Yamaico's new el Cheapo Project.

[firko]

Many of you will remember Yamaico's step by step build build up of his 465 Yamaha dirt tracker a couple of years ago. http://ozvmx.com/community/index.php?topic=9177.0
Well, Pete's back at it again and has decided to build a bike that's not intended to be a class perfect racer but be "just something to hack around on" at Classic Dirt, HBBB and that sort of event.

The object is to build a well behaved motocross oriented bike out of left over, donated and bargain basement junk parts. The budget is to be a nice round $1000. Peter is a very handy tradesman and is capable of doing his own welding, machining and engine building. He is even doing his own soda blasting and powder coating using equipment he's built himself. Of course most of us don't posess such a well equipped workshop but this exercise will hopefully show what can be done with a bit of lateral thinking, a reasonable amount of basic workshop skill and little overall outlay. If you haven't got a powder coater under the bench, don't worry too much, rattle cans do a pretty good job and paying for blasting wouldn't dent your budget too much.

Building bikes like this allows us to use a bit of hot rod injenuity and 'suck it and see' experimentation. If it doesn't work or looks wrong, pull it apart and try something else. Once you get rolling on these projects they become a lot of fun and the finished product is something unlike anything else in the pits. Follow this and see how a pile of shit can evolve into a unique bike.
 

The parts list starts with a KLX250 rolling chassis ($200), DT400 engine ($100, courtesy of Vandy), DT250 frame ($0, courtesy of Nathan S) and YZD guards and YZ125C tank (courtesy of Peters cousin Scott from VMX Plastics). Pete plans on fitting the forks, rear frame, swing arm and shocks from the KLX onto the DT frame in his usual Illawara Dr Frankenstein manner. Nobody builds a better Frankenbike special than Pete.

 The DT400 engine came with a YZ gearset and head so with a bit of porting, a 38mm Mikuni, YZ250 ignition, a decent pipe and some head reworking should see more than enough horsepower for some serious fun.

Here's the "Starter Pak" lined up ready to undergo surgery.

Pt 1 in Pete's words
"I started on the bike last night. Cut the old steering stop off the DT frame and fitted the steering stop from the KLX. Machined a sleeve for the KLX bottom yoke so I could use the DT steering head bearings. The front end all fitted up good so then I drilled out the spotwelds on the tank mounts and repositioned them for the YZ tank. The tank fits up good with enough clearance on each lock, but still have to cut the bottom out of it and beat out all those ball dents in the top. Tonight I’ll make the new front engine mounts as the DT250 and DT400 are different in the front. The two back mounts are correct, which makes it really easy to do the front ones. Once that is finished the next job will be to shorten the swing arm. The DT frame is a lot longer in the main frame than the KLX, so the standard length swingarm bolted into the standard position on the DT frame makes the thing look like a hillclimber. I can get about 50mm out of the swingarm quite easily, but I’ll have to reposition the upper shock mounts accordingly when I weld the rear frame loop from the KLX onto the DT frame. This could prove to be famous last words, but nothing appears like it is going to be too difficult with the whole project. I’ve done a budget estimate, and $1000 looks quite achievable."

[vandy010]

i bet Nathans jealous already looking at that frame
that'll be one cool bike when it's all done Pete

[firko]

Tacked the rear subframe in place last night and machine some sleeves to mount the rear guard. Have to finish the rear tank mount next and then finish welding out the frame. Getting close to a rolling chassis now. Looks OK I think, and measures up pretty much the same as the KLX with regards to wheelbase, rake, seat height etc. I would think that the DT motor would be a bit lighter than the KLX motor, so it should work OK. Still got all the fiddly bits to do – brake pedal, torque arm, chain rollers and wear pads.


Got the front engine mounts fabricated and installed. Shortened the swingarm by about 40mm and welded the new tube in. Made swingarm bushes out of nyloil, which is self lubricating nylon and was only $25 for a 40x300 bar. Really easy to machine and should last longer than the needle rollers that were in there. Welded a lug on the bottom triple tree (spare one from you) so I can bolt the YZ guards up to it. I then powder coated both the top and bottom trees, ready for installation. The next thing to do is mount up the swingarm and shocks so that I can weld the rear frame on and make the rear tank mount. All going pretty well so far.


Repaired the crank on the weekend. It was rusted really badly and after I blasted it I noticed the timing side seal surface was heavily pitted. I could buy a good second hand crank off ebay but I’m trying to stick to the budget so I machined down the seal surface 1.5mm and then made a sleeve out of an old gearshaft and shrunk it on, then machined it back to size. I also took a clean-up cut off the outside of the wheels – only a couple of thou so it shouldn’t affect anything. Put the wheels back together and trued them ready for motor assembly.

[pmc57]

Wow, if Yamaico Pete was a lady, I'd marry him.
I just love the step by step progress from someone who knows what he's doing around a workshop

[firko]

I Lowered the swinging arm pivot by 13mm last night, which took hours to do, but it was worth the sffort as the chain line looks and works a lot better. Also made the rear tank mount, lengthened the rear torque arm and finished welding out the frame where the rear loop joins. Have to do some mods to the seat as it conflicts with the rear tank mount, and then send it out for covering. I’d like to get an industrial sewing machine and have a go at making seat covers but dirt track legend Doug Platts does my seats and he’s an awesome trimmer.  I mocked the bike up and am still undecided about having the tank polished aluminium or painting it to match the guards.


The bike is starting to come together and looks pretty purposeful. I think the tank should be yellow (mf).

[Slakewell]

Firko
Will you make one of your custom aluminum air boxes.

[firko]

Mick.....have a proper re read, I'm not building this bike, it's Yamaico Petes project, I'm merely the presenter.
Creepy that you mention it though, just this morning I made a cardboard mock up for an alloy airbox for my Hindall.

[YZ250H]

I'm watching with interest as I'm sure many others are.  Fantastic to see a master at work undertaking what for me would be very tricky jobs.
These are always my favourite threads ... keep the photos coming 

[Slakewell]

A good pipe and carb setup ( a nice 38 bing) and a few port tweeks  this thing would be more than interesting.

[Tex]

This is a great thread! I'm looking forward to seeing the finished product.

It's great to see what people with some talent and good ideas can do, and all for under $1000, brilliant!

Tex

[vmx42]

I'll be checkin' in regularly to follow the progress… so keep on top of the build Firko!!!

[mx250]

I'm guessing here but I take it that it is the DT front loop with the KLX rear loop (from the swing arm pivot to rear of tank), welded on, (giving the KLX seat base and shock mounts already pre-positioned). And the KLX swing arm mount adapted for the DT frame.

Nice, neat, tidy, relatively easy and looks 'factory' .

[firko]

I'm guessing here

                                   
It's all explained in the text

[bazza]

Firko tell pete i feel a yellow 125 tanked blender coming on!!!

[vandy010]

am still undecided about having the tank polished aluminium or painting it to match the guards.[/b]
 

i like a lot of Yamaha paint jobs but must admit to not being too much of a fan of the polished tank look, except on some of the Brit bikes.
i wonder what a black tank/yellow stripe would look like as opposed to the yellow tank/black stripe