Throttle...Idle

[Kmccaslan]

I am having some trouble with my bike. My throttle seems to be sticking or either it is just idleing extremely high at times. It idles normally to begin with, but once I have allowed the RPM's to rise it is having trouble getting back to idle. This is happeing in between gears and when at a stop. If I rev the engine while at stop it will un stick and go back tonormal...if not it reamins high. When in between gears, it is causing some trouble. As I am entering 2nd it is stuck high and therefore tourques really hard on me. Let me know what I need to do for this issue.

[jjwaller]

Does your throttle cable need lubing or replacing?
Is it hanging up mechanically, or is it an issue of vacuum leaks or lean running.
Have you synced the carbs? First check that it is not hanging up mechanically.
Blip the throttle from the carbs not the grip. If it doesn't hang then, then try the grip throttle, checking that the linkage is in fact returning to idle.
If it is, then you have some carb problems.

[Athedra]

Had a similar problem after fitting a secondhand set of carbs on my bike. I did two things that seemed to have sorted the problme. Which one fixed it I cannot tell since I did both on the same day while the carbs where out.

Firstly I bought some Tool-grip (Rubber you paint on your tool handles for better grip.) I painted my intake rubbers on the outside with this to seal them up again. I got the impression that they where leaking some air.

Secondly I dropped my needles with one clip to give it a better seal. I was told that this will remove the slight jerk I got from pull away and also give my a more stable idle.

The carb balancing is a must. Just remind the guy that is doing it that when he adjusts the co2 mixtures on the carbs that the adjusters does not have shoulders like the other bikes, so if you screw the adjuster in all the way (for some reason they just love doing that), he is going to snap the tip of in your carb body, and he better start searching for new carbs for you as fast as possible if that happends.

If you snap it off, well good luck in getting them out. There is a forum on here somewhere that explains how to take them out with a draughting pin. I have been trying on my old carbs for weeks now, and stil have not gotten them out. I can however say that by the time I am done and have them out, I will be able to fir a m8 bolt in there by the way I have damaged the insides already. I am told you can freeze the carbs and then they come out easier. My wife will skin me alive if she finds the carbs in her deepfreeze.

[Tropic-al]

Throttle idle

I had a similar problem. After trying most of the usual fixes, more or less what has been adviced here, I changed the two advance mechanism springs. That cured my problem.
Good luck.

[TomRodgers]

Damn...if i didnt known any better, id swear YOU were working on MY bike!!

Tonight i used a CARBTUNE and started sync'ing the carbs. 1 to 2, 4 to 3, then balancing them 1+2 to 3+4. Now here is the fubar part. Without touching a thing, from about 1100 to 1300 rms....it jumped to about 2000 rpms and sat there for 20 to 30 seconds. I let out the idle screw until it came down to about 1200 rpms... revved it up, it came back down, almost died....only idling about 500 rpms, if that....set idle higher...back to 1200 rpms, let it set a while, then revved it up again....wouldnt come back lower than 2000 to 2200 rpms... WTF?? same thing happend after i took the CARBTUNE off. Mind you, these are damn near new carb holders (no splits/cracks of any kind). the only thing i can think of is that the #2 and #3 carb holder clamps arent getting tight enough. neither one tightens up like 1 and 4. I did notice a considerable difference with the 'odor' of things after syncing them up. i also backed out the idle mix screw on 1+4 to stop the sputtering they were doing. I have a color tune ordered, and should be here by wednesday, but any ideas as to the erratic idle. Also, it takes it considerable time to come back down from high rpms. i.e. goes to 9000 rmps smooth as a baby's backside, but takes 5 to 10 seconds to come back down to whatever idle it thinks is right....either the 2000 rpms or the 500.... ideas?

[Kmccaslan]

Really

This is mine exactly. I could not explain it as well as you did, but that sounds exactly like my problem.

[CatatonicBug]

Just a stab in the dark, but perhaps the PU coil wires need attention?

[cywelchjr]

Damn...if i didnt known any better, id swear YOU were working on MY bike!!

Tonight i used a CARBTUNE and started sync'ing the carbs. 1 to 2, 4 to 3, then balancing them 1+2 to 3+4. Now here is the fubar part. Without touching a thing, from about 1100 to 1300 rms....it jumped to about 2000 rpms and sat there for 20 to 30 seconds. I let out the idle screw until it came down to about 1200 rpms... revved it up, it came back down, almost died....only idling about 500 rpms, if that....set idle higher...back to 1200 rpms, let it set a while, then revved it up again....wouldnt come back lower than 2000 to 2200 rpms... WTF?? same thing happend after i took the CARBTUNE off. Mind you, these are damn near new carb holders (no splits/cracks of any kind). the only thing i can think of is that the #2 and #3 carb holder clamps arent getting tight enough. neither one tightens up like 1 and 4. I did notice a considerable difference with the 'odor' of things after syncing them up. i also backed out the idle mix screw on 1+4 to stop the sputtering they were doing. I have a color tune ordered, and should be here by wednesday, but any ideas as to the erratic idle. Also, it takes it considerable time to come back down from high rpms. i.e. goes to 9000 rmps smooth as a baby's backside, but takes 5 to 10 seconds to come back down to whatever idle it thinks is right....either the 2000 rpms or the 500.... ideas?

