Topics

1

General Two Stroke Talk / 96-01 YZ to Modern 02 + Gas Tank Conversion

« on: July 22, 2011, 05:27:52 PM »

Its been done before, But I'd thought I'd show you mine with the dimensions.

This is for a 05 tank. So it will be for the wider aluminium frame.

Tools you'll need

Box cutter
Hacksaw.
Some Hand files.
Center Punch with hammer.
Vice to hold it all
6.5mm Drill bit for the tank mounts.
Step Drill bit capable of drilling a 16mm hole for the rubber bushes.
Few beers and some good tunes.



Shift the tank rubber up the frame, re-zip tie it. The lower rubber mount had to be trimmed (Razer Blade/box cutter) on the side So the tank would slide over it snug. (picture shows the radiator cages I built). Also you will need to unbolt the Plastic tab and bolt that locates the seat off your 96-01 tank and bolt it to the newer style 05 tank.



Here are the brackets I made. From 40x40 3mm Aluminium angle. The rubber bushes with washer tube inserts are the same used on the radiators. Extra holes in the middle of the bracket are just for visual.



Here are the dimensions for the mounting holes for the Tank.. All measuring from the TOP leading edge downwards.

Use your 6.5mm drill bit to drill the holes



Here are the dimensions for the mounting holes for the Frame. Use your step drill at 16mm for the rubber bushes. They are bushes for the radiator mounts. I had a few spare.

Radiator Fill side (Right Side)



Gear shifter side (Left Side)



For the lower shroud brackets you can do this (Taken from another thread) 25mm hole centers apart. I'd use a bit of smaller angle for extra strength so there is a spine, stick it in the vice for the correct angle contact to shroud guard. Like the little angle shown lower on my welded mounts. Also shows another way to mount the tank using the 05 Plastic mounts on the tank.



This is how I did mine. I built Radiator cages since there is much on offer for these models. But with integrated lower shroud mounts for the newer guards. 6mm side thickness and crush tubes bolted front and rear. Shouldn't be able to wreck those babies in a hurry!



Here is my mount TIG welded on and angle inline with the guard.



I have a custom sticker kit in the works for mine. Should look sweet once its all done.

Hope this helps!! Feel free to ask any more questions.

2

Technical / 99 YZ 125 Stock Valving Stack Specifications

« on: July 22, 2011, 07:30:39 AM »

Hi guys, Trying find out the Fork & Shock Stock Shim stack arrangements for my 99 yz125/ 144 build.

Before I cut loose and open the forks and shock up, I'll be running it in and tuning/dyno before I touch the suspension.

I'm after specs on Both mid and cylinder/base on the 46mm KYB open chamber forks and the stack arrangement is on the rear shock.

And any problems/areas what can be addressed to make these old forks work well.

So far I can only get 01 stock valve stack specs. I've read that the rods changed from steel to alloy between 99 and 01. And apparently the 99 does NOT have the cylinder valve.

I have installed springs for my weight, .43 front (.41 stock) 4.8 rear (4.6 stock)


When I bought the bike :
Forks : Replaced the outer bush, new seals and new bottom bumpstops, the rest is un-touched and stock.
Shock :Fresh oil and gas. When it comes to opening that up again. I'll replace the seal head and bush when I come to re-valving it.

Its had 6 rides since, then I pulled it apart for the restoration.

Thanks for your help guys.

3

General Two Stroke Talk / 99 YZ 144. Australia

« on: June 29, 2011, 03:44:08 AM »

Picked up this old rocket. Big Plans!

The bike when I picked it up was 1 owner and just been ridden, thats it , but the engine was worked on by a bike mechanic. Still has plenty of compression just general wear and tear and neglect of a bike that age. ie bearings, linkage bushes fork seals etc.

My aim is to build it into 144. The only thing I'll be getting done is the 144 top end. So far I've rebuilt the forks and rear shock and gone through alot of the nuts and bolts that were seized, rounded or torn off which must of been from superman hanging off them with a 1 inch drive socket set. haha

Its a bad phone photo but its the only one I got when I first got it..

Bad black plastics and all! And dodgy stuff everywhere. All the bolts had no anti seize and seemed to be torqued up to "FT" tension (*@#in Tight) as we say.



Rode it for a while then gave it a freshen up. Flu designs sticker kit and full set of new plastics, FMF fatty and powercore 2 silencer. Not too sold on the graphics, might change them down the track.

Another bad night time dodgy mobile phone picture. Sorry. I didnt even ride it like this...



Then I decided to pull it apart.

Used my arms and hands in a sequence of motions. Result was back to bare metal then waved a spray gun around a bit and this happened.



New Swingarm linkage bushes and bearings, polished the swing arm and started to bolt it back together.



Bottom end is rebuilt.

With new OEM crank, bearings and balance.

Every bearing replaced. Every seal. 5th and 3rd gear dogs were a bit rounded, so they got replaced. Drive shaft collar, Crank collar. New gear selector drum segment. Drum stopper from a 02, has a better design. All new springs on p/v gov, shift shaft, shift stopper... New clutch plates, steels/fibres and springs along with the billet clutch basket. The list goes on. Everything will be tight and operating like new in there like its just rolled off the showroom floor.

The 144cc top end is being built and should be shipped shortly. Its a bored to 144cc and re-plated 02 cylinder. Ported/polished and high compression head. All done by Harris Performance in Texas.



Installed a divider plate into the Mikuni TMX 38 I'll be running instead of the TMX 36. Cost me $8.60 for a length of 1.6mm alloy. And about 3 hours of fiddling around. Works the same as a "Power now" insert except its on the straight bore side of the carb instead of the bell end. I made a jig with and straight edge and stopper for length, used a fine tooth hacksaw blade and some fine needle files. It was a nice fit, tapped in with a hammer. And a little bit of epoxy (devcon plastic steel) for extra safety.



Hopefully it works well with this. Boyesen RAD valve. Nice bit of gear.





My aim in this is to try get low rpm air speed increase for a bit more bottom & response and maybe torque. TMX carbs are not strong in the low rpm air signal department.

New ASI Aluminium Radiators. 40% larger. Dual cores. Should keep the little monster cooler. I'll be making my own aluminum radiator braces that has all the mounts built in to run a 05 yz gas tank.



So pretty much I'm waiting on the top end to arrive from Harris Performance. Suspension to be finished getting re-valved. Suspension tuner is still waiting for parts to come in for the forks and shock.

Once the motor is tuned and run in...

I have a friends stock 02 yz125 to run a comparison to my heavily modded 99 yz144 on the Dyno.

Should be interesting! Stay Tuned!


Cheers

Street Kleaver