So... I'm a newbie to this site. Just bought my first Magna, a 2000 with 14K miles on it. I've owned and ridden a lot of bikes, but none quite like this one. Absolutely love it. Except for one slight issue. It has cut out on me completely three times now. It really seems to be heat related because if I let the bike sit long enough (about an hour today) it fires right back up. This is not a fuel delivery issue because I opened the relief/drain screw on one of the carbs after it cut out today and fuel flowed out. I replaced the battery last week and it turns over just fine. It just won't start/run until it cools off. I'm a Magna rookie and may use incorrect terminology here. But, there are two ignition coils on this bike (one for the rear cylinders and one for the front cylinders). I see no way that they would both fail at the same time, especially intermittently and only when the bike is hot. I'm now considering what the two coils have in common and a local mechanic told me there is a pulse generator that could be an issue. Has anyone had this fail? If so, what are the symptoms? I don't mind replacing it, but would like some feedback first. Maybe there is just a bad ground?
Anyway, thanks in advance for any advice. Looking forward to curing this malady because this bike is just plain awesome (when it runs!).
Thank you...
Welcome KBAZ! Where are you located?
You will not find a nicer group of people and Magna owners. (I am biased though.) Magnas are awesome machines and truly unique.
Your actual problem
I have not personally known any one who had electrical / heat issues like you were talking about unless it's related to the regulator. That's not to say you aren't having an electrical issue and I'm sure someone can hop on here and provide some insight. I've heard of some people having electrical nightmares but I think most of them were also running a lot of accessories. And heat related issues are "usually" just confined to temperature switches being faulty and not engaging the fan during hot days or low speed riding.
However, I have experienced a similar issue when the fuel vacuum diaphragm started going bad on me. On the right side of bike just under the edge of the tank you will see the vacuum diaphragm that's supposed to cut off fuel to the carbs when the bike is not running. The diaphragm can go bad or just get clogged with a bunch of crap from the tank if the bike has set a lot (and yours has low miles). When this happens it can fluctuate fuel to the carbs so the engine stumbles. But I've also known another rider who had it just cut off fuel to the machine entirely and then it would start up a few minutes later.
When they go bad, they basically don't stay open to allow you enough fuel and then it doesn't shut off fuel when the engine is off... So gradually fuel returns back into the carbs and you can repeat the process all over again.
You may still have a different problem, but it is pretty easy to test this. Get a piece of fuel line and by-pass the diaphragm and see how it runs. Just keep in mind that you'll have to be diligent about using the fuel valve when you're not riding, otherwise gravity will continue to flow fuel into your carbs after you shut off the bike.
I'll be interested to see what others say.
Hey MagnaMan,
Thanks for the reply. Much appreciated.
I'm in PHX, AZ. So I guess I'm a bit of a rogue participant since I'm not from Texas...
I think the voltage regulator/rectifier is okay. I've got a local mechanic who tested the charging system first thing and it showed (based on my memory) about 13V and climbed to at or just over 14V when revving the engine. But that also was being tested when the bike had cooled off and was running fine. That's what is maddening about this issue. This mechanic was straight up with me and said if he could make it fail, he could for sure diagnose it. Otherwise, it's an exercise in checking all potential causes in the hopes of finding a clear fault. It would be good to hear from anyone who has had an intermittent R/R issue. One thing is for sure, it is hot in PHX so I'd say any heat related maladies are in play. Then again, I guess it gets hot in TX too!
Good thought on the vacuum diaphragm. He suggested that and also disassembled it for inspection. It all looked okay. This is why he suggested I crack open the carb drain/relief screw upon the next failure. I did that right away and fuel flowed out. It just seems to me like there is no spark. So, whatever could intermittently interrupt that, especially when the engine is hot, has to be considered. If anyone out there has had a voltage R/R act intermittently like this, please let me know.
Thanks again. Looking forward to getting past this issue so I can enjoy this bike. I've managed to put on about 150 miles thus far and have really loved it.
I have not heard of a pulse generator failure on a magna but I am sure it can happen I had one fail on a Goldwing that I owned and those are the symptoms if you have a manual check the procedure for testing the pulse generator I know it can be tested with a volt meter. If you dont have a manual I know there is a link on this site where you can download one. Welcome to the site and I hope you solve the problem soon magnas are so much fun to ride.
God I hate electrical gremlins.
This can be many different things.
Assuming that all the cylinders are dead electrically when this manifests itself, it could be the ignition pulse generator, neutral safety switch, side stand switch, ICM, clutch switch or engine kill switch. Some loose or corroded ignition system connection could also be the culprit.
You have got to get this problem to present itself to be able to diagnose it properly.
A Honda Service manual will give you the proper procedure for flowchart diagnostics. You can change parts all summer long and never fix it.
If you have the tools and patience, I will mail some copies of the manual to you for your use. Barring that, you will need to find a very good mechanic to chase this down. I'm in Dallas so I can't help you locally.
Magnas are fine pieces of equipment and this will probably turn out to be something very simple and inexpensive materials-wise.
My Magna is an 83; I don't know how different it is from yours. I had similar symptoms when a pulse generator failed intermittently. It was not heat related, but just random which your might also be. Mine has two pulse generators. In addition to the spark, one controls the tach and the other controls the fuel pump. Just swap them and see if the bike runs well but the tach now fails randomly.
Rick Frankenberger
Great feedback. Thank you Jerry G, Smoked U, and SkyRide. Much appreciated. Glad I found this site.
I ordered a pulse generator (my bike has only one). I found my exact symptoms on other sites (including Goldwing owners like Jerry mentioned). It's worth a shot in my opinion. I know it can be ohmed out, but if it is a winding that is intermittently failing I think it'll check fine unless I test it when it is misbehaving.
Looking forward to figuring it out because this bike is a blast to ride. I put Cobra slashcut pipes and a K&N air filter on it and had it rejetted. I must say, It has some boogie for a 750 and is also very nimble.
Will update this post once the pulse generator is replaced with the results. Crossing my fingers because I'm ready to ride even though it is like 112F here these days!
Quote from: KBAZ on June 16, 2015, 11:44:18 PM
GI put Cobra slashcut pipes and a K&N air filter on it and had it rejetted.
Did you take off the stock pipes? Do you still have them? I just recently scraped one of mine up.