You can always set the mixture by ear, as it sounds like your still too lean. One carb at a time, with the bike running slowly turn out the screw, you should be an increase in idle speed, when it stops rising and starts to drop again, start turning it in till you just hit top idle speed, then some turn in just a bit more (I don't) and repeat for each carb. Remember to turn down the idle as you work on them, as if I'm right it WILL increase a lot. Then sync again and it should be good.

[Athedra]

As far as I know, you are spose to balance from Carb 3 outwards. 3 being the main carb since it has your idle screw on it. I balance them the following way.

I first balance 3 and 1.
Then 3 and 4
Then 3 and 2
Then 1 and 2
Then 3 and 4

Then do the minor adjustments in between them. When you get a miss fire while balancing, just make you air-fuel mixture a tad richer, until she runs smoothly again.Once I have done all of this I set my idling to 1500 and take her round the block. If it changes from there, I spray some Carb-cleaner on all my joints. If my idling drops then I fix the leak and try again. Once all my leaks are closed, then I set my idling to 1000 and drive with her for a few days before putting her on the co2 emission machine to do my final mixture settings. This has been working for me for all my 4 carb bikes. If it is the right way I cannot say, but it works.

[DGXSER]

Athedra,

The way the screws are set up is that the screw between 1 and 2 adjust those two to be the same. Then the screw between three and four adjust those two to be the same. Then you can adjust the middle screw to bring the two sets together.

Not sure what screw your adjusting to try and bring one in line with three or two in line with three.

[Athedra]

Let me explain, if I have been doing it wrong, please help me right.

I have a 4 guage vacuum system, so plug them in and start up. Get my gauges to stand still and note Carb 3's Vacuum. I then adjust carb 1 (With the screw between 1 and 2) till 1 and 3 is in sync. I then adjust 3 and 4 to be in sync. (The screw between 3 and 4). Usually this changes my vacuum slightly on carb 3. I then adjust carb 2 to sync with carb 3. At this point they are fairly in sync. I then sync 1 and 2 and then 3 and 4. I usually end up with a backfire when doing carb 2 (Sofar has happened to me every time I sync carbs) so just make the mixture a tad richer to get rid of the back fire.

Please correct me if I have been doing it wrong all this time.

[CatatonicBug]

Let me explain, if I have been doing it wrong, please help me right.

I have a 4 guage vacuum system, so plug them in and start up. Get my gauges to stand still and note Carb 3's Vacuum. I then adjust carb 1 (With the screw between 1 and 2) till 1 and 3 is in sync. I then adjust 3 and 4 to be in sync. (The screw between 3 and 4). Usually this changes my vacuum slightly on carb 3. I then adjust carb 2 to sync with carb 3. At this point they are fairly in sync. I then sync 1 and 2 and then 3 and 4. I usually end up with a backfire when doing carb 2 (Sofar has happened to me every time I sync carbs) so just make the mixture a tad richer to get rid of the back fire.

Please correct me if I have been doing it wrong all this time.

Connect the gauges, and let the engine idle.
Adjust the screw between #1 and #2 so those two are the same, then the screw between #3 and #4, so those two are the same. Then, adjust the screw between #2 and #3 to bring the two sets together to match each other. You may need to do some fine-tuning after that, but that is the basic method.

The carbs are tuned in pairs, with #1 and #2 as a set, and #3 and #4 as a set.

[Athedra]

Duly noted. Will cut down alot of time out of my usual method. Thanks

[Bigfoot]

I noticed similar symptoms while syncing my carbs. Once they were properly sync'd, the problem went away.

[TomRodgers]

Bombay Sappire speaking here....I want ALL effing numbers to balance at the same effing time. WTF. No leaks. Advance working like it should. Spent the better part of 5 hours adjusting the idle mix screws to whatever setting they COULD be set at..except all the way out and in my hand...and this B!tch still wants to have a non commital idle!!!! Patrick...similar to your Succubus and Incubus theory...im about to haul Frankenbike out and play torture clips for 'Sunshine to hear to straighten her a$$ out!!!!! im done for tonight......