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Bill163

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4/1/2008

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USA

Bill163 7/18/2016 6:09pm

7/18/2016 6:09pm Edited Date/Time 7/18/2016 6:11pm

mark_swart wrote:

Thanks for the comment! I actually had my first ride on it this weekend. As anyone who has rebuilt one knows, the first ride usually isn't...

Thanks for the comment! I actually had my first ride on it this weekend. As anyone who has rebuilt one knows, the first ride usually isn't good, it's where you figure out what you missed. It basically runs like it has a rag in the air box. I am rebuilding the carb and putting in new reeds this week. It starts but just doesn't want to rev out. Power valve is working and opening fine, and it seems to run worse the longer it runs, which seems like it could be a reed blowback problem. Just slow to rev and messy / slow to clear out on top. Main jet was wrong, but I don't think it could be the soul culprit.
Still waiting on graphics too. Anyway, here's where we are now!

Its not the reeds your lower CDI unit is going bad a real common problem loss of power when hot don't ride it any more or you will melt the piston.Check Electrosport they have new lower units for $100 Also change the crank seal on that side cheap and easy no air leaks

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mark_swart

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2524

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11/2/2011

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Chapin, SC, USA

mark_swart 7/18/2016 7:03pm

7/18/2016 7:03pm Edited Date/Time 7/18/2016 7:05pm

Bill163 wrote:

Its not the reeds your lower CDI unit is going bad a real common problem loss of power when hot don't ride it any more or...

Its not the reeds your lower CDI unit is going bad a real common problem loss of power when hot don't ride it any more or you will melt the piston.Check Electrosport they have new lower units for $100 Also change the crank seal on that side cheap and easy no air leaks

I really appreciate that! I actually have a whole second ignition I can swap onto it. So you are saying it's the components on the stator, or the actual CDI box?
Crank seals are new and I was careful installing them so I wouldn't think they will be an issue. Will check just in case when I have it apart.

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MaxPower

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8/15/2006

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USA

MaxPower 7/19/2016 2:40am

7/19/2016 2:40am Edited Date/Time 7/19/2016 2:42am

I agree with Bill
I feel its your stator (not cdi)
Old RMs were known for stators going bad
At least every RM ive owned had the stator fail
Amazing job on building your bike

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mark_swart

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2524

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11/2/2011

Location

Chapin, SC, USA

mark_swart 7/19/2016 2:53pm

7/19/2016 2:53pm

MaxPower wrote:

I agree with Bill I feel its your stator (not cdi) Old RMs were known for stators going bad At least every RM ive owned had...

I agree with Bill
I feel its your stator (not cdi)
Old RMs were known for stators going bad
At least every RM ive owned had the stator fail
Amazing job on building your bike

Thanks! It actually came together quicker than expected, I happened to run across a guy on ebay who bought one, took it apart, then decided to go newer. So I picked up a LOT of stuff from him at a very good price. I was lucky, because when I split my cases I found third gear destroyed, and the left side case insert that goes around the main bearing was wiggling around. He sold me bottom end (blown crank) with ignition and top end for $75. It was extremely lucky. It also had a ported cylinder that was in better shape than the one that came on the bike (Paul Turner is etched in the side of it.)

With any luck, the ignition that came with my parts engine won't have the same problem. But it's good to know I can also buy a replacement if need be.

So I think once I get the ignition dialed I'll have a pretty decent bike. And come to think of it... I had an 85 RM 125 that ran basically the same way, back in about 1992. Probably the exact same problem!