Honda Express pocket bike chamber mod

Ive had My 1980 express for 14 years and the motor was pretty beat never got to ride it untill I found a 77 motor on ebay for not too much money a couple weeks ago. found the stock pipe sucked arse, I had a spare pipe so I decided to try a pocket bike chamber on the header. I had the pocket bike running with the pipe and it never sounded right so made sure to check if the header pipe on the PB chamber was extended in to the cone. It was by 2". I cut the pipe out took the 2" off rewelded and the PB header pipe fits over Express header pipe perfectly!!!. Pocket bike chambers are easy and cheap to get but you may have to remedy what I had to in order for it to be effective.

My welder is really starting to pay off now :-)


Re: Honda Express pocket bike chamber mod

here it is running :-)

Re: Honda Express pocket bike chamber mod

Jerry Graham /

Did you gain anything with the expansion chamber, any other mod's ?

Re: Honda Express pocket bike chamber mod

only thing i see wrong is you need to make a longer support bracket to help support the chamber. all your supporting is the header.

Re: Honda Express pocket bike chamber mod

Is it not mounted at the rear fender mount also?

Re: Honda Express pocket bike chamber mod

One trick to do on the cag pipes is cutting the center of the belly, and adding a 3 inch long section of pipe (is it 3 in diameter? I forget)

That will really give you some more low& mid range oomph out of that pipe.

Now it's really only good for top end, but with a lengthened belly, kaboom!

Then play with header length to really tune it in.

Chopping pipes and putting them back together is a fantastic way to learn how tuned pipes work, and what each variable does.

Just be sure to check your plug to see if you need to upjet dummy...

Re: Honda Express pocket bike chamber mod

Its running rich as can be right now. Did plug chop as soon as pipe was installed. It rocks the top end. Yes it has a rear fender mount tab just like the stock pipe did.

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