Spuds Porting and Tuning Thread

[Eddy_t]

I can't believe that anyone has or needs to "remap" the onboard computer. By remapping, we are meaning advance and retard on ignition and amounts of fuel air at different revs and in different circumstances - load, no load, bogging etc

 

 

 

The parameters are infinite and to start adjusting this area would be a can of worms!

 

 

 

I believe the software just downloads how the machine has been running and can set the carb back to default setting - a bit like your dealer can do on your car....well, some of them!

 

 

The software just tells you the mix ratio, engine speeds, run time, number of starts, etc. it also has the master reset button, that is all it offers.

 

 

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[elliott EGD]

Hi was just wondering if anyone has a pic of a well ported Ms200 pot for me to have a gander? Im in the process of building a dicent on up out of a few old ones have. Widend the exhaust port still well within the skirt and raised a fraction . Was going to leave the intake port and slim the bottom of the transfer . good idea ?

 

Also how is best to mesure the squish ?

[Eddy_t]

Hi was just wondering if anyone has a pic of a well ported Ms200 pot for me to have a gander? Im in the process of building a dicent on up out of a few old ones have. Widend the exhaust port still well within the skirt and raised a fraction . Was going to leave the intake port and slim the bottom of the transfer . good idea ?

 

 

 

Also how is best to mesure the squish ?

 

 

You've got to widen the intake or it'll bog like hell! If the saw is blowing more out, it needs more in! And make sure the muffler is opened enough or you'll be fitting a new piston!

 

To measure the squish, get a decent length of solder and twist it into a twin or quad strand, raise the piston enough to cover all ports and feed the solder into the cylinder until it contacts the wall, then raise the piston to TDC and back towards BDC, pull the now-squashed solder out and measure.

 

 

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[spudulike]

You've got to widen the intake or it'll bog like hell! If the saw is blowing more out, it needs more in! And make sure the muffler is opened enough or you'll be fitting a new piston!

 

To measure the squish, get a decent length of solder and twist it into a twin or quad strand, raise the piston enough to cover all ports and feed the solder into the cylinder until it contacts the wall, then raise the piston to TDC and back towards BDC, pull the now-squashed solder out and measure.

 

 

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Sorry Eddy, the ring ends run down either side of the top of the inlet port, if you widen them, they will snag and take out the rings - there isnt much you can do here, possibly a little shapeing but not worth it IMO.

 

You can take around 1-2mm off both sides of the exhaust port but measure the skirt to get the correct width leaving 2mm of skirt down both sides of the port.

 

Most of the gains will be from the piston and exhaust plus dropping the base gasket!

[Eddy_t]

Sorry Eddy, the ring ends run down either side of the top of the inlet port, if you widen them, they will snag and take out the rings - there isnt much you can do here, possibly a little shapeing but not worth it IMO.

 

 

 

You can take around 1-2mm off both sides of the exhaust port but measure the skirt to get the correct width leaving 2mm of skirt down both sides of the port.

 

 

 

Most of the gains will be from the piston and exhaust plus dropping the base gasket!

 

 

Does the ring enter the port? I'd have thought dropping the gasket would have allowed the port to be lowered and the base of the port to be widened also, if the top can't be, so it forms a sort of trapezoid shape

 

 

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[div_h]

It's not that white/grey colour anymore:thumbup: I had a feeling it had a knackered crank seal or something!

[spudulike]

Does the ring enter the port? I'd have thought dropping the gasket would have allowed the port to be lowered and the base of the port to be widened also, if the top can't be, so it forms a sort of trapezoid shape

 

 

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The rings are visible through the inlet port - if you widen the port by more than around 1mm, the ring ends will be too close to the port opening or will actually pop out in to the port.

 

Either way, it is not a good idea to have ring ends that close to an open port - 2mm is absolute minimum to avoid issues - believe me - I have done the work and know the build.

 

A little knowledge is a dangerous thing with this type of work - I don't profess to know it all but do know the limits to work within and some saws in detail!

 

If the owner had opened the inlet port - he would now be looking at an ash tray:thumbdown:

 

Not having a pop but giving a free lesson and experience!

[elliott EGD]

You've got to widen the intake or it'll bog like hell! If the saw is blowing more out, it needs more in! And make sure the muffler is opened enough or you'll be fitting a new piston!

 

To measure the squish, get a decent length of solder and twist it into a twin or quad strand, raise the piston enough to cover all ports and feed the solder into the cylinder until it contacts the wall, then raise the piston to TDC and back towards BDC, pull the now-squashed solder out and measure.

 

 

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Thanks eddy havent taken much out of the exhaust port. First time at it nice tipp the the squish ta

[Eddy_t]

I don't mind, I generally avoid working on toppers as the compact design frustrates me when you have to take it all apart to get the bit you want to fix, although saying that, the stihl 1110 and 1111 series isn't much better!

 

 

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[elliott EGD]

Sorry Eddy, the ring ends run down either side of the top of the inlet port, if you widen them, they will snag and take out the rings - there isnt much you can do here, possibly a little shapeing but not worth it IMO.

 

You can take around 1-2mm off both sides of the exhaust port but measure the skirt to get the correct width leaving 2mm of skirt down both sides of the port.

 

Most of the gains will be from the piston and exhaust plus dropping the base gasket!

 

Thanks spud built it up a bit this afternoon didnt want to touch th intake as it was close to the have red you mentioning 2mm as a maximum before stuck in my head. i ave used a liquid gasket

 

Widend the exhaust 1mm or so raised a bit and a little skim on the lower face. And my interprotation of a mufler mod only got a pick of it part done you guys think it would be ok dint wana go to mad