high idle

high idle coming off the x-way, 2,000 r.p.m. after driving the street 4 a couple minutes she goes down to 1,500. any idea where the gremlin rest causing this.

 

some one will tell me that im wrong but as far as reading other posts its the plunger on the inside with the vaccumm diafram. the plunger is sticking to the walls and not moving down very fast. its suposed to make a glunking sound when you push it up when the carbs are off the bike.

for me i took some fine steel wool to clean the side of the carb and the plunger its self.

hope that helps other people will reply soon with more ideas but i think that is what the culprite is. good luck

 

if it was the plunger, why doesn't it do the same thing when i rev. it?

 

I think we are suffering from the same problem. My bike is a 1985 Maxim 700 with 63K km on it. Runs great except for that little idle problem. Here is the link to my original post. You might get some info out of it.

http://www.xjbikes.com/Forums/viewtopic/t=14776.html

I did not do anything yet due to lack of time. If you have any success please keep us updated.

Cheers.

 

My guess is that you have a vacuum leak somewhere. I had similar high idle problems. Have you tried the unlit propane torch or starter fluid around the intake boots? Also, make sure you hit the throttle shafts on the carbs. That is where my leak was.

Just got through replacing the throttle shaft seals tonight, but I don't have the carbs back together to confirm that this solved the problem. However, looking at some of the seals, they were definitely leaking. To use a technical term, they were a bit wallowed out.

I am making an assumption that you have checked the cable and it is not getting hung up.

 

check fuel filter and petcock. if your bowls run low she will run lean witch will increase rpms. high fuel usage on the highway + limited flow of fuel to carbs = low fuel level in carbs. off highway low fuel usage allows bowls to refill.

just my 2 cents

 

what are the throttle shafts on the carbs? the vacuum leak may be right, but if i use my choke, the engine floods and gas goes out the overflow on the ground. anyone herd of this? this is my second xj. all i did to my xj750j was cleaned my carbs and put 45k on her before i sold it. this jx700n has less than 15k. i was thinking about the petcock myself. you know what? i liked the j better than the the n because the tourk started at 3.5k in 3rd gear and felt fatter than the n, starting at the bottom and going all the way up. i fell in love with the x body the first time i saw it when i was 14. so much for my opinion. this is a great site. the x.j.n. i got looks brand new, better than my x.j.j. did when i sold it but doesn't run as good.

 

The throttle shafts are what rotates when you pull the throttle. Once you get it started, shoot some starter fluid or use an unlit propane torch right around where the springs are between the carbs. If your idle jumps up, you have a leak at the throttle shaft.

While you are at it, also go around your intake boots to check them.

If that's not it, then take a look for things that could be causing it to go lean as listed above.

I just got my carbs back on after replacing the throttle shaft seals, and it has made a huge difference.

 

I just experienced and fixed this issue on my X as well. What I found was that after riding all winter, the throttle return springs on the front of the carbs were a bit gunky. They are hard to clean while on the bike, but you can get a spray tube nozzle in there and spray them off with your favorite clean and then hit them with some lube. Also lubed up the throttle cable and now they rotate and close nice and smooth with the 2k idle gone. Hope this helps.

Ride safe

 

I could tell from the video that there was plenty slack in the throttle cable. But that cable is a stiff one and I was wondering if you hsave tried isolating the throttle system from the carb rack to see what happens. You might disconnect the throttle cable at the carbs, start the bike and work the throttle from the point where it attaches to the carb. At least you would know if the problem is in the carb rack or in the throttle linkage. At least it's somehing to try.


Wamaxim

 

just went for a ride, as i rode, bike ran like it was getting less gas till it died. about 3 minutes. got started by, holding the throttle opened all the way while cranking. had to run at 4.5k r.p.m. to keep the engine running. seems to me it took the vacuum created by the high r.p.m. to suck enough gas to keep it running. when i got the bike it ran pretty good. 2 days ago i turned idle down from 1.5k to 1k after i got back from a short ride. the bike ran pretty good. it's hard to tell with a helmet on and going 80 plus, but she seems to run a little rough. you all are great. i think some kids might have messed with the fuel lines on the bike. can any one tell me or show me where the lines go so i can check em out? my yamaha manuel doesn't tell me.

 

I would pull the plugs just to check for fouling.
See if there black.