79 TS185 Misfire
 

My TS185 starts great and runs fine except when accelerating. It winds out fine if first gear and ok in second but in third gear and above it misfires -- kind of sputters. Once up to speed it runs fine.

Any suggestions on what might be causing this? Or, what I might do to diagnose the cause of the problem?

Thanks.

Hey Wernerschink. This misfire or inability to rev out properly seems to be one of the main problems that people have with the TS185. I had the same problem and traced it back to a faulty ignition coil which wasn't producing a hot enough spark to ignite the mixture properly. However, there have been people since that were unable to fix the problem with a different ignition coil, so it remains a bit of a mystery. Here's a link to a similar thread on HU http://www.horizonsunlimited.com/hub...evs-fine-42351

There is also a great site that EAnchak has started up just for the TS, TD, TC and TF models (they're all rather similar). It's worth checking out Suzukits . In the mean time, there are a few things that you could check on. Firstly, that the spark plug is functioning correctly. It's probably worth putting a new one in just to be safe. Sometimes they can look good on the outside but be breaking down on the inside. You could also check that the airfilter is clean, fuel is getting to the carb, and the exhaust isn't blocked. If all these seem ok, then it's time to get a bit more serious. Let us know how you go with these preliminary checks. If it's still acting up afterwards, post back and hopefully we'll be able to help you find the problem.

Cheers, John.

Thanks John,

I'll follow up on your suggestions. Do you have any thoughts on why it winds out OK without misfiring in 1st but not in the higher gears? It's like it fires 3 times correctly and misses on the fourth and follows this sequence until it gets up to speed, then doesn't misfire when maintaining speed.

Werner

The engine is under less load in 1st than in 5th. That's why the bike will stall if you try and take off on a hill in 5th. So it's easier to rev the bike out in first than in fifth. Misfiring is usually ignition related, but the symptoms can also be mimicked by an out of tune carb. If you have a timing light though, it would be a good place to start. Sometimes the air gap on the magneto increases with wear which doesn't affect the strength of the spark, but can put the timing out by a few degrees. So as the bike ages, the factory set timing is no longer as accurate. To check the timing, rev the bike up to 6000rpm, at which point the timing should be fully advanced and the mark on the flywheel should line up with the mark on the crankcase. If these lines don't line up, turn the stator plate a small amount in the direction it needs to go. Haynes also recommends that a bp7es sparkplug be used.

Once the timing is set, your next port of call is the carburettor. From memory the 79 uses the same mikuni 29mm carb as the 82. To check that the carb is set up correctly, measure the float height (which should be 24mm) and make sure the needle-clip is on the middle notch. If you have a manual in front of you, check to make sure the jets are all stock. There are a few more things that could be checked on the carb, but if the float height and needle-clip are set up correctly than it should be good enough for the time being.

Best of luck with these tests. Post back if you're unsure of anything, or if there's any progress. Good luck!

John.

John,

Thanks again. Your suggestions are really helpful.

Werner

The misfire is gone. It had been sitting for awhile and driving it and letting it sit and idle for an hour or so helped quite a bit. After that most of the miss was gone. Then switched to the bp7es spark plug and that got rid of the rest. Thanks again John.

Good to hear it's running properly. Enjoy! BTW, there is a new TS,TC,TF,TD site that has been created by EAnchak called Suzukits It's in its early stages atm, but still a good site if ever you're in need of some ts info.

Cheers, John.