ATC 250R, can't keep it on idle.

[HamadUP]

I have a Honda 250R three wheeler which I got a few weeks ago, I just managed to start it but I just cannot keep it on idle by its on, I need to keep blipping the gas all the time, and as soon as I left it off the rpm would drop so much that it will eventually die. I tried to increase the idle using the cable adjuster on both the handle bar and the carb cap but it seems that would increase the idle for a short time but it will still eventually die. I managed to keep it idling (but still on a low idle rpm) when ever I pull up the choke, but as soon as I push it in the rpm would drop and die. here is a pic of the carb, is there something that I'm missing?!

[350for350]

Just a suggestion. It will idle only with choke on. That means it's running too lean. I'd try cleaning the pilot jet. It could be partly or completely plugged. If that doesn't help, it may be too small and you will have to go up in size.

[Craigolsen18]

If you have a idle air screw I would look in your service manual and make sure you have it the right amount of turns out. Also check for any obvious vacuum leaks or fuel restrictions.

[onformula1]

I have a Honda 250R three wheeler which I got a few weeks ago, I just managed to start it but I just cannot keep it on idle by its on, I need to keep blipping the gas all the time, and as soon as I left it off the rpm would drop so much that it will eventually die. I tried to increase the idle using the cable adjuster on both the handle bar and the carb cap but it seems that would increase the idle for a short time but it will still eventually die. I managed to keep it idling (but still on a low idle rpm) when ever I pull up the choke, but as soon as I push it in the rpm would drop and die. here is a pic of the carb, is there something that I'm missing?!

You do not adjust the idle by the throttle cable on the cap or on the throttle.

You adjust it by turning the ""Choke knob" there are markings on the carb below the knob to help.


It will idle with the choke off unless you have another problem.

[HamadUP]

These are the steps that I took so far :

1- fresh gas mixed with 1:35 with 2-stroke oil (Yamalube).
2- fresh new BR9ES plug.
3- Removed the carb and cleaned it VERY well, the piot jet lookes it was a little dirty, cleaned it real well (its a 65 jet).
4- cleaned the air filter.
5- cleaned the muffler.
6- checked the reed valve, it was OK and looked new to me.
7- made a compression test, it was right at 180 PSI.
8- the small set screw (to the right of the fuel in let) was set at 3.5 turns from total seat, I'm not sure what that screw does, what is it used for???
9- The choke idle was set two turns from total seat.

After all that I still got the same symbtom!! it will idle as loong as I maintain blipping the gas, it will die as soon as I stop. It will idle much worst with the choke off.

What shall I do next?? I'm starting to loose my nerves!!

[yaegerb]

Step 8 above is your air screw. That should be between 1-2 turns out. Also, have you checked for air leaks by spraying carb cleaner around carb boot joints and gaskets? If you have an air leak the bike will immediately die.

[HamadUP]

I tried to spray around the carb to cylinder boot and there seems no leaks in that area. A friend mentioned that a 65 pilot jet is too much and that maybe the reason of the bad idle and the plug fouling.

[yaegerb]

In 85 the slow jet was a 52 and in 86 the slow jet was a 42. I assume you have a a stock carb, and assume you have an 85 (by the color of your cylinder in the above picture). Regardless, I can say with 100% confidence the reason your air screw is out 3.5 turns is because you are compensating for the huge pilot you have in your carb. I would get the proper pilot (if 1985, then 52), adjust your airscrew (no more than 2 turns out) and go from there.

[HamadUP]

I finally managed to fix all my problems!
As you may have noticed, this is a '85 model with a '86 carb, so I just bought a used '85 carb from ebay along with a rebuild kit and all the factory standard jets, I rebuild the carb back to EXACTLY the factory setting mentioned in the service manual and put it in the trike, I was so happy to hear it running from the 3rd kick after about 6 months! the choke is working and it idles great, I took it out around the neighbourhood for a quick test and boy how fast and responsive it was!

Thanks to all for all the helpful tips, I really learned a lot from this site.