Spuds Porting and Tuning Thread

[wisewood]

Hi Steve,

I'm after a little guidance on carb tuning.

I've fitted a dual port muffler on my stihl 066 and I'm concerned that without a tune up I risk leaning the saw out.

Do I tweak the L out a touch and leave the H screw ??

[htb]

I had to tweak the H screw on mine when fitting the dual port. Sounds better and stops the flexible chain brake handle.

[wisewood]

It was sounding a little too racey so I've turned the H and L out a 1/4 turn. I'll swap to a new plug at the weekend and keep an eye on the colour until I call in to the saw shop.

Revving it up without my ear defenders on and my ears are still ringing 15 minutes on!

[htb]

Revving it up without my ear defenders on and my ears are still ringing 15 minutes on!

 

The joy of dualports. Keeps nosy individuals away

[spudulike]

Hi Steve,

I'm after a little guidance on carb tuning.

I've fitted a dual port muffler on my stihl 066 and I'm concerned that without a tune up I risk leaning the saw out.

Do I tweak the L out a touch and leave the H screw ??

 

I would retune both but it is only the H screw that may cause damage. I would just tach the saw to 13000 - 13500 rpm, without a tach, give the H screw a 1/4 turn anti clockwise and check the plug colour after an hours running - it should be coffee colour!

 

I would be concerned about just putting on a dual port without any retune!

[wisewood]

I would retune both but it is only the H screw that may cause damage. I would just tach the saw to 13000 - 13500 rpm, without a tach, give the H screw a 1/4 turn anti clockwise and check the plug colour after an hours running - it should be coffee colour!

 

I would be concerned about just putting on a dual port without any retune!

 

Great! Thanks Steve. I've opened both H and L a1/4 turn so I'm on the right tracks at least.

I'll get it tached on my next visit to the saw shop now I have the right figures 👍

[jomoco]

I'm about to pull the trigger on a new 201T Spud, any recs?

 

Better and more durable than a 540?

 

My 200's fine, but my backup 020t AVE's still a bit temperamental at times, but still screams!

 

Do you trust these microprocessor driven new saws like the 201?

 

I run very high octane racing fuel, mixed with stihl's silver synthetic mix.

 

Thanks for any advice mate.

 

Jomoco

[Stubby]

[quote name=jomoco;1473568

 

I run very high octane racing fuel' date=' mixed with stihl's silver synthetic mix.

 

Thanks for any advice mate.

 

Jomoco[/quote]

 

 

I did read somewhere the very high octane fuel wont make the engine run as well as lower octane fuel unless you have the higher compression to make it combust properly .

[spudulike]

I'm about to pull the trigger on a new 201T Spud, any recs?

 

Better and more durable than a 540?

 

My 200's fine, but my backup 020t AVE's still a bit temperamental at times, but still screams!

 

Do you trust these microprocessor driven new saws like the 201?

 

I run very high octane racing fuel, mixed with stihl's silver synthetic mix.

 

Thanks for any advice mate.

 

Jomoco

 

The autotune is great when it works and is the way forward. Unfortunately you cant get in to the carbs and resolve some issues as you could on standard carbs. Sometimes people just jump on the autotune and blame that rather than diagnosing the real route cause giving it bad press.

 

One issue of these lean burn autotune engines is that they use much less fuel and therefore much less oil and this makes for bottom end bearing issues and possible top end seizes so.......a fully synthetic decent quality oil and a 40:1 mix would be my recommendation and sounds like you are there anyway - just use a fatter oil to petrol ratio to keep the saw sweet.

 

The technology will become more reliable as it did in the automotive world, just takes time!

[openspaceman]

I did read somewhere the very high octane fuel wont make the engine run as well as lower octane fuel unless you have the higher compression to make it combust properly .

 

That's my understanding, higher octane resists detonation better but comes at the price of less calories, so you have to burn more fuel for the same power.