Another 3HP Resto!

[jackeo21]

Hey all,

I have taken up the brutal task of rebuilding this 1973 3HP Briggs. The amount of dirt on this thing is ridiculous! The valve cover was barely visible when I got it. All but one of the recoil starter tabs are snapped off. This old girl was painted in house paint at one stage!

Luckily, everything was clean inside. The crank and rod journals are like new! the piston still has plenty of life left in it, and there is minimal scoring in the bore :thumbsup: The fuel tank is like new on the inside and the carb pickups are very clean. As bad as it looks, it's actually really clean.

This motor is going on a minibike.

So far I have the motor stripped and partially blasted, but have more sandblasting to do (I use garnet).

Was thing of doing the bike orange and black, so this motor is most likely going to be black :thumbsup:

Couple questions.
How do I get rid of the easy-spin cam lobe? What will I gain from removing it?
Does buying new valves help or improve the motor at all?
I saw somebody mentioned they used longer lifters. What would be the benefits of this?
How do I prevent the new carb to tank gaskets from leaking (all new ones do that :doah

I know these have been answered sometime in the past few years but I can never quite get a certain answer. Any help appreciated here.

So, feel free to discuss your mods/improvements for 2HP and 3HP motors here too. Painting techniques for these motors are good to know too.

Here goes another 3HP build thread! Hopefully I can start the bike soon :laugh:

 

[MCF2891]

Looks like you got yourself a nice little project. I noticed in your first picture you have a K and N air filter in the background. I would lose the stock air filter and keep it as a spare and put that other filter on it. You will definitely have more air flow going through that motor. I did that with my 5HP that I had built up.

I have swapped motors since then, I'm using an I/C 5HP Briggs with that same filter.

Sent from my HTC Desire 626s using Tapatalk

 

[jackeo21]

I think I will get a new pod filter for the 3HP. I put that K & N on my Modified 5HP, goes well and looks cool too :thumbsup:

 

[MCF2891]

I got the filter on amazon for a good price. I think it was like $15 You can probably find something similar to that for cheaper.

 

[Lucky7]

There is a guide for upgrading flat heads in the engine and modifications briggs section.

 

[jackeo21]

There is a guide for upgrading flat heads in the engine and modifications briggs section.

Yup, I have read that sticky many times :thumbsup: I only meant that you can discuss mods here that may not have been discussed before, but this forum looks to have every trick in the book :laugh:

 

[Lucky7]

Well I was looking at your questions you asked in your first post. Although I can only really answer one, I will try to answer it. So unless you valves are really worn(loose, lots of play, etc.) or really out of spec. There is no need to get new ones. Maybe try valve lapping. Really easy to do and gets a good seal between the head and valves. You can put little lines on the valve seat with a sharpie and then put the valve in and twist it around. If all the lines are gone then you valves "seats" good. If not then you valve doesn't "seat" or seal properly and could be warped, worn, etc. Hope it helps. :thumbsup: