Mc Bob's Twin McCulloch SP125C's

mcbob · Post by **mcbob** » Wed Jul 01, 2009 8:20 pm

Built to be a practice saw for my Twin 101b powered hotsaw i have only the fuel tank gasket and the throttle cable to finish off making this twin project something serious but if the twin 125c's prove strong enough i may not bother to run the Twin 101b's just yet.

Same setup as my Twin 101's the outboard engine in very easy to start and starts the second engine real easy.
Both engines have decompressor's as per the origional SP125C's and run BDC Carbs.

http://i18.photobucket.com/albums/b108/ ... in125d.jpg

http://i18.photobucket.com/albums/b108/ ... in125c.jpg

http://i18.photobucket.com/albums/b108/ ... in125b.jpg

http://i18.photobucket.com/albums/b108/ ... in125a.jpg

And if this you feel is not getting serious enough then you's better be watching for my next project Twin US 820 Modded to Copperhead standards and the engines are on there way deep south .............. bringing back the American grunt Downunder.

Mc Bob.

Mark Brubaker · Post by **Mark Brubaker** » Sat Jul 04, 2009 1:51 pm

You GO McBob!!!!

You got any video of these beasts making noise??

mcbob · Post by **mcbob** » Sat Jul 04, 2009 5:22 pm

http://s18.photobucket.com/albums/b108/ ... unning.flv

This is the noise of my Twin 101 running after it's first start but i have a few minor things to finnish off on the Twin SP125's before i can run it properly like the throttle cable and linkage to the throttle trigger next week i'll dig around the bike shops for more cable fittings as i'm out of them. Then i'll double check the auto oiler when it gets running so i still have a bit to do.
What will be interesting is the revs i can achieve in this dual setup i need around the 10,500 to 11,000 but i'll wait and see how efficient the coupling is.

Mc Bob.

Post by **Jeff Campbell** » Mon Jul 13, 2009 2:54 pm

Bob,
How do you start that beast, a recoil on a single 101 can be a test in strength and ability to endure pain? ... are there compression releases on the motors? Do you have to start this for competition, or is it a Hot Saw class?

I always wondered with these saws, what the the major safety issues? ...what happens when the chain brakes or pops off the bar .... do the saws kick? what safety precautions are taken?

Jeff

mcbob · Post by **mcbob** » Mon Jul 13, 2009 5:17 pm

All SP125c's were fitted with decompressors but i found that on the twin 101's it only needed one as one engine starts the other as far as being a hand full your right and they will take some getting use to as regards chain stretch it happens and the occassional derailment of the chain ....... myself i make my chains from brand new chain not old worn out stuff like a lot of racers do old chain with wear is faster but i err on the safety side.
Most chains when they derail only fall straight forward but if you snap a chain it becomes like a whip, on these two twins the 101 and SP125c the balance of the saw puts the operator off centre outwards so hopefully your out of the chain whip arc.
With this much power the chain trys to make a circle of itself and if you watch video clips of hotsaw racing you may see this taking place and this is when the chain derails and particulary when the operator changes over from one cut to another and especially if the chain clips the side of the timber off it comes.

There's a lot to consider as with the weight and enirsa ? spelling the brain is a tad slow this morning, so everything happens very very quickly the twin 3120 Huskie averages around 2 1/2 seconds a cut on a 14" log and thats the fella whom we wish and will beat.

Mc Bob

Mc Bob's Twin McCulloch SP125C's

Mc Bob's Twin McCulloch SP125C's

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Re: Mc Bob's Twin McCulloch SP125C's

Re: Mc Bob's Twin McCulloch SP125C's

Re: Mc Bob's Twin McCulloch SP125C's