serviced my carb after just aquiring one , can tell someone was there before , 2 oz of water in the linkage area. my tip for the worn philips was i used vice grips on the head , and the retaining screw on the floats i used a dremel with a cut disk and made a flat head screw. saved the headache
5:32 on time line. I have a real small pair of vice grips. On small screws with a thick head like those I clamp the vice grips on the side of the head of the screw and give it a slight twist to break them loose. There is limited room to ratchet the vice grip so I get as close to one side as possible when I grip it to allow for just a little movement. Works like a champ.
Yeah, now that the timing is working like it should, I get a little stumble when I snap to WOT. I'm considering putting the original carb back on to see if it runs better than this replacement one does. It doesn't take long, so I may just try it out of curiosity.
Fun watching this 👍👍 Got a 87 big bear myself here in sweden. Gotta change that rubber at the rear swing on mine also. Looks like a bit of work.. YOU should defently get a orginal muffler. It can be why its feel tired and doesnt run good. Othervice a valve adjustment/cam shaft worn
Thanks for watching! I'm slowly working on this project as time allows (between other projects) and making some progress. It seems like a good machine (if I can get it to run correctly).
At 28:57 you were talking about the passages, I do not know for sure but I am believing that those are the fuel enrichment circuits for when you snap throttle from idle to WOT! I wish someone would tell me for sure as I have been struggling with my carb starving for fuel at a snap to WOT. Update: that circuit is for choke only.
Did you remove the slide tube receiver frame and the needle receiver tube? If yes did your tube have air holes in the top end of it? Mixture screws... behind vertical center line of carb, air box side, are air adjusting screws. In front/engine side of center line are fuel mixture screws.
I'm not even sure what that is, to be honest. I ended up getting a cheap replacement carb and putting it on the bike - which changed basically nothing. CDI box is the next thing to try, I guess.
I removed the slide tube receiver frame, then the needle receiver tube/emulsion tube and did find that this model has air holes in it. 2 of the 10 were clogged. After cleaning and carb reinstall it still has a problem of fall on it nose at throttle snap to WOT. Fuel can be seen blowing backwards moderately at the throttle snap. If I put two fingers over the carb Venturi it will throttle up more or less normal. I am wondering if that apparent fuel blowing backwards could be an intake valve issue? I played with the butterfly and slide tube cable tensions to see if having them open at slightly different times would help and it did not. I had butterfly open first and then I had slide tube open first and then both equal and it never had any real effect on the throttle response idle snap to WOT. I have not as yet altered or checked to see if the main needle is at factory setting. I may change the needle to enrich it and see if that does anything. Keep in mind I have no history on this machine so I don't know what it was doing or not doing. I only know that it wouldn't start when I first tried and that led to cleaning the internal carb.
I have been working on the same carb. I have yet to find out how the fuel is enriched upon idle to WOT with no accelerator pump. There is a diaphragm on the right side of the carb called " air cut off diaphragm" the issue is not knowing if that has anything or everything to do with drawing fuel from the bowl and jet located on the bottom right engine side. I also have no info on the setting for the balance between the slide tube and the butterfly.
I have subsequently investigated more on this style of carb and found that there is not an accelerator circuit. Any fuel needed for throttle snap to WOT comes from the main circuit and moderately supplemented by the idle circuit. I had wondered about fuel enrichment needed at throttle snap from idle to WOT and investigated the choke circuit and if it also played any part in the fuel supply. Since the circuit is only open to fuel passage when the choke is pulled and is closed to no fuel to anywhere when the choke is off then that circuit is choke only.
you never mentioned what year this bike was, please let me know . I think I have the identical quad and mine is a 1992, I also have a 1993 350 big bear but it has a (1) cable throttle control only. I had the same problem with idle & running so I recently ordered a new carb from Amazon, hope it solves my idle problem. good video by the way. Thanks!
I'm not sure of the year. Part of the VIN number is missing and it includes the digit that records the year of manufacture. I think it's late 80's (88 or 89) based on a couple things (color being one of them) but I can't say for sure. It has a 2 cable throttle and a pull start, both of which I understand they eliminated in later years of the production run.
@@diymechanictv1233 yes: my 92 has 2 cable throttle and my 93 has (1) cable only. I think your is a 92 (my guess) look for the 10th digit in the vin (probably a letter) and starting from A as 1980 & B as 1981 and so forth if you can see your 10th digit on the lower frame or behind the gas tank. Good luck.
serviced my carb after just aquiring one , can tell someone was there before , 2 oz of water in the linkage area. my tip for the worn philips was i used vice grips on the head , and the retaining screw on the floats i used a dremel with a cut disk and made a flat head screw. saved the headache
Sometimes you have to be creative, right?
I had same issue with screws and used my ryobi impact and they came out with 0 trouble!
5:32 on time line. I have a real small pair of vice grips. On small screws with a thick head like those I clamp the vice grips on the side of the head of the screw and give it a slight twist to break them loose. There is limited room to ratchet the vice grip so I get as close to one side as possible when I grip it to allow for just a little movement. Works like a champ.
That hole/well on the outside edge of the fuel bowl on later models and some other models of same year is where the piston for accelerator pump goes.
Yeah, now that the timing is working like it should, I get a little stumble when I snap to WOT. I'm considering putting the original carb back on to see if it runs better than this replacement one does. It doesn't take long, so I may just try it out of curiosity.
