Suzi T20 rotor bad?

AnKhe105 · Posted: Wed Oct 06, 2010 7:41 am Post subject: Suzi T20 rotor bad?

Can a T20 rotor go bad? I really can't see anything that could go wrong but don't know. Pulled off the stator after checking and re-checking everything on the planet numerous times and still have weak spark on the right side. (Not hot enough to burn the gas). I noticed that the rotor is scraping on 2-3 areas of the stator. Not sure if that's normal but don't think so. Pulled the rotor off and seems to be on correctly and the key where it should be in the rotor groove.
It will idle with just one side and while running, I have about 8.5v on the left (good side) and about 7.5v on the bad??
Changed out points, condensors, coils, checked all connections many times. Switched the wires at the coils to see if I could get it to change sides. Won't even start at all then.
Every once it awhile it will fire correctly for a couple seconds but not long at all.
Thanks, Doug
It's driving be nuts!

KirkN · Posted: Wed Oct 06, 2010 8:41 am Post subject:

Well, I don't know the details of that model, so I may be off base but:

Yes, a permanent magnet rotor can go bad. They can lose their magnetism by suffering a sharp blow, like from being rapped by a hammer by someone trying to free it up.

I'm not aware of any way to re-magnetize it after this. Someone else may.

However, I'm not clear where/what voltage you're measuring. Doesn't this bike have "conventional" battery and coil ignition? A system where the stator output goes to charging the battery which then provides the voltage to the ignition coils? If that's the case, then the battery must supply the same voltage to both coils, not good voltage to one and poor voltage to the other. I'm thinking that your problem lies in wiring issues.

On the other hand, a rotor mustn't rub on it's stator anywhere, let alone 2 or 3 spots. Is the rotor rubbing on the stator iron core or on the windings? Perhaps the stator is not moounted correctly. Something sounds very fishy about rotor/stator contact...

AnKhe105 · Posted: Wed Oct 06, 2010 9:15 am Post subject:

As a novice here Kirk, I'll answer as best I can. Very simple 67 battery, 2 coils, AC generator system so I guess the answer is yes to your elec question. Rotor is scraping on the metal 2-3 areas of the stator as it's rubbed those areas. It's quite obvious when I take it off. I may indeed have rapped on the rotor and pried on it to get it off. Dint know I shouldn't do that but now I do! This bike ran fine early last spring til I tore the engine apart to re-seal the cases. Put it back together and obviously messed something up. Thanks, Doug

Was testing the voltage with a cheap multimeter at the points where the condensor wire attaches while running.

This is the rotor for that bike. Shall I take a shot at it?
http://cgi.ebay.com/ebaymotors/1966-suzuki-t20-x6-t250-hustler-sm46-rotor-_W0QQcmdZViewItemQQhashZitem43a221f3beQQitemZ290482942910QQptZMotorcyclesQ5fPartsQ5fAccessories

There is a new one on there from Paul Miller for I think $78 shipped???
Thoughts??

AnKhe105 · Posted: Wed Oct 06, 2010 11:19 am Post subject:

PRAISE THE LORD! I got it Kirk!! Had an old stator that I just put on and she's blowin' smoke bigtime on both sides!!! Have to do some little stuff and take er out. Can't wait to feel that X6 T20 power band!
Thanks for your input.

New problem. Ran fine for a mile, then started losing power til it died. Pushed it about half mile home, then tried it again and popped right off and ran fine again. Gonna leave it home til I get this figured out. Won't run when hot....HMMMM?? Anyone?

DRC1 · Posted: Wed Oct 06, 2010 1:11 pm Post subject:

Could it be that your not getting enough fuel to the carb bowl(s)? My petcock was so full of crap when I got my bike, it did the same thing. Didn't fill the bowls fast enough and I was using all the fuel. Then I let it sit for awhile and it ran again. Just a thought. Smile

AnKhe105 · Posted: Wed Oct 06, 2010 3:13 pm Post subject:

Thanks DRC. Checked that and even cracked open the cap. Got good flow it seems. Now it's back to firing on just one side.....I'm toast for today...

Tezza · Posted: Wed Oct 06, 2010 9:24 pm Post subject:

If one cylinder drops out try applying the choke . If it bursts into life again then it will be a blocked jet. Look on the engine side of the throttle slide and you will see a tiny hole at the bottom of the carb body. This is the path the fuel takes when the engine is idling and the throttle slide is closed. Remove the float bowl and unscrew the jet located below the hole and see if you can see daylight thru it and also thru the carb body. A thin piece of wire (I used a strand off a wire brush) poked thru both usually cleans them up. A dash of carb cleaner as well is even better.

AnKhe105 · Posted: Thu Oct 07, 2010 4:50 am Post subject:

Tezza, it's a scramler TC250 and has high pipes leaving a "trap" area when the pipes are on so any raw fuel can cause it to be blocked. (Hope that makes sense). If not, google this bike for a pic and you will see. When it's not firing, I think it can load up the pipes with trapped mix so when I'm tinkering with it, I take that pipe off. Blows out raw fuel something fierce on that side so really don't think it can be a carb issue?? Thanks, Doug

I'm back to thinking bad rotor. You guys think I should spring for one on fleabay??

