Tecumseh star vs. Hm100

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MrMurphy1025

New Member
#1
#1
VKE says the star engine and the standard production hm100 are different engines with internal parts that will not interchange. Can anyone elaborate on this for me and is the a production based engines suitable for a star clone build? Thanks.
 
ole4

ole4

#5
#5
Some Star info, intake is 1.250 EX is 1.125 stainless with 1/4 inch stems racing springs and alloy retainers. Machined aluminum Billet rod 3.960 center to center. Comes with a Tecumseh racing cam.
Bore 3 5/16
Strike 2.17/32
RPM 6000+
Cam 265 duration at .003
.325 max lift.

Article does not mention crank journal size.
 
H

Hexafluoride

New Member
#8
#8
The cam gears are different between the two: The star engine has straight cut gears while the HM engines are helical gears. Mike at precision cams will grind the star cam 703 profile on a HM100 cam though.
 
FirePowerMinis

FirePowerMinis

Active Member
#10
#10
125ccCrazy said:
points engine..yep the crank journal measures 1.187... I had to grind out the bump in the center of the bottom of the block so the dipper would clear..other than that the rod fits great.
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Hmmm. So my 1.375 crank could be offset ground and pick up .175 more stroke, 20cc or so... A little pop-up clearance cut in to the head would let it squeeze good and still flow decent.
 
roccosbike

roccosbike

#11
#11


This is a points ignition HM80 it has a star rod ,valves ,springs and keepers in it. The cam was welded and reground to star cam specs too. its had a few other mods done to it too and it is a torque monster. The Bonanza mini bike its bolted to is a lot of fun to ride.
 
jeffdubb8

jeffdubb8

#12
#12
Those Star Engines are truly incredible. Absolute monsters with tons of torque. Can push upwards of 40hp if you want to run alky and really push them...otherwise 25hp is easy peasy on them. If you want to know just about everything there is to know about them, call Mike Clements. He's a very nice guy who knows his sh*t! He just built 2 Motorsports engines for me. He's not cheap and he takes a while, but he's as good as anyone in the country. :thumbsup:
 
R

RegalX

Member
#13
#13
I am currently running a HM100 as well with an ARC billet rod. There is little info to be found online. I would like to put a cam and springs in mine this winter if I could locate them.
 
roccosbike

roccosbike

#14
#14
RegalX said:
I am currently running a HM100 as well with an ARC billet rod. There is little info to be found online. I would like to put a cam and springs in mine this winter if I could locate them.
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Then let me help you with info, get ahold of Precision Cams That's where I sent my original out of my motor cam to be rewelded and ground to Tecumseh Star cam specs, I got the valve springs from them too. I got my valves, lifters,guides and keepers from Mike Clements. Nothing like the sound of hopped up Big Block Tecumseh breathing through a header. :smile:
 
R

RegalX

Member
#15
#15
roccosbike said:
Then let me help you with info, get ahold of Precision Cams That's where I sent my original out of my motor cam to be rewelded and ground to Tecumseh Star cam specs, I got the valve springs from them too. I got my valves, lifters,guides and keepers from Mike Clements. Nothing like the sound of hopped up Big Block Tecumseh breathing through a header. :smile:
Click to expand...
I sent them an e-mail a while back and got no response. What did it cost to have your cam welded and reground?
 
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