Yx 160cc issues HELP!!!

[DustyFork]

Hey guys just needin some help with a bike I picked up. I beleive it's a atomik 160cc big foot. My trouble is that when I got the bike it was not running, on further inspection I found it had the stator pick up legs where snapped and was shortig out on the motor. So I got myself an inner rotor kit and installed it no probs. the bike now kicks over and idles ok, but you give it some throttle and it spits and spaters, runs like crap. I cleaned out carby which is 26mm mikuni which was ok and I came with the bike. Ajusted trigger many times with no luck. Plulling my hair out can anyone please help!

 

[Rodney68]

may of damaged the cdi when it was shorting out

 

[DustyFork]

It came with a new HP CFO with the rotor kit which I have wired up correctly

 

[DustyFork]

Sorry ment high performance CDI

 

[Rodney68]

you might need to tune the carby

 

[DustyFork]

I did read a fair bit on running carbs and as I understand it is that in the rev range you should be able to tell what jet to change and by size also checking colour of plug. Being the original carb wouldnt it still run ok even in at least one part of the rev range. It spits and spatters from off to a quater and from half to full.

 

[zwebx]

here ya go, http://www.miniriders.com/carby-tuning/25033-carb-jetting-tuning-dummies.html

also make sure your ignition timing and whatnot is correct, or play with it a bit before you change jets and whatnot (if it is an adjustable cdi)

 

[timeeh]

Another thing to check is that the carby is seated properly and/or that the manifold isn't leaking. Get yourself a spry bottle of some kind i.e WD40 or even a spray bottle of water and while the engine is idiling spray all around the inlet manifold, if the revs decrease/increase by themselves you have a leak somewhere. Fix this and it may just fix your problem, good luck. P.S Deleted the other thread for ya

 

[DustyFork]

Thanks for the tips guys, and thanks for gettin rid of that post for me timeeh. I will check that there is no leak this avo, just had another play with the needle clip with no luck. Seems every adjustment I'm makin don't improve it at all. I'm sure after some time will sort it out. I noticed that today it kicked over and idled fine. On quater it spatted a bit at half it was worse and at full it does. Does any one know ruffly what size jets I should run?

 

[Rodney68]

I have a YX150 with a fake VM26 and i run 20 pilot and 100 to a 102.5 main and the needle 2nd from the bottom. I know you have a 160 but i thought it might get you on the wright path.

 

[DustyFork]

Reset valve gap, tested for leaks-nun, adjusted pick up in irk, checked wiring and earth. Still no better yet! Will do plug test tommoro to see what jets I need. I'm running a 100 on the main and 20 on pilot, needle clip at bottom

 

[timeeh]

Reset valve gap, tested for leaks-nun, adjusted pick up in irk, checked wiring and earth. Still no better yet! Will do plug test tommoro to see what jets I need. I'm running a 100 on the main and 20 on pilot, needle clip at bottom

Hmmm, mate i'd kinda be leaning towards the IRK then, i have read many a dodgy story about them. Might be worth fitting a std one back in if you can get your hands on one, think they'll be pretty cheap too as people are always changing them to a IRK or the lightened daytona/lifan ORK.

 

[DustyFork]

Only got old black Cdi to test with will this work ok with irk?

 

[rotn50]

Some peeps have had them working but im not familiar with the wiring, the irk are dodgey as and you get lucky if they last longer than a day sometimes, id def go back to a std outer rotor kit as they are highly reliable and the std black cdi is also highly reliable.

 

[Westyftw]

I had a similar problem fixed it by taking out my carby adjusting the clip and the needle and then playing with the mixture screw and idle. That might help if not maybe the CDI is the way to go. But i would try adjusting your carby first. Might save you buying a new cdi but if your cdi is screwed theres not much ways around it.

 

[DustyFork]

Ok Xmas over now back to the bike. Changed Cdi and no change. Did a compression test and got 70 psi but the bike had only been warmed up for a minute. Does anyone know what compression reading I should get? Tommoro I will let it idle for 5 mins then do the test. I saw a post that said to put a teaspoon of oil in to see if I up the compression. If it goes up I guess the problem may be rings?? If I get no change this would poin to the valves ?? Am I right or wrong here??????

 

[DHZ_XR8cing]

I wouldn't be surprised if it is the IRK.
Have you tried riding it? If so whats it doing??

 

[DustyFork]

Can't ride it yet as I needs new spaces for the rear rim and I can only select 1st gear which is another problem to fix after I get the engine running right first. Engine is sputtering and splattering on idle to half throttle then dies with a back fire

 

[rotn50]

You need atleast 100psi to get it to continualy run even though a bit crappy, but normal compression is 150PSI even seen some go to 160PSI, when you checked the valves it may have been 180 deg out, i think the yx's have 2 marks opposing each other on the cam sprocket making it a little tricky to know if you are at TDC, you can pull the plug out and get a torch to check if the piston is at the top(180 deg out the piston is at the bottom)If you cant see gently use a screwdriver to feel for the piston. The irk i would get rid of immediatly, if it hasnt already poo'd itself it will when your riding or ready to go for a ride. I would get the outer rotor kit for it as they are highly reliable.

 

[DustyFork]

Rechecked the valve clearances today there are two marks on cam sprocket one with yx writin under it. By memory if you line up the yx mark with the arrow on the head that it tdc. I used the screw driver trick to find this one. At the same time I marked up my irk so I can do some more precise tunning. What is the right way to test compression with analogue gauge? Any I ideas to check my valves are seating without taking off the head?