Wanted, a complete usable crankshaft to suit XR75 77 model 5 speed engine. 

Couldn't Metty get a ride in the U.S. ?

No there was nothing on offer

Yes modern tracks are too dangerous, most tracks nowadays are just a jump fest which greatly increases the chance of injury compared to the natural tracks we rode on in years gone by.
A track doesn't need to be full of jumps to be fun or challenging and proof of that is the popularity of Conondale, it is one of the best and most liked circuits on the modern MX Nationals tour and also in the VMX scene.
Also the natural terrain track at QMP is a big hit with the Pro riders and many practiced there the week before the Conondale round and it only has 2 or 3 small ski jumps.
There are far too many spinal and other major injuries these days and many occur on a jump gone wrong..

Of all the bikes I've owned and ridden I'd have to say the 81 490 Maico motor is the best. Smooth broad and strong power delivery it just does everything right.. only negative is they can be hard to start

I put a 32mm mikuni from townsville on stock M1 and made the world of difference. I havent touched the jetting at all from what Tom sent. slip it in and rev the shit out of it. Happy days
Cheers Troy

Yes I'd go for a 32 also..

He's an importer in Tweed Heads, they're pretty average bikes with some plastics thrown on them to look good for the photos. I know a couple of guys who have bought from him.
Just remember these importers are in it to make a dollar, you don't get the same quality of bike as a local one that's been built to race..

That was on a couple of weeks ago and got to $18,000 and didn't make reserve.
People bidding obviously believe its the real deal for that money..

Only trouble with those cr125 Gem reed valves is they are a bit restrictive and you may lose some outright horsepower in place of the better bottom end. None of the privateer race teams used then back in the day. DG, FMF etc..

Yeah TD Hattrick is the place to go. 32mm

"The Normal"
Every track is different? a greasy wet clay track i would go as low as 5 or less, on a hard packed fast track with square edges ruts you would want at least 14 - 15 lbs. anything in between.

In an enduro I've changed pressure up to 4 times in one event as the terrain changes.

face it, you should run the lowest acceptable pressure for the track your on as the tyre will give more grip  with less pressure.

We're talking motocross are we not?  And there was no mention of mud riding.
If it was a mud race I'd still never go below 8-10lbs or you'll pinch a tube landing off a jump or a square edge bump beneath the mud.
You don't run low pressures in good conditions, the front will push and wash out and you will pinch a tube hitting sharp edge bumps and jumps. Unless you're just out there cruising around...
I've had flat tyres running 12lbs so there's no way I'd go less than that on a dry track.

Without the spring on, you could push them in about twice as fast as pulling them out (from memory ).

All good shocks have more rebound damping than compression to control the speed of the spring rebounding

You don't need to buy an old pair of koni's you just need to get shocks built with the correct damping and spring rates to suit a pre 75 bike. Pre 75 use lighter damping and spring rates to pre 78 and different again to Evo.
Ohlins and Works Performance are 2 reputable brands that build their shocks correctly to suit specific applications.

Big K would you generally say to go with the mikuni even on slightly later CR's like a 125RZ
Brett

Brett a 32 or 34 Mikuni is a better carb for the 74-77 CR125's but there is nothing wrong with the Keihin on the 125RZ and RA models, the RA carb is 2mm bigger than the RZ carb and a better choice.

The shocks are brand new from a well known dealer.
The spring rate was discussed at purchase and suggested springs installed. It was also advised by seller to buy the better type of shock for a number of additional benefits.

The thing is that I have been running around on a set of 1972 Yamaha shocks on an AT1 for 4 years now and they are still almost perfect for that bike. The RT1 has now had 3 different set on it, the first set where stuffed Yamaha ones (possibily from a CT1), second set where $75 imports that was just for sorting the rest of the bike out. I crushed the top eye on both sides (they weren't steel) after 2 races and as a mental note they definitely seem to offer zero damping anyway. The third set were not cheap but not a $1000 either. I'm certainly not a complaining customer (was told of pitfalls at time of selection), just dissapointed that I have to actually fine tune something that I would ordinarily take for granted would work out of the box. Unreallistic I know! It does seem obvious now that the rebound is way off, so I'll pull them down shortly and have a play.

However, I am struggling with the static / dynamic sag settings for older twin shocks. I know sag validates the spring rate (soft or weak) but with only 4" of wheel travel, I really don't want 1" taken up when sitting my fat as* on the seat!

It is a black art and a huge time taker to get right. Any helpful points taken with great respect at stage.

Peter B

If you only have 12mm of sag sitting on the bike your springs are way too stiff and if it takes 30 secs for the springs to unload then the shocks are over damped also. You've been sold a pair of shocks not suitable for a pre 75 bike and more likely to suit an Evo.
Like I said before there are well known dealers selling the wrong spec suspension to customers and you've just confirmed it! There are also certain suspension brands that have been around a long time and always get it right.
I'm rebuilding twin shocks for vmx customers pretty much every week so I see plenty of them and you're not the first with this complaint and you won't be the last!

If you're using modern bike settings to set up the rear end of a twin shock bike you are off the mark. Modern bikes have a rising rate rear suspension linkage system and twin shock has a linear rate, you can't run as much rider sag on a twin shock bike, it will ride too low in the stroke and bottom everywhere.

Yep that's what I'm saying but it is interesting to know what laden & unladen sag riders are using with either straight rate or progressive springs?

To be quite honest a lot of riders in vmx have no idea about suspension setup, they just ride it how it is or bolt on any set of shocks not even built for that bikes suspension geometry. I've seen shocks from a long travel Evo bike bolted onto a pre 75 bike and they are nowhere near the correct spring/damping rates and feel like rigid rear end. Even some well known suspension shops are selling the wrong shocks to customers because the buyer knows no different.