Boost bottle questions?

Can somebody tell me what is boost bottle…
what are the advanteges, is it for modified engines or can it be used on a standard px200…


I have already changed the float needle together with all gaskets…checked the float, nuts but no change. I’m not running rich either…

Is there anything else I should look for??


it’s a standard px200 dylan…I will take some pictures in a week and post it here so that maybe you can tell me if it’s normal or not…

thanks for showing interest,

Is the rubber bung at the back of the carb box in place? (the one that covers the mixture screw).

If you take the cover off the carb box then take the filter off (2 screws - not the idle one) you should be able to see where the petrol is coming from. Try wiping your finger on it because it can be hard to see. Try around where the fuel line joins the carb. If it’s not there make sure that the two screws that hold the carb top on are tight and that it’s not coming out there. If it’s not either if those two then it must be coming out of the overflow at the bottom of the carb meaning that you still have a float/float needle problem. If the float is sticking in the float bowl you will get this problem too because it is not shutting the fuel off when the bowl is full but then you would probably find that the bike was starving of fuel too.



Your mechanic is a bodge artist of the highest order…even I wouldn’t suggest drilling a hole in the carb box!! Sort the problem out rather than attacking the symptoms. As Dylan said, probably the float needle.


hi dylan,

here is a picture of the gas & oil mix leak…it doesn’t seem normal wright?? all the seals seems to be ok…can it be the plastic seal around the mix adjuster screw that leaks??..


turn you fuel off, open up the carb take the filter out is there excess fuel in the carb if there is clean it out so its dry,turn your fuel back on if there is excess fuel running out the back of your carb then youll need to replace the little round seal at the underneath of the carb. be carefull when you relocate the carb after replacing the little round seal, if its not seating right youll have the same problem as before so allways check by turning the fuel on and off.
Mind you i might be wrong. [:(] i ain`t no expert yet.

thanks a lot dirk for the detailed information you give…I will check the parts you mention…



I have some excessive gas&oil leak from my carb. to the engine block. I think that’s the mix flowing back into the carb. I have changed all the gaskets and float needle but no change… I thought maybe using a boost bottle might help…

also on some bikes I see a hose coming from the carb to the back of the engine block ( as in Stian’s bike at the sip’s catalog on page 69) . What is this? is it from the boost bottle or is this a solution for the mix leaking from the carb…my mechanic advised me to make a hole to the carb case and put a hose so that the excessive mix will flow to the ground not the engine block…what do you say??