Mikuni jetting on a 6 Day

[skiracer]

Looking for a jetting starting point with a 32mm

1976 MC 5 Original Owner
1976 Penton 175 XC
1985 20' Hi Point trailer

[Larry Perkins]

Can not help on that one but curious if the motor has any port work done on it because a 32mm is very big for a piston port Sachs 125 motor.  The original porting had no bridges to be able to add much size and no booster ports so I never ran one bigger than 30mm and that one had been dremeled to the point that it went through rings pretty quickly.  That is a lot of flow.  also post later how it works out if you do not mind.  Thanks!

Larry P

[skiracer]

Actually a fellow member has the bike, and I have the carb.  I appreciate your input, hope all is well.....

1976 MC 5 Original Owner
1976 Penton 175 XC
1985 20' Hi Point trailer

[Dale Fisher]

I run a 32mm on the Cheney Sachs and it scoots much faster than my ability.  The recently completed Berkshire came with a 32mm spigot mount that slips right on like a Bing but it hasn't been completely sorted (leaky gas tank and sticky gas metering needle).

Back to the Cheney...  I thought that I had scanned the clipping but it looks like the Carb, adapter mount, and slide were all part of a hop up kit.  The slide has been altered with the angle portion larger the what the catalog/marking indicate.





Dale Fisher
Penton Owners Group - President/Memberships
POG Merchandise
Mudlark Registry
Facebook - Penton Owners Group - Administrator
Facebook - Cheney Racing Group - Administrator

[HeathRobertson]

What size Jet Dale?  Or ballpark even, just something to start with?

[Dale Fisher]

I pulled this up using the search function.  The jetting for the Cheney won't help too much since the needle (unavailable) and slide (modified) are unique.

Originally Ernie Page's work?



Dale Fisher
Penton Owners Group - President/Memberships
POG Merchandise
Mudlark Registry
Facebook - Penton Owners Group - Administrator
Facebook - Cheney Racing Group - Administrator

[KJDonovan]

James / Heath,

I had these written down as a jumping off point.

169N8-Needle Jet
5F21 Needle (Clip on 2nd slot from top)
40 - Pilot Jet
155 - Main
2.5 Slide

May be a little rich, but better rich than lean.

Thanks,

Kevin

[Mickey Sergeant]

I run a 32mm mikuni on my 125.  Ported motor.
sea level 175 main
2500ft 170
4300ft 160
don't remember pilot or needle. what ever it came with is what is in there
I have been running this for 3years now

Mickey

[skiracer]

Great photo!  Thanks for the input.

quote:Originally posted by Dale Fisher

I run a 32mm on the Cheney Sachs and it scoots much faster than my ability.  The recently completed Berkshire came with a 32mm spigot mount that slips right on like a Bing but it hasn't been completely sorted (leaky gas tank and sticky gas metering needle).

Back to the Cheney...  I thought that I had scanned the clipping but it looks like the Carb, adapter mount, and slide were all part of a hop up kit.  The slide has been altered with the angle portion larger the what the catalog/marking indicate.





Dale Fisher
Penton Owners Group - President/Memberships
POG Merchandise
Mudlark Registry
Facebook - Penton Owners Group - Administrator
Facebook - Cheney Racing Group - Administrator

1976 MC 5 Original Owner
1976 Penton 175 XC
1985 20' Hi Point trailer

[skiracer]

Thanks everyone for the help with your input. It is well appreciated!

1976 MC 5 Original Owner
1976 Penton 175 XC
1985 20' Hi Point trailer

[HeathRobertson]

Yes, thank you all for the input!  Much appreciated

[JP Morgen]

6F5 needle is key

[skiracer]

And what needle jet goes along with that??

quote:Originally posted by JP Morgen

6F5 needle is key

1976 MC 5 Original Owner
1976 Penton 175 XC
1985 20' Hi Point trailer