T8's 750 Cafe Racer Project

[T8erbug]

Question. What foam are you using for the old seat base? Is it compatible with the polyester resin? Normal fiberglass resin? Where to get foam that is compatible. I.E., won't melt once you apply the resin?
No epoxy, please.
Tnx
G

I'm just using good old fashioned blue foam available at the Home Depooohh. I put body putty over it to finish it off and there is some very slight meltage from the bondo but I think it's mostly just from the heat given off during the curing process. It's not enough to do damage to the plug. Paint, however, on the foam will eat it right away. And as you know just about anything can be put on the bondo afterwards without a worry

[T8erbug]

Your brake stay's short reach and abrupt angle leave me wonderimg if an excessive amount of force at awkward side loaded angles would be generated, since the caluper will wat to push horizontally. It makes we wonder if the slightest amount of wear or slop would allow radial slippage movement if rge caliper/habger, sbd then more side loading if the stay's spherical heim jointsabd threaded connections.
Have other production bike used a similar setup?

Have another look - the caliper thrust is actually tangential to the disc and the arm angle follows this quite well. The arm itself is IMO well up to the loads involved. Can't see the point where it picks up on the swingarm but everything else is well enough done to give me confidence it's good too.
You may be surprised at some factory setups...look at some Ducati ones to see what you can get away with.

Greg is pretty much right on point with what I was thinking. I made sure the angle of the arm was not acute or obtuse or in other words in line with the force of the disc under braking. I can also adjust the length of the arm to change these angles but settled on where it is pictured. I have not seen any production bikes with a set up like this but have seen many aftermarket kits for springers similar to my design. I actually thought I came up with the idea when I later found out it's actually been around for a while haha. I won't flatter myself next time. Just "google" Springer Front Brake Kit and you'll see plenty of examples. In most of them you'll see the force is the same as mine just flipped so that the force the arm undergoes is a pull rather than a push. The principal is the same though and I'll be sure to report any binding or negative feedback if it happens. If it does and as long as I survive I think I know a guy who can come up with something

[T8erbug]

Alright, the good news is since my last update a lot has happened. The bad news is that not a lot has happened to the 750. In fact what has happened is negative growth. Progress reversal. I cut the rear part of the frame off.. again. I have since had Ben lathe me up another shock mount and tweaked the design of the rear end again. It will all be the same except lower profile. It will give me more shock cap clearance so the heads of my shocks don't ever come in contact with the frame, lower the rear end 1/2", and change the shock angle ever so slightly. This all came about because I rushed the job the first time and one shock mount was slightly higher than the other aka slightly askew. Not something I wanted to sign my name on so I started over with revisions. This time it should be lighter and closer to perfect, however, I have finally come to accept that this bike (as much as I want it to be) will not be perfect. No bike is. It's impossible. With the aid of modern tools, jigs, shops, etc, it can be close but not perfect. I have come to terms that I will build this thing as well as I absolutely can and that it will fall short of perfect BUT if it rides down the road in a straight line and can take me through the twisties I will be happy because that's what this is all about. I lost sight of that for a while and it's made this project take twice as long as it should. I want to RIDE! She's close and I can feel it. I'm finishing this frame, throwing some temporary paint on it, making the seat, throwing the motor in and I'm riding it. Not everything will be in it's final place but that's the point. It will be done enough for now. Done enough to take out on a ride and know what I need to adjust and tweak. This upcoming winter I'll take it all apart again, powdercoat the frame, paint the bodywork, and shine it up. I may even rebuild the motor. But for now, I ride.

I also picked up a YZ490 the other day because I got it for $290. It runs like a champ and is fast enough to scare me ha so I had to buy it. I went to my local powersports store to pick up some 2-stroke oil and when my buddy who works there asked me what the oil was for I told him I picked up an old 490. He asked me if I wanted a spare motor and as I thought about it I figured it's always nice to have a spare of just about anything so I said yes. Did I mention the spare is a runner? O and I also got that spare motor for free. When I asked him how much he wanted for it he just said, "mehh.. You can have it." ANNND as if it couldn't get better .. it does. That spare YZ490 engine came with a 98' YZ125 wrapped around it almost fully built . Lucky lucky lucky. Anyways so I added a few more ponies to the corral over that last little while and that's one of the reasons I've been less busy on the GS750 as well as the fact fishing tournament season has started and I am gone almost every weekend.