Rizingson · Posted: Thu Oct 07, 2010 8:12 am Post subject:

Doug,
I also have an X-6 Street version that I'm having similar problems with. Will run good for about a mile and then when slowing down for a stop or corner it will bog down loose power and die. Shuttling back and forth on the enrichment lever/choke, it come back to life but then I'll need to shut it off because the other cylinder is to rich. I won't take it apart again til next spring, but I agree with Tezza that your problems are carb related. Have you cleaned them?
Here's what I'd look for.
Plugged Idle jet
Enrichment valve not seating when choke is off
Float levels
Fuel flow through the petcock doesn't always equate to the right level maintained in fuel bowl. ie sticking float valve.
On the electrical side of things, the T20 has a reputation (documented back in the late '60s) for destroying coils if ran with no battery or bad battery. Check for leaking coils or visible cracks.

AnKhe105 · Posted: Thu Oct 07, 2010 8:56 am Post subject:

Riz, I cleaned them last year when I had everything apart but could be dirty again. What puzzles me is that I can pull the plug out the good side and it is nice and bright. Won't start when I do that. When I pull the plug on the right it will idle nicely but has a noticably weaker spark there. Have tried 2 different coils and even switched the coil leads to see if I could get it to reverse the problem (Won't start when I do that)....? Thanks, Doug

BTW: My "shotgun approach" to the problem is getting spendy. Order new coils? New rotor? Shhesh! This bike has a ton of cash in it already. LOL! I SHALL not be defeated however!

DRC1 · Posted: Thu Oct 07, 2010 10:21 am Post subject:

Bummer

Have you tried changing the plugs? Maybe clean points and make sure connections aren't hitting points cover, if so equiped.

AnKhe105 · Posted: Thu Oct 07, 2010 3:02 pm Post subject:

Oh yeah DRC, changed the plugs and even switched the known "good" plug over to the bad side...same deal. It acts like that side is gounding out but danged if I can find where. There is a points cover but acts up even when it's off.

Tezza · Posted: Thu Oct 07, 2010 10:51 pm Post subject:

It has to be just a process of elimination.
Check that the sump on the cylinder not working is free of any buildup of fuel/oil by removing the drain plug underneath.
Check that the points pivot point is lubricated. They have a habit of sticking sometimes leaving the points open a tad.
Disconnect the negative leads from the coils and swap them.Also swap the plug leads around . This will use the opposite coils on the cylinders.
Still not working???
Disconnect the choke linkage from the carbs and swap them around.
Makes it a little difficult to get at the idle mixture adjustment but it will give you an idea if its the carby.
Start with a fresh charged battery and you could even try isolating the charge circuit by disconnecting the posive lead at the rectifier.
There is a tech tip from suzuki for the T250 to increase the daytime charging circiut by bridging a couple of wires. Maybe its the same for a t20/tc250
I have noticed on my bike that if the battery is low and the indicator is flashing , sometimes the engine misses and it feels like a plug is breaking down.
If you are sure the charge circuit is good do not run the engine without the battery otherwise you will be needing to replace quite a few bulbs if they illuminate. They go very bright for a very short period of time. I have not had a coil failure when running without battery.
I have a can of "Start Ya Bastard" It's a very usefull diagnostic tool for carbys.
Good luck

AnKhe105 · Posted: Fri Oct 08, 2010 3:05 am Post subject:

I have a can of "Start Ya Bastard" It's a very usefull diagnostic tool for carbys.

LOL! Now THAT"S what I need Tez! Will be gone all day today but will be back at this bad boy tomorrow. Some great tips there to try. Never tried switching the carbs and not sure it's possible but probably is. Just a matter of switching the linkage from one to the other so will take a look at that option. Only thing is...that rubber boot to the air cleaner is a real pain to get back on but if she ain't runnin' as is I have to try something else. Thanks, Doug

dorT500 · Posted: Fri Oct 08, 2010 5:00 am Post subject:

Hey Doug,
Remember the #1 rule.....a fully charged AND known good battery before doing ANY type of engine troubleshooting. How old is your battery? Even if pretty new, how many times has it been discharged? Checked the fluid levels? Did you charge it several times during those months it was not being used? Set the battery aside for an hour after you have had it on a 1.5 -2 amp trickle charger.....then check the voltage again. While you are out today you may also want to pick up one of these to add to your arsenal. Good luck.

http://www.google.com/products/catalog?q=battery+hydrometer&hl=en&client=firefox-a&hs=SWq&rls=org.mozilla:en-US:official&channel=s&prmd=ivs&resnum=1&um=1&ie=UTF-8&cid=13435163568364576663&ei=afauTJiCBsOAlAeGmuzcBA&sa=X&oi=product_catalog_result&ct=result&resnum=1&ved=0CEoQ8wIwAA#