PlanetMinis Forums banner

2 classes added for MMSX MM8A Vintage z50 mm8A CRF50-88cc limited riders in each

5751 Views 33 Replies 16 Participants Last post by  50race
TBParts Vintage Z50 versus CRF50 88cc Class Confirmed for 2012 GEICO MiniMotoSX
Back to the roots of Minibike racing
Irvine, CA. (February 7, 2012) Most active Minibike racers got their start on either the Z50 or Honda XR/CRF50 so they are considered by many to be the roots of Minibike racing. has been in business for over 15 years and still sells a lot of parts to people that enjoy riding and racing the “older”, smaller bikes so they have stepped up to sponsor the classic classes for 2012. Each class will be limited to just 10 entries on a first come first served basis so if you are interested in racing at the biggest MiniBike race in the world, you better act quickly.

You can get the complete rules here: 2012 MiniMotoSX Rules

Entries are NOW OPEN and are available here: 2012 MiniMotoSX Entry Form

Make your plans stick around in Vegas during the Monster Energy AMA Supercross weekend to get on the track yourself and race for an AMA #1 plate. You can find race entry and event info at Ticket information:

For rules and race information visit or email [email protected]

Source Interlink Media Motorsports:
Encompassing the highly successful GEICO AMA MiniMotoSX fueled by Monster Energy, the GEICO AMA EnduroCross Championship Series presented by Lucas Oil and the AMA EnduroCross Grand Championships, the Source Interlink Media Motorsports brands reach millions of motorcycle enthusiasts with live events, web sites, television and magazine coverage. Visit or

See less See more
1 - 7 of 34 Posts

Tried signing son up today....will not go thru???? Emails I sent will not go thru, being sent back?????? Is sight down.

Txs, Gene

It went tried later on in the day.
Is the 88 class going to be checked for true 88cc bikes? I would hate to come all that way just to be beat out of a position from a cheater?

Dont worry about the cheaters.........Zac (Michigan Mafia) has done ok with his 88cc TRAIL BIKES for the last 2 years (2011, 2010) and Derek Rose (2009) Year before that.

Sports Racing Motorcycle racer Motorcycling Race track

Its been on the dyno for the last 3 weeks..............tuner her in for 2012.

Motor vehicle Vehicle Automotive tire Tire Bicycle handlebar
See less See more
Is the 88 class going to be checked for true 88cc bikes? I would hate to come all that way just to be beat out of a position from a cheater?
Vacuum gauge that hooks up to the spark plug hole. Stock 50's have a 41.4 stroke, strokers 51+. they will pull more vacuum(allot more). Don't have to tear motor all the way down just re move timing cover, mag cover, put motor at top dead center, re move timing gear, make sure at top dead center, put vacuum gauge in spark plug hole, rotate 180 degrees. 41.4mm vacuum spec is xxx and 51mm vacuum spec is 000.

You go home with a motor still in tack you only have to install timing gear back. better than tearing the motor all the way down.
in the 88cc class is it a stock head or can you run a race head ?

MM8 - Vintage Z50 vs. CRF50 88cc
8” Rear/ Front Wheel Amateur Class - No current AMA Pro license holders allowed. Must be 18 years of age or older as of race date. You must run an 8” Rear Wheel. All bikes must use Air-cooled, 4-stroke engines (maximum 88cc) with Open Cradle Frames.(no Aluminum frame), 2 shocks (or hard tail) on the frame 8” front wheels (maximum) are allowed. Manual Clutches are allowed. Maximum Wheel Base is 42 inches. Both wheels must be solid. NO regular spokes! Practice & qualifying - time TBD
Vintage Z50 88cc –one addition: No 4 valve heads
XR/CRF50 88cc – All must use Air-cooled, 4-stroke 88cc engines (no 49cc engines and no engines larger than 88cc) with Open Cradle Frames. 10” Rear wheel and 12” front wheels (maximum) are allowed. Manual Clutches are allowed. Engine Modifications are allowed except no 4 valve cylinder heads. Maximum Wheel Base is 45 inches.

Any head, but a 4-valve.
See less See more
The wheelbase for the z50 crept up 2 inches but still doesnt get the 45inches that a crf50 gets? have to get to work on the 3v heads maybe 5v heads guys.

Take a DOHC and do this to it.
View attachment 90637

The rules don't say anything about Fuel Injected 88cc with a little shot of hidden nos for the hole shot. Or an 88cc nitro methane with methanol or alcohol burner.

Dang they did put it in the rules.............Fuel Gasoline ONLY No Nitro, Alcohol, Methanol etc. LOL, But nothing about fuel injected or nos
Hey guys I have 3 Openings for the MM8A CRF 50cc-88cc ... Get entered ASAP.

Becky MMSX

Becky the MM8A class fill up yet?
Lol a little nos would get my big ass moving off the gate!!!! Tore the 115 down with a tear in my eye to make an 88 but should be fun revving the heck out of it.
Cable Technology Electronic device Electronics accessory

Could you imagine having it :aargh4: ...............LOL, I wonder if the piston would last with that little shot of nos without bumping up the main jet
See less See more
1 - 7 of 34 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.