Adjusting witha tach...

[DeanBrown3D]

Hello all I am buying a tachometer to adjust the saws I have. Am I right in this: Warm up saw, then run the saw with a chain on, at full throttle, and adjust the H screw on the carb until the max speed spec'd in the manual is reached?

Thanks,

Dean

 

[Lakeside53]

You can do it the way you suggest, and most do, but I just run it WOT with chain, look at the reading, throttle down, make a small adjustment, try again, repeat as necessary.

I don't like holding open a saws for more then a few seconds at a time and it's way too easy to get bit if you are making adjustments while the chain is at full speed.. I do a lot per day, and it's a number game, so I play it safe.

 

[314epw]

setup

I agree don't keep it wide open for too long!Get your reading shut it down to idle.make your adjustment,take it back up.Keep doing it till you get it right.A lot safer this way plus less chance of blowing a no load engine.
Ed

 

[046]

how far up do you go without a chain?

You can do it the way you suggest, and most do, but I just run it WOT with chain, look at the reading the throttle down, make a small adjustment, try again, repeat as necessary.

I don't like holding open a saws for more then a few seconds at a time and it's way too easy to get bit if you are making adjustments while the chain is at full speed.. I do a lot per day, and it's a number game, so I play it safe.

 

[Lakeside53]

how far up do you go without a chain?

Same.. in short bursts, but it's meaninless unless the chain is fitted and tensioned.

 

[DeanBrown3D]

Ok thanks all, that is in fact what I meant to do, rather than adjust them at speed.

Cheers,

Dean

 

[Drive_1305]

First I don't know what Im really talking about but:
I see that you guys tune carbs by using a tach and also by ear. In old dirt bike mags I read they would tune and jet the carbs by taking plug readings. I don't see you guys talk much about plug readings. I would think too that the max rpms listed for a saw are "safe" numbers that the company has come up with. Maybe the saw can be pushed some beyond the listed max- how much I don't know. If you can go beyond the max some, wouldn't it be important to take plug readings to make sure the saws not going to cook?

 

[NWCS]

the easy answer is you dont. you need some sort of load on the saw. without a chain is just trouble and potential danger.

how far up do you go without a chain?

 

[5555555]

I do most of my cutting at between 6000-7000 feet. To get near the max high-speed rpm numbers I had to adjust the HS needles to about 3/4 turn open or even slightly more closed, instead of 1 turn open. This is on 044, 046 and 066s. Are my saws going to be running too lean at that setting, even though I'm slightly below max RPMs?

Thanks,

Jim

 

[ShoerFast]

I do most of my cutting at between 6000-7000 feet. To get near the max high-speed rpm numbers I had to adjust the HS needles to about 3/4 turn open or even slightly more closed, instead of 1 turn open. This is on 044, 046 and 066s. Are my saws going to be running too lean at that setting, even though I'm slightly below max RPMs?

Thanks,

Jim

Less air = less gas

Here is a catch, your getting less power also, so you may be a tad lean to get your target speed,,,,,, not really a problem as there is also less heat at lesser power , knocking out some of the chance for a lean seizer or an over rev condition. If your slightly below the target speed, your fine with your setting, as that would becloser to the adjusted for alitutude (corrected) setting.

Most here will adjust slightly towards the fat end , as when it comes to loading the engine, (cutting) the extra cylinder pressures will use the richer mixture and cut faster, better a plug then a jug.