McCulloch Chain Saws

[Maintenance supervisor]

Also, when guys compare the 7-10 vs 700 a lot of them say the 7-10 is stronger, and it's been speculated that the porting is different. On this build I actually recorded the port timings and ignition timings. The intake duration on this stock 700 was only 126 degrees and the exhaust duration was 156 degrees. The ignition timing was 22 degrees advanced, which is less than what it's supposed to be from the factory. I modified the key and clocked the flywheel to get 26 degrees. I also modified the piston on the intake side to get an intake duration closer to 145 degrees. I wasn't sure if it was going to work, but so far so good!!!! Here's a couple more pics of how I did the velocity stack.
View attachment 786673 View attachment 786674 View attachment 786675

Looks great, how do you like that stack on the carb?

 

[emf123]

I think it's awesome and they should've built them all like this! The hard part was modifying the air cleaner cover to fit around it, then getting the stand-off to fit at just the right height. I also modified a factory air filter so it seals the carb box on the perimeter. There was a lot of JB weld and body filler involved

 

[emf123]

I did a little work on the muffler, basically just smoothed out the insides and got rid of the reed valve. Naturally, I over-torqued the one bolt that goes through the duct and snapped it off right at the case. So I drilled it out and tapped it to 1/4"-20 and put in a allen head bolt with loc-tite high temp red.

 

[mogulmasher]

Nice build emf123! Love the all black stealth look!

 

[Maintenance supervisor]

Pro mac 60 = firewood hero!

 

[redunshee]

Working on a Mac 3516. Rebuilt the Zama C1Q carb. Anyone know what the carb settings are?
Tried several to no avail. Might add that the purge bulb is currently set up with the push side connected to the top inlet and the suction side to the lower inlet or pump side. Might they be criss crossed?

 

[Timdog]

I can't get the magneto off of my old 650 any help would be appreciated

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[Goinwheelin]

I think you have to take the nut off.

 

[Maintenance supervisor]

I can't get the magneto off of my old 650 any help would be appreciated

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A cheap steering wheel pullers work well for me, hit the crank with some penetrating fluid, torque the puller down and gently smack the end of the puller nut and that usually does it.

 

[Timdog]

A cheap steering wheel pullers work well for me, hit the crank with some penetrating fluid, torque the puller down and gently smack the end of the puller nut and that usually does it.

I have a puller on it I let it soak with penetrating fluid and I hit it with a hammer and then I tried using a air hammer still won't come off

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[fossil]

You could try some heat in case the PO used retaining compound. If that doesn't work and I don't like doing it, you could hit the puller bolt with an impact gun. If you do, I'd back the nut on the crankshaft off some more.

 

[sawfun]

I had to put heat to the flywheel on an 890 to get it off, all while under tension from the puller.if you do this, just heat as close to the center of the flywheel but not the crank.

 

[Timdog]

You could try some heat in case the PO used retaining compound. If that doesn't work and I don't like doing it, you could hit the puller bolt with an impact gun. If you do, I'd back the nut on the crankshaft off some more.

The nut is at the top of the shaft os I don't mess the thread up

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[Timdog]

I had to put heat to the flywheel on an 890 to get it off, all while under tension from the puller.if you do this, just heat as close to the center of the flywheel but not the crank.

I've thought about using a heat on it really don't like doing it I ordered a chip for it just bothers me that I can't get it off

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[sawfun]

Try using a 50/50 mix of acetone/ATF instead of penetrating oil. I've had two saws that nothing I've tried worked to get the flywheel off. One was a 2100 Husky I sold as a parts saw and told the guy of the problem. The other one (a large Homie) I still have. I've tried vibrating them as well.

 

[rarefish383]

Well, I don't know how the acetone/ATF works on a flywheel, but I had an old Homie C72 that was locked up tight as a gnats azz. Let it soak for two weeks and it broke loose, put the comp gauge on it and it only blew about 60 PSI. Pushed it to the back of the bench for a couple months. Needed the comp gauge and it was still screwed into the C72 , so for the fun of it I gave it a pull. It blew 125-130. Said to heck with the current project and put the recoil back on, plug back in, and took it to the garage. Put a shot of mix in the carb, I think too much. First ten pulls got wet fuel blowing out of the exhaust, then a couple big puffs of smoke, then it fired up. Man, that C72 with no muffler sounds good! So, it works on froze pistons.

 

[Jethro 2t sniffer]

Also, when guys compare the 7-10 vs 700 a lot of them say the 7-10 is stronger, and it's been speculated that the porting is different. On this build I actually recorded the port timings and ignition timings. The intake duration on this stock 700 was only 126 degrees and the exhaust duration was 156 degrees. The ignition timing was 22 degrees advanced, which is less than what it's supposed to be from the factory. I modified the key and clocked the flywheel to get 26 degrees. I also modified the piston on the intake side to get an intake duration closer to 145 degrees. I wasn't sure if it was going to work, but so far so good!!!! Here's a couple more pics of how I did the velocity stack.
View attachment 786673 View attachment 786674 View attachment 786675

Real interested in the 700 vs 7-10 thing and it's good you have measured 1 of them now we just need the numbers off of the 7-10. I'm no expert at all but feel it could be the two different ignitions causing the difference but will never know until a 7-10 is measured. Anyway nice 7hundy you got there

 

[Maintenance supervisor]

I can't get the magneto off of my old 650 any help would be appreciated

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Oh I forgot to mention the most important part of this fix is to buy copies of your saws so you have plenty of time to let it soak up any fluids you have to loosen the flywheel.
Lots of copies!

 

[Timdog]

Try using a 50/50 mix of acetone/ATF instead of penetrating oil. I've had two saws that nothing I've tried worked to get the flywheel off. One was a 2100 Husky I sold as a parts saw and told the guy of the problem. The other one (a large Homie) I still have. I've tried vibrating them as well.

I used PB Blaster

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[Timdog]

Oh I forgot to mention the most important part of this fix is to buy copies of your saws so you have plenty of time to let it soak up any fluids you have to loosen the flywheel.
Lots of copies!

I Love having copies

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