Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: rlaj1004 on April 11, 2013, 02:24:32 PM

Title: Cutting down a frame
Post by: rlaj1004 on April 11, 2013, 02:24:32 PM

Anybody out there had experience cutting down a frame. I have a small girl that I doubt will get much above 5 ft. I know RC had his frames cut down. Just wondering if Aluminum is better, can it be done with a steel frame? what manufacture is better to cut down? Anyone done it? Know of any companys that do?
I have a little while till she moves to a big wheel but when she wants to race I think I will need to get her into a full size.

Title: Cutting down a frame
Post by: SachsGS on April 12, 2013, 08:17:33 PM

Modified many frames and would say that it isn't worth it - airbox/seat/tank alignment problems - just too much work. Steel is better, aluminum frames are either 6000 series (will require heat treating after welding) or 7000 series (self aging but hard/brittle difficult to work with). Why not get her a KX 100? If you are determined to lower a full sized bike use spacers in the suspension, cut down seat and a lowering link (all reversible)?

Title: Cutting down a frame
Post by: riffraff on April 12, 2013, 09:37:32 PM

Sachs is right, there's better ways to get a lower seat height than modifying a frame

Title: Cutting down a frame
Post by: factoryX on April 12, 2013, 10:13:53 PM

Now, throwing larger motors in smaller frame might be what your looking for. AKA blaster motor cr80/85 chassis.

Title: Cutting down a frame
Post by: Rm125guy on April 13, 2013, 03:36:44 AM

You could buy my kx100! Never raced (on a motocross track...) 

Title: Cutting down a frame
Post by: rlaj1004 on April 13, 2013, 02:21:59 PM

Well she is on an 85 now, I have a KX100 collecting dust and I have the CR125.  She is a itty bitty girl. As she says "dont mess with me I'm small but mighty " Seems that she would be at a disadvantage when she races against the big wheel bikes even on the KX.
I thought it would be relatively easy  I have heard several riders RC, Fiolek, and others, that have their frames shortened.

Title: Cutting down a frame
Post by: Coop on April 16, 2013, 01:54:41 PM

Quote from: rlaj1004 on April 13, 2013, 09:21:59 PM

I thought it would be relatively easy  I have heard several riders RC, Fiolek, and others, that have their frames shortened.

Consider everything that bolts to the frame. Cutting the frame means all that stuff needs modified as well. those pro's have professional mechanics and factory budgets behind them to modify the bikes. It can be done for sure, but it will not be "easy" or cheap really.

I am in the same boat with my wife. She is 5'2" and loves to ride. She can barely flat foot a ttr125L. She wants a newer bike with more power, maybe even a KTM with e-start (she has a lot of trouble kicking bikes over being short). But they are so tall they are out of her reach. Riding off-road in the tight Pa woods not being able to reach the ground is a serious disadvantage. Imagine getting stuck on a gnarly hill or stalling in a rock section and not being able to touch the ground from the saddle LOL.

Title: Cutting down a frame
Post by: eprovenzano on April 16, 2013, 07:18:31 PM

Coop dare I say this...  but would a CRF150R be the right size?  Maybe you can find one with a blown motor, and replace it with one that more two stroke friendly... Or how about a 85 with a flywheel weight?

Title: Cutting down a frame
Post by: factoryX on April 16, 2013, 09:31:17 PM

Actually my dad has a friend who put a crf250r motor in a crf150r frame. Service honda also does it.

Title: Cutting down a frame
Post by: factoryX on April 16, 2013, 09:33:03 PM

http://servicehonda.com/2010-models48/honda34/junior-r38

And not to long ago there was a cr85 on ebay with a blaster motor haha. Your mod list is endless. I would love a super mini with a yz250 motor.