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Messages - gnnova

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1
Briggs Flathead / Re: Flathead Port and Polish
« on: November 13, 2008, 11:53:28 am »
The short turn radius is the part of the port on a flat head that has the shortest turn between the underside of the valve and exist to the outside of the block.  Hope that helps.

2
Briggs Flathead / Re: Flathead Port and Polish
« on: November 12, 2008, 07:13:10 pm »
I agree with what most of the individuals are saying that most people don't want to give up their secrets.  On the intake, I will tell you that the short turn radius needs to be nice and round and try to get a good three angle valve job.  These two areas will give you the most bang for the time involved.  On the exhaust, add a pipe nipple in the threaded portion of the port and then work on the short turn radius but do not enlarge the port anymore than needed.  Its to big already.  That will get you started, but there is alot more to it than what I'm willing to give out.

3
Briggs Flathead / Re: Cams
« on: September 16, 2008, 11:39:48 am »
Precision Cams are good, Mike is the one to talk to.  I won the championship race and ended up second in points with an ALT212 in my SP.  George H. had recommended this cam to me a couple of years ago and it has worked good for me.

Ken
SP #355

4
Briggs Flathead / Re: Flathead issues, not happy!
« on: July 10, 2008, 08:06:34 am »
George you should remember my call.  I had the same problem this year with the same style rings.  The gap opened up 8-10 thousands in 3 races.  My leak rate was at 8% and I was blowing oil bad.  Everything checked out ok but I used a fine honing stone to freshen the motor.  I tried the type hone that George is suggesting and I have went 6 races with no problems.  My leak rate has maintained at 2% with a .005" ring end gap and no oil blowing out.  I believe that the thin rings that Briggs uses is very sensitive to hone quality and grit size.

5
Briggs Flathead / Re: 8hp rod Idea
« on: June 10, 2008, 07:26:52 pm »
Hey the link that is posted list Jere Stahl as a reference.  I worked for him in the late 70's early 80's building headers.

6
Briggs Flathead / Re: carb issues
« on: May 23, 2008, 10:56:25 am »
If the carb was not one with a smaller float needle seat designed for a fuel pump you will have a flooding problem.  If the needle seat and needle are ok and not grooved from use and age then this could be your problem.

7
Briggs Flathead / Re: 12 hp flathead
« on: May 12, 2008, 04:39:37 am »
Got the screws out with out taking the plug out.  Never did that before.  If you don't plan on using it over again, just get a hold of the flap with a pair of pliers and bend it in half.  You should be able to pull it out the breather hole.  I've never tried it that way but it should work.

8
Briggs Flathead / Re: 12 hp flathead
« on: May 11, 2008, 07:18:22 pm »
Its a round plug that is on the end furtherest from the flange that bolts to the block and directly below the aircleaner flange.  It is close to the full diameter of the carb itself.  It is pressed in and will need to be driven in towards the center of the carb.  When it deforms enough you can turn it side ways and remove it with a pair of pliers out the back of the carb.

9
Briggs Flathead / Re: 12 hp flathead
« on: May 11, 2008, 03:34:59 pm »
On a one piece you need to remove the plug on the breather end of the carb.  To do this you need to drive it out like a freeze plug in a car block by driving it towards the choke flap.  With the plug out there are two screws that you remove and the flap will come out and the shaft will go out the side.  The plug will need to be replaced from a rebuild kit because the old one can not be reused.  Also the shaft holes will need to be plugged.

10
Briggs Flathead / Bore size on a 31cu
« on: May 09, 2008, 05:55:24 am »
Does anyone know what the bore diameter is on a 31cu.  I'm at work and don't have a manual handy

Ken


11
Briggs Flathead / Re: LMT question
« on: April 19, 2008, 12:56:07 pm »
Before you put the adjustable needle jet in you need to take the main jet out and drill it to .052".  Its been a few years since I did this but I believe that is the correct size.  If you don't do this the adjustable needle will do you no good because the jet will be more restrictive than the needle will be.

Ken

12
Briggs Flathead / Re: walboro mods
« on: April 07, 2008, 07:58:58 pm »
George You must of had better luck with them than me.  I can't say how many times that I have had problems with new champions.  Changed the plug and the problem went away.  But thats just me. 

13
Briggs Flathead / Re: walboro mods
« on: April 07, 2008, 06:56:17 pm »
If you know the idle circuit is clean and there are no vacuums leaks.  You can try an adjustable  main needle valve, because if your going to race it you should have one anyhow.  Then if that doesn't help.  Then try a larger pilot jet.  You could also try a different carb just to see if it acts the same.  Also try a new plug and make sure the valve clearance is correct.  For what one cost just put a new plug in.  Don't use a champion.  Seen to many problems with them.

14
Briggs Flathead / Re: walboro mods
« on: April 07, 2008, 11:43:20 am »
You should be able to get your motor to idle with the stock setup unless you have a vacuum leak or dirt in the idle ciruit.  I would check for those problems before I modified the carb. 

15
Briggs Flathead / Re: 28ci combustion chamber size
« on: March 23, 2008, 10:40:13 am »
They are around 70cc's

Ken

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