Topics

1

Tech Talk / 1975 Yamaha YZ50B Pistons

« on: April 27, 2015, 01:57:31 PM »

Hi all, I have a 75 YZ250B race bike on a standard bore that needs new piston kit, these don't seem to exist anymore, I have heard some bikes have a 5mm spacer fitted below the cylinder fitted and then run a Yamaha TY250 piston? I can not find any prior comments here on this. Can anyone give me a link or comment if this is a good solution? Is it as simple as adding the spacer or are other issues then requiring adjustments for? At least those pistons 74-75??) seem to be available for easy purchase.

2

Tech Talk / 1975 YZ250B Spocket cover

« on: August 31, 2014, 09:33:32 PM »

I am rebuilding a 75 YZ250B to race and it is close to completion, a harder project than I thought as parts are getting hard to find, I am still looking for a standard size piston but that is not stopping me yet, my problem is the bike has the original sprocket cover or minimal cover if you like but the Regs state I must cover the sprocket? Not use the original setup that everyone actually raced at the time?  Unless I fix that I cant race it? What do people use? does DT2MX cover fit onto the bike? All help appreciated.

3

Suzuki / 1974 TM400 Resto nearly finished.

« on: August 06, 2009, 08:45:55 PM »

It's been a year since this bike project started, getting close now.

The bike that made grown men tremble in fear..... real men only need apply.

4

Tech Talk / 1974 Honda CR125 32mm Mikuni carb jets

« on: June 23, 2009, 08:16:22 PM »

Does anyone know what jetting specs should be used on a 32mm Mikuni for a 1974/75 Honda CR125? The standard settings on the 32mm dont work.

5

Suzuki / Suzuki TM400, 4 Pound Flywheels Make them rideable?

« on: April 06, 2009, 12:40:13 PM »

I have a 74 Suzuki TM400 under restoration and would think about giving it a few race days once its done if I could tame the motor, I have read that in its day you could buy 4 pound flywheels that bolted straight on and made it a much better ride but have never seen one or even if you can still buy them anywhere, has anyone came across these or know where to get one?

6

Kawasaki / 74 KX125 Wins 125 MX Shootout!

« on: March 26, 2009, 09:20:19 PM »

Found a 1974 Cycle World magazine that tested all the Jap 125cc in a MX shootout, its a good read with plenty of content, the test is uploaded http://vintagemx.com.au/?p=567 for general interest.

I just finished my 74 KX125 and apart from a faded gas cap and slight defect on metal plate surrounding rubber chain guide its near perfect! I am still deciding if I want to race it or not, after all the effort you dont feel like beating it up but at same time you want to enjoy it where it belongs - on the track!

7

Wanted / YZ360B Side Panels

« on: February 11, 2009, 10:37:18 AM »

I cant seen to find any supplier of aftermarket side panels for the 75 YZ250B or 360B? Anyone know where to get them as I wanted a spare white set for racing on each of my bikes.

8

Yamaha / 1974 YZ125A Vs 1974MX125A

« on: February 07, 2009, 12:25:57 AM »

I came across an old 74 Dirt Bike test article that lined up the Yamaha YZ125A against the Yamaha MX125A, I would have thought the YZ was way ahead but as I have never ridden one I had no true opinion, I rode the MX125 when it came out in 74 and as a teenager it was a lot of fun and I don't remember doing any actual maintenance on it except chain tightening/lubing and adding more fuel... Curious if anyone agrees with the test results, I posted the test here for those interested. http://vintagemx.com.au/?p=499

9

Introductions / Obsessive

« on: January 30, 2009, 05:04:24 PM »

Hi Guys, as new participant in the vmx bike scene I wish someone would have warned me about how addictive these old bikes are. I bought a 74 Honda CR125 to tinker with and before I knew it I bought many more vmx bikes and have filled my shed to overflowing with the bloody things!!! ...and I keep looking!

I am just finishing off a 74 KX125 to a high quality race standard and have already started on a TM250 before I even finished that... All good fun.