DR650CR????!!!??

A

alpinaclone

Been Around the Block
EDIT: I took out some photos of the stuff that dead ended to clear things up a bit.

I haven't posted much here yet, but in my intro thread, I alluded a project that I have recently started.

Here is the donor.
DSC_0013.jpg



The donor bike is a 1990 dr650s that I picked up for $450. It runs well, and it is a lot of fun. It is also ugly, too tall and softly sprung for the street and too portly for the dirt. I have decided to sharpen it's focus and ditch any dirt aspirations that the bike once had. I toyed briefly with the idea of a supermotard, but the bike would still be too tall and heavy for my liking.

The frame that I am going to use is a Suzuki gt250, This frame is much lighter, better looking, and the dimensions are much more inline with my tastes.(the dr's stock wheelbase is 59") EDIT.......nope........



The poor empty shell.
DSC_0019-1.jpg


The aim for this is going to be kind of a cross between a Suzuki TR250 road racer and supermono bike.

There is still a ton too do as you can see, but I am excited to get started. The garage needs a major cleaning. After that I a building a simple frame jig and will start hacking up perfectly good motorbikes.

Cheers, Matt
 
A very ambitious undertaking indeed. Although I think a better bet would've been to modify the DR frame to suit your needs. Far less work and it has the monoshock.
 
DrJ said:
A very ambitious undertaking indeed. Although I think a better bet would've been to modify the DR frame to suit your needs. Far less work and it has the monoshock.
Click to expand...

Ehh, the dr frame is big and ugly and heavy. As I said, it has a 59" wheelbase, that's deep into cruiser territory. Besides, I don't really care for mono shocks (and the linkage needs to be rebuilt).

For my goal of a sub 300lb bike, the stock frame and swinger had to go.

Matt
 
WOW - ambitious indeed!

So what's the plan to shoehorn that donk in there? Cut the top or the bottom of the 250 frame?

Keep us posted - this will be inspirational if you can make it work ;)
 
I would have to agree with DrJ on this one. It's a great idea (small/lightweight frame+ big thumper engine), but you've got a shitload of work ahead of you. I hope I'm not being too discouraging. Just out of curiousity, what's the weight difference between the two frames? Once you've added all the engine mounts and possible additional bracing (I'm no expert on the 250gt but most 70's japanese frames don't handle all that well). It really wouldn't be that hard to just get a a shorter swingarm for the DR frame,re-do the "subframe" and weld on some mounts for dual-shocks. Like I said, I hope I'm not discouraging, I'm just curious as to what sort of solutions you've thought of to tackle all the obstacles. Here's a few pics of a similar swap, looks like a featherbed? frame.

The UnFlying Finn


img630134.jpg

img630135.jpg
 
thanatos said:
img630135.jpg
Click to expand...

Very cool, I scoured the net looking for something similar, and you guys deliver.

That is kinda what I am aiming for, except there will be less negative space and it will be more compact.

As far as frame mods are concerned, I think that the bottom rails will stay, the tops will be redone and will splay out around the head. I won't know for sue until
I get the jig built and get the lump up in there. In addition to any mods needed to fit the engine, the frame will be braced a la the TR250.

As far as weight is concerned, the gt250 stock, is listed as 295lbs and I have seen the dr quoted anywhere form 333lbs to 375lbs. If anyone has ever played with a dr they will tell you they are built like a tank. Everything is super hurky, good for bombing along the desert, but not for light weight.
 
May I also chime in regarding your frame of choice? I won't rain quite as hard on your parade, however......
the GT250 was nearly as poor handling as the Kaw H1 and made what......9ftlb of torque? Since you're essentially going ot be rebuilding the entire frame be sure to brace it well around the steering head and the swing arm pivot. Both are miserable as it.
(Yeah I owned one.....)
I'm sure you've already planned for all this, I just don't want to see a brother disapointed or worse..injured.
The swing arm will need bracing too......

Stick with it though, sounds like it could be a riot once on the street!
 
Here's my thought, because I think you're on to something very cool. If you like the dimensions of the little bike, you could make a very sturdy jig off that. Once you're satisfied with the jig, chop the neck off the little bike and sand down the welds---NOT THE VIN. Then, turn it on the lathe very slightly to get overything smooth.

Finally, bolt the neck in the jig and connect the dots with some tubing. You're going to be sorta doing that now, so why not go all the way?

--Chris
 
Everyone's advice has been noted and we are all close to being on the same page. I am building a jig, and it looks as though most of the front of the frame will be modified and or replaced, I won't know exactly what for sure until I get it on the jig. I am addressing the weak points of the frame as I see them and it should go around corners well when I am done. I have considered doing an entire frame from scratch, but I already have this one and I think It will save me a few $ on materials in the end.
 
^^^ I've seen that one before. It's actually a dr800, I didn't know such an animal existed until a couple of weeks ago.

I picked up an early 90s gsxr 750 front end for the project, should be a little better suited than the dr forks. :)

I have had family in town this past week, so progress has been slow, but I hope to have some updates soon.
 
This project is not dead!!! I kinda forgot I had a thread going on over here. You can check most of the progress at http://vintagefighters.yuku.com/topic/489

Here are a couple of pics of where she sits now;

DSC_0134.jpg


DSC_0131.jpg


Here is what it should look like shortly;

zukinewmockup.jpg


I'll try to keep the updates going over here as well.
 
Knew you'd end up chopping the DR frame, mate. Making an almost totally custom frame for an outsided modern engine is a total pain in the ass. I don't mind what you'd done with it currently, and have heard that you can match up some GSX1100 carbies to give it a bit more oomph in the top-end. I envy this big time, its on my must do list - a big single cafe racer from an aircooled modern(ish) dirtbike.

Cheers - boingk
 
Yeah, I started chopping up the Gt frame and to get the engine to fit, there was nothing left. This seemed the logical way to go.

I am going to get it back up and running with the stock carb with a dynojet kit because I know that works and will minimize variables. After it is back on the road, a Keihn FCR39MX, I believe they are called, off of a Yamy yfz450 will be fitted. I also have a dual port head off of a DR600 that looks like it has more flow potential, so I may try that. Maximum overbore on this engine puts it roughly at 666cc.... DR666... Dr. Evil might be a fitting name.
 
I wasn't even aware this project existed until today! Very creative stuff man, looks like it'll scream.
 
DR 650 was my first road legal bike way back when, what a bitch to kick over, great fun tough. That thing will thump and if you get it right with the weight, stick like shit... Good luck and keep going!
 
What's up man? Been a member over here for a while, don't post too much though. I'll try to keep this thread and the one on vintage fighters updated.

88 and big R, the bike should be a monster when finished. It was pretty potent as a beat down enduro, so I imagine with 60lbs less or so it should be a good time. And yes, it is an absolute pigf*ck to kickstart...lol
 
Yeah I like big singles and twins. You'll get better at the kickstart thing jetting will help. It helps if you have some good boots makes it easier on your foot. Should be a riot.
 
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