Penton Owners Group

General Discussion => Penton Racing Talk => Topic started by: ossaracer on May 02, 2010, 03:09:46 PM

Title: 74 1/2 Mint 400 Gearing input?
Post by: ossaracer on May 02, 2010, 03:09:46 PM
Have a nice 74 1/2 Mint 400.  Hits like a sledgehammer. Already have enduro flywheel and down to 36mm Bing vs 38mm stock Bing to mellow it some.  Currently geared 14 x 54  (3.85 to 1) .   My 250s run perfect with 13 X 52 (4.0 to 1)gearing.   Anyone geared a 400 taller?  Thnking a 14 X 52 (3.71 ratio) would allow 400 to pull in each gear loger and make 2nd and 3rd less brutal hits?  Now 2nd gear already pretty low.

Anyone done a special added weight flywheel also?

Terry Gates
AHRMA racer/Penton-Ossa lover
[email protected]
Penton 100 Berkshire 72 - nice (on the way!!)
Penton 125 Six Days (3)
Penton 175 Jackpiner
Penton 250 Harescambler (2 1/2)  Love 'em!!
Mint 400 - sweet
Title: 74 1/2 Mint 400 Gearing input?
Post by: brian kirby on May 02, 2010, 04:03:45 PM
The MC5 400 had 14/52 on it when I got it and it was not good for cross country because you always needed to be between 1st and 2nd but it easily pulled 2nd gear starts even with that combo. I put 13/52 on it which is perfect for CC and just as usable for MX. Your 400 will easily pull 14/52 without even breaking a sweat, but I really didnt notice and difference in the "hit" either way.

I think you just need to man up and eat your Wheaties Terry! :D

Brian

'72 Berkshire
Title: 74 1/2 Mint 400 Gearing input?
Post by: Larry Perkins on May 03, 2010, 08:27:34 AM
Terry,

Does your bike have the weighted crank?  Some of the earlest Mints did not and they were a bear to ride.  Hard hitting suckers.  The second batch had heavier flywheel crank halfs.

Larry P
Title: 74 1/2 Mint 400 Gearing input?
Post by: firstturn on May 03, 2010, 09:06:44 AM
Terry,
  I agree with Larry on the crank and I think the 36mm carburetor is the way to go.  What is the timing set at?

Ron Carbaugh
Title: 74 1/2 Mint 400 Gearing input?
Post by: Mike Lenz on May 06, 2010, 04:45:16 PM
The secret is the right pipe.  The 76-77 MC-5 pipe makes it a hole different bike!