Building a SP125C / 101B Kart Saw

[Brian13]

Anyone? Looks like seal positioning is critical or a major air leak will result.

Got a pic. Sounds like the weep hole, main seal goes under that hole, and thinner seal goes above it. If I am at all understanding what your talking about.

 

[ausneil 1]

Did we wake you or are you lookin' to git your mouth washed out Neil ............... 090's different horse for a different course

McBob.

hahah,I have a soft spot for them as well and i'm not knocking them in any way or form, merely stating what some of our old timers have said to me who did work in our big timber in the 60's and 70's.

Even old Bill Boyd ( hardened mac man and lifelong professional log faller) said they were a top saw but they spent a lot of time in the workshop and his 090's hardly ever missed a beat. He gave me his entire mac collection from his working days which amounted to a lot of preloved stuff. I gave him a carton of tooheys old stubbies and he was satisfied.

 

[ozflea]

At least Bill will be happy

McBob.

 

[blsnelling]

Anyone? Looks like seal positioning is critical or a major air leak will result.

Are you talking about holes through the block where the seal seats? I haven't seen those on any of my 101 blocks.

Got a pic. Sounds like the weep hole, main seal goes under that hole, and thinner seal goes above it. If I am at all understanding what your talking about.

This cover may very well be from a SP125.

There isn't room for two of these seals.

 

[Brian13]

Yes that is the weep hole, iirc its to keep any oil out of the points. Should have one regular seal that sits just below that hole. And then one thin one that goes just above it.

 

[blsnelling]

Yes that is the weep hole, iirc its to keep any oil out of the points. Should have one regular seal that sits just below that hole. And then one thin one that goes just above it.

Why two seals? I've never seen a saw with double seals. Is it necessary with these new seals?

 

[Brian13]

Why two seals? I've never seen a saw with double seals. Is it necessary with these new seals?

That is the only series I have come across that have 2 seals like that. I have always reused the outer seal, because the bearing store I go to doesnt have a match for it. If you can find one I would put one on, cant give you a yes or no as to if it is absolutely necessary. It was there when I took it apart so I put the same back LOL.

 

[Dennis Cahoon]

Don't worry Brad.......those holes are there just to let the steam out......Hahahahahahaha!

 

[rupedoggy]

The hole between the seals are to keep from forcing a seal out, under pressure. You need two seals.
The other hole is to allow fresh air to the points. For some reason, unknown to me, the points will not work when all the air is burned by the points. or at least won't work well.

 

[ozflea]

Don't worry Brad.......those holes are there just to let the steam out......Hahahahahahaha!

Well you'd know Dennis your full of hot air.

McBob.

 

[blsnelling]

According to Terry, which I understand you can take to the bank, the outer seal is a dust seal needed to keep saw dust and engine oil out of the points. It's not needed on a kart. I'm assuming I can leave it out of this saw since it's running an Atom module, so no points.

 

[watsonr]

There is a cover that goes over the points to keep out the saw dust. Guess it wouldn't really matter on a kart...your building a saw.

 

[blsnelling]

But the first one's not running points, so shouldn't need the seal. I've asked Terry for clarification on that point.

 

[watsonr]

U could probably skip that seal and the points cover...however that slot in the raised area around the points holds a felt wiper. It would have soaked up any oil and does touch the crank to wipe it clean, I would not skip that part.

 

[ozflea]

Na still use both seals if you can get em

McBob.

 

[McC]

Brian13, thanks for embedding my youtube video of me running my saw, and my cousin Paul running his saw. Mine is a mc92 in a 250 frame, .020 over with no mods to the ports. Running a mac v4 intake and a tilly hr carb. Pauls is a mc93 in a 250, pretty sure it's a mac v4, but he runs a tilly hl. They are very close in power. I usually have it set rich, don't want to stick it. Set rich it will make 3 cuts in a 10x10 in about 6-7 sec. This year I leaned it some and it ran much better and time went down to 5.7. Lots of fun to cut with.

 

[ozflea]

The 92 and 93 are good engines and i don't quite grasp why the 91b/1 gets going a bit harder i have one here and at 100cc and a bit of port work it kills a 125cc

The 91b/1 is an outstanding engine

McBob.

 

[Teddy.Scout]

I've talked to a couple motorcycle shops about chrome-plating Magnesium and I think it possible from what I've heard.

Typically what they do is either deposit a layer of copper electrolytically and then chrome on top of that or they use a chromate conversion finish
which is then polished. There's a couple of websites that claim to chrome-plate Mag.

Chrome Plating services on Plastic, FIberglasss, Magnesium, Metal,

Black Chrome Plating - Arlington Plating Company

Nice info Jacob, The couple chrome shops i have delt with
said they can't do it.
I will check them out. Although i bet it's very pricey.


Lee

With the labor, prep, and actual material used to accomplish this,
(same as plastic with a micro layer of chrome)
Might as well gold plate it.
It is EXPENSIVE!

Looked hard at this when looking into options for a 090case.

 

[24d]

My sp125/101
View attachment 210494
View attachment 210495

 

[ozflea]

Lookin' good ol mate did you block off the origional decompressor valve ?

A saw with a flowing flag of stars and stripes over the fuel tank would look tuff.

McBob.