Rejetting the carb ?

[wbilotta]

A neighbor gave me a kart with a briggs 5hp Model#130202 engine. He also gave me a couple of boxes full of spare parts. As usual, I can't leave something stock so I did some research and was amazed at the amount of aftermarket/hotrod parts available.

So yesterday I took the head off and removed some of the metal between the intake/exhaust valves to make it easier for the engine to flow. Now that I've done this can I install a thinner head gasket to bump up the compression ? I'm thinking I've lowered it a bit by removing that metal.

I installed the billet aluminum air filter adapter so I can run an aftermarket filter and now I wondering if I can rejet the carb to flow more fuel ? I would also like to remove the metal in the middle of the carb inlet where the stock air filter retaining bolt threads into. This would allow for better airflow but I'm guessing this will affect the choke. Has anyone done this and if so did you have any problems ?

 

[beau5278]

We used to build stock appearing engines back in the early days of karting,on a stock appearing carb we would take the choke out and cut it so it was just a stub to block the hole,then take that piece out that your refering to and mix up some PC7 epoxy and epoxy that whole area,if you mix just a drop or 2 of oil in it,you can get the epoxy real nice and smooth but you want to blend that whole area into a nice gentle radius,try not use so much epoxy that it cuts down the air flow.You can also take a screwdriver and take out the metal that's in between the metering holes behind the jet,after you've done that,then you can play with jet sizes to see what works best.With the choke out of the carb,you need to run a soft filter so you can close off the carb with your hand to choke it,either that or carry a short piece of soft tubing and low a puff of air into the vent on your fuel cap to prime the carb.As far as the head goes,they make aftermarket gaskets that are about half as thick as stock briggs but you can also,either mill the head flat or find a 4hp head that is flat and put that on.