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So, I've been working on turning my stock 1983 Shadow VT750C into a little bobber project. The most info on this is in a previous thread you can find here:

http://www.hondashadow.net/forum/72...-heres-my-83-750-stock-muffler-taken-off.html

So the major things i did were re-doing the seat and taking off the stock exhaust. Since I took the stock muffler off the exhaust had starting running much hotter. That is to be expected running just the header pipes, so I was not surprised. I know that you should get the carbs rejetted after doing this, but it was not popping on decel and there was no loss of power. In fact I would say there was more power. I figured it should be ok to run for a while like this at least. I also added some slash cut extensions and wrapped the headers with exhaust wrap. I won't get into all the trouble I've had up to this point, but just little things like just a few inches short on the exhaust wrap and bracket issues.

So now the real fun starts. I had painted the exhaust extensions with high temp paint which needs to cure. 10 min idle, 20 min cool down, 20 min idle, 20 min cool down, 30 min normal run, cool down. And after wrapping one of the headers, (didn't have enough to do both sides) I started the curing process. I also knew that there would be smoking from the wrap as the moisture evaporates. Everything is going fine then about 12 min into the 20 min idle the rpm's suddenly drop and the oil light comes on. I shut it off and figure ok, done for the night. I start it up the next day and it's fine. Oil level is ok, maybe a little high, but better high than low right? My new order of wrap is delivered and I get to work. Finish it up and start to run it again. I go through the curing process again because I had some touch up painting to do on exhaust. Again, in the 20 min idle phase it drops rpm again. No oil light this time though. I try and take it for a little ride down the street and there is no power. I really have to gun it to move. I shut it off and tried again in about an hour. Starts up fine and runs same as always.

I find this post that seems to describe exactly what I'm going through:

http://www.hondashadow.net/forum/72-technical-discussion/109662-sudden-loss-all-power-rpms-help.html

Sounds like he's having an ignition coil issue. From what I can read that would make sense with what I'm going through. My guess is that by removing the stock muffler and having the engine run hotter it's heating up the ignition coil too much causing it to fail. I checked the plugs and the back cylinder was wet on both plugs while the front ones were kind of white and ashy. My fear is that i will order a new ignition coil and i will run into the same issue if my engine is running hot still. Will rejetting the carbs help the engine run cooler again?
 

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Yes rejetting will cool your engine temp (or at LEAST your exhaust temp)

Leaner = Hotter burn

Richer = colder burn

Personally i believe it was just happenstance that your coil failed when it did. But rejetting can't hurt any.
 

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If you’ll look at the photo of my bike I run very short turn downs right off the header pipe. I do not have any heating issues (that I am aware of after riding for 3+ years in this configuration). I did not need to rejet, bike runs to my liking. Now this is just me, mind you!

I would pull your spark plug wires (one at a time) and look at the spark carefully. Is it strong & blue, or weak? If two plugs from the same cylinder are weak, might be coil, or spark wires themselves. If your getting good spark I would not think coil, instead the plugs themselves. How old are they? Clean, gapped correctly? Also lift your tank and give the coils a good inspection. Cracked, or shorting on their mounts? Test them with a meter while you have the chance.

P.S. I also painted my exhaust tips and was not as fussy with curing. Painted and then just ran normally for a while. It will be fine, don’t sweat it, too much. ;)
 
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