Matt's '83 GPZ 750 Project

[Gix11]

Here's one from Matt in the states.

Here's his email:

"Love the site. I was looking through the pics and thought I would send you a pic of my 83 gpz750. Ive been working on it for awhile now but hope to be completed in the next few months. Here are some specs:
83 Kawasaki GPz750A1
90 gsxr750 front end, floating rotors, 6pot calipers, braided lines, remote reservoir master cylinder, graves clip ons.
95 gsxr750 braced,polished swingarm.
5.5" rim with 180 section tire.
530 chain conversion, custom made front sprocket and chain tensioner.
custom made cam chain tensioner, gsxr1100 flat slides with push/pull throttle.
custom exhaust.
Cut down frame with custom fiberglassed tail/side panels.
Custom Suspension linkage.

I still have alot to make/do to the bike to get it back on the road. right now it weighs 400lbs, 52% weight bias to the front. 22.9* rake angle with 3" trail. 56" wheel base. With the stock carbs it dynoed 80hp at the rear wheel. I hope to get 90hp out of it all motor then eventually turbo it. Because its a work in progress the photos arent complete but i hope someone likes them. One pic is how it looks at the moment. The other pic is when i had it on the road a few years ago.

thanks
Matt"

[Iceman]

Looks pretty good I reckon. Nice flowing lines, wide open at the back. Keep up the good work.

[fimpBIKES]

nice tough stance!!

should look great

[Tone]

Looks great that..thought it was a Buell at first glance.

[03gixxerpilot]

nice aggressive looking fighter, thats what its about
well done Matt

Drop a GPz900R motor into it mate, then it'll go like unholy Jesus, without the problems of a turbo setup.

Had an A5 one of them a couple of years ago, it was a damned fun thing through the twisties.

[Benz]

I'm doing something 'similar' to my ZX750 turbo What are you going to do about footpegs? I'm using a '90 gixxer arm without bracing, and the peg mounts will not work in their original mounting holes
Is there any problems with such a [relatively] small amount of trail? Is it super twitchy, or what?
Keep up the good work Matt, the old geeps are a great basis for a 'fighter.

[cutcat]

Hi Matt, top work, what are you going to use as a seat conversion? or is that just the standard seat cut down?

[shift1313]

Hey guys, thanks for all the good words. I spent about 30mins posting here with more pics and answering all your questions but it said i didnt log in and all my work is gone. Ill fill you guys in and answer your questions tonight after work.

matt

[shift1313]

well i guess ill ad some more pics. I made some headway on my tailsection project this weekend.












the part on the bike is the plug for my fiberglass mold. Ive got fiberglass on there now that i need to pull off in the next few days then i can lay the final fiberglass piece. The one in the pic is super heavy cause it alot of bondo and aluminum.

cutcat: as you can see in the pics the new tail has a seat pan area like a solo race tail. I might use foam like gp bikes but i might also fiberglass a seat pan and cover some seat foam and bolt it from underneath. That would be more comfortable in the long run.

Benz: For awhile i ran the stock rear sets, i just had them spaced way out to clear the arm, espcially the brake side. Ive actually designed a few rear sets for my bike, adjustable and non. I made a prototype from plastic but found that my feet were way to far back, im kinda tall. here is a pic and some cad drawings.






I dont think ill make the brass knuckles but it was fun to draw.
The bike has absolutely no problem with 3" of trail. I actually put alot of hours in designing my setup and making sure everything worked just right. I wrote an entire article on motorcycle geometry on streetfigthersclub.co.uk.
http://www.streetfightersclub.co.uk/...t=2371&start=0

that will link you to the post with all the stuff in it.
The bike handles great. I havent pushed much over 100mph yet but it was strong up there. I can let go of the bars at highway speeds with no wobble at all, thanks in large part to my rear end setup on the bike. On top of that the bike is extremely responsive to weight shifts or steering inputs. It falls into the turns very easy and pulls out of them just as easy. If you end up reading the stuff i wrote on the other site and have questions let me know.

chalk: Ive thought about motor swaps alot over the past several years. gpz900 motors arent easy to come by over here, neither are 1100 or 750turbos for that matter(for a good price anyways). Ive though about zx9 motors and zx10 motors but in the end this bike is okay how it is. It makes good power and i know i can get more out of it. dropping 100lbs off the bike does wonders for power/weight ratio. Any motor i changed to, especially a liquid cooled one, would really mess up the work ive done. My cg and weight bias is right where i wanted it and changing a motor this late in the game would be a huge headache. I plan on building more bikes to take care of that.

and thanks for the comments. i was really going for a clean tough look without any clutter on the bike. Its far from done but ive come along way since i started the project. Here are a few more pics of things. Ive made an mcct and some suspension linkage, tons of spacers and shims. brackets etc. I made the front sprocket for the bike(well custom offset). I hope to make some good progress in the next month or two so it will be back on the road by spring.


you can see the chain roller i made, needed it with this much of a swingarm angle or the chain rubs the frame on decel.


I had to make the mcct so the gsxr flat slides would fit. That huge stock tensioner hit the float bowls.

[Gix11]

Nice one Matt. I realy like the lines of that tail piece. When it's all painted up it will look really trick. Cheers for coming back to ASF as well mate.

[cutcat]

Hi Matt, looking good mate, tell me more about your front end conversion.

[shift1313]

front end conversion was fairly simple. Ive actually done a writeup on the whole bike but I can tell you about the front really easily. I took an old kz front end I had, it turned out the stem was the same as the gpz stem. I added material to the end of it with a tig welder then turned it down on a lathe. The gsxr lower bearing was a bit larger then the gpz, not by a whole lot though. The only thing i changed in the design was the bottom of the stem. The gsxr stem had a c clip around the stem to retain it. On mine i machined a lip in there so it would be sturdier. Because the gsxr also used larger bearings, when i reused the gpz stem bearings I had to shim the lower bearing up just a small bit to get them to seat. Because of this, the top of the new stem was about 1/8" short of making it to flush with the top tripple clamp. So i turned out a small adapter piece on the lathe. Basically just a washer with a step on it and voila. Instant front end swap. The whole thing is 2" shorter then the gpz front end, including tire, and this is where i get most of my rake angle change from, that and jacking up the rear end a good bit. If you want i can find the write up and link you to it. Also ive taken the weight of just about everything on the bike, except the gsxr front end, ill weigh that when i pull it off next time. If your interested i could post that stuff here too.

[zx12argh]

Sweet work mate - Once I finish my 12r fighter I'm going to start work on a PGZ900r I've got out the back. I might have to fight the spiders for it though. Its great to see tough machines coming out of old metal.

[Scrapyard]

Awsome work so far bud. Really like the seat unit. The rearsets are top too. Nice work man.

Yup exellent concept[8D]good lineskeep goin man[]

[shift1313]

no matter how much i like the classic lines of a single round headlight i just cant leave duals alone. I threw these back on tonight while my fiberglass is curing.








what do you guys think. stay with the single round 6" or go with something like this?

[Iceman]

I fuck'n love those ones Matt. Leave'em on for sure!

[shift1313]

i thought so. They are really clean looking, simple and take up enough room so it doesnt look funny.

[Gix11]

Exactly. Leave 'em on.