New thread - 1974 WR 250 not running

I'm starting a new thread here just to get back to the general problem of the bike not running. When I first got it, the bike start on the 2nd or 3rd kick (tickle the Bing until gas was running out). It'd run great for 15 minutes or so and die. It'd start up again and run great again after the bike had sat and cooled off. Based on the advice here and what Vintage Husky John L. told me on the phone, it was ignition. I replaced the coil first (because its easiest) with no improvement, and then replaced the condenser. That worked for a short period of time. After that, the bike would start, but feel like it was loaded up all the time and sound like it was or almost was backfiring.

I pulled the flywheel again, and replaced the points. That seemed to work, but it was winter, and I could only rev it in the garage. I tried to actually ride on the first warm day, and it did the same thing but worse. It'd start, and never get better than a bike that sounded like it was badly loaded up.

It has spark. How strong I don't know. Its "bluish" at best. I rechecked the timing, and that seemed fine. I pulled the carb apart, and decided to get a Bing rebuild kit and floats.

I just did the rebuild kit and floats, and there's no improvement. I had spoken to VH John, and he told me that he thought it was a dying Femsa that may spark when the plug is out but not have enough juice under load, and to get an electronic ignition. He doesn't sell ignitions.

So, unless someone has an idea, I'm going to get a Powerdynamo.

Any thoughts? This is driving me a little nuts

I had problems also. I decided I will travel 400 miles or so for a race with a ignition that may or may not work. Change to the power dynamo. Replace the kill button with a two wire button. The two wire has a separate ground wire that is more reliable. Make sure you have a good carb also. Jeff

Informative post. I can understand your frustration.

The fact that the bike malfunctions after getting hot certainly sounds like ignition. If you can part with a few hundred bucks then try a new ignition. If not then check the other coil you didn't replace, Femsa system has two. Also double check your points gap, should be between .014 and .018. When things get hot they expand and I imagine points gap will decrease. If the gap is too much less than the factory setting you may have toasted the new condenser.

Femsa is more difficult to set up than a digital ignition but they work great and are dependable when they're dialed in. Not knowing what shop manual you're referencing I've attached a pdf with two pages from a Husky shop manual regarding timing. Checkout what it says on page two about bad points and condenser.

Thanks. It used to run well and die when hot. Now it barely starts, then runs like it's really loaded up for 5 or 10 seconds, never clears, then dies.

As a long time British 2 stroke user I share your pain, several things I do to make life easier. Install the condenser by the HT coil it does not need to be behind the flywheel and this will take it away from the heat and vibration. It also allows the use of any condenser, I generally use one from a Mini car( real one not BMW). Re set timing when you replace points. The generating coil might be failing inside, replace or rewind. you should be able to replace the HT coil with a Japanese/Chinese one. The flywheel can be re-magnetised.
But to me this really sounds like condenser, classic blue spark which buggers off as soon as the bike is started!!
However if you have more money than time go for the electronic ignition every time.

^^^ great advice from stormer

In the US a Mallory or Ford V8 "Standard Ignition" (brand) condenser from NAPA is what I try to get... Used a Bosch condenser from an air cooled VW once and it worked good too. I have had "new" condensers fail or not even work out of the box... never happened in the old days. But these days condenser quality seems to be suspect, especially the ones with no markings. Having up by the coil makes it easy to swap out too.

You can also get a Bultaco condensor as they used FEMSA in the 70's as well. Hugh's Bultaco and Hogan's Cycle in Agawam ,MA should both have them.

FEMSA is so simple that there is nothing expensive to keep it from working unless the magnets happen to fall out of the flywheel. Just check all ground points including the front engine mount plates. Common on dormant machines.

Very good point on the earthing (grounding) points, I have often used a separate wire fro the engine casing to somewhere on the frame.