1979 CR125R Carb replacement

[nola_fiddy]

Hey all,
I have a 1979 CR125R that needed a new carb. I bought a Mikuni VM 34mm for the otherwise stock bike. I am having issues jetting the bike - still too rich.

I'm at the point where I need to order more main jets and needle jets to try and find the right jetting. My question is, should I go down to the 32MM Minuni VM carb? I think this may help out with my jetting issues - but I'm not sure. Or should I just keep adjusting the 34MM?

Any advice would be appreciated.

thanks,
nola_fiddy

 

[whenfoxforks-ruled]

Too rich on what circuit? Are you sure the engine is tight? Has there been any engine mods? Timing is set properly? New silencer packing and reeds? Properly mixed fresh fuel? What was stock, 32? Read Spank's jetting guide, http://www.dirtrider.net/forums3/showthread.php?t=128706&highlight=spanky+jetting+guide .

 

[nola_fiddy]

The bike had been sitting for years before I got it. I changed the two crank oil seals. Put a new piston, rings, wrist pin, wrist pin bearing and new gaskets on the top end. I checked the air intake for leaks - none present. The bike is bone stock.

The bike had a 32mm carb stock. I did not know that when I bought the 34mm. It runs rich in the middle mostly and sputters some wide open.

I am getting my cylinder replated this week and will play with the 34mm a little more before I go ahead and get the 32mm.

Thanks for pointing me to the guide. I will post my results.

thanks,
nola_fiddy

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