TT600R (3AJ engine) has no spark

[Walkabout]

Here we go again,
For anyone who does not know about my TT600R, it has had a few problems, for instance:-

http://www.horizonsunlimited.com/hub...starting-26306

More recently the base gasket leaked and the past 10 days or so have been spent in stripping the bike down and changing the gaskets for the upper engine. Anyway (take a big breath!) now it has no spark!!

The work I have done recently is well recorded here:-

http://www.horizonsunlimited.com/hub...blem-not-27049
and it was all mechanical work, no electrical stuff changed at all - in fact the only bit touched was the neutral switch connection which was disconnected for a while to help in removing the left hand crank cover.

It's a 2001 model in good overall condition, with what looks like a complete wiring loom in good condition (I don't have a wiring diagram - anyone got one for this engine/bike?).

With the background of those earlier threads, I have tried all the combinations of switching (and I reckon I have read every other thread in here about starting problems with this model of bike!).

That's it basically: I am now asking for advice about how to trouble shoot this latest issue.


Dave

ps The last thing I did before stripping down the engine was to fire up the bike - it was going great then!!!!!

[Walkabout]

...... I can get all of the lights, including the neutral light, to work when turning over the engine with the kickstart (so that means the generator is doing it's job OK and there is nothing wrong with the circuits that involve the regulator/rectifier??).

So, that leaves the CDI and the coil/condenser since there is very little else on this bike!!!!

Just a further thought,

Dave

[bolla]

Hi
I would remove plug cap from HT lead check that you can see some wires inside the ht lead hold the lead against the cylinder turn off petrol turn all lights and indictors off and kick over as hard as you can.
I had a similar problem after rebuilding my TTR turned out I was not kicking engine over hard enough
Thr generator has to turn pretty fast to make enough power for a spark not easy if you are trying to hold HT lead on engine and kick at the same time.
Good luck
Where are you located Walkabout

[Walkabout]

Hello Bolla,
I'm in North Yorkshire.
Thanks for the ideas - interesting that you have had problems after working on the mechanicals of a TT!

I am certainly spinning the engine over as fast as I have ever managed - the spark plug is out of course so it is turning as easy as an easy thing. Did you find anything else to be a problem, electrically, after your work?

I can't see a separation between the coil and coil lead on my bike - the two seem to be one continuous "moulding" - nothing like the ones that dis-connect from each other; however, I have had my wife holding the spark plug against the engine cylinder while I do the appropriate kicking - even tried earthing the plug on various bits of the engine and using both the old plug (the one last used when the engine fired) and a brand new irridium.

If I do as you outline, earthing the plug lead to the engine with, say, a bit of brass stuffed in the end, what does that do for the firing circuit? Surely I won't see anything if the circuit is completed via such a conductor?

Dave

[bolla]

Hi Walkabout
I ment if you unscrew the HT cap from the lead snip a couple of millimeters off the end of the lead so you can see the wire inside try holding this on the engine case.
With my bike I had my frame powder coated and some engine work I was checking for a spark because after powder coating I thought I might have bad earths I had no spark cleaned a few wires still no spark then in anger kicked very hard and got a spark.
You say you removed the netural wire are you sure the wire is not broken inside , this wire runs inside the casing and gets very brittle . I have had problems with this wire on an XT600 when the wire broke the engine would not turn over on the starter.

[Walkabout]

.....You must be reading my mind Bolla, I've been wondering about that little blue wire that goes from the neutral switch to "wherever". It is the only wire that I have touched in rebuilding the bike engine. I guess if it gets brittle (heat?) then I should have looked at it more closely while I had the left hand crankcase cover off recently!! Also, if it had that effect on your XT starter then it would do it for a kickstart on a TT?!

One more thing I have been "wondering about" is the various statements I read in various threads about "dis-connecting" such switches as this neutral one and the sidestand switch. In this context, what does disconnect actually mean? - bypass it, short it out, take off the switch completely - I gather that these switches work like a killswitch and short the engine to earth when activated - you can tell that I don't have a wiring diagram.

I also wonder if the paper gasket will be good for re-use if I take that crankcase cover off again.

Anyway, at present I am getting a multimeter up and running - new battery just fitted!!

That's the state of play right now,

Dave

[wonky]

You need to take the plug cap off or you wont see a spark. I was at a loss with this for a long time myself. Seems TT's have somewhat weak sparking capabilities!
Turn the lights off as well.....

chris

[Walkabout]

That was a good idea Bolla, about trimming the end of the plug cable - it looks like one moulding to my casual glance, but it isn't (and what do I know!!). So, I took it to bits and............

The short story is:-

The spark plug cap measures 10.62, the coil secondary winding measures 18.50 and the bit of cable in between measures next to nothing (as expected), all with the ohms set at "20K" - I guess that is the max on this digital multimeter.
That makes 29.12 total and I read somewhere else in these threads that the total should be in the range 14.88 - 22.32 x1000 ohms.

Even the central conductor in the Irridium spark plug measures 4.82.

But who cares, because I put the cable back together, kicked it over and there is a big fat spark right there - I guess all that pulling the spark plug cable on and off just loosened it enough to cause a gap + I noticed along the way that the wire in the bit of cable was a lot more shiny and clean on its ends after being screwed together a few times.

So far, so good; just need to add petrol to the equation now!!!

Still interested in what folk do to bypass the "killswitches" associated with the neutral and the sidestand - both reputed to be able to cause problems in starting.

Ta for all of the ideas - they all help to get the grey matter going along the right road!

Dave

ps I've just found that other thread about the numbers that I quote here:
http://www.horizonsunlimited.com/hub...nt-start-24624
The postings in there were also very useful.

[AlexD]

My neutral and sidestand switches came to me pre-bypassed. The sidestand switch can be bypassed by removing the switch and replacing it with a length of wire. Not sure what has happened to my neutral light and cut-off though - they're not there and they don't bother me!

[Walkabout]

Thanks Alex,
That's the bit I can't understand - if the sidestand switch acts to kill the electrics by shorting out to the earth then why make it active by inserting some wire so that the circuit is connected permanently? I would expect to remove the switch and not replace it, then it could not cut out the engine. Same for the neutral - just disconnect it so that it can't do the same earthing function?
All of this thinking is by direct comparison with the killswitch which we are told goes to earth when "activated" - maybe these 3 switches work in different ways?

So, my bike is running again; petrol + spark = explosion principle!

Good luck then with your electrics,

Dave

[AlexD]

I've been studying a wiring diagram in german where the symbols are too small to read! The sidestand switch acts through a relay and without knowing the pinouts for the relay it's hard to tell exactly how it works.

The easiest test would be to unclip one of the sidestand-switch connectors and see if the start button works. If not then you need to go down the shorting out route, like mine.

[nocduk]

manuals for XT600e xt600 and tt600 here
hope this helps some of you fellow riders just found this link

Parts Catalogue for XT600e
Workshop Manual for XT600
Workshop Manual for TT600

Please note that both workshop manuals are huge files (about 140MB) and will take a while to download.

Smokin` Lizard in the Downloads section.