Terry Syd
Addicted to ArboristSite
Crikey TK, chill out - I'll explain how to do it.
First off, EGTs are not the same Cylinder Head Temps. As I was modding the 450 Husky, I had to keep running the saw richer to keep it alive. I was basing that upon a couple of things. The spark plug temp was showing quite high while the mixture strength in the chamber was showing it to be on the rich side. The most significant indicator was the piston.
I had a previous piston that I had run for quite a while and had made some timing changes to. I could compare the darkness of the burnt oil on the bottom of the two piston crowns. The new piston was getting a lot hotter. The real worry was in the taper to the piston. The piston crown was now getting so hot and expanding that it had used up all the taper. I was getting full wear around the top part of the piston above the ring. I thought I might have to shape a 'clearance band' on the piston to take the power up any further.
I made a few changes to the fins of the cylinder to gain a better flow and blocked off the air injection - the temps dropped immediately. I pulled the plug after doing a plug chop and with the same carb settings and the plug was now showing a chocolate brown rich setting. The piston now has a layer of carbon on the area above the ring. Since then, I have upped the power some more and everything is still running at an acceptable temperature.
I didn't say I recorded an increase in power by blocking off the air injection. I mentioned Timberwolf's research that he did with monitoring the increase in temperature of the air inducted into the airbox. You could send him a PM and see if he will explain how he did the measuring.
ST, with the air injection blocked off and the air primarily entering from the back of the saw, there is much less trash in the air box. I still get an amount of dust that enters from the left side through the area of the primer bulb and carb screw access, but that is minor compared to the stuff that used to come in through the air injection.
First off, EGTs are not the same Cylinder Head Temps. As I was modding the 450 Husky, I had to keep running the saw richer to keep it alive. I was basing that upon a couple of things. The spark plug temp was showing quite high while the mixture strength in the chamber was showing it to be on the rich side. The most significant indicator was the piston.
I had a previous piston that I had run for quite a while and had made some timing changes to. I could compare the darkness of the burnt oil on the bottom of the two piston crowns. The new piston was getting a lot hotter. The real worry was in the taper to the piston. The piston crown was now getting so hot and expanding that it had used up all the taper. I was getting full wear around the top part of the piston above the ring. I thought I might have to shape a 'clearance band' on the piston to take the power up any further.
I made a few changes to the fins of the cylinder to gain a better flow and blocked off the air injection - the temps dropped immediately. I pulled the plug after doing a plug chop and with the same carb settings and the plug was now showing a chocolate brown rich setting. The piston now has a layer of carbon on the area above the ring. Since then, I have upped the power some more and everything is still running at an acceptable temperature.
I didn't say I recorded an increase in power by blocking off the air injection. I mentioned Timberwolf's research that he did with monitoring the increase in temperature of the air inducted into the airbox. You could send him a PM and see if he will explain how he did the measuring.
ST, with the air injection blocked off and the air primarily entering from the back of the saw, there is much less trash in the air box. I still get an amount of dust that enters from the left side through the area of the primer bulb and carb screw access, but that is minor compared to the stuff that used to come in through the air injection.