3AJ clutch doesn't disengage and other woes...
 

Over the last few months I've been building a 3AJ I bought off ebay in bits. I'm pretty mechanically minded but have never owned a bike before and certainly never done anything this involved. So eventually the thing is in one piece instead of many but the damn thing won't start. Most of the problem here seems to be the clutch not disengaging properly:

When building the bike I couldn't find neutral, move through more than 2 gears or disengage the clutch. I took the cover off, separated all the clutch plates out, oiled and replaced. This at least meant I can rattle through the gears and find neutral, but not trigger the neutral light or neutral relay for the starter.

I have adjusted the clutch cable to maximum and it frees off a bit, but not enough. Also, it won't start on the button in neutral without the relays clicking it off immediately - overcurrent I guess. I'm charging the battery now to see if that does anything, but I'm not hopeful.

My mate gets very tired trying to push start it too and so I haven't had much of a go at that:-/

Getting a bit frustrated now, ideas?

Pictures for the curious at:

http://www.flickr.com/photos/4981785...7594237835258/

hiya i am also just starting to rebuild my engine i bought a bike of off ebay and it has had so many problems where someone has done some weird things or left bits out. with the clutch have you checked all the components in the push rod parts there is supposed to be a shaft then a ball bearing that pushes against an adjusting bolt in the centre of the clutch just an idea. i had the opposite the clutch was permanently disengaged this was down to the splines of the clutch miss aligned.

Perhap but:
 

The guy I bought it from dismantled it to paint the frame, the engine and gearbox was taken out as a lump and not opened up. He said it was running before that. I suspect it's a worn part or something that needs adjusting, or maybe it'll free off when it's running but at the moment I just don't know.

Hi Alex,

I have decided that the XT600's are too difficult to bump start, so would recommed that you get to the bottom of why the electric start isn't behaving. This might involve (temporarly) bypassing the neutral sensor, clutch lever and side stand switches, their signals are fed to the CDI which should refuse to start in gear unless the clutch lever is pulled in and the side stand up - If I remember correctly.
If your neutral light isn't coming on that could be part of your problem.

I'm not very clear on your clutch cable adjustment, my understanding is that you need to do trhe following:
1) remove clutch cover, if bike lent enough then oil wont escape

2) put maximum slack in the cable

3) undo the loc-nut in the centre of the clutch and screw the screw in until it just touches something behind it, then back the screw of one quarter of a turn and lock the lock nut

4) Replace the clutch cover, having replaced gasket if necesary (if you grease both sides of a new gasket they can often be re-used a number of times)

5) re-adjust the clutch cable free play so that there is 3 or 4mm of gap betwen the edge o the lever and it's mounting bracket wheh the lever is pulled in to the point where all slack is taken up

It is probably wise to lube the cable before doing this, unless you have done so recently.

Also note that if the bike is stationary you will need to spin the back wheel to move through the gears.

Hope this helps

Mark

Ok, thanks. Useful stuff on the adjustment, I have merely screwed the adjusters on the cable to max. New clutch cable too so that should be ok. I'll try your adjustment method, and hope that I don't need to order another gasket because it seems to take 10-14 days for the dealer to get stuff in. Grrrrrr.

The electric start I will try again after clutch adjustment, the kickstand switch has been bypassed by someone before I got the bike, and I have refurbed the clutch micro-switch so it shouldn't be anything to do with that. I can hear the starter relay click on to energise the circuit when I pull the clutch lever in.

Put the bike in nuetral.... Can you move the bike forwards and backwards with no resistance ??

Put her in gear then pull in the clutch lever and try again to roll her forwards and back.. Easy ?????

If its not dissengaging then a common issue is notches on the clutch outer basket and sometimes the inner.. These notches grip the plates and stops them moving apart ! Very common on toquey singles, especially old ones.

Update:
 

Tedmagnum, thanks. I'll check the basket when I adjust the clutch lock nut.

