Frame reenforcement

[79XS11F]

I am close to being ready to start work on my hop up bikes frame. I am sure there are others on the board who have reinforced their frames. Other then fork braces ... how did you do you reenforcement and were you happy with the results? Did the work pay off? Does the bike handle better for the effort?
Rob

[AlanB]

Hi SF,

The European "Sport" model (5K7) came stock with a braced frame. A search should find some pics, or call me.

I have a braced swing-arm, which came from the USA to me;


Some members (UK and USA!) have made and fitted solid mounts in place of the rubbers with good results.



Again, try a search.

AlanB

[79XS11F]

Hi Alan .. Nice swing arm. I was planning something along those lines but seeing this one tells me how I will do it. That looks pretty clean and tidy. Whats the total drop down measure? Does it affect road clearance?
I already have a set of X chops Alloy mounts. I also have a PIC of the sport frame and the only real difference I can see is the solid sheet metal behind the battery box
Rob

[TopCatGr58]

Hey Alan,

You said that swing arm came from the USA! Was it a custom made item? I'm just curious because I did a similar thing to mine with some square tubing, but was told that it served NO ENGINEERING PURPOSE! I disagreed, partly because why would they design them similarly on the new machines if they didn't actually work and were more stiffer/stable? I realize that the newer ones are being made from Aluminum which isn't necessarily as strong at the same thicknesses as steel.

Hey Rob,
I'll post a few photos that IIRC PGGG posted about someone....a structural engineer I believe that did some frame reinforcements up around the front of the frame steering neck! I don't know whether it helped or not, and there was some other discussion in
This thread about it that you might find useful?



T.C.

[79XS11F]

Hey that would be great TC. The sooner i get the frame completed the sooner i can road this bike and get garage back. After all the best place to store an engine .. is in the frame :-) LOL lOL
Rob

[AlanB]

Hi TC,

I have no real info on the arm; It came off a bike which was broken up here soon after it was imported.

I never saw the bike, and never spoke to the seller, so I don't even know what state the bike was from.

Hi SF; Try this;

CLICK!

Originally posted by MikeF on the UK site. The brackets under the front of the engine are for a brace to bolt between the rails; It is not shown in the photos. Not sure what you mean by "sheet metal behind the battery"?

Hope this helps!

AlanB

[79XS11F]

Sorry . Looks like the sheet metal is in front of the battery. The PIC is not too clear but I was guessing that there is sheet metal in the frame there. That would do I pretty good job but a single tube would have been just as good
Rob

[AlanB]

Hi SF,

I know that frame; It started out as a Sport (you can see the mounts for the brace under the front of the rails!)

However, It has been modified here and there........

Apart from the bracing and the lugs at the rear of the top rails, A stock Sport frame looks pretty much like an SG frame.

AlanB

[79XS11F]

OK so that's not a factory unit. It's been modified by someone. Must have been using POD air filters for that to work. I had intended to do a lot of gusseting because it's fast easy strong and cheap.

[GNEPIG]

With the aluminum motor mounts installed, the motor shouldn't move anymore (as much anyway), so why not build a brace from the frame/back bone to the top of the head/valve cover? Like on the XS650.
That should provide enough support and you wont have to add too many braces(more weight) all over your frame.

I seen the top motor support brace on a super road race XS11 thing once. That is the basis for my reply.

[AlanB]

Hi SF,

I have done a few frames (mainly kawasakis.....) Usual plan is a "Z" brace (Two crossmembers with a diagonal between!) under the headers, another across the frame where your pic has the sheet-metal (You do need pods!) And something similar under the motor, if the sump will allow.

Add as many gussets around the headstock as you dare, and a couple around the swing-arm pivots.

Think carefully about it before you start; it is easy to end up with a beautifully strong frame which is no use 'cos you cannot get the battery (or coils...or carbs..... or some other essential bit!) fitted or removed.......Yes; I have done it!

And if you are not absolutely sure of the quality of your fabrication and welding skills, either leave it alone and keep telling the boys about "what you will do next!" or get a grown-up to help you.

AlanB

[79XS11F]

Hey Alan ... I will not be doing the wielding myself .. I know my limits. I am paying close attention to access with this frame thing. i want a non moving frame but not at the expense of maintenance or re & re access. This is why it is taking so long to get it done. It is a one shot deal for me and i MUST get it right or strike a good balance for all aspects.
Rob

[xschop]

send in the reenforcements

this 3/16 angle iron is rock solid and easy to do and doesn't get in the way. with those alloy mounts this is the trick....http://www.xs11.com/forum/showthread...&pagenumber=11

[79XS11F]

Hey Xchop ... Looks like your doing a chain drive setup there. The mono-shock is a great idea with a lot of work involved. Looks like your into up to the elbows so to speak. The angle iron across the bottom there is an easy way to reinforce that frame at that location and I will keep this in mind when the job is started.
I have a 1979 midnight special frame here and I will use it's tubing where tubing is wanted and gussets at other locations.
Rob

[pggg]

Most of these points you could brace without interfering too much, you'd need to be dead sure before welding is all. The r/h sidecover, a strut straight across would mean a re-vamped electrical area, the front frame around the exhaust headers and camchain adjuster you'd need to position well, same with all the others though, the rear strut under the l/h sidecover would mean out with the plastic toolbox, there's probably room for more struts on the lower frame area too, hell you'd have to be keen to do all this, but solid mounts and beefed up swingarm too, doubt the bike'll be weaving much then