H50 with Mikuni carb setup

C

cfh

Well-Known Member
#41
#41
I don’t run h50 motors but I do run the HS50 motors with chikuni style carburetors. Depending on your exact motor, I found a 22 mm carb with anywhere from number 90 to number 95 main jets m4 style works well. The size of the jet does vary motor to motor. For example late model tecumsehs with the small exhaust valve seem to want a smaller jet. If you’re running a big cam that’s gonna want a bigger jet. Also the style of exhaust dictates change. But in general #90 to 95 Main m4 jet encompasses all the modifications I have done on any HS50 motor

You can buy an m4 variety jet pack on eBay for cheap. I do not suggest drilling jets. That really does not work well compared to actual factory drilled drill jets, for a bunch of reasons.

also the carb size be it 19,20,22mm does not seem to Change jet size. That is, 90 to 95 main jet is still the norm even For a 19mm carb

lastly, Chikuni carbs off eBay or alibaba really aren’t as advertised in the last year. You have to measure the carb when you get it. I had somebody sell me a 22 mm and it was really a 15 mm carb. And the quality of the Chikuni carbs has changed dramatically too. I’m having a hard time currently finding a good 22 mm carb from any of the typical sources. But when I find one that I like I tend to buy a lot of them. They are cheap. And the sources change. All the Chikuni carbs are a little different from month to month or year to year. They were far more consistent before Rona....
 
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delray

delray

Well-Known Member
#43
#43
maybe this may help little for you markus if you do go with a dellorto carb. i have seen couple big blocks with 22's on them and the bikes really move out for being all stock points engines. only mod is the header pipe on them.
one of the bikes is a member here rupp72 ...nate. seen this bike in action and it moves.
36517408_187554875274952_6486677923053961216_o.jpg
i would think that motorsports engine you are getting has the hot coil,better flowing valves,maybe cam? big thing is the ports bigger on your engine? then a vintage 5hp? if so maybe a 24 may run better? take some testing to find out.
 
Skipp

Skipp

#44
#44
delray said:
maybe this may help little for you markus if you do go with a dellorto carb. i have seen couple big blocks with 22's on them and the bikes really move out for being all stock points engines. only mod is the header pipe on them.
one of the bikes is a member here rupp72 ...nate. seen this bike in action and it moves.
View attachment 271706
i would think that motorsports engine you are getting has the hot coil,better flowing valves,maybe cam? big thing is the ports bigger on your engine? then a vintage 5hp? if so maybe a 24 may run better? take some testing to find out.
Click to expand...
Curious if that bike of rupp72 has a billet rod?
 
C

cfh

Well-Known Member
#47
#47
That link above is not the dellorto that you want

basically you want to UA or UB model. I have a lot information about the Dellorto on my webpage. more than you’ll probably find anywhere else in regards to putting them on a Tecumseh. I’ve tried nearly all the models from a UA16, UA18, ua19, ub22. Info about configurations in regard to float bowls, jetting, differences in specs between all the models. I’m running about a dozen Dellortos on my bikes. There’s a lot of complications in regards to Dellortos. Pretty much have all that information laid out to make it nice and easy for you to figure out what you wanna do.

everybody wants a UA19 because that was what was on black widows. But they’re also really expensive, probably twice the money of say a UA18 or a UA16. And frankly the UA16 and ua18 perform pretty much identical to a UA19, even on a modified motor. The float bowl differences are probably the biggest factor between the models

One of the biggest concerns is an air filter. On rupp black widows they used a trumpet, which basically means no air filter. There’s a couple ways around this To get a filter, some slicker than others. But for gods sake‘s don’t run these things without an air cleaner of some sort

dellorto makes a really nice air cleaner. But they’re expensive and kind of hard to find.... Black widow motorsport has an inexpensive way to put an air filter on a Dellorto trumpet. But it looks really dorky.
 
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M

Mark Brooks

#48
#48
Wow what a great thread! Thank you all!
Tremendous amount of info here. Great read... now i gotta go open up n read the other hunert windows i opened while reading y'alls thread. The way i have it figured that'll be at least an all day venture proly more like a week or a month... he'll let's just got with a lifetime! Lol

Thank you all again greatly appreciate the wisdom and knowledge shared!
 
C

cfh

Well-Known Member
#49
#49
to get a Dellorto at any sort of reasonable price i look on ebay and often buy 'project' carbs. from this mess i'll probably get a couple two or three decent working UA/UB dellortos. Things that are often missing are the slides and the top piece with the choke. There's a ME style carb in the pic below... that was in a bulk dellorto buy, but it's not applicable to a Tecumseh application. The carb on the left is probably too big (i think it's ub24), that probably won't work either. You can see the three Dellorto air cleaners at the bottom of the pic, those are hard to find.

dellortos.jpg
 
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