Jinlun JL50QT-4 (i wanna go faster)

[ronaldihino1]

I dont really know much about mopeds but i was wondering how i can get my Jinlun JL50QT-4 to go faster. At the moment its going around 25mph and slightly over on the flat. Uphill about 20mph, and downhill i can get it going off the clock (50mph+). I've had a look at the carb lid and there was no brass screw there but the plastic that would of held the screw was partly snapped.
I've heard all this stuff about lighter rollers and etc.. but wasn't sure what weights are the best ones to get. Also, i have a small problem with the throttle. When I open up the throttle fully the moped seems to lose power quite a bit and then pick up again and then lose power again etc.. What the hell's going wrong??? I'm not sure if when I fell of it affected it or not coz I had to order a new throttle handle as the other 1 was pretty badly damaged. If anyone could give me answers that would be gr8. Cheers

[ronaldihino1]

I forgot 2 include dis with the last post. Is upjetting the carb a worthwhile try aswell or not really? If so, how much bigger should the main jet be from the standard one?

[baotian]

ok i also get the loss of power when i pull the throtle back whilst moving, but only for a second and then its ok, i have just this hour changed the standerd rollers (6.5g) to 4g ones and the aceleration is grately improved but top speed you probly wont see any difrence.

i would make sure that under your carb lid, make sure the black rubber seal is sealed and no air is getting in, also make sure none of the air pipes are kinked.

before doing all that is the bike deristricted, if not get that done first and that should sort the speed out.
but if your getting 50mph plus going down hill then you must have done somethign to it

[cb50j]

I get 45 on the flat, off the clock down the right hill, standard rollers on mine were 8.5g........using 4.7s now........speeds are pretty much the same with far better acceleration......... #sprint#

[ronaldihino1]

so basically i shud get 4 gram rollers, that will improve accerleration rite. i've been on the beedspeed site, shud i get standard 4g rollers or the mallossi ones??? i'm gonna go out in a bit and make sure the air pipes aren't kinked and to make sure the rubber seal on the carb is properly sealed. Can i fit the rollers without having to buy an impact wrench?

[cif]

i've got the same throttle problem, open the throttle up and she dies, then picks up and dies again, so on,

I changed the carb, jets, air pipes, plug, changed settings, It's still the same, I'm at my wits end with this bike.

[cb50j]

1st thing I tried was changing the circlip on the needle to the bottom notch, with a bit of adjustment on the fuel/air mix screw I've had no problems........I'm now using a freeflow filter with the excess hoses just kept out the way it feels more powerful

.................. #sprint#

[Macrofeet]

you might try changing the fuel valve

i did this on mine today they get damaged quite easy apparently

i also changed the carb

i havent tryed my bike out yet for a long distance but i'm hoping it will bet better

[Macrofeet]

i've also orderd a freeflow filter as i think the airbox has issues i have the qt9 btw

Heres some things to try and check

Clean the carb replace the jet with an 88
Change the fuel filter
Set the mixture screw to 1 1/2
Cut all the pipes as short as they will go without being stressed fuel pipe air pipes etc check they are not kinked or blocked
make sure the spark plug gap is correct with a feeler gauge try diffrent clip settings on the carb pin
make sure the mesh on the carb is not broken
check the oil lvl replace after 300km if you have not allready
make sure the breaks are not to tight

[Macrofeet]

Replace the rollers with between 4.7 - 6g for better revs

Replace or test the coil and spark plug if you are still having problems

this is in reply to cif btw

[hypojam]

If you set the fuel mixture screw to 1 - 1/2 turns out from in the bike will burn stupidly rich

Even at 2 turns outs from in my bike was burning rich, 2&half turns out from in is the best from my experience

[Macrofeet]

typeo i ment it as one and a half turns