Spuds Porting and Tuning Thread

[spudulike]

Just now, bmp01 said:

 This ought to be a Sticky at the start of the thread.  

Quick edit of '...crown inlet side of the piston...' maybe ?

I meant that some bike tuners cut the front edge of the crown of the piston where it interacts with the exhaust port thus giving a very similar effect to lowering the exhaust port. I also recently found it on a Wiseco Dominant piston I was asked to fit to a 372XP.

[spudulike]

12 minutes ago, Retired Climber said:

I honestly don't know if it's a good question or not. I'd imagine your insurance company would bend you over as well if they found out a modified saw was involved in an accident (once the HSE had a go). 

 

Edit. Anyone know enough about PUWER to know if it's relevant?

 

They are good questions and can't say one way or the other. Many would say that the modification allows the user to complete a more forceful and accurate cut with less chance of it splitting and then there is using a smaller saw to do heavier work giving less fatigue on the body.

All are the reasons most like a modified saw and were the reasons many of the yanks started porting......046, 2.5' bar, semi skip chain, ported instead of lugging a 066 or 084 about all day!

I guess H&S would ask if it was a contributing factor or not!

[Retired Climber]

10 minutes ago, spudulike said:

That is one reason I don't push the revs beyond the manufacturers maximum recommended specification. An air leak or just a well used engine can also peak out of this specification and have had to pull many limit caps to get the saws back in to the black but the safety reason is one area I am careful about.

In answer to your question - ported/modified saws should only be used by the owners of the saw and in no way would I recommend or condone giving a modified saw to an employee.

As an employer you have a duty of care to your employees health and safety so it isn't wise to give them a ported saw.

In my world, my customers ask for a saw to be ported, I don't sell it to them, they ask for their saw to be modified. When it is done, I check out the safety devices on the saw, cleaning, lubricating and servicing them. 

I have asked many when their saws were last serviced.....I usually get a blank look on that one. Coming from an engineering based manufacturing past, we used to have to check all heavy plant safety devices at the start of each shift, carry out preventative maintenance, training etc and log the lot. 

If the H&S get involved in a serious accident, I would imagine they would question when the saw was last maintained and by whom........now that is probably a big grey area judging by the state of most of the chain brakes on the 200s I get in!

Thanks, that's interesting. I agree, letting employees use a modified saw is asking for trouble. It's one thing a saw unintentionally being a bit more dangerous than stock, but to intentionally make modifications to make it more of a risk to use would be bloody difficult to defend in court. 

 

Equally, making a saw louder than standard has health and safety implications too. 

[spudulike]

My first saw I ported was my own 346XP, I was on Arboristsite at the time and spent a little time talking to Brad Snelling (well known US tuner) about it. In his words - don't change the stock port timing and don't hog the lowers out too much. 

Interesting point on the port timing as this was the reason it all kicked off. Seems the 346 port timing is pretty much bob on and the guys on Arboristsite still call their 346s "ported".

Mixed up world we live in!

[bmp01]

6 minutes ago, spudulike said:

I meant that some bike tuners cut the front edge of the crown of the piston where it interacts with the exhaust port thus giving a very similar effect to lowering the exhaust port. I also recently found it on a Wiseco Dominant piston I was asked to fit to a 372XP.

I know. But its skirt trimming on inlet side as you said and crown trimming on exhaust / transfer sides (not crown trimming on inlet side, which is what needs editing...).

STICKY..... STICKY..... STICKY..... 😀

[spudulike]

Just now, Retired Climber said:

Thanks, that's interesting. I agree, letting employees use a modified saw is asking for trouble. It's one thing a saw unintentionally being a bit more dangerous than stock, but to intentionally make modifications to make it more of a risk to use would be bloody difficult to defend in court. 

 

Equally, making a saw louder than standard has health and safety implications too. 

I am not going to defend any of this as I carry out the owners wishes and it isn't illegal to do so. You should hear those WCS "Bark Boxes", they make my muffler mods sound quiet.

Porting is for those that like/want it and it is a "Marmite" like thing.

[Retired Climber]

3 minutes ago, spudulike said:

I am not going to defend any of this as I carry out the owners wishes and it isn't illegal to do so. You should hear those WCS "Bark Boxes", they make my muffler mods sound quiet.

Porting is for those that like/want it and it is a "Marmite" like thing.

I'm not asking you to defend anything, I just asked a question to which I didn't know the answer. Having said that, the more I think about it, the more obvious it is that it's a bad idea ( to use a modified saw for work). 

 

[spudulike]

I have re-read it and what I said is correct. The lower skirt on the inlet side dictates inlet timing and the top edge of the piston crown on the piston dictates the exhaust timing.....or am I missing something

Edited March 7, 2021 by spudulike

[Rich Rule]

23 minutes ago, Retired Climber said:

I'm not asking you to defend anything, I just asked a question to which I didn't know the answer. Having said that, the more I think about it, the more obvious it is that it's a bad idea ( to use a modified saw for work). 

 

Whilst I agree giving a modified saw to an employee could turn nasty.

What’s not to like about a ported saw?

 

Lighter saw, less fatigue and overuse injuries.  More power, less likely to barber chair or split out on you.  I think a lot of saws are underpowered for manufacturing and environmental reasons.  That is why I refused to use the first generations of 201t.  
 

They were borderline dangerous IMO.

 

 

[Rough Hewn]

Can you get 20hp out of an 880/881?
Would it last?
How much £?
[emoji106][emoji106][emoji106]