Heymow - Lawnmower Racing Forum

Mower Building / Setup Help => Project Builds => Other Interesting Builds => Topic started by: ray. on October 10, 2011, 12:15:14 am

Title: Briggs Bike- Need help with Engine mods
Post by: ray. on October 10, 2011, 12:15:14 am
(http://i257.photobucket.com/albums/hh237/Cb2010usa/IMAG0031.jpg)

My briggs bike is almost done. Motor on it, runs strong. But I have another motor set aside for rebuild, and during rebuild, I want to make it run. Currently has a smaller moto slide carb on it that seems to work.

What are we talking for significant increase in power? high lift cam? oversized pistons? Just looking for some opinions on what my best bets are, I can find very few parts for it. I am mostly curious about the camshaft, but havent been able to find much info on them.
Title: Re: Briggs Bike- Need help with Engine mods
Post by: George Herrin on October 10, 2011, 06:28:35 am
And neither do we since we do not have a clue as to the specific motor you have other than it has a red cover.
Title: Re: Briggs Bike- Need help with Engine mods
Post by: Caudy155 on October 10, 2011, 07:24:49 am
Looks like an opposed to me... there are more and more things you can do to them but id put a vannie on it and forget about it as far as problems sake... arc rods midwest super cub billet steel flywheel for that type of application and a nice cam will give you plenty of power and reliability... really nice bike though...
Title: Re: Briggs Bike- Need help with Engine mods
Post by: Wheelhorseracer on October 10, 2011, 11:45:31 am
A V-twin can easily be made to look like a Harley V-twin... for sure it would need a billet flywheel since you will be running above governed RPM...
Title: Re: Briggs Bike- Need help with Engine mods
Post by: Rooster on October 24, 2011, 06:27:00 pm
Yep That is an Oppy.

First, put the rest of the tins back on it before you cook it.

Put a set of ARC Rods in it and AVS Pistons.
Call Tim Iskenderian at http://www.smallenginecams.com, he has a great cam for that engine.

Unless your racing that thing, I don't think you'd want to go to the expense and trouble of re-sleeving for bigger pistons. It adds some Horsepower, but not enough to mess with for a "fun" machine. Unless you just want to do it to say you've done it, lol.
I'd put better valves in it, a good Port & Polish and some head work.
Call EC...get a carb!
Button it up and let 'er Rip!

Keep the revs down, under 5500 and it will run great and last a long time!
Title: Re: Briggs Bike- Need help with Engine mods
Post by: mowinmachine on October 24, 2011, 08:16:35 pm
Perhaps a dumb question... But Oppys can run on their sides?
Title: Re: Briggs Bike- Need help with Engine mods
Post by: Rooster on October 24, 2011, 08:20:07 pm
They made Horizontal Oppy's .
Title: Re: Briggs Bike- Need help with Engine mods
Post by: BIG AL 202 on October 25, 2011, 01:54:07 pm
They made Horizontal Oppy's .
Hope thats one of them!
Title: Re: Briggs Bike- Need help with Engine mods
Post by: meanmachine on October 27, 2011, 09:16:08 pm
i'm not sure but i  think those bikes are inside a house, if so that is a very cool picture
Title: Re: Briggs Bike- Need help with Engine mods
Post by: ray. on December 25, 2011, 12:18:14 am
Its an horizontal model, I have two motors for it.

Yes, it and another bike were sitting in our back room!!   :omg: Bike is nearly done now, Its down to wiring, then it will be a long process of tuning everything up, Gear ratios, Clutch weights, ect.

(http://i257.photobucket.com/albums/hh237/Cb2010usa/IMAG0227.jpg)

Title: Re: Briggs Bike- Need help with Engine mods
Post by: Rooster on December 27, 2011, 10:12:32 am
Love to see some pictures of the other side, what kind of tranny are you running?

I mentioned before about putting the tins back on it, another thing is that plate over the flywheel..with the stock flywheel those engines tend to over heat, that plate will increase those tendencies. If you run the ARC flywheel, it really moves some air and fixes that problem. As a matter of fact I have problems getting my race engines to run hot enough!

Get a mill built and get us some video!
Title: Re: Briggs Bike- Need help with Engine mods
Post by: ray. on October 06, 2012, 01:17:20 pm
Cant believe its been this long!

We'll shortly after my last post on here. I ran the bike and decided that I HATED the Clutch system

(http://i257.photobucket.com/albums/hh237/Cb2010usa/IMAG0070.jpg)
(http://i257.photobucket.com/albums/hh237/Cb2010usa/IMAG0071.jpg)

So I worked up the funds and found A harley 5speed and clutch system and swapped out the other system for it. Also took out the shaft drive, Converted to Chain. Also have a 2-1 exhaust now.

I'm much happier with it now. I have run it up and down the road, but with the mikunki, it was barely running, carb was too rich and there was hardly any power, but even with all the carb problems it didnt have a problem pulling up to 50mph in 3rd gear. (and it wasnt even pulling that many RPM's. At this speed the carb was loading up. But with the Stock carb. I think it will run great.

I have my spare motor apart.

Got a Cam from Don on the way, ARC flywheel and rods with the shorty .020 over pistons. All going in very soon.

I have a carb question though.

I had a mikuni slide, and it was way out of tune, so for now, I decided to rebuild one of my stock carbs and give her a try.





Any one have some input on how you ran your cables to the carb?

I am planning on putting one of those semi-circle levers that you find on motorcycle carbs onto the throttle shaft, along with a spring.
Title: Re: Briggs Bike- Need help with Engine mods
Post by: jake318 on October 18, 2012, 12:47:53 am
GREAT BUILD , WE ( THE RACE TEAM) ARE DOING A BRIGGS V-TWIN MOTORCYCLE BUILD ALSO. I wrote you an email on the subject  and if  we can help  give us a ring .