New Tecumseh HS40 carb(s)

delray

delray

Well-Known Member
#84
#84
yes I did wonder little about that. the carb cfh had was a ub. with a ub carb you could make it work if there was a clearance problem.
weird how the brochure shows a dellorto carb mounted up close to the block, but rupp72 said he had a clearance issue trying to mount it like that. nice if rupp had a better picture of that in there brochures.
 
C

cfh

Well-Known Member
#85
#85
Does anyone know how to decipher the Dellorto letters? for example, UA versus UB versus MB for the prefix. And after the carb size in mm, the suffix like S or S2... ?

Prefixes:
Ua
Ub
Ubf
Ma

Suffixes:
S
S1
S2
Bs
D
 
Last edited:
C

cfh

Well-Known Member
#86
#86
Another Dellorto to try, the Ua18s. This was on ebay for pretty cheap (as far as Dellortos go, still way more than the china clone carbs.) It's just one MM away from the fabled Dellorto Ua19s (as used on the Rupp black widow), but if you notice, it's significantly different in design. This Ua18s carb can not be mounted sideways like the Dellorto Ua19s.

I probably won't use a trumpet for the intake. Instead i'll be using a filter. One less thing to buy i guess, and that will make the motor more happy.

 
Last edited:
C

cfh

Well-Known Member
#87
#87
cfh said:
Does anyone know how to decipher the Dellorto letters? for example, UA versus UB versus MB for the prefix. And after the carb size in mm, the suffix like S or S2... ?

Suffixes:
S
S1
S2
Bs
D
Click to expand...
S - "Sinistra" or "left" in Italian. Left hand idle mixture and idle speed screws.
D - "Destra" or "right" in Italian. Right hand idle mixture and idle speed screws.
B - Generally rubber sleeve "elastic" type fitting.
A - Generally clamp type fitting.
Other suffix letters have no specific meaning, they have certain original applications .
 
C

cfh

Well-Known Member
#88
#88
Installed the India-made Dellorto Lambretta 19mm clone carb on a hs40 Tecumseh motor, and lit it up. Works pretty darn well! I have never run this carb before. It was $30 on ebay, and another $10 for the (more appropriate) choke assembly, and probably $40 from Black Widow MS for the intake assembly. Posted pictures of the carb earlier but never reported back with the results. It works very well!



 
Last edited:
C

cfh

Well-Known Member
#89
#89
On the 16mm carb and the Tecumseh hs40 or hs50, i'm going to try some re-jetting. Turns out in the winter (which we have in michigan right now!), the 16mm slide carb doesn't like the cold weather. Wants to run with the choke on. I will try some jets and see if things change. It runs great in the summer, but not so much when it's 30 degrees F out. cfh
 
massacre

massacre

#91
#91
Figured I would add to this thread.
Put a 22mm Chikuni carb on my MTD today and it was like where have you been all my life?

Bike starts first pull idles great. I actually have part throttle now, a lot more control than the stock carb. Stock carb is good too though don’t get me wrong but for this bike it’s just what the doctor ordered.

Big thanks to member cfh for inspiration on this.
 
You must log in or register to reply here.
Top