I need HELP! 1967 Suzuki T20 scrambler, MY TWIN IS A SINGLE!!

[Hops]

I have been working on this problem for weeks now and I am stumped! This is my first post and I hope its in the right place. Here goes my problem: Its a 1967 T-20 Suzuki scrambler I bought it as a project so I have no history on it but the guy did take out the main fuse so there isnt one in it. I have replaced the transmission oil, cleaned the carbs, gas is good, new spark plug caps and new spark plugs, new points and condensers and only ONE coil is firing. Both coils tested ok at the shop, Timing is pretty much lined up with the lines on the alternator so that should be good but only one plug has spark. When I got the new condensers, they sent me two right ones but I put them in anyway I dont think condensers have a right or left. If I let the condenser with no spark "free air" it (not attached to the points plate) then there is a weak spark but it only sparks when the good spark fires. Also I do NOT have a battery in it, I figure if one is sparking with out it the other should too. Hopefully you understand and can help me because I am ALL out of ideas!

[Easy Rider]

Originally Posted by Hops

I have been working on this problem for weeks now and I am stumped!

I'm assuming that you don't have a shop manual and I don't either.
Your odds of finding anybody who is an expert on the bike without a manual are pretty slim, SO...........
I recommend that you first put everything back to normal, as much as possible: Put in the missing fuse and put in a battery......and anything else that is missing or disconnected.
After that, if you still have the same problem, you probably should try to find a shop manual.
Regardless of the "test", I think a coil is still the likely culprit. Switching them should prove whether one of them is bad.

[Hops]

I have tried switching the wires feeding the coils. the exact opposite happens the spark is good for one that was bad and the good spark wend bad. I also do have a clymer manual from the 60's so I do have some specs but the manuals from back then are pretty poor. One more thing, the ignigion switch (where you put the key in) is missing so the guy before me wire nutted all the ignition wires together becasue there is no key. I have a wiring diagram and I think I have the right wires together. I will wire it for day time riding so then I only have to connect two and I will let you know what happens. Thanks!

[Clint]

Sounds like you've shown that ER was correct about the coil, right? I also suspected an ignition problem. Those old systems weren't nearly as robust as modern digital hardware.

[Hops]

I dont think its the coils because each one will fire fine on the right condenser. If I hook them up to the right condenser both coils will fire and spark fine. How do I even start checking the ignition system? Are you talking rectifier or what?

[Easy Rider]

Originally Posted by Hops

I have tried switching the wires feeding the coils. the exact opposite happens the spark is good for one that was bad and the good spark wend bad.

If by that you mean that you left the HV output connected to the same plug and switched the (12V) input to the coils, then the coils are good and something is amiss back down that input wire.......pinched, loose, corroded wire, (in or out of the distributor) or something in the distributor itself.

[Hops]

By the distributor do you mean the stator or the revolving thing in the center or do you mean the entire assembly... probably the whole assembly huh? Thanks for your guys help this is the most progress I have had in a long time!

[Easy Rider]

Originally Posted by Hops

By the distributor do you mean the stator or the revolving thing in the center or do you mean the entire assembly... probably the whole assembly huh? Thanks for your guys help this is the most progress I have had in a long time!

No the distributor is where the points and condensor are located (usually).......come to think of it, if there are 2 sets of points and 2 spark plugs there probably isn't a real distributor. So to rephrase, the problem is likely at or near the set of points that serves that cylinder.

And the stator has NOTHING to do (directly) with producing the spark. It might be attached to the same shaft that has the cam lobes on it for the points but that's just for mechanical convenience.

Good luck!

[palanon]

Sounds like an old school ignition problem. By your description of changing plug wires you have one of three problems.

1.)Coils - if you have 2 separate ones, switch the Coil and feed wires. if the cylinder won't fire off both feed wires, you have a bad coil or wire.

2.) Points - You'll have one or two(the rocker thingy). Chances are one. The crank lobe will open the point twice a rev. check condition and insure the gap is within spec on it's highest point. You'll also need to see if the timing marks on the crank and plate are very close at that point.

2A.) Place a volt meter, set on Resistance( ohms 0 ), on the isolated screw of the points and the base plate. Insure that the point(s) open connection at the proper timing mark.

3.) Condenser - If you don't get any spark or voltage break at the points, this puppy is dead.

My guess, without looking at it, it a bad coil. However, you need to change ALL wires to confirm this.

On any point and condenser bike, it's always good to have plenty of spares. Older bikes can go through points like oil filters ( often ).

Try bikebandit.com and ronayers.com. They have microfiche for most bikes and older parts, sometimes. Also try a search for your bike and see if there are any BBS groups to help.

If you can find a manual, I could probably help more.

Old School Baby !!!

[Tab B.]

