TS 250 PWK carb

[Kruh]

Been looking into replacing the needle, since it is still a bit rich around and past 1/2 throttle.
There are needle sets available, but I'm debating wheter I should buy just the needle I need or the whole set. Since the price is a bit high for my liking (cost as much as the whole carb).
In any case, first I wanted to identify the needle that comes in these carbs, and after a bit of searching around for the correct chart, I finnaly found all the necessary info.

The needle that comes in these replica carbs is a JHQ.

I attached the chart down bellow.
Hope it helps.

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[Kruh]

So you're saying, the needle that comes with these replicas is a JHQ, wherein:
J --> taper = 3 degrees
H --> L1 = 24.05mm
Q --> D = 5.05mm

Do I understand that correctly? I'll have a look what mine is.

That is correct.
Except one typo; the diameter is 2.505 mm

I can confirm that all three needles I got with these carbs are exactly the same. So I assume the vast majority of replicas have the same one.


Well, first the main jet, than the rest is the correct way of doing it. But I have done that.
I very happy with the pilot jet and air screw (I thinks its spot on) and I think the main is very close. But the mid range has been a bit of a struggle.

[Kruh]

This chart is a bit easier to understand.
Also these are all the needles that come in those 10 piece sets.

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[Kruh]

Looking at your numbers, I noticed I made a few mistakes. First of all, my taper turns out to be 2.6° (accidently rounded it off to 3). Later I also realized, the keihin chart measures L1 from the first clip notch to the start of the taper. Which I didn't measure.

The lenght of my needle is 57.8 mm.
Taper lenght, C = 33.7 mm
Diameter A = 2.50 mm

So I'd say you are correct, its something closest to a HFQ.
To me, they seem to be the same model, accounting for a margin of error. Whether its down to our measurements or the actual manufacturing of the needles. I mean, it is a bit tricky to pinpoint the exact start of the taper.

Thanks a lot for your input. Wouldn't notice my mistakes otherwise.



Also, I mixed some thing up redarding the jetting. It is slightly rich under 1/2 throttle, when on 2nd notch and lean at around 1/2 to 3/4 throttle, when lowered all the way.
So, from the commonly available needles, a JJQ needle might work. Since A is the same, but the taper starts later (should help low throttle), and with a steeper taper, should allow for more fuel in the mids. Maybe even the JJS might work. Others have a smaller A diameter, which wouldn't work.
Will look further into this, there a a few more models available in a few webshops.

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[Kruh]

The power jet mainly has an effect on full throttle anyways. Which is an area where MZs rarely are, atleast from my experience.
It is very rare for me to use full throttle, because the bikes revs out way before that.
I did not notice any difference either when I used an OKO with a power jet.

Some people have been using 28 mm carbs (common size). Claiming better low end power. Which makes sense, since a smaller diameter carb would put the intake resonance lower in the rev range, thus increasing power down low. Also, it should make it more responsive to throttle inputs.
Considering all of the above, I do wonder if a 28 mm carb was a better option overall, even for me. Let alone a 32 mm like you had.

Actually, my ETZ251 ran fine with this cheap carb. But it also runs fine with the original BVF, so I put that back.

So you did't find any major differences between the two in performance or drivability? Not sure if you already mentioned it somwhere else.
If so, it is interesting, considering the pwk was oversized an, like you said, not perfectly jetted.
I sadly wasn't able to compare, since my original bvf was very worn out, so it wasn't even worth bothering with.
Although a replica, its still a modern carb design and I would expect it to slightly outperform the bvf, when jettet properly of course.

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[Kruh]

On riding at full throttle: I guess it depends on the rider & on where you ride. If it's in a city or built-up area, true, rarely full throttle, and I keep to the indicated speed limit. But on twisty country roads, which is what I do mostly, if I ride alone there is a lot of full throttle on the ETZ, or actually with any bike.

That is interesting.
Perhaps some of that may be due to differences in powerbands between the TS and ETZ. With the ETZ being more oriented towards the upper rpms.
It is quite likely I just don't ride it hard enough, but if I'm recalling correctly, my TS seems to rev out already at around 3/4 throttle, even on twisty roads.
Perhaps, I'm just being fooled by the tachometer or worn out engine components, making the bike vibrate more than it should.

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