Trying to test 261c on my dyno. Tach is funny???

[redfin]

Oh how I would love to get my paws on either Brads or Randy's 261s. Mine with just a dual port and timing bump impresses the heck out of me.

 

[blsnelling]

Oh how I would love to get my paws on either Brads or Randy's 261s. Mine with just a dual port and timing bump impresses the heck out of me.

Have you tightened the squish yet. You can almost get away with no base gasket on these. Squish is huge from the factory. Compression will end up around 190. There's no need for additional machine work on these, other than setting squish.

 

[redfin]

Not yet Brad, its on the list. On my bench now is my 44 with a ported 46 jug. Eager isn't even close to the word I'm looking for to run this saw.

 

[Duane(Pa)]

I've done over 50......probably closer to 75 of them.

I'm done "tweaking" the numbers on it. Very happy with the way they end up.

Me too!!!

 

[wyk]

Could be it has a multiple spark discharge circuit to help ensure combustion, but those circuits are usually more useful when the engine's throttled back, not at WOT.

If anyone ever finds a circuit drawing of either Stihl's or Husky's electronic systems, please post it so we can figure this stuff out.

Chad did say they acted weird once he put a load on it. It does sound like MSD, doesn't it?

 

[Mastermind]

Have you tightened the squish yet. You can almost get away with no base gasket on these. Squish is huge from the factory. Compression will end up around 190. There's no need for additional machine work on these, other than setting squish.

I had to reply to this.........probably start another fight. Oh well.

Brad, without a base gasket and no machine work the 261 has about .012" squish clearance. Is that acceptable to you?

 

[blsnelling]

I had to reply to this.........probably start another fight. Oh well.

Brad, without a base gasket and no machine work the 261 has about .012" squish clearance. Is that acceptable to you?

I knew you couldn't leave me on your ignore list very long, lol. Go back and read my post. I said you can "almost" get away with it. I later mentioned machining to set the squish. Also, I've seen them with as much as .015", IIRC. That would be fine with a factory squish band. I wouldn't go a bit tighter though.

 

[Mastermind]

OK.......I see what you are saying.

It did read that no machining was needed.......at least in my pea brain.

Thanks for clarifying.

I did wonder what was being talked about when Redfin typed your name......

Later.

 

[MustangMike]

If you guys care to divulge some of your secrets, It would be nice to know what saws you can get away with removing the gasket w/o addl machine work (if any).

Would the change in engine timing be a negative?, Also, it would effectively increase the stroke (even though the actual stroke remains the same), the portion in un-ported cylinder is longer. Both this, and the smaller combustion chamber would combine to increase compression (a good thing to a point).

 

[Mastermind]

Never.....ever just toss the base gasket without checking squish clearance.

 

[Stihlalltheway]

I've done over 50......probably closer to 75 of them.

I'm done "tweaking" the numbers on it. Very happy with the way they end up.

Thanks for answering my stupid little question. You always take the time to answer any questions anybody has about your work and I really appreciate you taking the time to do that, as do others I would assume. You, hedgerow, and the dodgegeeks are probably my favorite people on this forum.

 

[John R]

I have a tach I attach wrapping the lead wire around the plug wire three times tightly securing it with a zip tie. The 261c is giving funny rpm readings. If the saw is running wot with no load the rpm reads correctly but as I increase the load and the saw decreases rpms the tach increases to 15,000 rpm range when I'm guessing the saw is really at 9-10 k. Is the cm screwing it up or do I have a faulty tach. I think I have another tach in my stash somewhere I'll try.

Just proves that you can't slow down a Stihl.

 

[Leimkuhler]

My TTO tach has a sensitivity settings for vibration. My manual says the vibrations can mess with your numbers.


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[MasterMech]

Oh how I would love to get my paws on either Brads or Randy's 261s. Mine with just a dual port and timing bump impresses the heck out of me.

How close are you to Middletown NY? My 261C-M will be there and it has been to Randy's recently...... Upcoming G2G on the 13th....