Building a SP125C / 101B Kart Saw

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I got the NOS BDC14 in the mail and checked it out. The only thing that looked like it needed to be replaced was the duckbill valve. The lever height on the NOS carburetor was a ways above the height of the housing. I did not adjust it because I figured the supposed factory setting was adequate. The result are the same when trying to start the saw it still only pops a few times and either floods easily or doesn't seem to be getting the proper amount of fuel.

I'm wondering if I should use a different head. The one I have on the saw currently was labeled as NOS High Compression option. Terry Ives a Kart specialist recommended using a non-high compression head in the chainsaw application to get higher RPM's. I'm wondering if the High Compression head would work better with Race Fuel or an alky blend with the BDC16 carburetor.

I have the standard compression head but it's not a NOS product. I did mill out an tap it for a compression release valve so it should be just a matter of dis-assembling the saw to swap out the head and re-torque the head bolts to try this new configuration.
I know this is an old thread, but in case anyone could use some info, the lever on mine is set at .010 down and try different stiffness Springs to eliminate the flooding. I did this and mine works fine.
 
I'm a VERY, VERY bad man. The parts for my 101 are all still setting in a box, just waiting to be put together :(

I wasn't here for the first build, but read the whole thread & loved it--especially the completed pics.

Now I learn that you never finished yours?! C'mon, Brad! Knock it out this weekend! ;)
 
I wasn't here for the first build, but read the whole thread & loved it--especially the completed pics.

Now I learn that you never finished yours?! C'mon, Brad! Knock it out this weekend! ;)

I own that saw, and it still looks great. I have only made a few cuts with it. It is really difficult to start. The tank leaked, but I sealed it up with Casewell Tank Sealer, and it has been good ever since. A little bit of the paint peeled on the tank, and I touched it up so that it is barely noticeable.
 
I own that saw, and it still looks great. I have only made a few cuts with it. It is really difficult to start. The tank leaked, but I sealed it up with Casewell Tank Sealer, and it has been good ever since. A little bit of the paint peeled on the tank, and I touched it up so that it is barely noticeable.
That really bummed me out when you showed me where the tank seam leaked :(

Any idea why it's hard to start? Carb issue?
 
That really bummed me out when you showed me where the tank seam leaked :(

Any idea why it's hard to start? Carb issue?

The freakin compression is so high, that I can barely get it to turn over. Every time I try to start it I think that I will break the starter or pull cord, or my arm for that matter. It will start on the third or fourth time that I get it to turn over for more than one revolution. Nothing at all wrong with the carb.
 
The freakin compression is so high, that I can barely get it to turn over. Every time I try to start it I think that I will break the starter or pull cord, or my arm for that matter. It will start on the third or fourth time that I get it to turn over for more than one revolution. Nothing at all wrong with the carb.

I had a 790 that was like that and I never did figure out why. Oh well, poor Aaron has that saw now.

My 101's both seemed impossible to start, as did a ported 880 I had. But after starting them 5 or 6 times they seemed to get easier and the just stayed that way. So maybe it's an initial break in? I dunno. Maybe I just learned how to start them or grew stronger overnight?
 
I'm new to ArboristSite, I joined cause I like what I see, mostly saw talk. I just bought a 101D and I'm having it bored out, well I got to looking at the block and noticed it's got the two boost port dimples on the side of it. Now I've been watching videos of The Chainsaw Guy and he keeps pointing out these dimples mean the block is a "101B" so I'm all mixed up, this is my first 101 engine, from what I've read, all 101's have the same bore,stroke & horsepower . What makes the 101B The Crown Jewel.
 
I'm new to ArboristSite, I joined cause I like what I see, mostly saw talk. I just bought a 101D and I'm having it bored out, well I got to looking at the block and noticed it's got the two boost port dimples on the side of it. Now I've been watching videos of The Chainsaw Guy and he keeps pointing out these dimples mean the block is a "101B" so I'm all mixed up, this is my first 101 engine, from what I've read, all 101's have the same bore,stroke & horsepower . What makes the 101B The Crown Jewel.
Someone will likely correct me, however, I believe all 101 blocks except the MC versions are the same. The "D" version has the bigger end of the crank for the larger kart clutches and won't work with a saw clutch unless you somehow made your own. That engine will work fine with a standard size PTO end crank like from any other Mac kart engine, 797, or 125. by the way, welcome aboard.
 
Any 101b for sale always wanted one love the sound I got 790 that I want to put 101b in could this be my time

i know a guy selling a sp125 with the cart motor. Wants lots of $$$. He sent it down to the chainsaw king to work on who posted a video about it
 
No. You cannot use two of these seals on the flywheel side. They are too thick. I used the original outer seal. The outer seal isn't used on a cart engine, and this saw will not have points. I could have actually left it out. The purpose for the outer seal was discussed some pages back.

@blsnelling What ignition system does it have?
 

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