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Discussion Starter #1
Hello members
Question , I'm going to do a a 108 stroker kit on my 69 Z50 , I already have a 20 mm carb
On it now with a 88 BBK with race head , question is will I be able to get a 24 mm under there
When I do the stroker set up ? Thanks
 

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use the 20mm carb. A 24mm carb will forever be problematic off-throttle unless the carb is an MJN24. The best running 108 I've every done had a mikuni VM20 on top .
 

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Discussion Starter #6
use the 20mm carb. A 24mm carb will forever be problematic off-throttle unless the carb is an MJN24. The best running 108 I've every done had a mikuni VM20 on top .
Glad to hear that, everyone on here was saying to use either a 24 or 26 to get the most out
Of a 108 , I was going to see if a 22 would fit , glad to hear a 20 would be fine . Thanks
 

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I just put a VM26 on my 117 stroker and I love the new found power. I had a 24 and it was lacking just a little bit. Now she's a breather!
 

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Regardless, I would spend the time and make sure you get a genuine Mikuni. my 24mm was a knock off that I ran for 14 years and now that I have a proper running rig, it's make the enjoyment that much more fun. I didn't know it could run so good. just 2 cents. hope ya find the sweet spot;
 

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Not sure on tank clearance with a 69 but my 86 z50 with a vm22 clone on a Lifan 125 is like a mm from touching each other (carb to tank petcock). I had to go with a 90 degree petcock for it to work so an even bigger carb on my setup wouldn't fit. Also yes a genuine vm20 or 22 would rip on a 108.
 

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I inserted a 1" x 1" piece of wood under the rear tank mount on my '69 hardtail to use the TB Parts 20mm carb and manifold. I also used a TB Parts petcock with the 90° outlet so it would (just barely) clear the UNI filter. If you were intending to use the TB Parts 24mm carb it will not fit, it is taller and a little wider than the 20mm carb in the pic HERE. You can see that there is no heatstop, using it would have pushed the filter up into the petcock.
 

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Discussion Starter #12
I inserted a 1" x 1" piece of wood under the rear tank mount on my '69 hardtail to use the TB Parts 20mm carb and manifold. I also used a TB Parts petcock with the 90° outlet so it would (just barely) clear the UNI filter. If you were intending to use the TB Parts 24mm carb it will not fit, it is taller and a little wider than the 20mm carb in the pic HERE. You can see that there is no heatstop, using it would have pushed the filter up into the petcock.
I didn't think it would fit , what I thought was a 20mm carb on it now turns out to be a 19 mm, its pretty tight but it fits nicely , I see from your picture that a ShengWay 20mm will really be a snug fit , I kinda like the way the 19mm fits, I'm thinking about doing a 108 stroker, what would your opinion be if I stuck with the 19mm on a stroker ? Might not be worth doing if I can't fit a proper carburetor . Thanks
 

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I swapped in a different engine/carb setup than the one above, it is a "small block stroker" engine with a 48mm bore and TB Parts 51mm stroker crank, and I tried out a Molkt PZ22 carb for fitment. I ordered it from Amazon seller XLJOY for around $25 or so. It takes genuine Keihin jets and seems to work real well with the TB Parts manifold. You can see how it sits in this pic
 

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To answer your question, I've run the Shengway 20mm carb on 108 stroker engines with no problems, you'll have plenty of low-end torque. I would think you'll have similar results using the 19mm carb you have.
 

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I can second that. Running TBs 108 strocker with their 20mm carb. Jetted correctly and it runs great! I’m geared for top end and have reached 65mph (on a hill) on 8” wheels and trust me, that’s plenty fast. Cruises at 52mph on flats. Geared lower and it could be a wheelie machine for sure.


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Discussion Starter #16
I swapped in a different engine/carb setup than the one above, it is a "small block stroker" engine with a 48mm bore and TB Parts 51mm stroker crank, and I tried out a Molkt PZ22 carb for fitment. I ordered it from Amazon seller XLJOY for around $25 or so. It takes genuine Keihin jets and seems to work real well with the TB Parts manifold. You can see how it sits in this pic
Great , I ordered one couple days ago hoping it's a shorter profile to fit under the tank, from the pictures i seen it looks like it's shorter and from your pictures it looks like it might work out for me ( did you raise your tank with the PZ22 ? ) and also what's a good starting point for a main jet on a 20 and 22. Thanks
 

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On a 20, and at 100ft above sea level, here what I did:

Carb. 90-92 main, 38 pilot. 3rd (mid) needle position.
1-1/2 to 1-3/4 OUT. Adjust 1/4 IN till perfect.


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My 20mm settings are similar to 66Cooper's- 90-92 main , 38-40 pilot, 4th needle position from the top, and 1.5 to 1.75 turns OUT. For the PZ22 that came with a 75 main and 35 pilot, I went up to an 82 main and a 40 pilot and the 4th position for the needle clip.

The same air screw settings and adjustments, as well, with a 1/4-turn IN at a time to fine tune it
 

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Discussion Starter #19
My 20mm settings are similar to 66Cooper's- 90-92 main , 38-40 pilot, 4th needle position from the top, and 1.5 to 1.75 turns OUT. For the PZ22 that came with a 75 main and 35 pilot, I went up to an 82 main and a 40 pilot and the 4th position for the needle clip.

The same air screw settings and adjustments, as well, with a 1/4-turn IN at a time to fine tune it
Did you have to raise your tank with the PZ22 ? Thanks
 

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I leave the piece of wood in place on the bike, so, yes, the rear of the tank is raised 1 inch.
 
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