Best place to drill for pulse line?

[francisjohn]

I'm currently working on a 372xp using a Tillotson HS-274. The Tilly carb has an external pulse (there is a barb coming out of the carb that is for the impulse)

I've been online easily for 8 hours as of right now trying to find information regarding the ideal location.

I've heard it doesn't take much to activate the diaphragm, but of course you want a strong pulse.

I read some drill into the intake adapter they're using as it provides a strong pulse, and the shorter the pulse line is the better.

Now when it comes to 4Ts, I was reading about NOT drilling it in certain sections to prevent fuel or oil from entering the impulse line. While I know nothing about 4-strokes, I'm wondering if something similar could happen if drilling the pulse fuel fitting in the transfers.

I appreciate any insight into this, thanks.

 

[DieselTech]

I'm currently working on a 372xp using a Tillotson HS-274. The Tilly carb has an external pulse (there is a barb coming out of the carb that is for the impulse)

I've been online easily for 8 hours as of right now trying to find information regarding the ideal location.

I've heard it doesn't take much to activate the diaphragm, but of course you want a strong pulse.

I read some drill into the intake adapter they're using as it provides a strong pulse, and the shorter the pulse line is the better.

Now when it comes to 4Ts, I was reading about NOT drilling it in certain sections to prevent fuel or oil from entering the impulse line. While I know nothing about 4-strokes, I'm wondering if something similar could happen if drilling the pulse fuel fitting in the transfers.

I appreciate any insight into this, thanks.

Look up Tinmans saws. It's a youtube chainsaw channel & he has a video on it. It's for chainsaws but the same should apply to one of these lil engines.

 

[GW's Motorized]

You could tap off the valve cover's crankcase vent if it has one.

 

[Chainlube]

Are you working on a saw or bike engine? But the transfer is the best spot.

 

[GW's Motorized]

You could tap off the valve cover's crankcase vent if it has one.

Are you working on a saw or bike engine? But the transfer is the best spot.

He mentioned something about a 4 stroke.

 

[DieselTech]

I'm thinking he is working with a 372xp cylinder.

 

[francisjohn]

Look up Tinmans saws. It's a youtube chainsaw channel & he has a video on it. It's for chainsaws but the same should apply to one of these lil engines.

Let me see if I can find the video

You could tap off the valve cover's crankcase vent if it has one.

This is for a 2T

Are you working on a saw or bike engine? But the transfer is the best spot.

It is an MB. 372xp, it's all built I just need to get the pulse squared away.

I'm thinking he is working with a 372xp cylinder.

Correct

He mentioned something about a 4 stroke.

I see the confusion. I was reading about pulse drilling on 4Ts, and it talked about where some places aren't as good due to oil being able to contaminate the pulse. I was using that information and applying it to 2Ts in regards to if there are any sections that could contaminate the pulse line (such as in the transfers and fuel mix getting into it)

 

[Chainlube]

This is the only 372XP I know of.

Are you going to solder up the case or use an adaptor plate? The transfer is really the best spot for the bung.

 

[robe]

I remember there was quite a line of discussion on how to make this happen. I searched but couldn't find any anything. Maybe in Wilitboost threads?

 

[francisjohn]

This is the only 372XP I know of.
View attachment 210529

Are you going to solder up the case or use an adaptor plate? The transfer is really the best spot for the bung.

Yup, we are talking about the same thing my friend.

It's a 372xp (Hyway big bore cylinder) 52mm bore and 38mm stroke.

Just for clarification on your question, are you talking about the 372xp build or the carb? Regarding the transfer being the best place, that appears to be the consensus.