open reed engines

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Gene Fitch
Posts: 2
Joined: Thu Jun 28, 2007 8:03 pm
Vintage Karting items owned: 70 Dart A bone
2 PP 81,s
1Mac7
4 Mac 91

open reed engines

Post by Gene Fitch » Wed Sep 19, 2007 4:49 pm

Can any of you guys explain the open reed engine.Sounds like a good winter time project.
thanks,Gene

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Bill Johnson
Posts: 85
Joined: Wed Jun 20, 2007 2:26 pm
Location: Hickory, NC

Re: open reed engines

Post by Bill Johnson » Thu Sep 20, 2007 2:33 pm

Its usually a fully ported Mac engine running a GEM V12 intake, and twin tilleys on alky. I run them Road Racing Enduros.
MacDaddy

Ernie Fisher
Posts: 29
Joined: Mon Aug 13, 2007 11:00 pm
Vintage Karting items owned: 1958 Hovey Hawk
Konig Power

Re: open reed engines

Post by Ernie Fisher » Thu Sep 20, 2007 4:47 pm

Gene,

Reed Open was an IKF class that had all the big names. Very fast 100cc class that featured "open" modifications, no fuel restrictions, multiple carbs, etc.. This class was dominated by the Macs, but Power Products and West Bend 610,s were also allowed to run. I remember driving one of Dave Bonbright's modified 610 Benders and giving Gary Hartman all he could handle at a big race out west one year. We did not win it, but were a close second, with many Macs behind us. I have raced against many highly modified PP's also, and they were very quick as well. It is always to keep one thing in mind while getting a reed open ready to race! They are very short-lived, and can get very expensive! I would recommend staying away from building open vintage motors of any brand, as they are getting harder to find, and also the parts. Best of luck to you with your Vintage Karting endeavors!!

Ernie Fisher

Gene Fitch
Posts: 2
Joined: Thu Jun 28, 2007 8:03 pm
Vintage Karting items owned: 70 Dart A bone
2 PP 81,s
1Mac7
4 Mac 91

Re: open reed engines

Post by Gene Fitch » Fri Sep 21, 2007 9:53 am

Thanks for the open reed info.I have a picture of the intake side of A Mac 91b & it shows 2 ports in the cyl.wall appox. 1 x
1 1/2 inches.Is this the only mod.req'd.? How critical is the
location height from the bottom of the cyl. wall.It seems to me
that the intake flow is much greater than the exhaust openings.
I raced A PP 58 back in the 60's,so this is a new learning experience for me.I got back into karting (vintage) last year &
had forgot how much fun it is.
Thanks,
Gene

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