Fixed Jet...........Whew!!!

[rahtreelimbs]

With all the contraversy over fixed jets I got quite an eye opener today. I modified a Shindaiwa 360 last fall. I put an extra port in the muffler amd increased the compression ratio by eliminating the cylinder base gasket. This saw has not missed a beat since I did this work. The mods were well worth it, The saw runs much stronger now. I put a tach on this saw today.........14,700 RPM! I couldn't believe it. The saw is totally non-adjustable, fixed hi-speed jet. Unlike some of the recent Stihl 026's the carb has remained stable.

Guess I'm just lucky.

 

[jokers]

Hi Rich, has this saw had much use since you modified it? Is it supposed to run at 14.7k?

Russ

 

[bwalker]

14.7k sounds like my 260 pre adjustable carb. Thats slightly less than my 260 screamed out too before I swapped to a adjustable carb. I think you will find the saw will cut much better when you get the rpms down a bit. My 260 cuts much better at 13,600 rpm than it did screaming with a fixed jet carb and will likely last longer/ run cooler with less rpm.

 

[jokers]

I just picked up a used 026, 3 yrs old, that looks like new inside and out, in fact the chain doesn`t even appear to have been sharpened. Tached it at 14.7k yesterday so off comes the carb because it has a fixed jet. Figured I`d bump the .056 jet up to a .057 since I happened to have one handy. Well it had a .054 in it so I threw a WT220 carb on it and she runs great now! Odd thing is that I was told that the WT220 was for an 026 but I haven`t seen it listed anywhere in the Stihl info as such. I don`t remember it being listed as an 026 carb but it works. Figured it was worth a try.

You`re right Ben, something under 14k is where it`s at for the 026.

Russ

 

[rahtreelimbs]

I believe 13,500 rpm is the correct speed. The saw cuts well at 14,700 rpm. Changing the jet is a real PIA. I have a lot of time on this saw if it went south tomorrow it would be a great loss. This saw lacks nothing as far as low-end power goes.

 

[chainsawworld]

rich,
i think i missed something. you must have done more than what you said. marty

 

[bwalker]

Hey russ, my 260 actually had a 52 in it if I remeber right. Ran like crap till I had the 57 in it, but them it was on the rich. I them switched to a 56 which was too lean again. After that fiasco I ditched the pos carb and put a adjustable carb( with the intellicarb feature I might add)on. The saw has ran great ever since and I can fine tune it via tach for optimum performance every time I use it.

 

[rahtreelimbs]

Originally posted by chainsawworld
rich,
i think i missed something. you must have done more than what you said. marty

Hey Marty,
All I did was the ported muffler and the cylinder base gasket elimination. I did replace the rings while I had the cylinder off. I bought this saw used, how many hours were on it before I got it is anybodys guess.

 

[bwalker]

Rich,Dont you worry about a base leak without a gasket. Are yoiu using threebond or something simular to seal it?

 

[rahtreelimbs]

Originally posted by bwalker
Rich,Dont you worry about a base leak without a gasket. Are yoiu using threebond or something simular to seal it?

That is a real good point. I failed to mention that I used Permatex Anaerobic Automotive Grade Gasket Maker to seal the cylinder. The guys at Baileys turned me on to this stuff. No problems so far. I used this saw a my first test.

 

[Crofter]

What would the effect be here in the change in port timing from removing the gasket thickness. I can see the increase in compression and squish efect, but what would the timing change have been to torque curve etc.

Frank

 

[chainsawworld]

frank,
that was my question but i was sneaking around it not to give away a saw builders secret. he did increase compression but dropped the port timing. perhaps when experimenting with saws one should only make one change at a time to get the exact results from each change. marty

 

[bwalker]

By removing the gasket and in effect lowering all the ports you would lose peak HP. You also would have a wider, lower power/torque curve.Keep in ind that the increase in comp will make up for some of the hp lost due to lower the ports. In all likelyhood this saw will cut as fast and will be more forgiving of operator misjudgement than the way it was stock.

 

[066 stihl]

I think removing the cylinder gasket is a good ideal if you dont have a way to machine the cylinder. Make sure your squish clearance is .020-.025 less than .020 and you are asking for trouble. You would need to raise the transfers and exhuast port timing the thicks of the gasket to get back to stock timing.

066 stihl