1980 GS1100e Front end swap

[johnnay]

So I made a little more progress this weekend - fabbed up the crosspiece that I'll weld the shock mount to. Fits like a glove, and should look pretty trick once it's done - as long as I don't farg up the welds..[-o<

For those of you following this thread, I know it's slow going, but you should see my car project - 5 years now and all I've got is a rolling frame..:-D

On a positive note, the underground power line from my house to my garage is finally in, so I'll have real power today!! (I've been doing all this via extension cords up until now).

[80GS1000]

Looking good Johnnay! Are you going to brace the top shock mounting frame member? What's your plan on how to attach the top of the shock to the new frame piece?

[johnnay]

The crosspiece is 1 5/8", with only a 10 1/2" span, so it's plenty strong as it is. I'll just weld two braced tabs to it that sandwich the shock eye, like on the centerstand crosspiece. I could weld a braced horizontal tab to the crosspiece and use one of the GSXR upper shock mount bolts like runrx02 did, but my method keeps the whole assembly lower, leaving more room for battery/electronics etc.

[80gs1100]

So, how exactly did you make a top shock mount for you rearend?? I'm doing the same thing on the same bike, but I haven't decided what to do about the upper mount. Please post some more pictures....great job so far!!

[johnnay]

Thanks for the comments - I had a bent 1 5/8 tube left over from another project, and I'm using it as the crosspiece - pics above. For the shock mount I'll be using two of these:

http://www.aa-mfg.com/pdshop/shop/item.asp?itemid=339

[johnnay]

Ok, 80GS1000 isn't around to fill my fix of looking at other people's progress, so I had to go out and do some work on my bike..

Here's a pic of the shock mount welded in - geometry is (theoretically) good, and the bike's stance looks good, insomuch as I can determine it without the seat and tank, and with the lift in the way. Can't wait to ride it, but I have a few things left to do...

Rearset mounts
refinish swingarm
530 Chain & sprockets
36mm GSXR carbs
paint tank, side panels & tail
seat pan fabrication & upholstery

hope to have it back together by the end of May...

[80GS1000]

Looking good Johnnay! From the picture it looks like you already welded on a couple of tabs for your rearset mounts?

[johnnay]

Thanks, I was pretty happy to get that in there. As for the tabs, those were already there, for the big aluminum passenger footpeg thingys (the 1100's equivalent of the passenger footpeg frame extension that you cut off) - I just have to weld on a couple more for the lower rearset bolts. I think (hope) they'll work out well for positioning, since they seem to work well for the shift lever, although I'll probably have to use some spacers to move the rearsets out a bit. Probably won't be able to tell for sure until I get the seat made, but if worst comes to worst, I can just fab a plate and mount the rearsets to that.

[80GS1000]

What did your final geometry numbers wind up being? Also, how much static sag is there in the shock now that the bike's weight is on it, and with you sitting on it?

[johnnay]

My numbers look like this:

24 Fork Angle (Castor) in degrees
3.94 Trail in inches
54.42 Rear axle centerline to centerline top of fork tubes, inches
59.5 Rear axle centerline to front axle centerline, inches
39.16 Top of fork tube centerline to ground, inches

I set it up so that it's pretty conservative (not much choice with such a long wheelbase), but so I can shorten the dogbones to steepen the rake and shorten the wheelbase a bit if need be.

Not sure what static & loaded sag are yet - had to quit working on it right after welding in the crosspiece... will try to measure today.

[80GS1000]

My numbers look like this:

24 Fork Angle (Castor) in degrees
3.94 Trail in inches
54.42 Rear axle centerline to centerline top of fork tubes, inches
59.5 Rear axle centerline to front axle centerline, inches
39.16 Top of fork tube centerline to ground, inches

I set it up so that it's pretty conservative (not much choice with such a long wheelbase), but so I can shorten the dogbones to steepen the rake and shorten the wheelbase a bit if need be.

Not sure what static & loaded sag are yet - had to quit working on it right after welding in the crosspiece... will try to measure today.

Sounds pretty good, your bike is going to feel much lighter and drop into corners much easier. 24 degrees up front is still pretty steep (a brand new GSXR 1000 is 23.5 degrees) and may be a bit twitchy compared to stock - any plans on fitting a steering stabilizer to help get rid of potential (hopefully this'll never happen) head shakes/tank slappers?

Also curious what your forward/rear weight distribution is - the shorter forks should get the weight forward a bit which is a good thing.

[johnnay]

I do have a steering stabilizer. The interesting thing would have been to measure the geometry with just the front end swap alone, before the monoshock conversion - I rode it that way last summer, and it did turn in quicker. It also felt a little "twitchy", but no shakes or wobbles. I may ride it without the stabilizer to see, and then fit it if necessary (hopefully I won't find out the hard way...!:shock: )

Still lots to do before it's rideable, though..

[johnnay]

finally took a pic and found a minute to upload it - this is how the bike sits now - just have to buy a chain, put it back together and make a new wiring harness (oh, is that all...!).

Of course, a seat would be nice, too..!

Any suggestions on where to buy chain in Canada, or that will ship here? I had an Ebay vendor refuse to ship me one because the weight meant it wouldn't have a tracking #. I told him I didn't care, but he still wouldn't do it - bummer.

I was looking at a black EK 530 MVXZ x-ring chain - any opinions?

[80GS1000]

Right on Johnnay, looking SWEEET! Did you chop the rear subframe too? Is your monoshock conversion all done now?

I bought my EK X-ring chain from http://sumofallparts.net/product_res...5-fc1e5d0b2256

Great customer service and prices. 120 links should be plenty, it's looking like my bike will need about 118 links using 520 chain.

[johnnay]

yes, subframe was chopped and angled up slightly..

thanks for the site - I'll check it out.