cutting the subframe to lower seat height


9 replies to this topic
  • SurfaceToAir

Posted January 28, 2014 - 12:59 PM

#1

I was searching around here and didnt see any pics of a WR or CRF with a cut subframe to lower the seat height.

My seat is cut down already, and though I am good when I am going, the technical stuff gets a little harder at slow speeds since I can barely still touch the ground.  It sucks being short, with a 30-ish inseam...

 

I am looking to lower the seat another inch.

 

The bike is a 2008 WRF 450.

 

I am tossing around cutting the subframe down. The issues I see running into when I do are:

* The exhaust wont bolt up any more, so I have to mod that.

* Seat wont fit against the tank the same way, since the seat will be tilted away from the tank.

* Airbox wont fit against the carb the same. May have to make mods for that..

* Possibly the tire will rub when bottomed out..

 

Has anyone here cut their subframe and can comment? Do you have any pics?

 

thanks-

Dustin



  • lourencom

Posted January 28, 2014 - 02:46 PM

#2

before you try to cut your subfram, wich I wouldn't recomend. I would try to lower your race sag and front forks. Anothe alternative is to use a lowered shock lingage.

 

http://www.motosport...ring-Link-Black


Edited by lourencom, January 28, 2014 - 02:53 PM.


  • DRZ04

Posted January 28, 2014 - 06:25 PM

#3

I put the Devol link on my 2013 WR450F and it did lower the rear of the bike a full 1 1/4". I also raised the forks in the clamps. It is still too tall but now instead of 1 foot on tip toe I can now get the balls of both feet on the ground. I also had SDG cut down my stock seat about an 1" to 1 1/2". I like you have a 29" to 30" inseam and it is a pain at low speed when you need to dab. I am no longer a racer so I don't mind the "adverse effect", as some say, to the suspension it has. You are correct about shortening the sub-frame changing how other items bolt & fit up.



  • stevethe

Posted January 28, 2014 - 06:57 PM

#4

I think one of your biggest problems might be the tire hitting the fender.

 

I believe Graves did cut the sub frames maybe a half inch on the supermoto race bikes. However they have 17" wheels.

 

If I was to do my suspension all over again on my dirt wr450 I might lower the shock and forks an inch.



  • SurfaceToAir

Posted January 28, 2014 - 06:58 PM

#5

Sag is set to he proper amount, but I might be able to go more.. Forks are also up in the tripple clamps. I guess putting a lowering link in there is a good, cheap thing to try. I have been tossing it around, though so many people discourage it. But yeah- its a removable hard part that if I don't like, i can take out..

I called Factory Connection today about lowering the suspension..  Will run me about 700 plus shipping.. So a lowering link is probably the best thing to try next.

 

Cutting the subframe seemed like a good way, but now it seems more complicated that it seemed on the surface.  I can TIG weld fine, but the rest of the stuff attached to it seems to be too effected.

 

cheers-

Dustin



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  • stevethe

Posted January 28, 2014 - 07:11 PM

#6

It's not that hard to shim the rear shock. I lowered my supermoto with Racetech shims when it had stock suspension. The forks can also be done mostly yourself. I had Racetech machine a groove for the C-clip. You might check around for a u tube DIY.

 

The lowering links don't help the suspension geometry to work well.



  • stevethe

Posted January 30, 2014 - 08:19 AM

#7

Hum fork lowering for smarties. Found in the suspension section.

 

http://www.thumperta...ks-for-dummies/



  • CaptDan

Posted January 30, 2014 - 09:09 AM

#8

What some of the YZ 2-stroke guys have done to lower the rear of the seat is simply slot the lower mounting holes on the subframe.

 

An additional 1/4" slotting on the holes lowers the back of the seat about 1/2".

 

As others have said, drastic modification (cutting) on the subframe brings the risk of the rear tire contacting hard with the fender.

 

Slotting the holes a little bit at a time allows you to lower the subframe in increments, and not over shoot the modification.



  • SurfaceToAir

Posted January 30, 2014 - 09:15 PM

#9

@SteveThe- thank you. That is helpful. I didnt understand before how the shims would lower it. Thats a good article. I could probably do that work myself.

 

CaptDan- I might also try that. Seems like a better way than going full tilt on the cut and weld. I wonder if a half inch is worth the trouble/ modification.  Will noodle on that a bit.

 

Thanks guys.

 

I'm still curious to see a pic of a bike with the subframe altered.

 

cheers-

Dustin



  • killerbee2112

Posted April 05, 2014 - 09:48 PM

#10

Might check out Yamalink.com.






 
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