just finished my first porting job

[spankrz]

i just finished my first porting job on my 031, and i have to say for not knowing what i was doing, i can't beleive the difference it made. i just polished up the intake side, made the exhaust side about 2 thousandths wider and polished it up, cleaned up the transfers, and polished the carb bore. i will have pics coming soon and hopefuly a vid, but i never imagined that little bit of work would have such good results.

 

[ARsawMechanic]

I'll be watching for the pics. I've been wanting to do it to one of my own saws, I will probably get up the nerve in a few months after reading alot more articles on here about it.

 

[spankrz]

well here are some pics. the intake was about done getting polished and the exhaust was about done with the grinding and soon to be polished. sorry guys, i forgot to take final pics before i put it on the saw. once i get the saw tuned well i will shoot a vid and put it up.

intake side
http://s969.photobucket.com/albums/ae179/spankrz/031/saws/?action=view&current=0118002017.jpg

exhaust side
http://s969.photobucket.com/albums/ae179/spankrz/031/saws/?action=view&current=0118002018.jpg

 

[poulson01]

What's that uvula thing in the intake?
I have a project 031 that I was thinking about porting and I was thinking about grinding that thing off.

 

[JohnnyBoy1986]

the starting jobs look good but in you exhaust pic (not to try and burst your bubble but) it doesnt seem like you've accomplished anything. Widening the outside and middles of the port is fine, but the point is to widen the actual port inside the cylinder as well so that it will allow more airflow out. Your cut marks in the pic dont seem to have made it that far, i would look at a few more examples and give that another try.
Now about that little "teet" hanging in the intake port, i am not so sure what it is for either but i took one off of an 028 Super i did for a friend and his performed just fine, be careful when removing it to NOT raise your port any. Good luck with this, i hope you are happy with your results

 

[donthraen]

looks pretty nice do you want to do it on my rebuild job (clinton d6) lets put more power on it LOL.

 

[spankrz]

i thought about grinding that little thing out of the intake but the best i could figure it was for the piston rings. i am sure that they would be just fine if you put a good bevel at the top of the port but i didnt fool with it. i just opened the throaght on it a little where it gets smaller halfway through and polished it well. on the exhaust port i did a little more grinding after the pic, but was too eager to get it on the saw and test it all out to take a true after pic.

 

[poulson01]

i thought about grinding that little thing out of the intake but the best i could figure it was for the piston rings. i am sure that they would be just fine if you put a good bevel at the top of the port but i didnt fool with it. i just opened the throaght on it a little where it gets smaller halfway through and polished it well. on the exhaust port i did a little more grinding after the pic, but was too eager to get it on the saw and test it all out to take a true after pic.

I don't think it's for the rings. The port isn't that wide and the "uvula" doesn't touch the piston, does it? I have to take a look but I think it just dangles there. I think it's for turbulence or port gas velocity. Either way, I don't think it could contribute much low speed performance and mixing, compared to the amount of restriction at higher rpm.
I think 'll remove mine. My saw won't be needing a gag reflex!:spam:
Your port work looks nice and clean by the way.

 

[donthraen]

the uvula thing

At this time I have 3 saws open and nun have it in the cylinder like that does but nun are stihl maybe IL open my 012 av up to sea also my last post its a D65 not d6 typo sore

 

[jambalini]

I've worked on may 125 GP bike engines in my time and a simular piece in the middle of the port is for the ring ends to be supported as they pass the port. Are the ring ends in line with this piece? If not, I don't know what it is for either, get rid! The other thing to watch is if and when you do this, because the port is then quite alot more open, the ring will ,as previosly mentioned, need quite good lead back onto the cylinder wall. In addition to this (stay with me) you will need to put a small chamfer onto the top edge of the piston ring groove. This is because the piston will try and burr over the piston ring and result in the ring sticking into the piston. By putting the small chamfer on it, the burr dosen't occur as you have already removed the material where it would occur. You will never suffer ring stick if this is done properly.:hmm3grin2orange:
I know this is hard to follow, so if you need proper details, then get back to me and I will post some pic's and instruction I have from my racing days.

Andy

 

[poulson01]

That's a great tip. What do you use to cut the ring grove with?

 

[jambalini]

I used an oil stone with a 45 degree corner on it and plenty of parrafin (very thin oil like heating oil would be fine). You obviously need the piston off the crank with ring removed to do this properly and thoughly clean it afterwards.

Andy

 

[poulson01]

Wow. Steady hands. I'll give it a shot.