Triumphrat

walshja

I have a 1995 Thunderbird with 5k miles.

I just started getting her going again and an old problem I have had is still there.

I had the carbs cleaned at my dealer and the bike runs fine, until she heats up, then it feels like I am losing cylinders 1 at a time until the bike dies. I let the bike cool off and she runs fine until she heats up again.

The bike was sitting for a few years and previously I had this problem but it only seemed like I was losing 1 cylinder, never all 3.

No idiot lights come on telling me the bike is over heating, and the fan never comes on, but it sure seems like after riding the bike for a bit, that is when it dies, I sit for a 5-10 minutes and she starts up and runs fine, then dies all over again.

I am thinking it is 1 of 2 problems

1. bad coils, but if the coils were bad, wouldn't the problem be constant?
2. the bike is over heating and shutting down??

does anyone have any thoughts on how I can diagnose this problem?

thanks, joe

HunterThompson

How about a combination of both problems. The bike warms up and the coils get warm and fail.

parrycm

I think the symptom of failing when warm and affecting all 3 cylinders points to the ignition pickup. It's a hall effect sensor in the front righthand engine cover and you can see the lead come out and go up to the wiring harness.

Just IMHO...

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Chris

"Panniers can never hold everything you want, but they CAN hold everything you need."

walshja

is that a possibility? that when the coils warm up they begin to fail?? all 3 of them !!!

i hope it is something that simple . . .

triple3john

I've had the same problem and it was the ignition pickup. Not expensive to fix and the bike has been ok since (which is several years ago now). Mine is also a 1995 and interestingly the original pickup was made in Germany and this was a common fault.The later pickups were made in UK.

walshja

this sounds promising !!

is this an easy fix?

is there a way to test the ignition pickup? or is it cheap enough to simply replace and see if the problem goes away?

thanks for your help, you always have answers !!!

parrycm

http://houseofmotorcycles.bikebandit...RD/All/2292639

$71 for the part. I don't know how to test it. You could buy it and if it doesn't work, reduce your loss by selling it in the Classifieds here or ebay.

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Chris

"Panniers can never hold everything you want, but they CAN hold everything you need."

jimmyj900

Actually it's a Darlington trigger. A Hall sensor usually has 3 wires and is a constant voltage device while a Darlington is a constant energy device where the output voltage varies with rpm much like a magneto.

Yeah, it's possible. The trouble is that folks generally don't notice a weak (bad) coil until it begins acting up at higher rpms or quits so they can be failing for quite a while until they become inoperative.

There have been been several cases of thermal failure of the ignition coils reported, so if you're correct about the cylinders shutting down one at a time it's probably the ignition coils.

If all three coils quit at the same time then it's probably the pickup coil.
There's no over-temperature shutdown on these bikes (unless the engine seizes) so that's not an issue.

Jim

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walshja

well thanks everyone, I ordered the ignition pickup as I think based on your descriptions, that most closely resembles my problems.

when installing the pickup, are there any special instructions? or things to watch out for?

I am certainly not a mechanic, but know enough to get myself into trouble !!

thanks

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joe
1995 thunderbird, tiger cams, TOR pipes
1978 Yamaha 650 special
1983 Suzuki gs550
1979 WR250 Husqvarna, 1972 Honda MR50

Hagrid

It is an easy fix. I replaced mine this spring after experiencing the same symptoms. After taking off the timing cover it only requires the removal of two torx screws and un-plugging the connector. Installation is the reverse. I'll double check my manual but I seem to recall the air gap between timing wheel "****" being 0.8mm.

If you want to test the pick-up you could try the "aerosol cooling" method. When an electronic component starts to fail intermittently when heating, cool it down to test. This is an older analog radio guy trick. You spray an aerosol cooling spray on various electronic components and when you hit the right one the radio works. You could try the same thing here to be sure or be Mr. Wizard but I'll bet it is in fact your pick-up. They sell the stuff at Radio Shack.

Good luck...Hagrid