sub frame support help...

[seamax]

This is what my bike looks like. This winter I'm thinking of making the tail look more streamline to expose the rear wheel more so I want to remove part of the rear subframe.



I want to cut this part off. (stole this pic from another member) Do you think there would still be enough support for the seat if this part was removed? If not where do you think I should brace the existing support after this part is cut off while still keeping the brace hidden, maybe within the tail piece. Or reinforce the subframe with additional beams?

[The Buddha]

If you knew how thin that thing is you're not even mention the word cut within 10 ft of it.
Anyway, It will prolly bend like a pretzel.
The thing is going to need triangulation for retaining strength.
Cool.
Buddha.

[O.C.D.]

Um, if you think that you can remove that without issue then you better leave it be.  The way Suzuki designed that already is pretty paltry.  To remove that support is even worse.  You need to triangulate that bar if you ever want to ride it again.

[DoD#i]

I'm with the others in terms of what makes sense (leave it the heck alone).

If you really want to pursue what seems to me a nutty vision (but then, my visions seem nutty to others as well) you could perhaps find a local blacksmith or spring shop, and get a nice chunk or two of heavy leaf spring bent to make a seat support. Exactly how you'd connect that to the remaining frame I'm not clear - undoubtedly more rearranging of stuff that normally lives in the space under the seat, likely the frame petcock, and fabricating/welding brackets. Beware of welding the spring stock (it likes to crack) and don't save money by using old leaf springs (they are also prone to having fatigue cracks in them, and if the spring breaks, your butt will meet the rear tire.)

I suppose a whole crapload of carbon fiber might also let you get away with something like that, but the triangle is a good thing, really - nice and stable.

[gregvhen]

You can remove that peice with no structural issues as long as yo add support. I would suggest making a curved peiced (2 peices one for each side) to curve from the point from where you are cutting to the top bar.  In the pic, the green and yellow are two differant options.  I would suggest if you are a heavier fellow to go with the green. or maybe do two curves cause that would look pretty sweet too.  DANG it. well you would understand if i could figure out how to post pictures. i have it saved on my desktop as untitled, and i have no clue how to insert it.

[Bluehaze]

oh please dont mess with that bike. it has been my inspiration for modding my bike. It is a masterpiece already..

[gregvhen]

oh please tell me how to insert an image. i clicked the button, and pasted the destination between the two [img] destination [img] things.  i pasted the D:\Documents and Settings\greg\Desktop\untitled but it didnt work so i assume that is not what im sposed to do.

[T1z3R]

you cant paste a location on your computer. [url] is for a web address.
host your pics somewhere like photobucket then paste the link between the [URL] tags.

[kappa2006]

hey, that pic looks familiar haha.  Theres no way that subframe will be strong enough with that lower section removed.  Definately going to need to design new supports, like I'm doing in my current build.  Check it out sometime.

[gregvhen]

Alright figured it out. sorta.

http://s966.photobucket.com/albums/ae150/gregvhen/?action=view&current=untitled.jpg

check that pic and refer back to my green yellow comment.

[gregvhen]

by the way, is it a total bi-otch to remove and reinstall the airbox for anyone else here? ive done it several times on a katana 1000 no problem and thats four carbs, but it always takes me easily 30 minuetes to get it right on my twin 500

[kappa2006]

I haven't had that much of an issue with mine.  Ripping it out isn't an issue at all.  But when reinstalling, I leave the 2 silicone couplers between the carbs and the engine loose, and disconnect the fuel petcock from the frame.  Then once everything is in position, I tighten everything up.  Seems to be easier that way.


or.....just ditch the airbox and go with the K&N lunchbox.   aaaand rejet.   

[seamax]

Alright figured it out. sorta.

http://s966.photobucket.com/albums/ae150/gregvhen/?action=view&current=untitled.jpg

check that pic and refer back to my green yellow comment.

That would clean that area up a little but I'm going for the no support from the frame at all look, where it is just the seat and tail sticking out. Supporting the seat with a spring sounds cool. I'll have to look on how I can mount a spring under there.

[The Buddha]

Airbox re-install - pull the filter off it, and put your hand though that hole and get the boots on the carbs.

BTW I remove the carbs without taking the airbox out. Remove all the screws etc and push it back towards the battery box. Then unbolt the manifolds (put 6mm bolts with 8mm hex heads in place of the phillips crap) and pull the whole kit and kaboodle up and out with cables still attached.

Cool.
Buddha.

[BaltimoreGS]

by the way, is it a total bi-otch to remove and reinstall the airbox for anyone else here? ive done it several times on a katana 1000 no problem and thats four carbs, but it always takes me easily 30 minuetes to get it right on my twin 500

I find it easier to put the carbs on the airbox first and then wrestle them into the intake as one unit.

-Jessie

[gregvhen]

That would clean that area up a little but I'm going for the no support from the frame at all look, where it is just the seat and tail sticking out. Supporting the seat with a spring sounds cool. I'll have to look on how I can mount a spring under there.
[/quote]

http://s966.photobucket.com/albums/ae150/gregvhen/?action=view&current=untitled-1.jpg

If your looking for the no support look then I got another idear. Alright, this time look at the purple, if you use solid bar, you could get away with 1/2" bar (if square or round tubing use 3/4") and take two long rods (one for each side) from the end of the tail frame and all the to the main frame close to where the sides of the airbox.  se how the purple line goes behind the top bar of the original frame. if you do it this way you have plenty of strength from the X pattern and because of the angle when you sit on it, your weight wants to swing the top (original frame bar) down, but with the added bar, swinging that top down is pusing almost directly on the added strut.  So its like cementing the rod in the ground pointing stright up, and balancing ontop in hopes of compressing it.  Not gonna happen.  

and you wont see the added bars because of the angle.  

[gregvhen]

knew I forgot something, alot of the strength in this design comes when you weld the purple bar to the top frame bar thats already there. where the X is created, weld the bars together.

[tt_four]

Well, to start, I read as much as I could, but didn't get through all of it, so sorry if this is a repeat.

the first thing, and this depends completely on whether or not you ride with a passenger, but from the lack of pegs, I'm guessing you don't. The triangle on the subframe is long, and is clearly meant to support two people. While you do still need a triangle, you can make it waaaayyy smaller if it only needs to support the front seat. The smaller the triangle is, the stronger it will be, but it still has to be big enough to support the top bar. Cut it, reweld it so it meets the top bar about 3/4ths the way back the seat. If you wanted you could probably even lift it up at the end where it welds onto the actual frame up front. You would just have to make sure you never put any real pressure on the back end.

As always, for any real modification questions, I'll refer to you www.customfighters.com

the guys there are super helpful and supportive, and have build just about anything you could ever imagine.

Your bike looks great by the way. Even gsxrs have the subframe sticking out, so don't let it bug you too much.

[Paulcet]

This is what my bike looks like. This winter I'm thinking of making the tail look more streamline to expose the rear wheel more

Expose the rear wheel more?!?      Only way I see would be to cut the swing arm and ditch the chain.

[tt_four]

Hmm, now that I look at it more with your idea of exposing the real wheel more.... cutting that lower brace is going to expose the empty space in front of the wheel, and the more of a gap you put in front of the wheel, the closer the tail is going to look to the wheel. Right now it's still in an even upward angle. If you reduce that angle on the subframe it's going to look like the tail is pointing down. If you really want to put a gap there, I'd cut the bottom part of the subframe, heat the top and bend it upward to an angle you like, then weld an extension into the bottom bar on the subframe, so you're actually lifting the angle of the whole tail.