Trouble shooting a GS250T

[Briars]

Good day gentlemen,

I have a nice little 81 GS250T which I did quite a bit of work on to get it going well.

But now I am experiencing electrical problems. It is not firing on the left side. It began to miss and I reached down and pulled the plug wires to see which was missing. When I pulled the wire up a bit it began to run very well. I turned back to home and the lights surged and it died. I found a blown main fuse and the tail light and a few of the indicator lights on the dash are out.

That to me indicated a regulator or ground problem.

So I started to trouble shoot the thing.

I checked the coils with a ohm meter both checked ok with one being a bit low on the secondary. 20.7 if I remember correctly. But that was the side that is firing.

I then tried to check the igniter using the ohm meter as the jumper and with key on and watching the plugs to see if they fire. That was per the factory service manual. I could not get the plugs to spark using that method. So I decided to just hit the starter and I got fire on the right side and no fire on the left. I then jumped the igniter wires from the working coil to the side which was not firing and I got fire. So I deduced the coils are ok, with one being a bit week.

I then checked the regulator/rectifier per the factory manual and got open readings on all legs. So I assume it is blown completely.

I also checked the stator. I checked the three wires for continuity and against the ground per the stator papers and the stator is fine.

So I am confused and need help, could the stator problem cause the igniter to not hit on the one cylinder leg? Or do you think when the stator blew it also screwed up the one leg of the igniter? Or could a bad igniter damage the R/R.

I think I need both the R/R and the igniter. Should I purchase both or get the R/R first and if that does not fix it get a new igniter.

Lastly do any of you know of a good source for the igniter. Are there any aftermarket or alternatives to the oem unit?

Thanks so much, I have found this site to be a wonderful resource.

[pete]

First off, the tests in the manual for the R/R aren't conclusive and for example won't work with my multimeter at all. It depends on how your meter does the diode test as to whether it works or not.

Read the stator papers on the main GS page for an accurate way of testing the charging circuit as these are known weak points on the GS'

http://www.thegsresources.com/gs_garage.htm

http://www.thegsresources.com/garage/gs_statorfault.htm

It also sounds like your left plug cap may be a little dodgy, and you can replace that with a generic NGK one, but first I'd just trim back a little of the HT lead and put it back on and see if that solves it.

Did you get a mega welcome from BassCliff when you first joined? Have a good read through that which will answer most of these things for you

[Briars]

Well I reread everything I had, the Haynes manual and the Suzuki manual and tried checking the igniter again. Still no spark across the plugs with the key on and touching the bl/w wire with neg side of meter and brown and green/white wires alternately.

So I think the igniter is shot. Could it still spark on the one leg while turning the motor over and not get a spark while testing per the manual?

Will the R/R have any affect on testing the igniter? I don't think so but may be wrong.

I have spent the last 5 hrs searching parts and have decided on the R/R to get but the igniter is freaken expensive. I will have to go with a used one I guess, it is common to the 250, 400, 450, 500 and 550 most in the 80-81-82 vintage with a couple as late as 99.

Please give me advise if you got any.

Thanks

[pete]

I'd really check that plug cap if I was you.

Also, check the voltage at the coils with the ignition on, it should be really close to battery voltage. I had to clean my ignition switch and kill switch properly to get rid of about a 2v loss.

Also, you can quickly ground the coil input (with ignitor disconnected) to see if it sparks at all.

[Briars]

I will check it again as you suggest.

I have found a Reg/Rect but not sure if it will work, it is quoted as an "04" Honda CBR 1000RR it is SHINDENGEN sh678fb. One the list that quotes the ones that will work there is a sh678b, is that the same one with just a letter missing?

I goggled the sh678b but did not return any results.

[Doug]

I have a similiar problem with my GS250T

Greetings,

I have been having the identical problem as you described. I got my bike cheap, I'm a total nube, but I'm having a great time learning. If there are any guys that have seen this before, your advise is greatly appreciated, and I'll be ready to give your suggestions a try.

The original start button was completely missing so I got one and it tests fine.

Jumping the starter and battery wires I could see spark and got the bike to start (once).

The R/R was fried (burnt/melted wires) so I purchased an aftermarket replacement.

Hooked up the new start button and the R/R and still the start button does not kick in the solenoid and turn over the start motor. Solenoid tested 3.8 ohms as per the service manual

I'm thinking that it might be bad ground to the solenoid (someone suggested running a wire from one bolt of the solenoid to negative battery terminal).

Could it also be a bad/dirty or not fully engaged neutral switch? The console indicates the bike is in neutral however could it be a fault here is prohibiting current to the solenoid?

If you have a bad neutral switch would it prohibit the Igniter test as outlined in the service manual from working?

[pete]

I'm not sure on R/R's as I haven't gotten that far yet, but as for the ignitor, you need to rule everything out first before replacing it unless you know someone you can borrow one from.

If you can get spark on at least one plug, but the ignitor test doesn't work on the same plug, then I'd say that definitely does *not* prove your ignitor is faulty. Doesn't mean it's good, but definitely shows that the ignitor test is not valid.

Grounds are the first most important thing as that also influences the charging system. The best solution is to move all your grounds to one common point that you know is good.

The stator papers are a really good guide as to determining if your stator is good/bad and if your R/R is good/bad, but grounds and connections will play a big part in your R/R performance also.

You really need to compare voltage at the battery compared to at the coils and various other places on the harness and ensure you're getting as little voltage drop as possible.

It did take me several hours to go through my harness connections properly to eliminate almost all the voltage drops.

[Doug]

GS250 Ignitor Test

Greetings,

I have found that the ignitor test will not work unless your multi-meter passes 1.5 volts to the cdi during the test. The FSM or The haynes guide may have been written when recommend tester would provide the needed 1.5 volts when set at the specific resistance level. Resistance is measured by the meter is done by placing a voltage at each of the probes and then measuring the drop. It could be that your meter is not delivering the needed 1.5 volts.

You can still test the cdi by using a 1.5 volt battery, connected correctly. The negative lead connects to the black/white on the ignitor and the postive lead connects to the brown or green/white. Reversing the polarity can damage the cdi, so keep them straight.

Remember the ignition should be turned on. Good luck.