hs40 carb upgrade

massacre

massacre

#2
#2
Pretty sure you can. You might have to make some sort of adapter since the bolt pattern on Mikuni carb is different from Tec carb.
I am running a 22mm Chikuni carb on an Hs50 and it works great.
I know some with Hs40 have also run Mikuni carbs, i will let them respond.
 
H

Havasu Dave

Moderator
#3
#3
HS40 with cam Mik VM22, PZ16 on an H30. Another PZ on an H30 running an HS cam in testing stage. All of these could handle a Mik VM22. Just make sure you know how to fabricate a manifold, and tune carburetors. Not hard, especially if you make them as ugly as I do. 21 Mik3.JPG 66.JPG Tec3.JPG LH7.JPG
21 Mik3.JPG
 
massacre

massacre

#4
#4
Glad this question came up
Has anyone come up with a good intake length?
Obviously there are clearance issues and heat and other factors
But I tried some calculators and didn’t come up with anything concrete as to any optimal length
 
C

cfh

Well-Known Member
#5
#5
I've played around with manifolds and slide carbs on HS40 and HS50 engines. My conclusion is this.... it does not make much difference what you do, it all works pretty well. i've used stock intakes and made my own, straight and curved, it doesn't seem to change much (anything?) That's my experience any who. My engines are pretty stock though, aside from an open exhaust and a 16mm to 22mm slide carb. The carb itself makes the biggest change from my experience. Slide carbs give an added performance boast and also made the engine more controllable. And for a nice price.
 
delray

delray

Well-Known Member
#9
#9
massacre said:
But with a known exhaust length, there’s got to be a way to figure out an optimal intake length, right?
Click to expand...
just try to keep it on the short side. sometimes you can run into problems if it's to long. shorter the better for your application.
and for exhaust headers. can't say enough how good a robertson's torque tube is.....:scooter:
 
delray

delray

Well-Known Member
#10
#10
kidgambit said:
i got a hs40 recently and was qondering if u can run a mikuni aftermarket carb. if so what size.
Click to expand...
safely say this style 22mm mikuni/clone carb would be one to use. very easy to tune from a mild to hot rod hs-motor and parts are easy to get....mikuni jets,pilots....etc...

just a friendly reminder if you do go with a aftermarket carb you will need to run a billet rod. stock rod will SNAP!
 
C

cfh

Well-Known Member
#12
#12
i agree shorter is better with the intake manifold length. but i don't think there's any magic length. i would say straighter is better too. but again, there's no formula. common sense is probably the best indicator.
 
K

kidgambit

Active Member
#13
#13
delray said:
safely say this style 22mm mikuni/clone carb would be one to use. very easy to tune from a mild to hot rod hs-motor and parts are easy to get....mikuni jets,pilots....etc...

just a friendly reminder if you do go with a aftermarket carb you will need to run a billet rod. stock rod will SNAP!
Click to expand...
any idea where to get a upgraded rod
 
C

cfh

Well-Known Member
#15
#15
Out of the box the 16mm carbs on ebay run pretty well on an HS40 and HS50 engine. Any of the other variants will need jet changes. They are all an improvement over the original Tecumseh carb. It's the single best and cheapest modification you can make to these engines.
 
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