No promises on when she'll be done but I am back to work on it and I'll post some new progress pics when the welding begins.

[posplayr]

If you are interested in frame bracing, which I did to my 1000 then this is a good read. You will find out that the only, or recommended , bracing is C, D(in red) and E.

http://www.thegsresources.com/_forum...ame+bracing%22

That is about the cleanest frame bracing I have seen.

[posplayr]

Alright, the good news is since my last update a lot has happened. The bad news is that not a lot has happened to the 750. In fact what has happened is negative growth. Progress reversal. I cut the rear part of the frame off.. again. I have since had Ben lathe me up another shock mount and tweaked the design of the rear end again. It will all be the same except lower profile. It will give me more shock cap clearance so the heads of my shocks don't ever come in contact with the frame, lower the rear end 1/2", and change the shock angle ever so slightly. This all came about because I rushed the job the first time and one shock mount was slightly higher than the other aka slightly askew. Not something I wanted to sign my name on so I started over with revisions. This time it should be lighter and closer to perfect, however, I have finally come to accept that this bike (as much as I want it to be) will not be perfect. No bike is. It's impossible. With the aid of modern tools, jigs, shops, etc, it can be close but not perfect. I have come to terms that I will build this thing as well as I absolutely can and that it will fall short of perfect BUT if it rides down the road in a straight line and can take me through the twisties I will be happy because that's what this is all about. I lost sight of that for a while and it's made this project take twice as long as it should. I want to RIDE! She's close and I can feel it. I'm finishing this frame, throwing some temporary paint on it, making the seat, throwing the motor in and I'm riding it. Not everything will be in it's final place but that's the point. It will be done enough for now. Done enough to take out on a ride and know what I need to adjust and tweak. This upcoming winter I'll take it all apart again, powdercoat the frame, paint the bodywork, and shine it up. I may even rebuild the motor. But for now, I ride.

I also picked up a YZ490 the other day because I got it for $290. It runs like a champ and is fast enough to scare me ha so I had to buy it. I went to my local powersports store to pick up some 2-stroke oil and when my buddy who works there asked me what the oil was for I told him I picked up an old 490. He asked me if I wanted a spare motor and as I thought about it I figured it's always nice to have a spare of just about anything so I said yes. Did I mention the spare is a runner? O and I also got that spare motor for free. When I asked him how much he wanted for it he just said, "mehh.. You can have it." ANNND as if it couldn't get better .. it does. That spare YZ490 engine came with a 98' YZ125 wrapped around it almost fully built . Lucky lucky lucky. Anyways so I added a few more ponies to the corral over that last little while and that's one of the reasons I've been less busy on the GS750 as well as the fact fishing tournament season has started and I am gone almost every weekend.

No promises on when she'll be done but I am back to work on it and I'll post some new progress pics when the welding begins.

[URL="http://s1178.photobucket.com/user/t83rbug/media/temporary_zps6ef6b2a6.jpg.html"]

Good Luck you have made a lot of progress even if some of it was backwards but you arr close and I'm sure you will be ridding soon.

[T8erbug]

Took the bike to the bronze shop after work today for some welding. My skills as a welder have come a long way on this project. I have much more to learn and I'm stoked to become a better fabricator. Today I was able to rework some straight stock onto the old frame hoop so that the bend could be re-used. Saves me time and money. I was also able to get a couple pieces welded onto the frame so that I can mock up and create the rest of the rear at home. I threaded the shock mounts and everything went very smooth. I'll be out of town this weekend but hopefully more progress early next week.

[mlymanz71]

Dang the bike is coming along nicely! That bike is going to look sweet flying around the streets.

[T8erbug]

Here are some before and afters from today's work. Just smoothing out the filler welds in the rearsets.










A little Dremel tool goes a long way when it comes to details. I cleaned up all the welds as well as a lot of corrosion and junk from the rearsets, levers, and rear MC. I also smoothed out all of the casting marks. It was nice just to do something little this weekend. I should be getting more done on the frame this week. Once the frame is done I will put the engine back in and work on the tail. Just details after that folks.

I was mocking up my headlight just to see where things needed to be and ran into some issues because of my steering damper. I could mount the headlight as everything sits now but the headlight would be too high in my opinion. It throws off all the lines so I'm going to move the damper a little over an inch lower. All I have to do is flip-flop one side and make a spacer for the part that mounts to the stem. I'll post pics as I figure it all out.

