Now I'm rebuilding one

[Drew]

So, since the DT motor was an epic fuckin fail, my bike is getting rebuilt around a GT125 motor instead. Which is much more betterer anyway, since Suzuki is BOSS!

To catch anyone who wasn't watching my last thread toward the end, after discovering my failure with the DT AJ kindly donated his GT125 to me. Which I shot up to Himatangi and picked up yesterday. Cheers AJ, you're an absolute star!

When I got it home, I put the kick start on it and tried to turn it over...FUCK, this thing is seized! Talk to AJ about getting the spare motors up from CHCH asap.

Turns out, that I'm a spaz AGAIN. The kickstart return spring is bung on the motor, and when I put the starter on it was already round to it's stop.

I only found this after I'd pulled the head and barrels off unfortunately, but since the crank cases were full to the brim with two stroke oil it needed to be done anyway.

Today's progress was made up of getting the motor out of it's GT roller, and rebuilt on the bench. Highlight? NOT cleaning surfaces and making bloody base gaskets, that's for friggin sure! Then getting the DT lump (free to whoever wants it, otherwise it's scrap), out of the MVX frame and removing the (as it turns out over engineered) mounts I spent so long getting just right.

In unrelated news, the rule on carbs for F4 says, "F4 2 stroke engines over 104cc are restricted to carburation equivalent to a single 24mm carburettor". Now if I take this to mean surface area must be equivalent, I'm allowed two 17mm carbs. But, as many people will tell you, it is very easy to increase the size of the opening by reshaping the barrel of the carb, without increasing the sideways measurement of 24mm.

Does that mean I can get a 24mm carb, bore it out to bloody near square, and then match that surface area in two carbs?

It's a rule stretch, but a rule break? Thoughts?

[quallman1234]

What happened to the DT? No idea with the Carb rule, multiple ways of interruppting it... If it aint too quick then people won't care .

[Drew]

What happened to the DT? No idea with the Carb rule, multiple ways of interruppting it... If it aint too quick then people won't care .

When I first got the DT it needed some assembly. Bryce instructed me on how to make sure there was enough clearance between slug and head, which I did. But only in one spot. Turns out the head gasket is not located and was sitting off to one side, and once I fired it up and got the revs up the piston has been making a sandwich, with the gasket being filling, head and slug being the bread. Result? Piston pinching the top ring...and a bent conrod.

[Ocean1]

Does that mean I can get a 24mm carb, bore it out to bloody near square, and then match that surface area in two carbs?

It's a rule stretch, but a rule break? Thoughts?

Pound to a pinch of shit there's a clause in the book somewhere that says that if there's any doubt you get the ruling body's clerk of pedantry to clarify.

He's almost never in favour of cheap fun.

[crazy man]

if l was you l would run 2 mvx carbs with a manifold down to 17 mm

[Drew]

Pound to a pinch of shit there's a clause in the book somewhere that says that if there's any doubt you get the ruling body's clerk of pedantry to clarify.

He's almost never in favour of cheap fun.

For now I'll sleave down a couple of the 21mm flat slides from an MVX to 17mm, then out of round that to increase the area.

[FastFred]

.... the rule on carbs for F4 says, "F4 2 stroke engines over 104cc are restricted to carburation equivalent to a single 24mm carburettor". Now if I take this to mean surface area must be equivalent, I'm allowed two 17mm carbs. But, as many people will tell you, it is very easy to increase the size of the opening by reshaping the barrel of the carb, without increasing the sideways measurement of 24mm.

Does that mean I can get a 24mm carb, bore it out to bloody near square, and then match that surface area in two carbs?

It's a rule stretch, but a rule break? Thoughts?

A rule break is my thoughts .... but try taking a pole on it.

If your right I know what TeeZee will be doing tommorow ..... he already knows that with more flow through the carb (more carb area) he can pick up some usefull low end torque on his 30+hp engine as the current 24 is strangling things a bit.

[Henk]

Every thread I've seen on this seems to go with a 24mm round hole or the equivalent area pi R squared is your friend here

[Drew]

Every thread I've seen on this seems to go with a 24mm round hole or the equivalent area pi R squared is your friend here

It doesn't say "round hole" anywhere in the rules is kinda what I'm driving at.

[Drew]

A rule break is my thoughts .... but try taking a pole on it.

If your right I know what TeeZee will be doing tommorow ..... he already knows that with more flow through the carb (more carb area) he can pick up some usefull low end torque on his 30+hp engine as the current 24 is strangling things a bit.

30 fuckin ponies! I somehow don't think I'll manage to DOUBLE the standard power of 14.2 that I have, don't mention anything about this to him!

[Ocean1]

Make a split manifold symetrical about a horozontal centreline, (top and bottom carb ports).

Run a single 24mm carb on one port, nothing at all on the other.

You'll need a special size main jet and a very very skinny needle.

[Drew]

Make a split manifold symetrical about a horozontal centreline, (top and bottom carb ports).

Run a single 24mm carb on one port, nothing at all on the other.

You'll need a special size main jet and a very very skinny needle.

You're gonna need to open paint, and draw me a picture. I can't visualise anything from reading it sorry mate.

[Ocean1]

You're gonna need to open paint, and draw me a picture. I can't visualise anything from reading it sorry mate.

Don't have me crayons here.

Imagine a manifold for two carbs, one above the other. Now take one carb off and run the other one as rich as fuck.

If you can make it work you'll be a clever boy, but in the few months it takes for the rig to be specifically outlawed you'll be fook'n quick.

[Madness]

In unrelated news, the rule on carbs for F4 says, "F4 2 stroke engines over 104cc are restricted to carburation equivalent to a single 24mm carburettor". Now if I take this to mean surface area must be equivalent, I'm allowed two 17mm carbs. But, as many people will tell you, it is very easy to increase the size of the opening by reshaping the barrel of the carb, without increasing the sideways measurement of 24mm.

Do the rules mention a sideways measurement? I'd have thought that if the inlet wasn't round the measurement would be taken at it's widest point.

[Drew]

Don't have me crayons here.

Imagine a manifold for two carbs, one above the other. Now take one carb off and run the other one as rich as fuck.

If you can make it work you'll be a clever boy, but in the few months it takes for the rig to be specifically outlawed you'll be fook'n quick.

So, just leave the second 'port' open? It might work if the second port had a butterfly. Technically I suppose it is just a breather hole and not part of the carb.