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The 2-Stroke Garage => Turning Wrenches => Topic started by: niteowl on June 09, 2021, 05:21:56 PM

Title: rd350 bottom frame crossmember
Post by: niteowl on June 09, 2021, 05:21:56 PM
 any of you guys remove the big crossmember on bottom when de-tabbing?  My plan its to take it out and add a plain cross tube just in front of it. That way I think I can move kickstand forward to clear pipes better too. I've heard comparable year TZ's had nothing at all there so I'm not too concerned. Any thoughts?
Title: Re: rd350 bottom frame crossmember
Post by: 747drvr on June 09, 2021, 05:27:15 PM
if you do remove the cross tube , try to find an old case to put in the frame while you remove it. if you cut it with nothing in the engine will not be properly aligned for the chain and suspension. cut and weld in with a bare engine block if you can. learned this the hard way with a dragbike frame. :whistle:
Title: Re: rd350 bottom frame crossmember
Post by: niteowl on June 09, 2021, 05:38:21 PM
Yep. that's what I have in mind.   or a careful measurement!  yrs ago I'd have learned it the hard way too!
Title: Re: rd350 bottom frame crossmember
Post by: teazer on June 10, 2021, 04:26:46 PM
Good idea.  I had a TD3 years ago and decided to reinforce the frame with a front cross tube.  The fab guy did an awesome job, but unfortunately the motor was now too wide for the frame.  Funny how that works...

So I took a saw to the cross tube and watched the frame tubes spring open leaving a 3mm gap in that tube. Not sure how the welder clamped it all up, but obviously he got it wrong.

Bolt the crankcases in and then cut and weld the new cross tube.
Title: Re: rd350 bottom frame crossmember
Post by: Bullockcm on June 14, 2021, 07:35:47 AM
Pretty common modification/weight loss procedure on race bike destined frames.  I believe all of the RD frames I have purchased as road race frames with the exception of a Daytona that the builder wanted to be able to return to stock had the cross member removed.
Title: Re: rd350 bottom frame crossmember
Post by: sav0r (CL MotoTech) on June 14, 2021, 10:37:36 PM
The cross member is there seemingly to support the kickstand and not much else. If the frame springs a bit after removing it, oh well.

They tend to fill up with dirt and grime too.