Hoo boy, old school, you aren't kidding. I had a 72 T250 Suzuki, same as the t20 essentially. My dad did the old school stuff for me then, so I have nothing to add here. BUT, I will say that if the coils are bad, and you can't find OEM replacements, old school car coils can be used. That is what my dad did when I cooked my coils because of a bad battery connection. The only thing is, the car coils required some kind of ballast resistor, so they wouldn't over load the condensors. Unfortunately, I know nothing of the ballast resistor values that would be needed, or how they would be put into the ignition system. My dad did all of the head scratching. He was way into electronics, so this was pretty simple for him. She never fouled a plug after that. IIRC, this kind of coil swap was not uncommon for lots of 2 stroke fans. Lots of RD350 Yamahas had it done too. So, are there any more old schoolers out there who can chime in on this??

[palanon]

BTW - there are after market coils. As long as you know the resistance range, you can get a generic one.

For my ol' 76 KZ twin, I go to Z1 Enterprises.

If your serious about getting the old girl running, try to find a shop manual. Once you start moving the base plate to adjust gap and timing, it's really nice to have.

Ignition on old bikes is pretty straight forward. However, depending on the bike, it can be a real PITA to work on and keep in spec. I had an old Husky 360 that needed constant adjustment.

[Tab B.]

Ya see, there goes that damn aftermarket again. Making life easier. Sheesh.
Hop, PM Palanon if you need to. He has had his hands in lots of points equipped vehicles. Me, I avoid them like the plague.

[palanon]

Haha !

My favorite was my old 1970 International 1210 with a 392 big block. I'd start it up, climb under the hood, loosen the distributor and rotate it around until it sounded just right. It needed to be done a couple times a month. After awhile, it was a cinch to do it by ear. I'm almost to that point with the KZ. Kawasaki uses REALLY cheap screws on the points and plate. It needs readjustment often.

[Hops]

I have the manual but all it made me realize is that Clymer has made progress in leaps and bounds since the 60's. Besides telling me a few specs for timing it is pretty useless.
So you guys are constantly talking about coils thats what I thought too BUT the shop tells me they are good... The dealers around here suck... which is probably the norm wherever you are. But I get a good spark if I switch the wires. This is what I mean when I say I switch the wires... I have two condensers two points two coils and one cylinder... just kidding... anyway the left coil is fed from a white wire (bad spark) and the right coil is fed from a black wire (good spark). Just before the coils, on the wiring harness, they are spliced by plug in connectors you can just pull out. So I pull them out and connect them in the reverse order SO... the white wire (bad spark) leaves the condenser gets almost to the coil and then it rides on the black wire and the coil sparks good. But the black wire comes from the condenser then before it hits the coil it is switched to white and now this has a bad spark.

[Hops]

I just went and tried some advice you guys were giving me and I noticed something. If I hold the left (no spark) condenser to the points plate it will arc to the points plate whenever the good coil (right) sparks. If I attach the condenser directly to the points plate (where it is suppose to go) I will not get ANY spark... If I dont attach the left (no spark) condenser to a ground then it will have a weak spark at the EXACT same time the good coil fires. Thanks for all your help I figure I can show you a picture of what it is I am talking about so I tried to upload a picture Hopefully it worked... and yes old school

[Easy Rider]

Originally Posted by Hops

I just went and tried some advice you guys were giving me and I noticed something.

I think we've gone about as far as we can go until you get a simple multi-meter (and learn to use it, if you don't already know). The cross-coupling between the two coils is not unusual, if they are mounted physically close to each other.

The switch you have done proves that the coils and plug wires are good.
There is one bad "input wire". The problem is with that wire or the points/condenser assembly that it is connected to or with the 12V input to that assembly. Pretty simple stuff really.........but you've GOT to have a meter. Are you sure that set of points is opening and closing ???

[Hops]

I am sure that both of the points are opening and closing. I also have a little analog multi meter that I have a pretty good understanding of how it works. I also have a continuity tester which is how I figured out where to set the points for timing. But when I started tinkering around with the points again the continuity tester would beep (indicating continuity to something) even when the points were fully open. But when I was setting the points I only had continuity when the points were closed... maybe this could be something with the input wires you were talking about???

[palanon]

You should only get continuity when the points are closed. I'm assuming you cleaned everything and checked connections. Extra fine sand paper and contact cleaner are helpful.

I'd replace the points, condenser and wires and save the old ones as spares. There's nothing more frustrating than going through all that work to find out the problem was a 20 cent length of old wire.

[Hops]

I replaced the points and condensers. The wire is ok because I tried running a new piece of wire right from the condenser and the same thing was happening. So if there is a bad piece of wire then it is... somewhere behind the condenser condenser itslef. I know the continuity should not be there when the points are separate but BOTH sets show continuity to SOMETHING all the time. So even the good spark is showing continuity when the points are open??? This is such a pain

[palanon]

This is hard when I can't see it. With a clip, secure the black wire from the meter to the engine. I usually use a cooling fin. This will free up one hand to rotate the crank with a wrench. Check that they break at the proper time. If they don't, and all parts are new, something is grounding out. That can be a PITA to find.