Good news on the starter motor, it was a bad earth increasing the circuit resistance which in turn led to the starter motor drawing more current than it should and cutting out on overcurrent.

Now I have a starter motor that healthily turns the engine while it is in neutral, it doesn't however start:-( I did lots of cranking with variations on choke and throttle position but didn't get anything. My spark plug socket didn't fit so I could't check for spark yet, but the exhaust smelt of fuel so I'm pretty sure it's an electrical problem. I'll keep you updated...

You HAVE to check the spark before you go digging any further. a 19mm Deep socket will fit the plug.

Idealy you want to check for a Good healthy spark, good compression and then worry about your fueling.

If you have a good spark and good compression, i suggest blasting the airbox with some power start and see if that gets things going. Hook the battery upto a car battery and keep it cranking.. You may need to draw fuel in...

This should be called the starting saga now...
 

I had the spark plug out and I have a spark, I gave the engine a few cranks and I'm pretty sure that I could smell fuel from the spark plug hole. I'm not really sure what to check next. Ideas?

As long as its a strong continuous spark then you can move on. You want to buy or borrow a compression tester and check that you have sufficient compression for the motor to run.

Go and buy a can of powerstart and spray into the airbox.. If its electric start, Hook the bike upto a car battery and crank it over in 5-10 second bursts (so you dont over stress the starter)..

Either way keep cranking.

If your compression and spark is good and you still dont get it running with power start then post up again...

Fuel
 

It's a 3AJ, so there is a fuel pump. If level is approaching low in the tank you need this pump to get fuel to the carb. But for that, engine must run.
So:
- Check that there is fuel in tank
- Check that it also arrives at the carb float bowl: open taps, unscrew a few turns float bowl drain. If fuel comes out, let run for awhile to refresh. Close drain
- Start
- If no fuel comes out, you can hookup the tank with a hose directly to carb inlet, providing the level is sufficient

Remark: these bikes do not seem to start on fuel that has been sitting in teh carb for a while. Bad staring, especially at lower temps, is normally cured by refreshing the fuel in the carb, see above.

Auke

Just squirt powerstart into the airbox with the fuel supply turned off (to prevent drawing bad fuel) The engine should run for about 10-20 seconds on the powerstart fumes. Its an easy diagnostic !

And still the damn thing doesn't start:-(

Ted, I've been having a go with Power Start and getting nothing - however see below on fuelling. I wish I had a car battery to do as you suggested, but without a car it's a bit of a problem. I have to settle for having a crank and then putting the battery on charge overnight.


Aukeboss, so that's what that vacuum driven thing is on the carb, a fuel pump! Right, I drained the float bulb and have given it plenty of cranks but the bulb hasn't filled up again, surely this isn't right? I've also tried combinations of fuel tank cap off and drain screw open to see if it needed priming or something - nada.

I am now viewing the joint between the rubber intake manifold and the head with suspicion. If there wasn't a good enough seal, then I wouldn't have a decent vacuum, that would make starting difficult to impossible and would also prevent the fuel pump from working.

Looking at my bag of bits there didn't seem to be anything to clamp the rubber boots onto the head from the carb side. Sure there are hex bolts that go through the two holes on each boot, are they supposed to have washers on the outside of the boot - that wouldn't seem like much help?

Oh, yeah: New spark plug yesterday and it does "chuff" when I crank it, I'm pretty sure there's compression there.

Sounds like you battery is screwed too. Have you got a mate with a bike who you can jump upto with their bike running. If your crankimg allot and getting nothing with the power start, then sounds like theres something else a miss here !

Your getting a strong continuous spark arnt you ? Valve clearances being way off will give you low compression too.

The spark plug gives a near continuous spark with break now and again, I've just been out and checked it again. The battery gives me a fair amount of time cranking, if you add up all the cranking today it's probably had 2-3 minutes worth. It's beginning to sound a little slower, but it's got a few turns left in it yet.