[T8erbug]

I got some nice looking parts from warp 9 this week to complete the brake and shift levers. They are built for their levers but I figured I could machine the ends of mine to work with their stuff. They turned out pretty well considering all the work was done with a dremel, drill press, and grinder. I had to notch out a line in the brake lever to make the brake tip work. I used my drill press on high speed with a dremel cut-off wheel attachment to notch it out by sliding the x-y vise back and forth until I reached my desired depth of cut. It worked pretty well!

[Morrison]

Very nice. Are you going to use the stock shifter linkage and lever arm w the left rear set or whats your plans with that?

[T8erbug]

Very nice. Are you going to use the stock shifter linkage and lever arm w the left rear set or whats your plans with that?

I am using the lever arm that came with the rearsets (fits great!) and I had to lathe up a new shift linkage to the correct length and cut threads for it. I did it all a while ago when the engine was still in the bike, I just didn't post pics because it wasn't overly exciting.

[silverbullet132]

Would you be able to make another one of the steering stops/damper mounts? pm me please

[T8erbug]

So I revised the rear end of the bike.. again. Luckily I didn't have it all put together yet so I didn't have to tear down and start fresh. I decided I'm not going to have a rear hoop. There are a few reasons why. First of all my revised plan should be way easier and cleaner to fab which is always good. Second, it will shed close to 5lbs of weight off the back of the bike, give or take a pound. Third, with Ben wanting to mill the entire tail out of MDF for a perfectly symmetrical plug we will be able to revise the shape of the tail for use without the hoop. I got the idea a week or so ago while I was mocking up the tail so I could make my triangular shock mount gussets. With the tail on the bike and no connecting hoop it actually looked pretty clean and the lines all matched up beautifully. Once I thought about it some more I came up with a few ways I'm going to shape the tail around the two ends of the frame to make it look factory. The other added benefit is that they are much lower profile and the shock clearance will be a TON better. You'll see what I mean in the pics. The overall look and shape of the tail will stay the same with only minor adjustments to give the back of the tail a finished look without the use of a hoop. The hoop was just such a pain to line up, it made everything weigh a ton, and it just complicated EVERYTHING. That's one of the main reasons the shock mounts were askew last time. So without further adieu here are some pics of what's going on.

This is Travis. He runs and operates Bonner's Repair in Midway, Utah. He's a stud and is actually the one who came up with the idea to bend the gusset on one side rather than weld three pieces together. This way I'd only have to weld two together and it would have a much cleaner look. Of course he'd come up with it, he's got the machine to do it! He punched the holes within seconds and had both units bent in just a matter of minutes.




Once I got them home I began the fitment process with the grinder (which I'm really beginning to hate).

[T8erbug]

So, here's the clearance stuff I was talking about. The old setup had to be ground out for clearance and it was still just a millimeter or so from touching the shock cap.


Here is the clearance of the new setup




Old VS. New (the older one is much bigger than the new setup but I'm holding it a little further back in the pic)


You can see why the old way was so stinkin' heavy!


And Lastly, I finally came across a clean used front M/C off of a CR250 so I bought it and mounted it. That completed my braking as far as the big stuff like calipers and masters so I had Galfer make me some custom stainless steel lines that should be here by Monday or Tuesday. They thought I was nuts when I asked them to make 2 brake lines with 4 different applications ha. CR250 front M/C-2001 GSXR caliper and 1993 GSXR M/C-DRZ400 caliper. I'll get them mounted and bled asap and post an update. I should be able to weld up all the tail end tomorrow so wish me luck.

[T8erbug]

O and check these bad puppies out One is an original 82' YZ490 and the other is a total frankenbike. 98' YZ125 frame and components with a late model YZ490 engine and engine cradle. The best part is I got it for free! I just had to buy all the rear braking components, a rear tire, do some minor weld repair, get a few nuts and bolts, and buy some handlebars. She's almost a complete bike! I also bought a new seat and tank for it that should soon be here. They are 82' YZ250 body parts so that this thing will be totally retro styled to fit the generation of it's engine. It's going to be a fun/scary bike when it's done! Dirt bikes go together SO much easier than street bikes. The uglier the better