Steven's 3120XP

He helped me out when I was learning to square file.

 

He's a fine old dude.

He called me up after Jerry broke that first record last year.......he was on top of the world.

Said he had orders for bike saws start stacking up before the chips all stopped flying.

 

Did you see the lines on the wood that he hit every cut?

 

Here's a couple more pics.......I'm done for the day. I'm gonna hit the shower.

The rough in is done on all the transfer passages. Tomorrow I'll do the intake ports, then slick it all up.





I'll make a few posts about modding the carb.......but some trade secrets are involved there.

 

nope ,chiquita banannas

 

what kind of chain and grind do they use?

 

.325" usually. I would imagine it is full chisel but may still be semi chisel.

 

Rookie question #236 : do the finger/ bridge ports direct towards exhaust side to promote earlier (or more complete) ignition due to spark plug electrode location in jug?

 

Mike got the last name respelled for ya, but its Jerry Gingras. Met him several times over the years at races and raced against.

 

It's about more transfer flow.

 

For a 3120 like this using 32:1 what is the breakin or recommend breakin. Then how hard can I push it or lean once broken in? I have been gental on mine so far. Does not take long to use a few gallons of fuel.

 

Work em hard.......that's what they are made for Doug.

 

When you remove material from the inside cylinder wall of the transfer - is this the case of two 12" pipes deliver more flow than one 24" pipe.
I guess it's near impossible to grind the backside of the cylinder side transfer wall - without some type of rotating tip grinder(I have a cable driven grinder developing in my mind)

 

For all out race saws boost ports are put directly across from exhaust to get old mix out.

 

Cool. Looks a bit rough on the bar when he rolls the log with the saw and bar.

 

There are several different ways to gain more transfer flow.......these type of ports are just simple and easy to do. They also have a high flow velocity......that matters on these engines.

The ones across the transfer bridges are more for flow direction than they are for additional flow. They direct the incoming charge upward. The ones at the back over the intake act as boost ports and help clear the exhaust. In my mind I can see them working together to do both, without losing too much out the exhaust. You can't tell from the pics, but there are three different transfer heights involved here.

Here's a pic of a few of the tools I use.