Another SP-125/101b build

[leeha]

Looking good Charles.
I'm sure you'll have the carb figured out soon.
Kind of a pain cause you have to pull the fuel
tank to get the carb off. Been there on mine.




Lee

 

[cpr]

The tank's been on and off 40 times in the last week tweaking throttle linkages, no big deal, there. I can do it in under a minute now . I'll probably ruin the gaskets though. I put ThreeBond on them trying to keep air leaks down on this hot rod. Easy enough to make more though...

 

[parrisw]

That saw looks awesome with that bar. Well done. I love those macs.

 

[blsnelling]

Very nice. That bar certainly does give it some serious attitude

 

[hoss]

The fifth throttle linkage finally gave me the travel I was looking for...

and with that, assembly is done.

I filled it up with lube and fuel and braced myself...

On the third pull it touched off the prime I'd given it, ran for a second, and then the fuel pump caught up to the impulse and flooded it. I mean FLOODED.

I pulled the plug and roped 3oz. of fuel all over my leg. I could see every impulse sending geysers of fuel from every jet in the carb. Something inside isn't right, but I'm really close now.

All the pics are nice, but that first one is shaweeet!! Luv that little shorty header.

 

[cpr]

Great resource on these carbs.

http://rearenginekarts.com/McCulloch%20Pressure%20Pulse%20Carb.pdf

 

[cpr]

Spent the afternoon working on it. I thought maybe the dry side of the diaphram wasn't blowing down correctly because of the ear I cut off the top of the reed pyramid to clear the fuel tank. I cut off the bottom one, but it's still doing it. More practice lifting the tank and pulling the carb to check stuff. In the course of the tweaks on the carb, I added a little bend on the throttle shaft and can now get a full wide-open, so there's been a positive.

Believe it or not, the compression test was far worse than the true starting procedure. It's actually not that bad to start and I've popped it now several times with no snap-back issues.

I LOVE this thing. Can't wait to get the carb sorted!

 

[psgflier]

If you can find one, you might think about putting a cp125 cover on your saw. It'll pull a lot more air.
Carl

 

[cpr]

Good news/bad news.

First the bad. Saw is all apart now mopping up fuel that weeped out of this impact damage I hadn't noticed before on the tank. That is sitting drying out so I can fix it.

The good news. I think I have the over-fueling problem figured out. I have never had a metering lever that was too high, so I've been complacent and just taken it for granted... This one was about .050 above the body. I reset it to .010 under. I'm REALLY tempted to say screw it on the leak and try to make some noise today and fix it later because I'm too busy the rest of the week to play with it.


EDIT: Yup, I'm goin' for it!

 

[cpr]

Idles great, but the lever is too low now. It won't accellerate right.

That's a good thing because it hits so hard I shook a bunch of stuff loose, including the flywheel. No harm done other than the key. Off to the hardware store.

Sucker's LOUD!!! I mean LOUD!

 

[ozflea]

Well what did you expect with that drain pipe on the end of it use a muffler of a 895 or something its very similier to the 125 muffler dut has the extention to fit the exhaiust opening of a 101

McBob.

 

[Ambull]

Well what did you expect with that drain pipe on the end of it use a muffler of a 895 or something its very similier to the 125 muffler dut has the extention to fit the exhaiust opening of a 101

McBob.

I think he doesn't want any back pressure. I like those little square Gem mufflers. Good flow, and good sound. I would recommend one of them over a "drain pipe"

 

[Stihl Wielder]

loving that saw, and I just finished up reading the whole post. Lets get that thing figured out and post a video of it. I can't take the suspense any longer.....

 

[Ambull]

This type is a little bigger, so the rear shroud needed to be trimmed.

 

[carym2a]

I think he doesn't want any back pressure. I like those little square Gem mufflers. Good flow, and good sound. I would recommend one of them over a "drain pipe"

Dbl check those screws for good locks or lockwashers, I need one of those Gems for mine

Cary

 

[cpr]

On the road right now. I have puck mufflers to try at some point. As for the pipe: This is the Motor City and this what we do!

 

[ozflea]

Eh whatya say i didn't hear ya ..............................

 

[cpr]

It's together and running. No cutting until tomorrow, but 2 vids later tonight of it running. It actually over loaded my camera and shut it down twice! Did I say it's loud?

Forgot to mention, that the bar fits perfectly after shimming the studs. No grinding necessary.

 

[ozflea]

It's together and running. No cutting until tomorrow, but 2 vids later tonight of it running. It actually over loaded my camera and shut it down twice! Did I say it's loud?

Forgot to mention, that the bar fits perfectly after shimming the studs. No grinding necessary.

Well Mac did make spacer plates to fix that

 

[cpr]

Stupid youtube...

Whatever, here: Part 1.
[video=youtube_share;zwbevU_o3iY]http://youtu.be/zwbevU_o3iY[/video]