Frame Reinforcement

[Mathh]

check this one out

Take a look at this semi classic racer. Solid motor mounts and stiffening of the frame below the rear of the tank / above the chain drive / alternator drive.

[79XS11F]

Re: send in the reinforcements

Originally posted by xschop
Hey rob, don't forget that you will have to notch the lower frame tube to pivot point for your chain clearance, it looks like that one front reinforcement will be in the way. I just used a 3/16 thick plate (1"x4" ) bridged from the edge of the pivot bolt housing to the lower frame tube....Looking good, What color will you paint it?

This is why I post the photos on a project like this. I over looked the clearance for the chain. xschop, got a PIC of where this "notch" needs to be ?

Rob

[xschop]

notch details

Very easy to do, but FIRST weld on your brige piece, THEN notch afterwards.....chop

http://www.xs11.com/forum/showthread.php?threadid=16407&highlight=chaindrive

[79XS11F]

OK .. So I will have to move my swing arm reinforcement pieces to the outside as you have done and or keep it straight as compared to being turned in like it is. that may become a good place to mount a chain guard as well. Thanks xschop.
Rob

[AlanB]

Hi Rob,

I have an old welding manual somewhere in the house; If my memory is not playing tricks, it recommends NOT carrying gussets right down into the corner of tube joints, but to leave a gap right in the corner; like the japs tend to! Something to do wth limiting distortion.

Don't alter the patterns until I find the book..... It can't be too far away!

The advice might be in Tony Foale's book on frame design; If so, I know where to find it! I'll let you know.

AlanB

[79XS11F]

That makes sense Allen. If there's no flex at all things break. That an easy fix on the fitting. i will actually be using clay to get the exact fit of the parts.
Rob

[Montreux_Blue]

Re: check this one out

Originally posted by Mathh

It reminds me of my first bike (dirt), my 1977 yz80c!

[79XS11F]

Aquick update on the frame work

I have over the last few weeks managed to get started on the cutting of the steel for the frame but it is not going well with an angle grinder with cutting disk attached. Anyway I had reason to cross paths with the lad who will be doing the wielding today and he has offered to also help with the cutting and fitting of the pieces. He has a new plasma cutting torch :-).
So it looks like perhaps next weekend, if I'm ready, the frame will be completed for the cost of a case of beer. Finishing the frame will allow this project to move forward much faster over the COLD months.
Keep you posted and will post photos when the frame work is completed.
Rob

[TopCatGr58]

Hey Rob, ever take an photos of the reinforced frame?

Hey Rob and folks,

Resurrecting this thread for both the photos and to restart the discussion a bit. I'll be performing an Engine transplant to a new UNBENT frame, and am wanting to MOD it to try to help reduce the frame flex that these bikes like to exhibit.

I may or may not also go to SOLID engine mounts vs. making my own Poly ones?? Can't recall if folks have reported any increase in frame vibration with the solid mounts vs. cushioned ones?

I'm going to find the photos(found them recently but forgot to copy the links to them) and add them to this thread for comments.

T.C.

[TopCatGr58]

Here's the thread that was linked to in the other thread about frame bracing. It's 10 years old, but has good info and opinions about frame bracing.

http://www.xs11.com/forum/showthread.php?s=&threadid=6589&highlight=frame+br ace

I DID do the swing arm bracing, but never got around to any FRAME bracing.

Here are a couple of the photos the PGGG had posted, I had saved them to the XS11 site photo folders.





What I like about these images is that they also show the wrapped plate that normall fits around the steering neck and along the bottom frame tube(s) has been removed. I had forgotten that it showed this. And I had noted with recent photos I took as well as from other posters....like this one from DrShankles about him smoothing out the frame/neck welds...



So...looking at this last photo....I could see the larger lower frame tube going into the steering neck box but near the MIDDLE of the box....and was wondering if there was only the wrapped sheet metal around the bottom of the neck. But the PGG images show that there is another smaller diameter tube that is welded to the bottom portion of the neck to the frame for additional support.

T.C.

[motoman]

I have over the last few weeks managed to get started on the cutting of the steel for the frame but it is not going well with an angle grinder with cutting disk attached. Anyway I had reason to cross paths with the lad who will be doing the wielding today and he has offered to also help with the cutting and fitting of the pieces. He has a new plasma cutting torch :-).
So it looks like perhaps next weekend, if I'm ready, the frame will be completed for the cost of a case of beer. Finishing the frame will allow this project to move forward much faster over the COLD months.
Keep you posted and will post photos when the frame work is completed.
Rob

Didn't see this sooner or I would of reccomended 1/8"x1' angle with corners cut to fit for zero clearance. BTW, I'm a certified welder and metal urgest.

[crazy steve]

TC, I don't think that solid motor mounts will do much for you unless you cross-brace the downtubes off the fork neck. The problem here is there's a lot of stuff in the way. Yamaha added an additional brace on the XJ frame in an attempt to address this, but I don't think it contributes much. Maybe a bolt-in cross brace (with the mounting bolts in tension, not shear) would be worth a look.

But I personally feel that the main limit to handling is the fork design. We all know that the skinny 37mm forks flex, you're running extended tubes, so more flex. In your case, I think an 'intermediate' brace between the tubes below the lower tree but just above the fully-compressed point on the tubes would be well worth looking into. This could be fairly easily built on your mill.

The other fork issue is the relatively short XS fork stem. Most newer bikes have stems that are 1" longer or more, which reduces the leverage the forks apply to the frame. This is a much tougher fix; a longer tree stem wouldn't be a big deal to fabricate, but cutting the existing stem tube out of the frame and welding in another one would be some finicky work. Or maybe cut the lower bearing recess off and fab a new longer one that press-fits into the existing tube and weld that in place.

Food for thought....

[madmax-im]

Hey Rob and folks,

Resurrecting this thread for both the photos and to restart the discussion a bit. I'll be performing an Engine transplant to a new UNBENT frame, and am wanting to MOD it to try to help reduce the frame flex that these bikes like to exhibit.

I may or may not also go to SOLID engine mounts vs. making my own Poly ones?? Can't recall if folks have reported any increase in frame vibration with the solid mounts vs. cushioned ones?

I'm going to find the photos(found them recently but forgot to copy the links to them) and add them to this thread for comments.

T.C.

Ah ha...so thats why you are swapping out the frames...I had been wondering ya know....and since yyou didnt answer my PM...I was just guessing...

[mack]

I'd be curious

to see how rob addressed getting the coils in and out with the bracing he used.Must have been a real knuckle buster.

[Schming]

Hey Rob and folks,

Resurrecting this thread for both the photos and to restart the discussion a bit. I'll be performing an Engine transplant to a new UNBENT frame, and am wanting to MOD it to try to help reduce the frame flex that these bikes like to exhibit.

I may or may not also go to SOLID engine mounts vs. making my own Poly ones?? Can't recall if folks have reported any increase in frame vibration with the solid mounts vs. cushioned ones?

I'm going to find the photos(found them recently but forgot to copy the links to them) and add them to this thread for comments.

T.C.

Hi T.C.,

I am interested in frame reinforcement for my SF Euro Conversion also and will be posting a detailed thread when I start the conversion.

Here are some pics of the XS 1100 Sport 5K7 frame that may help ya:







Here's a link that may help also:

https://yamahaxs1100e.wordpress.com/2010/01/30/1978-yamaha-xs1100-modified-bike-part-2/