can i get away w/ this

i have a 58 jet w/ a biturbo and id like to know if i put a 65cc kit can i get away w/ out upjetiing and will i get more power from upjetting

Re: can i get away w/ this

no

Re: can i get away w/ this

ou can restrict the carb to hell to choke it up but that would be pointless in getting a kit.

Re: can i get away w/ this

will it be useless to by a kit w/o upjetting

Re: can i get away w/ this

Jets are cheap. Buy a kit and buy some jets. End of problem.

Re: can i get away w/ this

You're increasing displacement by 40% or so.. This is not a trivial thing. This is not like overboring a cylinder a few thou..

In essence you're building a whole new engine. Would the manufacturers have used your carburetor with your mainjet on a 70cc engine? No way in hell is my guess.

If maximum power is really the goal, jetting changes alone couldn't be enough... another carb, a different pipe, gearing and ignition upgrades, etc. would almost certainly be called for.

but if all you want to do is enjoy a little more power while assuring the engine has adequate fuel to avoid running too lean, that carb and a larger jet may be all that's required.

Wait till you get the kit installed. Get everything set up as best you can with the limited information available.. and then do some analysis which must include plug chops. If a plug shows definite signs of a lean mix / overheating while all other tuning parameters are apparently correct, jet upwards.

can i get away w/ this

30 years ago I was into high performance my moped and the best carburetor to use then was an chain saw carb , ok it takes a lot of hours and some drilling to have the engine vacuum connected to the carb . but this are the ultimate solution on an difficult problem . but you kids today belve its just to buy an cylinder and change to have 50 mph , but it aint that easy . the last cylinder I tuned up was an yamaha dt 50 mx that I was preparing for my son to his 15th birthday, here in Sweden an moped aint allowed to do more than approximately 19 mph ( 30 km / h ) and max 1 HP .

without to change any vital measurements I had it to do over 45 mph , I still used the original cylinder and carburetor ( 12 mm ) and original intake ( 10 mm ) and of course no changing in final gear . this was an street legal moped ;-))

now you gonna tell me that this is impossible , but it aint . if you only use your common sense instead of your parents money to buy illegal cylinders and stuff . I can tell you a little of what I did to the yamaha , I took the carburetor and put it up in the lathe and made it conical , from 16 mm in the outer end to 12 mm in the inner end . then you have the inlet between carb and cyl , same there I made it conical from 12 to 10 mm . its still legal ;-)) 12 mm carb and 10 mm inlet .but the cylinder was in an very bad shape, the casting was of an miserable quality and I used over 8 hours with an tiny ingersoll and rand grinder to shape up channels and exhaust port , all angles and radius allover , but I didnt enlarge anything but just very very small fine tuning and when I was ready I sandblaster the cylinder all over , both out and inside . then I re bored it to 42 mm in the milling machine and bought an new piston .

now you now what to do to have an +45mph moped

if we will start change parts and measurement in an dt 50 mx there are no problem at all to have an top speed for + 80 mph . okay its difficult and it will take weeks to build .

Re: can i get away w/ this

hey thats cool! doing an overbore. essentially you are turning your moped stock cylinder into a performance cylinder. but you didnt enlarge the ports at all? this is what people like smitty do for a living. i wonder what he would say about your methods

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