Super Jet 61x matching ports

[trojoro]

I was wondering if it is a good idea to match the aluminum cylinder with the sleeve so that it is a smooth transition, it seems like there is about a 2mm diffrence in the sleeve and the 61x casting. do many of you guys do this? and if so what tools do you use to get up into the cylinder?

thanks trevor

 

[waxhead]

Yes its worth while doing. you will not get a massive gain but you will get a gain

 

[Nuklear6]

As said above, it is worth while to do, HOWEVER. BE VERY careful not to change the angle of the port roof. Those angles are very intentional to direct the flow of fresh air fuel. A 2 stroke uses the force of the new air fuel charge to push the burnt gasses out the exhaust port. If you change the angle of the port roof you could disturb its ability to do the above mentioned efficiently. Thus doing more harm then good.

 

[trojoro]

Sorry in new to 2 stroke engines, so basically if i stay away from the sleeve and just grind down the excess aluminum in the port i should be fine?

 

[Nuklear6]

Sorry in new to 2 stroke engines, so basically if i stay away from the sleeve and just grind down the excess aluminum in the port i should be fine?

Not exactly. The aluminum you will be grinding up to match the casting to the sleeve has a "roof" angle. You need to make sure that angle stays constant as you grind away the aluminum up toward matching it to the steel sleeve.

 

[trojoro]

okay i understand. would a right angle die grinder be the right tool for the job? i dont see what other tool cold fit up into the cylinder to reach the boost ports

 

[Nuklear6]

Boost port actually I use a pencil air rotary straight in from the top. Transfers I use a combo of 90 degree and 120 degree air rotary. All with a cone carbide cutter. Key is do an occasional dip into atf with the cutter keeps the aluminum from building up on the cutter.