TZR250 3MA HYBRID (race)

[EEKNOWS]

Think Warwick is talking about a primary type needle jet with one hole at the top of the nozzle that when installed lines up with the air corrector???

[Louis]

Well there is certainly something I over look.

Sadly I don't have tz carbs, so its still difficult to see/understand what you mean.

But think I'll be close.
you say:

But instead of the air from the air jet mixing with the fuel in the emulsion tube, it forms a 'pool' of air that helps atomise the fuel as it exits the needle jet. This is why I think you will need to cut off or cut down the ring that runs round the outside of the 610 needle jet so that it can work like the 633 type does.

Like this:


If this is the case, than there should be a clearance between carb body and needle jet so the air can go past it
But it would hardly mix as the air is outside the emulsion/needlejet


The next question would be where does that air comes from?,
I could think off one thing making the original airjet inlet on the carbs body adjustable with a screw

You realy start to make me think here

Would (my) idea not work? I really liked the idea not to use air correction at all
Just a easy setup, a main jet and a needle jet and the needle to controle it all.

how does the sugo stuff have it on the 3xv?

Lozza,
Do you mean this type

[Warwick]

Well there is certainly something I over look.

Sadly I don't have tz carbs, so its still difficult to see/understand what you mean.

But think I'll be close.
you say:

But instead of the air from the air jet mixing with the fuel in the emulsion tube, it forms a 'pool' of air that helps atomise the fuel as it exits the needle jet. This is why I think you will need to cut off or cut down the ring that runs round the outside of the 610 needle jet so that it can work like the 633 type does.

Like this:


If this is the case, than there should be a clearance between carb body and needle jet so the air can go past it
But it would hardly mix as the air is outside the emulsion/needlejet


The next question would be where does that air comes from?,
I could think off one thing making the original airjet inlet on the carbs body adjustable with a screw

You realy start to make me think here

Would (my) idea not work at all?
how does the sugo stuff have it on the 3xv?

Yes, you've got it Louis - that's exactly what I mean (first pic) . The air comes in where you have removed the ball, so you could use a jet here to meter the air - or use a mixture screw perhaps? The TZ carb body is effectively the same as the 3MA main body, so if you remove the stub from the original VAJ air intake hole and tap the body there to suit, I think a TZ air mixture screw would fit and so allow you to adjust the air bleed to the tip of the needle jet? Using this set-up will (I think) improve part throttle fuelling (better fuel atomisation I guess?) than using the unmodified 610 jet as that effectively seals off any air bleed to the tip.

The 3XV Sugo set-up uses the same idea as you have in mind for the 3MA (same 610 type NJ), but I'm not sure it's ideal - which is one of the reasons I use the TZ carbs instead - and they work brilliantly I have to say...

By the way, why are you using the 633 needle jets to sit the 610 jet on top of when you could just block up the holes in the stock 3MA emulsion tube instead? Surely that would achieve exactly the same effect as your original plan wouldn't it? Or am I missing something? Perhaps the greater diameter of the lower portion of the 633 jet would be better though?  Anyway I think It's only if you use a needle jet of the same kind of external shape as the 633 type that would make any difference to the fuelling ?  Hence my idea bout removing the ring.

The problem you will have though is that the 610 NJ will need attaching to either the sealed 3MA emulsion tube - or the modified TZ Nozzle/Jet Somehow. This might be problematic as you don't want it coming loose and getting sucked into the engine . I was thinking about trying vertical slots in the ring first, to see if that improved things, while still holding the NJ in position - and stopping it getting sucked into the motor...   

Anyway, I haven't actually had the chance to actually try out all this myself on the 3MA yet of course, so bear in mind that this is just my speculative theory for the time being... I will get to it, but feel free to try it out yourself first of course. I think my 3MA is unlikely to be running again until next spring as I have other things I need to do just now.

Luck.

