Dirtbike won't run without choke on. Carb Cleaner?
 

My brother in law is complete dub. He was given a new crf 150r a couple of years ago for his birthday. he rode it a couple of weeks, and then put it away to never ride it again.

Occasionally when i was at my inlaws i would take it for a spin, but only after 1000 kicks, starting fluid, and having to leave the choke on.

Now, he owes me a bunch of money for paying his fines so didnt go to jail, and i am taking possession of the dirtbike since it his only asset, and selling it to make sure i get my money back.

One of my friends told me it is likely blockage in the carb. I was just wondering the proper procedure of using carb cleaner on a dirt bike. And if anyone has any other advice.
I would like to avoid taking the carb off if possible.

thanks guys.

Re: Dirtbike won't run without choke on. Carb Cleaner?
 

To do the bare minimum I think you would have to take the carb off to hit all of it right with some carb cleaner. It takes time to do it right.

Re: Dirtbike won't run without choke on. Carb Cleaner?
 

Should i avoid using an air compressor to blow it out for any reason?

(incase it isn't obvious, my experience with carbs is minimum).

Re: Dirtbike won't run without choke on. Carb Cleaner?
 

Find out what type of carb it is first then go from there. I would clean the choke cable first and see if it runs normal after that.

Re: Dirtbike won't run without choke on. Carb Cleaner?
 

:thumbup:
ty

Re: Dirtbike won't run without choke on. Carb Cleaner?
 

If it's been sitting with fuel in it, then you will need to pull the carb and clean it. Also you will want to drain the tank and flush fresh fuel through it.

It's one carb, if you can handle a wrench you can easily do a quick clean and get it running. It's really not hard, it should take you 30mins and a $3 can of carb cleaner from Autozone. It will get it running, you also will want to clean the spark plug, or replace it.

You only need a phillips head screw driver and a flat head screw driver.

Here's a link that should guide you through the entire process:
http://dirtbike.off-road.com/dirtbik....jsp?id=413750

Re: Dirtbike won't run without choke on. Carb Cleaner?
 

Sounds like you've either got an air leak, a clogged main jet, or a leaky needle valve.

According to this pic you've only really got two places to leak.
http://www.bikebandit.com/houseofmot...m2256sch304257
1) The o-ring between the carb and the head.
2) The o-ring where the top cap screws onto the top of the carb.

A quick test for this is to soak the two potential leak areas with WD-40. This will temporarily seal any tiny leaks, allowing you to start the bike more easily and let it run without the choke (which is actually a fuel enrichment on this bike, not a choke). If that works, replace the two o-rings and you're back in business. If not, you'll need to go inside.

If it were my bike I would remove the carb and clean it out. Don't settle to just squirt it with carb cleaner. Get a can of paint brush cleaner or a can of carb dip. Take the entire carb apart and soak everything for a few hours. This will dissolve all of the varnish, scale, old fuel, and any other crap in there. Take a tiny piece of wire and poke it through the main jet and any other orifices you can see. After that, blow backwards (from the bowl) through any other passages with compressed air to dislodge anything that might be in them. Put everything back together with a new carb kit and you'll be back in business. A new carb kit will only set you back about $12 from ebay. They usually come with parts to build a few different carb models, so be careful to pull the right parts out of your kit. The last ones I built came with three types of air screws, four main jets, two pilots, etc. All of the parts have their size etched on the side, so just make sure to keep track of what size you take out so you'll know what size to put back.

During disassembly be very careful with the needle valve assembly. They usually have a delicate felt washer between the needle seat (the part that looks like a hollow bolt) and the carb body. If you break the washer it will leak onto the ground forever.

The worst case is that you have a burned valve. This will cause low cylinder pressure, which can require the use of starter fluid when starting. Check the compression to see if this is the case.

Good luck. If you have any carb questions feel free to e-mail me.

Re: Dirtbike won't run without choke on. Carb Cleaner?
 

As others reccomended, take the carb all apart and clean it thoroughly...

If the bike just wont idle without choke, the first thing to check is for a clogged pilot jet. If you clean nothing else when you mess with the carb make sure to clean out the orafices for the pilot and main jet...

Re: Dirtbike won't run without choke on. Carb Cleaner?
 

ABSOLUTELY, in fact, I have had this problem more than once over the years with my fathers' and brothers ATV's (which I hate :P) and i would say that a good 80% of the time it is either the pilot and/or main jet. Good advice. I would also like to say that when the carb is taken apart , change the gasket which seals the float bowl to the carb main body , if the bike is 5 years old or more. This has been a culprit as well. Whenever I open a carb I usually change that immediately even if it "looks ok".

Re: Dirtbike won't run without choke on. Carb Cleaner?
 

Also, to PREVENT this from happening again, use a good fuel stabilizer like "Pri-G" and put that in every single gas container you use for your bike/s. On top of that, RUN the bike with the fuel valve in the *OFF* position when you are about to put the bike away, and let the bike stall. This means that there is no more fuel in carb and therefore no way for the jets to get clogged from the fuel residue/s. I have a 1985 Honda XR 600R which I have had since it was brand new and I never had to remove the carbs EVER.......and thats because i follow this practice :)