn't designed for that kind of input...

[Anonymous]

yea.. depending on what kinda car you're attached to, you could easily bork your charging system on your bike.

[Dave_A]

OK... Back to the original topic:

I have now ruled out any sort of float related problem...

THe 'issue' is that the bike will turn over properly WITH THE SPARK PLUGS REMOVED.

However, ONCE THE PLUGS ARE IN PLACE it will no longer turn over...

[Sandy]

It could also be a bad starter ground, starter relay, or starter brushes. It will turn over great with the plugs out (no compression) but cause the bad brushes, connections or relay to fail when the extra load on the starter, due to the higher compression, is encountered. The starter is automatically grounded through its case to the engine case so grounding is not likely a problem. The easiest way to check for a bad relay is to jumper the large terminals on the starter relay together with a screw driver or fairly heavy piece of metal, there may be some arcing here so don't use a good screw driver and make sure you short across the nuts and not the threads. If the starter turns over properly then your starter relay contacts are shot and the relay should be replaced. You can also do this by connecting a battery positve terminal directly to the large black wire on the relay and the negative to the frame somewhere. You might be able to pry the relay apart and file the contacts, but that would only be a very temporary fix. As for the starter button, it should be good because it only operates the relay, the relay is what powers the starter motor. If the starter won't function with power hooked directly to it then the most likely cause would be the starter brushes. If the starter can be removed without removing the carbs repairing it shouldn't be to difficult. Just remove the starter cover, the positve wire, the two mounting bolts and it should come out easily to replace the brushes, I'm sure they are available. I haven't had to remove a GS starter while the motor was in the frame so the question is, are the carbs in the way? Hope this helps.

[Dark Jedi]

I think most are not understanding...

By Turn Over, you mean crank, at all. Not fire, run, whatever, but to turn at all?

With plugs out, you remove the compression, allowing it to turn, right?

Sounds like a valve is not opening, I suspect it's the exhaust valves. With no outlet, the compression becomes so high that the starter motor can't compress it all the way over. With the plug out, that excessive compression is not there.

Take off the valve cover and make sure the cams are turning and compressing the valves.

[nabrams]

I would do a couple of sanity checks first:

1. Can you push start the bike? After a month of sitting, you'll probably need a couple of friends to push you along for a while (more than one attempt). If you CAN push start the bike then you know it's not a valve problem and is most likely a weak/faulty starter or bad wiring to the starter (since you've been using your car battery).
2. If you can NOT push start the bike after multiple attempts (you don't even hear an "almost" start) but the engine DOES turn over, then you may have a fuel delivery problem or bad spark. Both of those topics have been covered at length in other posts.
3. If the engine does NOT turn over even during a solidly fast push start (you come to screeching halt when you let the clutch lever out), then you've probably got an intake or exhaust valve issue on at least one cylinder. Of course, the way to test this would be to leave the spark plug out for one cylinder at a time.

[Sandy]

If the problem is not with the starter as I suspect it might be, DO NOT TRY TO PUSH START THE BIKE. If something is in fact mechanically stuck you have I good chance of making things much worse by actually breaking something and doing more damage than you currently have. As also suggested try replacing the plugs one at a time to see if you can narrow the problem down to a specific cylinder. You might want to do this by hand cranking the engine. To do so, remove the right hand ignition cover and turn the engine over using the large nut on the end of the crankshaft, not the small one.

[Dave_A]

1) With the plugs OUT:

The bike turns over just fine... Push the starter down and it keeps going as long as you hold the button down...

2) With the plugs IN: You get a 'twitch', but nothing more. Think 'Bike in 1st, brakes on, push the start button'... It tries to turn, but can't quite make it... I have tried checking each cylinder with one plug in place, the problem is present on all 4.

3) I have NOT done anything to the cams, cam-chain, or tensioner, and I *have* observed all valve buckets moving properly before I put the lid back on...

Remember This was a 100% functional bike when I took *only* the cam cover off to deal with a persistant oil leak. I just got too busy to re-fill it with oil & put the cover back on untill now

[saaz]

Been there, done that...

The compression is obviously too much for the available starter power. Years ago I tried jump starting my bike off a car, but it was no better than with the flat battery (your battery must be marginal if it does not turn over with the plugs in..it has no cranking power). I was using some crap, cheap jumper leads..they were useless!

Try some decent jumper leads, they make a world of difference. The difference between barely tirning over and starting in my case. Even if the battery is just about dead, with decent jumper leads the bike should turn over and start. Do not run the car, even when starting another car. That will just cause voltages spikes.

[Dave_A]

Update

Tried hand cranking...

It's a bit tough at the top of the compression cycle, but it DOES turn with a socket wrench on the crankshaft nut...

I guess I'll have to try charging the battery to full...