Zongshen 155z ho big problem

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could be right there m8,really guts me as i didnt really want to buy it,but the seller said he will look after me,but sort of over it now.I did try a 100 main and changing jets didnt make it change at all,same result ova and ova.
 
try get it to a pitbike shop mate, it should be something simple, just a pain to spend coin on a new donk, but sounds like you need a win of some sort with it.
 
If its a bent valve its a cheap and easy fix.
Does the bike run at all???
It could be as simple as a tuning issue. We need more info if you want help to sort it out.
 
DHZ_XR8cing said:
If its a bent valve its a cheap and easy fix.
Does the bike run at all???
It could be as simple as a tuning issue. We need more info if you want help to sort it out.
Click to expand...

Read my 1st post mate
 
DHZ_XR8cing said:
Your's would throw a mist of fuel back because 102 on a stock engine is way to big.

Try a 98 and see what it does.
If it still does it then you know its not a jetting issue.
Is the OKO a proper one or a copy??
Click to expand...

Ahhh okay hmmm well....

Fuel misting :

Intake reversion "fuel standoff" is not so much an indication of jetting..

A perfectly tuned motor can have this regardless of jetting.

Intake tract length / harmonics

Cam timing (overlap) etc..

Both my bikes do it with two completely different carb settings ... ones a 155z and the other is the updated 160ho

Ive come across this in many many motors of all sorts


Im 100% sure there running perfect ..


Big jetting Does sound like a legit reason and i value your input but in my case its defiantly not it .....
 
Last edited:
nickv1980 said:
Ahhh okay hmmm well....

Fuel misting :

Intake reversion "fuel standoff" is not so much an indication of jetting..

A perfectly tuned motor can have this regardless of jetting.

Intake tract length / harmonics

Cam timing (overlap) etc..

Both my bikes do it with two completely different carb settings ... ones a 155z and the other is the updated 160ho

Ive come across this in many many motors of all sorts


Im 100% sure there running perfect ..


Big jetting Does sound like a legit reason and i value your input but in my case its defiantly not it .....
Click to expand...

I guess a fuel mist would be quiet common but I have not come accross it as yet on my engines. Not that I have noticed. On saying that this bloke's problem is fuel spitting so I take it thats a fair bit more than just a mist.
I'm not saying it is a jetting issue but its a easy thing to rule out.
If there bike is running perfect with plenty of power through the rev range with no flat spots or bogging then I cant see a problem really. Unless its spitting heaps of fuel out.
Are all the nanifold ports and gaskets lining up? There is so many things it could be and without seeing it it's just a guessing game.

I would like to hear if anyone else runs a 100-102 on a stock engine.
 
i run a 105 main 45 pilot on a 26mm oko yx160 runs fine, whack the 188 kit on and still runs fine, thought about your float? iv had this happen where it dribbles out the air cleaner side of the carb and the air filter becomes all wet, maybe take a video of the bike running without the air filter so we can see whats happening?
 
^^^^ good point, could be overflow mate or even the fuel sealer is damaged or even missing :

media.nl


As for the stock engine, I ran a 102, 36 no problems! - on OKO 26mm
 
good point but if it was damaged wouldnt it come out of the overflow instead? i have tryed the molkt 26mm and oko 26mm and mikuni 30mm,all brandnew carbys,and all do the same thing.....? the oko 26mm runs fine on my yx150 so that tells me the float level and carb are fine,run a 100 and 38 pilot for that test
 
id be checking for slight intake valve bend... apart from that there couldn't be too much more..
you've covered all other bases..

and a 102 in an oko on a stock 160/155 is fine up here... but please remember everyone's climates are different so it too changes a tune...
 
would a real mikuni 24mm carb from Braaap work on this engine?
 
with your oil leak,
are the 2x o rings for the stator plate bolts/screws fitted behind the plate?
 
i had the same proplem and it was the cam chain that was slack so it was putting out of timing
 
well got a new engine and same again???????starting to wonder if these engines a luck of a draw
 
DHZ_XR8cing said:
I would say its something your not doing right or one of the parts your bolting on it.
Click to expand...

I agree with DHZ_XR8cing its very un-likely 2 dud engines ......

Ive got to 160ho's one from brand new and the other was a second hand one and both throw a little mist of fuel backwards but nothing that concernes me at all the filter catches it anyway they both run excellent ....
 
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