[EEKNOWS]

Yeah I was talking about a primary nozzle, get the top and front edges on that shroud razor sharp

[Louis]

Aha, good to know that I understand your idea correctly

By the way, why are you using the 633 needle jets to sit the 610 jet on top of when you could just block up the holes in the stock 3MA emulsion tube instead? Surely that would achieve exactly the same effect as your original plan wouldn't it? Or am I missing something?

It is not that simple as it looks, the original holes are corroded (by fuel and air) so the solder tin wont fill the holes properly.
If you drill the holes to 1mm and then use tin to fill them, a lot of tin will go trough it and sits inside the needle tube.
Of course you can drill that out, but that leafs a rough service inside the tube.
Therefore I started with the brass tube around the emulsion tube to close all the holes and leaf the internal clean. But I'm still not confidence that the brass tube seals off properly. The brass tube may pressed oval in the lath (as its pretty thin)

With the 633 needletube i can machine off the top and it will be a sollid closed needle tube like the oem sugo 610
Than I'm sure that the only leaking point (if it will be there) could be between the needlejet and needle tube.


Another thing, this bike will not be THE bike.
What I mean with this is, it is just build to have a track bike/learning bike/fun bike
I did not do any thing at the engine
-stock 3ma-10 cylinders
-stock head with 0,9mm squish
-stock reads with connection tube between the carbs rubbers
-home made pipe's but with a length that should peak around 10000rpm (no hp pipes)
-stock carbs (with the lets say. (sugo setup))
-a ignitech and a battary

In small term's this is not the bike that will be seen as ''whow'' its build to be a winner.
(all in hobby terms of course )

No or less, when I was building this bike lots and lots off very good ideas came up in me.
Wrote it all down and already started to collect the parts that I need for it

My first unfinished track bike is sad back in a corner and is starting to be a donor bike for the rest.
That one will be rebuild from the ground up, with all the ideas I have.
I wont tell you guys what parts I already bought for it, but when finiched it should be a very very good working bike

Enthusiast as I am, it really is a big effort not to start building it
I really pouch my self to finch this one completely, so it can be used for what it is build fore.
Fun on a track.

[Paul]

Another thing, this bike will not be THE bike.
What I mean with this is, it is just build to have a track bike/learning bike/fun bike
I did not do any thing at the engine
-stock 3ma-10 cylinders
-stock head with 0,9mm squish
-stock reads with connection tube between the carbs rubbers
-home made pipe's but with a length that should peak around 10000rpm (no hp pipes)
-stock carbs (with the lets say. (sugo setup))
-a ignitech and a battary

louis, that setup alone should see you at about 63-65HP, you don't really want more on the std crank do you? you can win races with that bike for sure.

My first unfinished track bike is sad back in a corner and is starting to be a donor bike for the rest.

that is sad boetie, you nearly had it man! are you continuing with your emulsion tube work? i am following you there, my TZ and TZR both run primary tubes and i want to bin them on my 3ma's. sadly i bought sugo carbs for 3ma and am sticking with them.

i ask you to please show me the brackets you made for the 3xv tank. the bike from capetown has a rusty tank and my spare 3xv tank is like new.
also, those fairings, where did you get them?

onwards we go..............

[Louis]

louis, that setup alone should see you at about 63-65HP

That would be great, but i'm more aiming on mid 50's. Hope, with good mid power so it will be easier to ride

i ask you to please show me the brackets you made for the 3xv tank

Next time when i have the tank off will make some pictures from that mod.

Small update:
Why i have this


Because i have scored a compl. SP gearbox with dry clutch, in very good condition.


Think the bike deserved it, so here you go.


Here you have it in action.
http://www.youtube.com/watch?v=pajKuS9Zbk4

currently working at the carbs.

[tzr-v4]

Nice Setup you've got Louis...

You should come to the RD500LC meeting at Magny Cours Club track in the end of June with the RACE 3MA.

[maccas]

Hi Louis,

Looking good as your work always does!

