does my dragster 125 need a fuel pump?

Hey all, I recently built an engine for my dragster, completley standard to give me a feel for working on this type of engine, got it together but its given me trouble since day 1, basically its never seen more than 40-45mph, always used to get to a certain point and then be boggy, i borrowed a number of parts off my typhoon to try and get the draggy running right but never did, the last thing i tried was the variator,

and when i did there was not much difference and the engine cut out whilst riding pretty much when i shut off the throttle felt a bit like a soft seize, it started back up but it was very noisey so i nursed it back to the house and havent touched it since. I havent been too bothered since but i took the head off today and the piston had some black soot on top that i could wipe off fairly easy. would this indicate any odd running issues?

one thing i have overlooked this entire time is a fuel pump, the motor is a runner 125 motor originally but i couldnt find too much info about the dragster having a fuel pump online (and the tap is right above the carb)
would not having a fuel pump cause any of the problems i have been having and more importantly did the bike originally have one?

 

did the runners not have a dual tank.

fuel was pumped from the main tank between the foor footing into a header tank above carb/under seat then gravity took over and fed the carb fuel. ?

may wanna check if that main fuel tank pipe is leading to a secondary header tank , if so its possible you need a fuel pump to keep that header tank charged with gas

 

The Dragster doesn't have a pump it's gravity fed, make sure the petrol tap is working properly, if in dought replace it.

 

yeah the runners have some weird dual tank system, i couldnt find a pump on the donor runner i had though so i assume someone else got it first, didnt think it needed a pump myself thats why i never really bothered, the tap is brand new however it is not a proper italjet one, it came from a peugeot speedfight, which has the same fuel light connector, i was having trouble getting the genuine italjet tap however as italjet uk were being very awkward with me. my buddy reckons the peugeot tap should be the same bore and have the same flow rate as the italjet one and it shouldnt have made a difference,

truth be told im actually buying an air cooled motor for this tomorrow thats been freshly built, the loom aint the best on the bike and i dont really trust the cooling system for this reason, I also dont have a battery which i hear can cause some problems around town if the fan cant kick in hard enough. its a more naked than normal dragster, so will also be nice to be able to take off the water pipes to clean things up a bit

 

Is the auto choke working (getting warm) when running? If running the a/c motor make sure you use all a/c stator/cdi ! I'll take the dragster engine off your hands!!

 

The fuel pump on the 125 runners is under the left hand footboard.
Fuel goes from the tank to the vacuum fed pump, feeds up to the reservoir tank which holds the fuel tap, and then on to the carb.
If you're not using the runner tank it shouldn't be a problem.

 

i remember connecting it up to a battery and it moving a good bit, a lot more than a recommended minimum 2mm i read on some website, but i did always suspect it.

Why do you say to make sure Im running the ac stator and cdi? I have the lc set here and the guy is giving me the choice of ac or lc, ive been very interested in the lc swap though since ive read about it,

have wanted to try it with my typhoon also but havent gotten around to it and would like to find out just how much it needs to be rejetted, and if it can be possible to run with a dellorto/ runner carb and airbox combo instead of the mikuni ac setup

have plans for the motor, gonna go over it carefully making sure nothing is broke and then its going into my typhoon with a disk break and a 172 on top

 

125 runners had the 20.5mm dellorto with a 98 main jet as standard, with the standard airbox, if that helps

 

The L/C stator/flywheel/cdi has a different advance curve, the a/c is fixed and engine will run hotter than the A/C setup. This info is on the site somewhere!

 

i know the thread alright hence my interest in this mod, im definitly gonna try it out with a small upjet once i get this motor in and running but trying to gather some extra info before i commit to the mod.

I have a Jolly Moto for the dragster, which is currently on my typhoon, also interested in seeing how the 2 of these work together.