Hot Tips for the 75 RM125M?

[DR]

  a 75kg RM125S eh..I'll take 3 please!! just stirrin' ya Loz

but wait...an example, the steel rear sprockets..weight = 1.7kgs give or take a few grams. An alloy rear of the same size = 600grams. There's over a 1 whole kilogram saved just on this 1 item alone. Easy peasy!

Engine mods are really great Loz especially for DT, I know little about this subject and build my engines stock hence I look at the other areas. Areas that actually make me feel more comfortable and relaxed on the bike..the more relaxed I feel the faster I go. Discounting all the little things in favour of just engine mods and more HP doesn't sit well with me and a combination of the 2 would be far more desireable..just my veiw

Greame, I realize you are no novice and you've more DT experience than I'll probably EVER have. In saying that I also realize your bike setup would obviously be quite good already otherwise you'd not be hunting more HP. Lozza's head mod does sound like the go    

[Lozza]

A TZ/RS 125 weigh about that much.

One item that robs HP is the chain, dropping to a 420/415 non o-ring chain is a good idea. Unsprung mass is the best to remove unfortunately the most expensive.

[Graeme M]

Couldn't I just go on a diet? Much easier for me to drop about 4 kg. I'll report back in two weeks...

[tony27]

Thats pretty optimistic 

[Graeme M]

Would you believe 2kg? In 3 weeks?

[tony27]

For me it only goes the other way

[Davey Crocket]

Your dreaming Graeme, spend the money.

[TT5 Matt]

why dont you remove the steel airbox?after all it wont work with the bigger carb and weighs at least 1.5kg's,swiss chese the brake shoes,drill the brake cams/arm's out

[oldyzman]

Hey Lozza,
What do you suggest re the head in the lathe...
Cheers Brett

[Lozza]

Graeme,
have you decided anything with this, I'm assuming thinkin' time is free

[Graeme M]

Haven't gotten too much further over the past few weeks. Gained a kilo so clearly losing weight isn't going to work!

I am currently cleaning the frame etc and redoing bearings and so on, aiming to get the shocks rebuilt. I've not yet had the broken barrel stud fixed but that should be this week. I have done some fiddling to get the 34mm carb to fit using a S manifold, and I have a good S head sitting there waiting to be blasted to tidy it up. Beyond that, it's still just a pile of bits in the shed.   

[211kawasaki]

Graeme
one thing I learnt over the last 20 odd years of TM125s is that you can over do the mods. I still run the std 26mm carb on my TM and its no slouch and has left many a CR in the dust. I even went back to a standard pipe after the kit TS pipe and a Gemco pipe from the states made no midrange. What I have done to the bike is blueprint the cases, ports, cylinder in detail; increased the compression slightly, balanced the crank and ditched the air box.
There are lots of guys why know a lot more about making a bike go fast but this bike has been fast and reliable for 17 years of racing and a huge amount of it in the 90s dirt track.
So for my 2c worth do the engine to perfection keep it standard then modify if you need.
Should be no different for a RM M / S

211

[trailietrash]

I am currently cleaning the frame etc and redoing bearings and so on, aiming to get the shocks rebuilt. I've not yet had the broken barrel stud fixed but that should be this week.

Is the broken stud the short front stud or one of the other five studs?

[Graeme M]

Front left barrel locating stud.

And yes, not getting too carried away with mods is probably sensible. But if an S was a little quicker than an M, upping the spec towards the S must surely help. So on my limited budget that will be it. Toss the airbox, add the 34mm carb, pop on a nice clean head instead of one with pitting everywhere, clean up the ports and away we go. However it runs then is what I'll have to live with. And it'll be fine for me to tool around with.

I'll report back in a couple of months once I get that lot done and go for a ride. My aim is the second ACT club day of the year on April 10. Gotta have the RM and the YZ ready to go by then.

[trailietrash]

Front left barrel locating stud.

Sorry Graeme
I must have the thought of head studs for these bikes stuck in my brain at the moment and miss-read that you needed a barrel stud.

The short head stud is supposed to be NLA from Suzuki while all the others are still available. The short head stud has a longer threaded section for the head bolt which makes it as long as all the other head studs and not the same as just machining a bit off the bottom of the standard bolt.

I am curious to know why, maybe a very cheap way to make all the studs a similar size an not let the front one expand too quick with heat?

and sorry again for hijacking the thread