4 stroking on take off WTF?

no matter what jet I have in it seems to 4 stroke on the take off.

Here is my setup.

za50 magnum

70cc k-star

15:15 sha

78 jet

tecno bullet exhaust

hi comp 50cc head

could this be some kind of airleak?

Re: 4 stroking on take off WTF?

How could an airleak cause 4 stroking?? I'm no puch expert but to me a 15.15 is pretty small for 70cc, and a 78 jet is pretty big for a 15mm carb.

Re: 4 stroking on take off WTF?

I know other people are running this setup.

Re: 4 stroking on take off WTF?

15 is fine with a 70cc. Lots of people are running 15's on 70cc's. I would say you might need to advance your timing... That's my first guess as long as it's all good. How does the mid range and top work out with this main jet?

Re: 4 stroking on take off WTF?

down jet or lean out your idle mixture or you have more air at take off but still plenty of gas at WOT

4 stroking on take off WTF?

I 'll argue that comment about the 78 being too small. Not too familiar with the kstar's or sha's, but temporarily ran an 84 on a 14mm bing with stock airbox on a 64cc polini. Maybe reedvalve engines need more gas?

Does the carb have a neddle with different settings? Lower it if possible. However, a 19mm carb would work much better with that set-up.

Re: 4 stroking on take off WTF?

timing is advanced all of the way. Plug chop shows I am running rich. I went to a smaller jet and it still four strokes at take off. but the midrange and topend are fine. Also I am at sea level.

Re: 4 stroking on take off WTF?

🇮🇹💦 Of the Loin /

ok, go to a smaller jet then.

Re: 4 stroking on take off WTF?

leaky carb? fuel leak that is...if fuel is getting past the jet at partial throttle it would four stroke, and not be so noticeable at full throttle. just a shot in the dark.

Re: 4 stroking on take off WTF?

my old bing I could adjust the needle. but this carb I can't

Re: 4 stroking on take off WTF?

Sounds like you are too rich. If you are rich at take off (i.e. low RPMs) then you are probably rich at the top also. Generally it is easier to feel the bike being rich at lower RPMs. Since you plug chop told you are rich, then you are rich and need to down jet.

Re: 4 stroking on take off WTF?

) Cupermcnewbster ( /

for sha's you can't get the best of both world. You either need to jet for low/midrange or top end.

Re: 4 stroking on take off WTF?

roadent$ craig /

i had this exact problem, its an electrical issue.. points are most likely arching... i wouldnt go riding too far or youll be pedaling home like i did last night.

Re: 4 stroking on take off WTF?

the come with a 68 jet in them stock... That isn't too big for that carb.

Re: 4 stroking on take off WTF?

Here is my setup

Puch Maxi

E-50

70cc airsal kit

70cc HC Head from Treatshq

Dell SHA 16.16

82 main jet

Proma GP

Kit and Pipe only have 120 miles on them. as well as head.

I had air leaks and i put new better gaskets on and it has helped some. There is a airleak in top of SHA because i broke one of the screws off in i and so i only have 1 side bolted down and the other ducktaped. It seems tight, but i kknow it's leaking , gotta be.

I was having a hell of a time getting it to idle. Someoen told me that if i didnt have jetting right, i wouldnt be able to idle in the first place. So after checking for leaks 3 times over and getting as many out as i possibly could, i upjetted and messed with idle mixture a tad bit as well as adjust throttle tension cable a bit, nwo i get a very idle , better than it was stock and doesnt engage clutch.

However I also notice i 4 stroke on take off if i give it too much gas. Just at teh very very beginning though if I WOT it. Once i hit low mid/ mid range i take off and once i hit 30, 30-45 is very very nice but then i top out with my 14x45 gearing. I think it's just the SHA carb sucking. It seems to have better take off when the engine is cold lol, then when it's hot. Well it doesnt seem like it does, it does actually. Heard of my friends 80cc dirt bike doin the same thing.

Re: 4 stroking on take off WTF?

🇮🇹💦 Of the Loin /

if it is better when its cold then you are too rich. downjet.

Re: 4 stroking on take off WTF?

yea gil that is what it is doing.

Re: 4 stroking on take off WTF?

sha carbs = sucky poo poo

Re: 4 stroking on take off WTF?

btw ILIA,

bings jets do not have the same numbering system as dellortos.

example: 82 Bing Jet doesn't equal 82 jet in Dellorto.

Re: 4 stroking on take off WTF?

I think I am going to invest in a new carb. so should I go for the 19 or 21 dell. ?

Re: 4 stroking on take off WTF?

21 will be a bit harder to tune and possibly overkill.

19 phbg IMO.

Re: 4 stroking on take off WTF?

yea I'm going to order a 19

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