help with a week spark on my 84 tt600

[jazyjc]

hey every one, i'v been reading the threads for a whilt now and they are very helpful. I have an odd problem, all ohm readings are good on every thing but i don't get a spark. If I tap the kill switch while kick starting the bike I get a week spark. I tried to bypass the kill switch and no spark at all. Any ideas will be helpfull. Thanks Jeff

[aukeboss]

What do you mean by 'tapping'?
As far as I remember, the kill switch will connect the wire from the CDI to the ground. So, just pulling the connector should eliminate it from the probable causes. Check please before relying too much on this though.
To check the ignition, there's two basic ways:

1. exchanging parts with known good parts. Required: spare parts or another bike with helpful owner. If you have these at hand, go for it.

2. checking from downstream to upstream:
A - Spark at plug? Yes -> ok, no -> go to B
B - Remove plug cap, hold HT lead close to head, start. Spark? No -> go to C
C - Primary current going to coil: check that, when you kick, a voltmeter indicates a pulse to the coil. Connect meter to orange wire and earth.
D - Check for pulses from the two pickup coils (green - green/white and green - red/white wires.
E - check for pulses from the charging coil - brown/red wires
Etc.
The above is not complete, but you should get the drift.
Two things to keep in mind:
1 - A lot of problems are caused by bad connectors or broken wires. Especially the last one is difficult to localise
2 - Although everything could check out fine, it might be coils or CDI is weak. Only way to find out is by method 1.

Good luck
Auke

[Bill Ryder]

I have worked on other machines that would spark with a cycling of the kill switch or ignition switch. Replace the CDI or "magic black box" and the cheapest way is as previously stated by borrowing a know good unit. This is part of the interesting side of working with a 23 year old bike.

[jazyjc]

Thanks for the reply guys. By tapping I meant, if I am kick starting the bike I get no spark. I start pressing the kill buttom fast when kick starting the bike and I get a weak spark. My friend who works on bikes alot said what the hell! I road the bike for a while when I got it and it keep running rough at mid rpm. I did all of the normal stuff, new plug, messed with the carb adjustments and then checked the electric stuff and I did not get a good ohm reading from the pickup coil. I took the side cover off and found that the pickup coil had come apart and there was cooper wire every where. That's what started me checking and replacing everything. I got a new Hyperpak cdi box, used pickup coil with good ohms reading, checked all wires and grounds and here she still is with the weird spark problem. In checking for pulses while kicking, what would you set the meter on? Thanks guys, i'm at a loss for this one. One more thing, i did take the ignition coil to a local bike shop and they tested for me and he said all is good.

[aukeboss]

Set your voltmeter at something like 50 V DC, go higher or lower as required. If you use a digital one, it will indicate overload, so no danger of frying things.

Why did you change the CDI box if you are not sure that the original one is broken? In my experience the Yamaha parts are the best, there's one organisation that has the cash and the will to really optimise.

Auke

[jazyjc]

I was told to check the ohm reading on all parts and if they were good the cdi box must be bad. Did you read the problem I am having? I am still stuck on this one.

[aukeboss]

I did read.
There's no easy way to find the fault in these systems, except by the brute force method as described in my first post.
So, your coil, CDI and pickups are supposedly OK. Then we have as primary suspects: lock, kill switch, wiring, plug cap, earth connections. And (yes, I am hardheaded) as secondary suspects: coil, CDI and pickups.

Good luck!
Auke

[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.