Slide carb questions
- Thread starter CohibaTractor
- Start date
I have a VM22 on a hs50 and it runs fine but the engine is modified and from 3/4 throttle on there is no difference in acceleration. I am about to try a 21mm PWK flat slide carb on it just to see if it makes it any different. I looked at a PZ16 but flow testing it flows low 40 CFM. The VM22 flows 88CFM and the 21mm around 70CFM so I think it is a better fit than the PZ16. I have not tried it and it may be a while before I do but I will ad test results to this thread when I do.
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Better than a PZ16, but if you are going to the trouble to modify the engine, you might as well get it breathing better and hog out the intake around the valves, and maybe even a cam. But even making it breathe better, you could use the VM22 Mikuni, or the cheaper VM22 Chikuni. Or see how Ole does with that 21, since he does a very detailed analysis of flowing various carbs and head configurations. I use the 22mm Mikuni on my hot rod builds.
I've used PZ16 carbs on many stock HS50 engines with excellent results. But if you do any cam modifications, a bigger carb is in order. Then i move to the PZ22 carb. I have also used the pz19 carb but my thought is if you really need 'more', might as well just get the pz22. Experimented on about 50 tecumseh motors adding a slide carb, so i've had quite a bit of experience with this. Not just with the PZxx carbs, but also with Delorto carbs ranging from 16mm to 22mm.
In general the pz16 works well "out of the box" on a stock motor. Nearly every time i've moved to a pz22 carb, it has required a change in the main jet. So you'll need to get a M4 jet kit (i buy them off ebay for about $10), and play with the main jet.)
On the cam issue, i weld and grind my own cams. made a cam duplicator and use a Dynocam 255 as the "master". Had good luck with this, but it does take a bit of time to tig weld the cam lobes, and then re-grind the cam. Because of this, i just bought 12 dynocam 255 cam. If you buy in bulk they are a nice price. Saves a lot of work on my end, as grinding your own cam is a bit time consuming.
In general the pz16 works well "out of the box" on a stock motor. Nearly every time i've moved to a pz22 carb, it has required a change in the main jet. So you'll need to get a M4 jet kit (i buy them off ebay for about $10), and play with the main jet.)
On the cam issue, i weld and grind my own cams. made a cam duplicator and use a Dynocam 255 as the "master". Had good luck with this, but it does take a bit of time to tig weld the cam lobes, and then re-grind the cam. Because of this, i just bought 12 dynocam 255 cam. If you buy in bulk they are a nice price. Saves a lot of work on my end, as grinding your own cam is a bit time consuming.
I’ve used the pz20 from Amazon on 3 hs50s. Just pulled the governor, used the billet rod, opened the intake cavity a little, fabricated an intake and replaced the throttle cable. I’m happy with the results. https://www.amazon.com/Carburetor-K...f9-a84b-5978f047adc8&pd_rd_i=B07NTX9X57&psc=1
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also when you get a PZ carb you like, buy a bunch (since they're under $20 each, not a bad idea.) Because the china made ones do deviate over time. and often the 'new' version isn't the same as the one you bought a year ago, and it doesn't run as well...
http://www.pinrepair.com/minibikes/p/snowblow119.jpg
http://www.pinrepair.com/minibikes/p/snowblow119.jpg
I've been fabricating intake manifolds out of billet aluminum on the lathe. I'd just come in from doing one when I saw this thread yesterday. I turn the engine side to the original 20mm diameter, then starting an inch back, graduate the bore in five steps (.1 steps) back towards the carburetor end, where I get the full 22 mm.
This allows me to go along later and port match the manifold to the block which is 20 mm roughly, but machining the manifold to a slight angle to accommodate that screwy bolt pattern these things have. (Without digging into the side wall and making a hole)
@Skipp this is yours.
This allows me to go along later and port match the manifold to the block which is 20 mm roughly, but machining the manifold to a slight angle to accommodate that screwy bolt pattern these things have. (Without digging into the side wall and making a hole)
@Skipp this is yours.