I have a question about the 633 emulsion tubes. Are they the type found in the TZ's from 3TC through to 4DP and 4TW etc.? What size orifice did you go for? (R-2, R-4 etc.)

This has got me thinking about my 3xv you see.

Cheers,

Dan

[Warwick]

Not Louis I'm afraid, but yes Dan. 633 series are 90s TZ type Needle jets.

Posted before, but as a reminder I use a 633 R3 NJ with a 6FI80-61 needle (oe fitment to early 90s TZ - 91-93 models off the top of my head in the track 3XV. Have the part No if you need it? In the TZ parts books though obviously). Works very well indeed on my set-up, but most relevant TZ combo's probably would TBH I reckon. To try the 633s in your SP carbs you may need to modify the body internally a bit. Or make up some kind of 'hybrid' NJ using a modified SP nozzle and modded 610 jet as discussed with Louis above. The pics above show how it would work.

[maccas]

Thanks Warwick!

Yeah I could be tempted to give it a try in the 36's at some point you see. I could even use the VAJ to control the MAJ size too which could be interesting. Not sure how this would affect the situation with the MAJ not being in the bellmouth. I keep meaning to test this and will do the next time I am on the dyno!

Looking to Louis' picture below, does the needle jet in the TZ carbs sit at about the same height relative to the bottom of the carb bore? I know Louis' pic is of the smaller 32mm 3ma carbs. I might order a TZ needle jet and take some pictures with it fitted over xmas.



As long as there is a gap around the tip of the needle jet for air to pass through from the main air jet surely everything should be ok?

Thanks again mate!

Dan

[Warwick]

Yes, that's why the 633 jet differs from the 610 Dan. If I get the chance, I'll take a few illustrative pics for you at the w/end.  I have all the relevant jets and carbs kicking around - it's just finding the time that is tricky... I'll do what I can though.

[maccas]

Hi Warwick,

That would be great if you get chance but no worries if not. It was just when you said I may have to modify the body internally, wasn't sure if you meant near the needle jet hole or elsewhere. Out of interest I rang Webbs up today the 6FI80-61 needle is discontinued at Yamaha ( I'm guessing Dennis Trollope could get some though) and the 633 series needle jet is still available at £33 a pop. I might try Allens during the week to see how their prices compare.

Thanks again for your time, Warwick.

Louis, you can have your thread back now  sorry for diluting it with 3xv chat lol.

Dan

[Louis]

Louis, you can have your thread back now   sorry for diluting it with 3xv chat lol

No problem Dan, I have finished my carbs today to

What did I do:
Off course the biggest problem was that the original powerjet where stuck. The previous owner off the carbs already tried to get them out with no results leafing me with destroyed powerjet's

Well don't want to go the same route as I did with the Marlboro bike, so ordered a handset of micro drills with hand peace.
So I could drill my powerejets at the dimension i wanted it.

Where do you start for such setup, I Google a bid to get a certain idea where to start.

Here is my starting point.

32mm 3ma1 carbs:

-Closed emulsion tube.
-Q4 Needle jet
-Needle clip on top (original 3ma1 needle)
-Mains 350
-Powerjet .50
-pilotjet 25
-airjet srew 3 turns out
-New Needle valve seats

She runs not to bad, even idles when she is cold on the choke (That is new for me )
https://www.youtube.com/watch?v=ct58CFLUF9E&feature=youtu.be

Have to make a couple off small bracket, but then she should be ready for the first test ride.
Why o Why I have this bike ready in the middle of the winter.

[Paul]

i am intrigued
what emulsion tube was it in the end?
have you dropped the airjet completely?
yes winter will slow you europeans down a little, our summer has brought tonnes of rain, but at least its warm.
i dispise the airjets and would love to dump them, im hanging to hear how it goes
my carb setup is almost identical to what you get there, i have a few spare tubes, tell me what to do, ill run tests to. here where the weather might be better than there