Penton Owners Group

General Discussion => Penton Talk => Topic started by: Nightwind15 on April 17, 2019, 04:02:25 PM

Title: Mikuni Conversion
Post by: Nightwind15 on April 17, 2019, 04:02:25 PM
Hi,
Question. Penton 250 Hare scrambler 1975.   I called Sudco and talked to a tech about converting to a Mikuni carb.  He said I needed a VM36 Mikuni.  So....I ordered it a throttle cable and new throttle.  The VM36 came in and the venture orifice ends are too big and the air intake boot is not going to work, no way.  Did I get the wrong carburetor?  The Bing on it was a 36 model 54.  Please email me if you have any clue what I need. [email protected]
Thank you in advance.

Nightwind15
Title: Mikuni Conversion
Post by: Dale Fisher on April 18, 2019, 08:23:22 AM
Much to see on all of the Mikuni conversions (125, 175, 250, etc.) using the Searching the Message Board feature.

http://www.pentonusa.org/forum/topic.asp?TOPIC_ID=14244&SearchTerms=harescrambler,mikuni


Dale Fisher
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Title: Mikuni Conversion
Post by: Mick Milakovic on April 18, 2019, 08:42:50 AM
I've got a 34 on my 250 now and it's a little small so i'm fitting a 36 also.  after jetting and fitting i'll add to this post.

Mick
Title: Mikuni Conversion
Post by: JP Morgen on April 18, 2019, 12:36:07 PM
The Mikuni bell mouths are much larger than the one on a Bing, same size on 34mm also, will not fit directly into the airboot. When I built some Pentons with reed valve and Mikunis I mounted an eccentriccly bored plate to the carb and cut back the airboot until it was big enough to fit the outside of my round plate, very tricky and time consuming job.
Title: Mikuni Conversion
Post by: Doug Knight on April 29, 2019, 12:07:35 AM
A new air boot can be worked to fit a VM36 by the use of a heatgun. Wear gloves and go slowly, when the vinyl gets shinny work fast, too hot it will blister. May require several attemts. It helps to trim (shorten) some of the flange off the back of the carb for an easier install.

The VM34 is almost a direct fit

YMMV with your skill level
Title: Mikuni Conversion
Post by: Larry Perkins on April 29, 2019, 07:40:24 AM
When JP Morgan built the reed motor I raced a VM34 was used and it was bored to 35.5mm.  It fits and with some trimming the original airboot was used.

Larry P