Got the Yz 60 now I need a little help :D

[jor2daje]

Ok so I picked up the bike today, looks way better than I expected. I managed to start it a couple times but it was tricky and as soon as I touched the throttle it would die. I took the carb off and cleaned it pretty well with carb cleaner, although it didnt seem to dirty. The guy I got it from thinks it needs a new needle. What do you guys think could be causing this?

Here are some pictures, I could also use a little help with set up of the carb.

Im not sure where this clear tube should go, I thought it was a overflow thing but there already one on the bottom of the carb.

what does the flat head brass screw on this side adjust?

Thanks in advance for the help guys, cant wait to ride this thing.

 

[Kaptain Krunch]

Not sure where that hose goes, looks almost like the fitting for synching carbs on a twin carb engine. Try putting your finger over the end and see if it idles different (lower). You could also spray some pb blaster or wd40 through the hose and see where it comes out in the carb. If it shoots right into the bore, then block it off, if it goes into the bowl, leave it.

That little brass screw is air mixture, should be 1 1/2" turns from lightly seated to start.

 

[jor2daje]

Ok thanks kaptain, it goes into the bowl so i guess ill just leave it for now.

I set the air mixture like you said and adjusted the fuel but now I cant get it to start at all even when I went back to how it was, what are good baseline setting for fuel and air?

Thanks again

 

[jor2daje]

Well Ive got it running pretty good now, and I found out what the tube is. While running with the tube not connected I would start to lose power at about 3/4 throttle. So I looked up tuning and found this great article http://www.scribd.com/doc/9726341/Two-Stroke-Proformance-Tuning In it I found that yamahas from 76' onward used a mikuni powerjet carb. This type of carb uses a tube in the intake that leans out the mixture when the intake air speed gets high.