Hello,
A shot in the dark, but I'm wondering if anyone has a pdf manual for this jr. ATV I just bought used. I'm looking to clean the carburetor and it would be great to know the specs.

Thanks,
Tom

 

Hey, use the jets in the carb as a base line. Start from there. That is if the manufacturer has not ground off the screwheads to the bowl. They also like plugging the A/F adjustment too. Tuning a carb is a process. Only do one jet at a time. Slow/pilot jet first :0 to 1/8 on the throttle. Next is the needle jet; 1/4 to 1/2 throttle, basic needle adjustments are done by raising or lowering the clip position . Higher the clip leaner the fuel, lower the clip richer the fuel. The clip sets the depth of the needle in the emulsifier tube. The main jet is last on most carbs, 1/2 to WOT. I would recommend looking up how to jet carbs online. I am just giving you the basic starting points and everyone has their own methods. Good luck I hope I helped .

 

Cleaning carbs does not involve changing or adjusting anything. You take the jets out, clean them, the holes they came from and the float bowl, out, with compressed air, check jets are clear, and put them back. If the engine is a Honda cub clone, it will almost certainly have a Honda cub clone carb, so any instructions for cleaning will be the same as for a Honda. As the previous post says, some Chinese carbs have tamper proof float bowls, that you need to drill the heads off to get into the float bowl. Unless you have just moved the bike to a very high altitude, you should not need to alter air/fuel mixture screw, so that can stay sealed off.

 

I appreciate the responses, guys.

I have already done a bunch of reading and watching how-to videos for carb cleaning and I took a stab at doing a full cleaning.

I took some photos along the way, but like an idiot forgot to snap pics of carb fully opened up exhibiting all the jet positions. Here are some photos of the machine and carburetor,
https://photos.app.goo.gl/jp95XNtA7NS1g4BPA

Inside there was a pilot jet and main jet *i think*. I noticed that they were fully screwed in so after cleaning I did the same thing. This is where the manual would come in handy. The carb was not gummed up that bad so after cleaning I wasn't surprised that the machine showed little improvement. However, it ran well after getting started. Starting the machine has always required several attempts where it starts and then putters out. It takes some convincing.

Recently however, I haven't been able to get the machine started up at all. It will turn over once or twice, but then nothing. I checked the spark plugs and there's definitely spark. So, I'm thinking either something is plugging a jet now or else it's something beyond my knowledge.

I'll probably open the carb once more to see if any dirt got in. After that, it may be necessary to take it in to a shop.

Any other suggestions of probable cause would be appreciated.
Regards,
Tom

#2 in this photo is the Air/Fuel adjustment screw, I believe. I haven't played around with it much.

1. I believe is the idle set screw 2. I'm assuming is the Air/Fuel ratio screw

 

We have a Honda 90 which has always been a swine to start cold. Finally had the time to check the carb properly and found the choke butterfly isn't attached to that lever on the outside, it is attached to a spring which is attached to the lever, under the round plastic cover, except ours wasn't, it would partly close the butterfly when you put it on choke. Some bikes need choke for a cold start, even in hot weather, and this bike is one of them. Once the spring was attached properly the bike starts much better.