Building a SP125C / 101B Kart Saw

[blsnelling]

This thread is to document me being overcome by yellow fever, lol. I bought a 797 that showed up on Monday. Then yesterday a SP125C came that I will be building with a 101B kart block, as well as some other go fast goodies. Then today, another SP125C showed up that already has a 101 block in it. It lost compression. I will be going through it and sending it back to it's owner.

Here are the three saws. The first one here is a Super 797 I just bought off eBay. It's very clean and runs great. I plan on leaving this one entirely stock..

<iframe width="640" height="360" src="http://www.youtube.com/embed/EzrXjKRf5FU?rel=0" frameborder="0" allowfullscreen></iframe>

 

[blsnelling]

This is the SP125C that I will be building for myself using a 101B block, sloper intake, BDC or Tilly HL carb, and some kind of performance muffler. It's going to be prettied up with some chrome and flashy colors, yet to be decided.

 

[blsnelling]

This is the one that already has a 101B block. However, it lost compression and will need a going through. I'm doing the work and sending it back to it's owner. I will be doing this saw before I build mine.

 

[blsnelling]

Now, here are the parts I have to work with for my 101B build. This cylinder obviously need bored out. I have a .030" over piston, but I don't think that will clean it up. How far can you go with these?

 

[blsnelling]

 

[blsnelling]

I have two pistons.

This one is said to be .030" over.

It appears that perhaps this cylinder has already been bored before, although I'm not sure how much.

Here are some misc parts.

 

[blsnelling]

That's all the pics for now.

 

[cpr]

I've heard as much as .070 over. Your 101 block has been ported. The transfers look fine, but the exhaust has been raised. Be curious to see how that plays out. My ported one has been raised more, but that one will be piped, alky as that's what it was built for.

Looking forward to this!

 

[ptjeep]

 

[Ambull]

If the cylinder is shot, I think it is possible to re-sleeve them. Probably costs a bit more. Then the exhaust raising issue could be fixed.

Subscribing!!

 

[Jacob J.]

That one gouge goes pretty deep. I doubt that one will clean up even going .070" over. The largest piston made by the factory was .050" over and the largest piston Wiseco made was .095" over. Supposedly there's an ART piston out there somewhere that's .110" over but by that point the sleeve is so thin it's ruined. That block might have to be re-sleeved (it's been "needled" pretty hard.)

The 84470 piston is .010" over and the 84474 piston is listed as .030" over. The intake side transfers have some pretty shoddy looking porting. I'm real leery of "ported" kart blocks because there was a lot of hacks back in the 60's and 70's chopping up these blocks. I only buy blocks with stock ports.

 

[cpr]

True JJ. The only reason I agreed to buy the ported one that I have is because I know and trust the guy who ported and assembled it.

 

[Freehand]

opcorn:

 

[leeha]

Nice project Brad.
Looks like the 101 block is at .020 over already.
I have a 797 that has an aftermarket .070 piston
in it. And brian13 has a 797 with an .080 in his.
You have some pretty good gouges in your block.
Looks like a wrist pin bearing failure. I would be
surprised if it cleans up since it is already at .020
over. If it we me, I would look for another stock
block. Just my opinion.




Lee

 

[Brian13]

Nice project Brad.
Looks like the 101 block is at .020 over already.
I have a 797 that has an aftermarket .070 piston
in it. And brian13 has a 797 with an .080 in his.
You have some pretty good gouges in your block.
Looks like a wrist pin bearing failure. I would be
surprised if it cleans up since it is already at .020
over. If it we me, I would look for another stock
block. Just my opinion.




Lee

Mine was .80 over and it was a Wiseco piston. I just saw on on ebay an month or two ago advertized a .100 over. Think it was Wiseco as well. Looking forward to watching these builds.

 

[procarbine2k1]

Yellow fever? Took ya long enough!

 

[ale]

This is all over my head but I'm looking forward to learning something. Good thread!

 

[Jacob J.]

Mine was .80 over and it was a Wiseco piston. I just saw on on ebay an month or two ago advertized a .100 over. Think it was Wiseco as well. Looking forward to watching these builds.

Actually I think that was a Fuller piston advertised as Wiseco.

 

[procarbine2k1]

McCulloch Super Pro 125 with a 101b Kart Engine .................

I love the look of the 101B cover as seen on the link above. If you are going for some flash, I love the red white and blue.

 

[Teddy.Scout]

Have #2 .100 pistons, labeled as "special" for the 101 series boxed by Wiseco.

After what JJ said, safe to assume a resleeve is due after .080.

Will see if the next one can be ground to .130 and sleeved accordingly.
(be awhile for that, ya know, CAD funds and all!!!!)