C125 '77 model standard specs for 34mm Mikuni

[bigthumpa]

Trying to get some specs for a 1977 CR125 fitted with a 34mm Mikuni for a mate who is trying to get his bike ready for the Nats. Anybody able to help?

Cheers
Nick

[Momus]

Try Tom at TD Hatrick the Australian Mikuni people mate. He is pretty reasonable with information.

I bought a 30 mm Mikuni for my CR125M that needed no changing and was a vast improvement over the oe Keihin

[bigk]

I have jetting specs for 32/34 Mikuni somewhere, I'll find them & post them tomorrow.
K

[alexbrown64]

Bigthumpa.. these are from VitalMX members..

The carb is VM34 and I would love to get your jetting specs. I started with a 310 main and 35 pilot with the clip in the middle of the needle and a 2.5 slide. Mike

Here is what I run for jetting: VM34 Mikuni 300 Main (290 used occasionally) 45 Pilot (yes 45!) 6DH4 needle 2.5 Slide
Cutaway. You didn't mention what needle you are using. Start with needle in the middle and go from there!

I started with a 320 Main, lots of plug chops, went to a 310 more chops, 300 had best power and plug color.

Mike,

Thanks for the jetting specs and I'll let you know how it turns out. I am in the mid-atlantic at sea level.

Thanks for those jetting tips! They all seem pretty right premixing 32:1, except the pilot (I think I need to go down to a 40), but other than that the bike pulls like mule. If I had an issue it would be the exhaust note, which is really deep (doesn't sound like a 125 until you get into the mid to top). This is an obvious side effect of the Proto-pipe. But, one good plus is that I will never have to lube my chain again for sure. Mike

http://www.vitalmx.com/forums/Old-School-Moto,22/76-Honda-CR125-Elsinore-Build,1283982

[bigk]

This is what I have in my notes for VM34 (or VM32) Mikuni on 1977 CR125:
Main jet: 300
Pilot jet: 35
Needle: 6DH2 (2nd clip from top)
Needle jet: QO
Slide: 2.5
Cheers,
K

[alexbrown64]

Take a look at this 76 for sale over at eastcoast vintage mx... 6K...



Cheers,
Alex

[bigthumpa]

Thanks everyone for the info, I have passed it onto Mark who is working feverishly to get his bikes ready for Busselton this weekend.