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Discussion Starter · #1 ·
She's up an running like a top!!!



I'm so very happy to be riding again, although I'm taking it easy since it's been so many years since I was last on a bike.



I had a young man change out the mechanical seal (thanks again, Doward!) for me and get her going. Everything seemes to be fine with one exception...



The temp gauge would climb up to the maximum for a few minutes and then come back down to normal, but now it just goes to max after a few minutes of riding (or idling) and stays there. The bike runs fine and I can put my hands on the cylinders and crank case for several seconds so it's not like it's heating up to a meltdown of biblical proportions.



My mechaninc took the thermostat out of the parts bike and tested it before he installed it, and ended up getting an O-ring kit for putting it all back together. I put 42 miles on it without any signs of trouble



Any suggestions?
 

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It could be the 7 volt but it could be something else.



Place your bike on the centerstand and run it till warm. Then slowly turn the handlebars each way and see if the needle change is because of that.



My brothers bike had a similar problem and every time the bars were turned to the right the gauge pegged and to the left it went back to normal. In the middle if coming back from the right it stayed peg. Using my test light I found that when I had the clamp on the key and light on the headlight bucket it went back to normal. Took it off and it pegged out again.



So look at your wires and grounds.
 

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When its showing hot

I'd open the temp sender wire connector in front of the carbs and behind the thermostat and measure the voltage

on the green/blue wire

You dont have to, but it may be easier to whip the tank off to do this

With ignition on you want see 7V on this wire

any more, then then its obvious the 7V regulator has failed

Quite a common fault on these bikes.



If it shows hot and you get a steady 7v then that indicates a real problem
 

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Discussion Starter · #6 ·
Thanks guys...I'll give it a try this afternoon!
 

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Discussion Starter · #7 ·
Well I checked it and got a whopping 0.53 volts so that sounds like it may be the problem. I'll get an infrared sensor on the crankcase and cylinders tomorrow to be sure. I'll also recheck the voltage as it was getting dark and I'd had a belt or two to double check.



It sure is great to be riding again!!!
 

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Well I checked it and got a whopping 0.53 volts so that sounds like it may be the problem. I'll get an infrared sensor on the crankcase and cylinders tomorrow to be sure. I'll also recheck the voltage as it was getting dark and I'd had a belt or two to double check.



It sure is great to be riding again!!!


I always check my Cylinder temps at the back of the cylinders in the middle of a water jacket and they are around 80/85 Deg C to avoid a false reading because of the exhausts at idle and because I have an Electric Fan conversion they will rise a little and fall as the Fan cuts in.
 

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Glad to hear you figured it out, the 7V reg. is a pretty easy fix. You could buy a used one off ebay and take a chance or you could even make your own. I think Marshal(?) on here was selling some DIY one's at one point?
 

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Discussion Starter · #10 ·
Even with the temp gauge burried all the way over the cylanders are still only reading 185-195 farenheit so well within normal limits. I check the temp every time I get home and pull into the shop.



The only issue is the left cylander is always about 20-30 degrees cooler...fuel mixture and or carb synch I'm guessing?
 

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Discussion Starter · #11 ·
Update bump...I picked up the parts bike a few days ago and replaced the 7v reg this afternoon and everything works fine!
 
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