Engine not turning over, clutch trouble

[jaguar65]

Hi everyone, I know you are all interested in my progress with my project bike and I plan on writing a detailed descriptive account on the whole affair, however, I'm trying to get it ready for an MOT this saturday and I'm trying to sort out some problems.
My plug sparks, there is fuel in the carb, with no spark plug in the head the engine turns over fine. However, when the plug is placed back into the head and tightened, the engine does not turn over completely, it is as though something is jamming it. The flywheel can be rotated by hand through a full cycle but it is quite hard to turn it over at the top of the stroke (compression). I have had this engine running so it makes me think that the problem may be due to the motor not having enough torque to turn the engine due to the battery being a little flat as it has been sat for about a month.

Also, I am having trouble with my clutch as I tried to bump start the bike this evening to no avail. I adjusted it until the point at which it was strenuous to pull the lever back (very tight) and yet the flywheel still rotated.
I'll be draining the gearbox oil and taking a look at whats going on inside tomorrow but if anyone has any pointers that would be great.

Thanks
John

[Rs06 Ant]

Were in Manc r ya m8?

[williamr]

Only guessing, but it sounds as though your batteries flat. Failing that, check the condition of the wires and connections from battery to relay to starter.

As for the clutch, it could be that the plates are stuck together with old oil. Adjust the cable so that there's a bit of free play, then strip the clutch. You'll be able to see if the plates are sticking. You might be able to use petrol to get oil off when it's dismantled, but you may need new friction plates.

Rob

[random0082]

If i remember rightly, the bike was sitting for a while with no cylinder head on before you bought it? if so, id strip the engine and check the bottom end too, you dont know whats corroded, id rather find a knackered bearing etc then have it disintegrate at 60 odd mph! all the best and good luck with the MOT

[jaguar65]

I live in Sale, connections all seem fine. I've got a jump starter, I'll try that tomorrow. As for the engine, I took it to pieces, rebuilt the gearbox, bought new casings with a crank and flywheel attatched (checked out the big end bearing and it was fine), got a new barrel, had the head smoothed, bought a new piston, rings, sparkplug, little end bearing and rebuilt the whole thing. Got it running a while ago but then turned it off straight away as I was unsure if there was oil getting in (did not seem to be any smoke at the exhaust) and there was no coolant.

I'll take a look at the clutch tomorrow and try to jump start her.

[jaguar65]

Just had a read of a few other threads and it seems that other people can start their bikes on only 9V, why can my battery at 12V not turn over the engine?
The bike is started in neutral, the spark is good, the system turns over just fine with no plug installed, it does not seem normal that the battery cannot overcome the compression when others can start their bikes on only 9V.

Suggestions?

[Gearbox Geezer]

Check the starter motor bolts. Mine came loose and it was struggling to start ( actling like somthing was jamming the engine like u described )

The bolt heads snapped before I relised the problem and now I have no start motor and will have to strip the whole fucking engine down if I want it back.. which is annoying since I have no time on my hands at the moment..

[williamr]

Just had a read of a few other threads and it seems that other people can start their bikes on only 9V, why can my battery at 12V not turn over the engine?
The bike is started in neutral, the spark is good, the system turns over just fine with no plug installed, it does not seem normal that the battery cannot overcome the compression when others can start their bikes on only 9V.

Suggestions?

A sulphated battery with high internal resistance can show 12 or 14V charge, but the resistance means that it can't flow the current needed for the starter, and it will drop a lot of that voltage when you start to draw current - initially, until the starter is up to speed, you will drop more volts internally than across the starter.

I don't actually think a battery at a genuine 9V will start a bike either. If it's being measured while the starter is cranking, the battery voltage will drop, as I've explained, and may well be 9V or even quite a bit lower while it's cranking, but will show a higher voltage otherwise. The dash tends to give low readings anyway - you need to use a hand held meter. Also, a battery with buckled plates giving an internal short in one cell will have a low voltage but may still be able to deliver enough current for the starter from the other 5 cells. The state of charge can only be checked with a hygrometer on each cell in turn. The voltage is misleading.

Rob

[jaguar65]

I'll check the starter motor when I get home from work this evening. I've removed the clutch and its currently soaking in some petrol to loosen it up.
The battery is also charging. The annoying thing is that the engine ran not so long ago, and since then I've not tampered with it, aside from filling the radiator with coolant. There is fuel in the carb, and I've even tried starting it with a wet spark plug but to no avail.

I tested the battery with a multimeter and it read 12V 9A but it is only about 2 months old so aside from having been in the bike for this time without seeing too much action, I don't see why it wouldn't be able to turn the engine over.

Suggestions?

[jaguar65]

Stripped and rebuilt the clutch, thats working fine now, the starter motor bolts are tight, plenty of fuel, tried to start normally, same problem, engine won't crank.
Tried to bump start, sounds like the engine is on the verge of starting, then nothing.
Tried to jump start, no difference to trying to start her normally.
I really don't know what it could be.

Can anyone help?

[jaguar65]

Motor has had enough, tried to start it once again and it turned over a few times, gave up, the electrics went off and smoke billowed out from under the bike.

Game over

what now?

[jaguar65]

I tell a lie, it didn't turn over, it turned the flywheel back and forth as it always does before turning really slowly, then it died.

[Rs06 Ant]

Id get it to a garage pal. Superbikes on chester road are pretty gd.

[jaguar65]

Yeh I could take it to a garage, but these aren't the most complex of engines. Having had the engine running I doubt the reason it does not now is complex.

Anyways, my battery is well and truly fucked now, one of the terminal hoops is melted through and the bolt welded to it at this point.

Has anyone's positive terminal ever melted like this?

[OldSkool]

Replied to other thread before read this one but deffinatley something with starter. It will bump but you need someone to push you on it while you bump down on seat while dumping the clutch... and i long downhill road helps!!!