New yx160 Molkt carb idle issues

[Darkreign]

Hey guys ive been doing alot of reading about these terrible jetted molkt carbies some bikes come with. my new atomik nitrous mid size yx160 came with one and from first go its idled really rough, rev hunting, boggy on take off till u get over 1/4 throttle and it opens up and then the bike shoots off like a rocket. my mate and i have tried changing the mixture screw and setting the idle screw but nothing seems to help. we leaned it out a bit and it slightly helped but still far from how anyone would want to ride it. im wondering if its worth me looking into fixing these carby issues or just pissing it off and grabbing a mikuni carby kit to replace it.

If i should get rid of it is 26mm the best size for a yx160 or should i go bigger. i know when i get a new carb it wont be pre tuned but we can change what we need to. i personally know almost nothing about carbs and have no idea how to change jet sizes and stuff like that. what would be the easiest way for me to get this bike purring?

heres a video i uploaded to show how its idling rough. have a good listen, i can hear it pretty well so id assume most people can.

New Atomik nitrous mid size yx160 Carb Issues - YouTube

Thanks in advance guys

 

[Darkreign]

Well i ended up just going and buying a mikuni 30mm carby. $68 not a big deal

 

[timeeh]

Should of got an OKO.... Those carbys a ****e....

 

[Darkreign]

even after putting the new mikuni on the idle is still rough but its no longer boggy before 1/4 throttle. being this is a brand new motor im gonna run it in next weekend when i go out riding and see if it improves once its run in. if not then change the carby needle position and then if not i have no idea whats going on

 

[DHZ_XR8cing]

have you done your valve clearances??

 

[my67xr]

have you done your valve clearances??

+1, definately adjust them...

 

[Darkreign]

sorry i dont know much about that. i have an idea what it requires im looking at a youtube video. so if valve clearances arent correct would that cause a rough idle? also how do i know what the clearances should be on this motor?

 

[Darkreign]

oh also since i changed the carb i had it spit back thru the carb twice and now without choke its dying

 

[DHZ_XR8cing]

I would say the inlet valve has zero clearance. You need to get some feeler gauges that have .003 and .004.

 

[Darkreign]

changed the carby needle position but it didnt improve. feel like i should just take it to a bike mechanic and get them to sort it out. such a pain in the ass. my pit pro ran perfect out the box so to be in this situation i feel disappointed. could anyone estimate how much something like this to sort out would cost at a mechanic?

 

[DHZ_XR8cing]

Have you checked your valves??

 

[Darkreign]

nah not yet. i havent got any feeler gauges. ill grab a set tomorrow, and today i jumped straight onto the carby cos with the original carb it seemed like it had a vacuum leak like the carb wasnt sealed to manifold. i was reading through threads at work today and it seemed very similar to something another guy was having and it coulda been unsealed carby to manifold. so anyway yeah after that i put the mikuni back on and tried messing about with needle position but like i said no good. so when u say i need .003 and .004 gauges are they the valve clearances it would need to have? like i said i dont know much about doing valve clearances so itd be something totally new to me and i just dont wanna **** it up

 

[Darkreign]

ok i been watching about doing valve clearances and it doesnt seem that difficult. make sure engine is at tdc on compression stroke by taking off stator cover, take off tappet covers, loosen the inner and outer nuts, insert feeler gauge and tighten the inner nut til it has slight resistance, do up both nuts tight, check again to make sure nothing has moved then do the same on the other valve. do everything up and complete correct?

sorry if i sound like an idiot or totally unsure but thats probably cos i am totally new to this. any more feedback or something i ahve missed would be great


edit* does anyone know what size spanners i need to loosen the inner nut on the yx160?

 

[Darkreign]

ok so update. i checked the intake valve clearance and that was pretty damn close didnt need much but the exhaust valve clearance was pretty off. only problem is one of the bolts that holds the valve cover on was really lose, when i took it out i could see the thread on the head was totally stripped and had the bolt had shavings of alloy all around it. now im getting mad. once i got it back on i can see its leaking oil now so isnt sealing properly due to the thread and on top of that making the adjustments hasnt solved a thing.

is it possible that cos the cover isnt sealing its causing issues?