Seized chainsaw

[Snobdds]

Stanford? did a study on 2 cycle oil ratio. It showed in laboratory tests that a richer oil mixture produced more horsepower. They got the highest hp at 12:1
That was in a laboratory setting. On the racetrack, I found that 20:1 was best results. I used pure synthetic.
An air-cooled 2 stroke engine loses 30% of its power when it arrives at operating temperature. Whatever friction you can remove creates less heat and more power.
There is a difference between performance and environmental politics. We are at risk of losing 2 stroke entirely if EPA gets there way. All 2 stroke manufacturers will recommend a lean mixture to prevent losing there markets. A quality machine and quality synthetic oil can run fine at 50: but they will not last as long as a richer mixture.
Note that you will have to breathe what you burn and absolutely will have to jet the machine with the ratio you choose.

I don't disagree on the fact adding more oil results in higher HP. However the question becomes Why is such a rich mixture needed when nobody uses straight 30w non detergent oil anymore?

 

[fishdrivel]

You may be thinking of Gordon Jenning's two stroke oil ratio test: http://www.bridgestonemotorcycle.com/documents/oilpremix6.pdf


For motorcycles I scale the amount of oil to the riding use: road race engines get more than MX or enduro engines, which get more than observed trials engines. On my trials bikes I ran 75:1. Trials engines are mildly tuned and don't spend much time at WFO but you want them to run cleanly and never load up.

Chain saws are industrial engines that are even more mildly tuned than trials engines. A trials 250 is about 10hp per 100cc while a 92cc MS660 is 7hp. And the saw is fan cooled. But on the other hand, it spends a lot of time at WFO. 75:1 is a little light for that. I have been successful using high quality synthetic oil at 50:1. Exactly zero lubrication related problems in 24 years of running saws. But if you want to run 32:1 or 40:1 that's fine too.

I don't think oil ratio caused the OP's problem unless it was 0:1.

You'll laugh to know you offended me when you said that
"road race engines get more than MX engines"
What we put a professional 2 cycle motor through on the pro circuit was brutal.
I agree that a hig h quality synthetic is "fine" at 50:1 on modern chainsaws. I would never dream of anything less than 20:1 on my motocross bike.
The article was interesting, though not the study i was referencing. I will red later. When they used Castrol bean oil They lost me. Maybe I'll understand using rancid gorilla fat later, when I keep reading.

Wish I could see the piston

 

[fishdrivel]

I don't disagree on the fact adding more oil results in higher HP. However the question becomes Why is such a rich mixture needed when nobody uses straight 30w non detergent oil anymore?

Needed? In pro racing, 1/2 horsepower could be the difference between 1st and 10th
We even dyno tested gas.....

 

[Snobdds]

Needed? In pro racing, 1/2 horsepower could be the difference between 1st and 10th
We even dyno tested gas.....

who racing chainsaws?

 

[kenmbz]

Chainsaw racing is a thing - hot saw and speed competitions.

 

[Snobdds]

Chainsaw racing is a thing - hot saw and speed competitions.

I know but nobody is talking about chainsaw racing expect for the guy pushing super ratios of oil. Are we even talking about the same thing.

 

[Jstpssng]

Nope. My neighbor and I are the kings of dull-chain sawing and we, also, have never seized an engine. Sooted up the mufflers, seized chains to bars, threw chains.......... but never seized an engine.

Last year my mother said she was tired of mowing around an old stump from a maple my father cut down years ago, and asked me if I could cut it off level with the ground. Instead I decided to remove it. It would have cost $300 to get a stumpgrinder to do it so I fired up my Husky instead. If you want to really dull a chain try driving it down into an old stump repeatedly and cutting roots with it. In hindsight if I did it again it would be with an old chain, not one which is almost new. I didn't even bother to try sharpening.
It didn't hurt the saw a bit, or even the bar; although the blue smoke was pouring off the wood as I cut.

 

[MossRoad]

Loggers and racers.
Weekend warriors I have often witnessed setting the bar on the log and pulling the rope. It takes very little waiting to warm up but grab that throttle with a death grip immediately, and you won't like the results.

Love to get my hands on an RD400 stock. Collectors item now!

https://www.cycletrader.com/listing/1976-Yamaha-RD400+European+Grey-Market-5013880560

 

[MossRoad]

Loggers and racers.
Weekend warriors I have often witnessed setting the bar on the log and pulling the rope. It takes very little waiting to warm up but grab that throttle with a death grip immediately, and you won't like the results.

Love to get my hands on an RD400 stock. Collectors item now!

I do miss riding that bike. I gave it up when we had kids. Still have it, but in little bitty pieces.

 

[kenmbz]

I use a sawzall on roots where needed.
Using a chainsaw seems like a futile way to remove a stump.