Here I go again,Briggs build

[curtisfox]

The book says the cubic inches no hp rating, 9 cubs, but would be about right. Lawn mower engines with 9 cubes very from 3 to 4 hp, and would be the carb that make the difference. That's like a Kohler engine the 12 and 14 hp have all the same internals, but the 14 hp carb is 1/8" bigger.
Your bike is really looking nice, like the tank. Take your torch apart may just need a new orifice, get them at ACE.............Curt

 

[cannonball2]

That's really nice work on the frame mounts, very clean!

I painted my tank with Rustolem industrial flat black, comes in the tall can. I expected it to slowly be removed by gas spillage. Its absolutely fuel proof.

I happen to have both a B&S and a Tecumseh 3hp. The Briggs is the model with the separate fuel tank and the close fitting up draft carb. Looks like it will fit in my unused GT2 frame with little to no mods. Hmmm you got me thinking, shouldn't have read this thread. Oh well.

 

[scratchbuilder]

Ok I get it now..on the hp thing..carb making the difference..bigger opening, more air, more gas, more hp the lite is on., the tank needs sanding and I'm thinking, bed liner paint for a thick covering. I never thought a round tank could be so easy, sure beats 65$. Thx curt.

 

[scratchbuilder]

CB2, you know I had a pred79 and I must have got one that slipped by qc because it made a lot of noise in the value train, I'm guessing. But I think we have all had experience with a Briggs growing up. And what a difference the carb made. The frame if you look close, I actually cut into the down tube to get the engine 3" more to the front. Give a man a welder, and look outdo it, do it, build it.....

 

[cannonball2]

Was never much of a Predy fan though I have used em with ok results. Have done several builds with the Lifan 2.5hp flat head and really liked them a lot. Guess its time to use the little Briggs. Its fairly old maybe a 67 as I remember. Been packed away along time. Hopefully will be able to use the updraft carb. I do have a carb like the one you used from when I put a Honda clone ATV engine in a bike. I can use if I need to. Will probably ditch the pedals and use the bottom bracket as the jack shaft.

Your build is the inspiration I needed for another 4stroker.

 

[scratchbuilder]

Hey, that's what this build is, just parts in the bins. What made it happen was a yard sale. The frame came with a rusted Springer... 5$ the engine with a rusted clutch..3$..how can I refuse. I've bought a new comet clutch, and the pz carb. I don't know...its just fun to throw something up on the table and see where it goes. Thx!

 

[scratchbuilder]

Thx,SB, thx, CB2... My first juice tank...you were the inspiration to 'just do it'

 

[silverbear]

Awesome, Possum! And the next tank will go even easier.
SB

 

[curtisfox]

You can go to AutoValue or NAPA, get there outdoor power equipment service parts catalog.( Free ) in the front of each engine section is the Hp chart, it very a between serial numbers, so 800, 900's re 3 hp just depends on the number................Curt

 

[scratchbuilder]

Welll..just about done. Took a ride with the 18 freewheel, swtich to 16..going back to 18. Gonna pack some tools and go for a long ride Sat.hey curt, ill go see my Napa store in interested in that.

 

[scratchbuilder]

I mounted the tank with a rubber abs coupler to my rack with. I was at home depot going to get a piece of 4" abs and cut a bit more than in half so the can would like snap in..but a 10' piece is 17$ their 2' piece is 11$....so looked around some more and... the rubber got attention..had to cut the rack and reinstall the pieces I cut out. It'll work!!

 

[scratchbuilder]

Hey.....since your here. I've search for 3 speed sa jackshaft and no go. Can you help with the how 2's. Like how to put a sprocket on the opposite side...or just how is it done.

 

[curtisfox]

Bike looks good, like it a lot. There is specks on other engines also. ............Curt

 

[cannonball2]

Hey.....since your here. I've search for 3 speed sa jackshaft and no go. Can you help with the how 2's. Like how to put a sprocket on the opposite side...or just how is it done.

A 4stroke will be pretty hard on the internals. I used the SA fixie hub its really stout. Stands up to pedal starting a CG with no issues. Also since it doesn't freewheel you have engine braking which I like and it will turn backwards just fine unlike standard 3speed hubs.

I modded a sprocket to fit the spoke flange which could be done on either side. On this build I wanted the drive all on the left. It has worked out well. This bike rides and sounds like a small motorcycle.

Nice build BTW.

http://motorbicycling.com/showthread.php?t=58233

 

[scratchbuilder]

Wow, my thinking of a Js 3speed was not really possible! Read though 'abbynormal'( loved that movie one of the few I can watch again & again) I got a good education of how-to ...but my Sa is an oldee with the oil cap.. oh yeah zirk it! Dang, now I'm inspired for another build.. When I put Blue(the name for Briggs build) next to DelRio, Blue looks really small. It a 26 frame on 24s. I see what u mean about your Maytag..having this, having that, very interesting, its take a while to see what's goin on.

 

[cannonball2]

Very few folks have caught or at least commented on the title. Good old Marty Feldman.

I am running a Nexus on my last build powered by the 49cc commercial engine. So far so good. I didn't have any luck with the older Shimanos. The Nexus is nice because the direct drive gearing is 2nd leaving a lower and higher gear. The SA fixie is direct in 3rd so all gears are lower. I am able to get well into the 30s with a 49cc cruising below any vibe level. Would be hard to do with a single speed with out turning ones hands and butt to mush.

The Nexus is cheap. I bought a new one off ebay for $18(hub only), if it trashes you can just swap the internals into the existing wheel/hub. Might just work with the Briggs if you are easy on it shifting. Having an auto clutch helps immensely. Its worth a shot if you have one.

 

[scratchbuilder]

My nexus is a freewheel, flipping it would not work right? What is a commercial 49? I'd like to try the 79 lifan, but am Leary of it being rev limited. I found on my hs142 a round body cdi is rev limited, gas bike purchased, whereas the the on the engine is a sq. body, and the plug wire is on opposite corner. Luckly Kc had one.

 

[cannonball2]

Heres the build for the 49cc. http://motorbicycling.com/showthread.php?t=60263

These are nice little motors. Not much in the looks department, but if you want a reliable MB this is a good motor to start with in a 2stroke.

If you put a common 3spd to drive on the left you have to drive the hub and use the original input sprocket as the output. Due to the power flow through the hub(at least the older Shimanos) you wind up with only 2spds(actually 3 but 2 are the same.

The reasoning behind the double left side drive was to eliminate all the parts needed to make the common shifter set up driven on the right. The one I have really works well. It requires careful frame and wheel set up, but once that is worked out the rest is pretty easy. Also due to the chain spacing bike chains are the only ones with enough clearance. I run HD BMX chains on all my builds and have never broken one. You just have to be careful when buying a rear sprocket not to get the thicker ones for the larger chains.

 

[scratchbuilder]

Yeahcb2, my rear sprocket is a one piece interchangeable one so bmx chains are a right fit. I'm gonna mock up a Js w/ the 3speed to give me experience with the setup. I change out my Js freewheel for 18 t..much better, got engine braking now, none of that coasting. Oh, when you mentioned commercial 49, I was thinking 4 stroke, was why I asked, my goof.

 

[cannonball2]

Post pics of the mock up. Like to see what you come up with.