Turns out, I was able to " eliminate" 1 cable and it worked great.
Another MAJOR problem with these is the rubber covered connection from carb to engine. They always seem to fail and suck air
Yeah, the parts bike I picked up was parked for that reason. Luckily, mine is good though.
Fun watching this 👍👍 Got a 87 big bear myself here in sweden. Gotta change that rubber at the rear swing on mine also. Looks like a bit of work.. YOU should defently get a orginal muffler. It can be why its feel tired and doesnt run good. Othervice a valve adjustment/cam shaft worn
Thanks for watching! I'm slowly working on this project as time allows (between other projects) and making some progress. It seems like a good machine (if I can get it to run correctly).
At 28:57 you were talking about the passages, I do not know for sure but I am believing that those are the fuel enrichment circuits for when you snap throttle from idle to WOT! I wish someone would tell me for sure as I have been struggling with my carb starving for fuel at a snap to WOT.
Update: that circuit is for choke only.
My issue ended up being timing (as I came to suspect later on). Check out the newer videos on the channel for the resolution of the issue.
I bought a new carburetor for my Yamaha moto4 350 an it's doing the same as yours what to do
Is the needle valve adjustable? Some have grooves to change the height rich or lean.
what is the purpose of that orange plastic piece over the main jet,mine doesnt have that
Just a rubber cap. I'm not sure what the benefit of it would be.
thanks for replying
@@diymechanictv1233
Did you remove the slide tube receiver frame and the needle receiver tube? If yes did your tube have air holes in the top end of it?
Mixture screws... behind vertical center line of carb, air box side, are air adjusting screws. In front/engine side of center line are fuel mixture screws.
I'm not even sure what that is, to be honest. I ended up getting a cheap replacement carb and putting it on the bike - which changed basically nothing. CDI box is the next thing to try, I guess.
I removed the slide tube receiver frame, then the needle receiver tube/emulsion tube and did find that this model has air holes in it. 2 of the 10 were clogged. After cleaning and carb reinstall it still has a problem of fall on it nose at throttle snap to WOT. Fuel can be seen blowing backwards moderately at the throttle snap. If I put two fingers over the carb Venturi it will throttle up more or less normal. I am wondering if that apparent fuel blowing backwards could be an intake valve issue? I played with the butterfly and slide tube cable tensions to see if having them open at slightly different times would help and it did not. I had butterfly open first and then I had slide tube open first and then both equal and it never had any real effect on the throttle response idle snap to WOT. I have not as yet altered or checked to see if the main needle is at factory setting. I may change the needle to enrich it and see if that does anything. Keep in mind I have no history on this machine so I don't know what it was doing or not doing. I only know that it wouldn't start when I first tried and that led to cleaning the internal carb.
Accelerator pump mine has one
I have been working on the same carb. I have yet to find out how the fuel is enriched upon idle to WOT with no accelerator pump. There is a diaphragm on the right side of the carb called " air cut off diaphragm" the issue is not knowing if that has anything or everything to do with drawing fuel from the bowl and jet located on the bottom right engine side. I also have no info on the setting for the balance between the slide tube and the butterfly.
Yeah, it's all kinda Voodoo to me! I don't know why it has to be so intricate...
I have subsequently investigated more on this style of carb and found that there is not an accelerator circuit. Any fuel needed for throttle snap to WOT comes from the main circuit and moderately supplemented by the idle circuit. I had wondered about fuel enrichment needed at throttle snap from idle to WOT and investigated the choke circuit and if it also played any part in the fuel supply. Since the circuit is only open to fuel passage when the choke is pulled and is closed to no fuel to anywhere when the choke is off then that circuit is choke only.
you never mentioned what year this bike was, please let me know . I think I have the identical quad and mine is a 1992, I also have a 1993 350 big bear but it has a (1) cable throttle control only. I had the same problem with idle & running so I recently ordered a new carb from Amazon, hope it solves my idle problem. good video by the way. Thanks!
I'm not sure of the year. Part of the VIN number is missing and it includes the digit that records the year of manufacture. I think it's late 80's (88 or 89) based on a couple things (color being one of them) but I can't say for sure. It has a 2 cable throttle and a pull start, both of which I understand they eliminated in later years of the production run.
@@diymechanictv1233 yes: my 92 has 2 cable throttle and my 93 has (1) cable only. I think your is a 92 (my guess) look for the 10th digit in the vin (probably a letter) and starting from A as 1980 & B as 1981 and so forth if you can see your 10th digit on the lower frame or behind the gas tank. Good luck.
Were you able to find a 2 cable carburetor on Amazon or was it the single cable. I need a 2 cable carburetor and cannot find one.
No, I just used a single cable carburetor and took one of the cables off at the splitter. It works great.
@@diymechanictv1233 so did it originally have the double cable carburetor. If so, it ran ok with the single cable carburetor.
do you have a link to the re build kit?
No, I don't sorry. Amazon links are troublesome as they go dead often as sellers and listings change.
parking brake wiring is shorted i know im a year late
Actually, it ended up being a bad pickup coil in the stator, so the timing wouldn't advance. Took me a while to find that one!
@@diymechanictv1233 How did you fix the bad pick up coil> Any advice or video on how to verify/troubleshoot and fix?
Actually, there's a follow up video to this one on my channel that shows both!