Engine RPMs racing once it warms up

[Nessism]

[ScottMc1100L]

Sell the bike and buy something newer. Wrenching isn't for everyone.

You know personally, I think I can see where he was coming from? And, it was funny.

All I ever see his Nessism helping people. Every once in a while, people just show up to these (and other sites) just asking a question as if they are the first ones it's ever happened to (it's the "It's all about me" generation we're living in now). The hardcore veterans of this site (myself NOT included) read this stuff over and over again. Personally, I'm more willing to help someone who's made at least a slight effort, not just showing up with their hand out, likely never to be heard from until their next problem and repeat performance. A lot of these sites are set up similarly. The search feature is there for a reason. Get off your a$$ and give it a whirl.

FWIW, I'm having a lot of trouble right now with my 700 carbs, which is how I found this thread. Scrolling through this section opening threads hoping they might offer some insight. I prefer to ask questions after at least trying to find a solution here. Additionally, I do better seeing it done and not reading it.

[ERJpilot]

I mentioned it in my first post, but I guess I had already struck a nerve at that point. I replaced orings and seals on the bike, in fact that was done before I did my thorough cleaning (and dipping and soaking) of the carbs. I have searched through the forums looking for possible causes of the problem and everytime I do a search I seem to uncover more info.

This page http://cycleorings.com/intake.html sure seems like the answer to my problem. The orings that I took off were completely hard and flat. However I replaced them with the viton orings and used new screws on the intake boots, so that is part of what is adding to my frustration. That step was completed early on.

I was a little peeved that I wasn't making headway when I wrote the original post so perhaps I made it seem like I wasn't "getting off my ass" and using
the search feature but I assure you I have been. I'm not standing here with my hand out looking for a magical fix, just some extra nudges and support to get me going or continuing in the right direction...

[Calvin Blackmore]

I mentioned it in my first post, but I guess I had already struck a nerve at that point. I replaced orings and seals on the bike, in fact that was done before I did my thorough cleaning (and dipping and soaking) of the carbs. I have searched through the forums looking for possible causes of the problem and everytime I do a search I seem to uncover more info.

This page http://cycleorings.com/intake.html sure seems like the answer to my problem. The orings that I took off were completely hard and flat. However I replaced them with the viton orings and used new screws on the intake boots, so that is part of what is adding to my frustration. That step was completed early on.

I was a little peeved that I wasn't making headway when I wrote the original post so perhaps I made it seem like I wasn't "getting off my ass" and using
the search feature but I assure you I have been. I'm not standing here with my hand out looking for a magical fix, just some extra nudges and support to get me going or continuing in the right direction...

If anyone who is a member of this Forum is upset over a simple but repetitive question then they can ignore it.

Ther is never any need to sound off on a newbie to the site and make assumptions that are unfair and hurtful.

The condescending tone of some of the older members to new ones is often repugnant and I am cetain that it scares them away.

That is what the off topic discussion groups are for.


did you check you carb diaphraghms for pinholes?
I had one that was ever so tiny and it made my life hell till i found it and replaced it.

[Calvin Blackmore]

and it all seemed to go back together just fine without and extra parts.

gee I wonder what that would sound like in a surgical recovery ward?

[ERJpilot]

did you check you carb diaphraghms for pinholes?
I had one that was ever so tiny and it made my life hell till i found it and replaced it.

I inspected them for holes when I had the carbs out and apart but that doesn't mean I didn't miss one. Doing a carb rebuild is a new experience for me so I couldn't say what looked right and what didn't when I had the carbs apart, but I know I checked for holes in those rubber diaphragms.

[centeno711]

Little trick I use....guys stop him if its bad for motorcycles

If its leaking air a little soapy water will tell you where

If its drawing air a little ether spray will also tell you where....spray it in likely places just in quick bursts...when the motor revs up suddenly you know where its drawing at.....obviously at the air filter it will rev.....

Gl

[BassCliff]

Hi,

There have been many members here who have had to dip their carb bodies two or three times before they are really clean. Just a thought.


Thank you for your indulgence,

BassCliff

[1_v8_merc]

Airleaks will easily cause RPM's to rise, or "hang".

Even extremely small airleaks, I had an airleak that was causing my RPMs to slightly hang, I sprayed WD-40 and carb spray all over the carb boots and never got RPM's to jump....then 5 minutes later found 2 of my carb boots weren't quite tightened down enough.....they were tight, but not TIGHT TIGHT.
I torqued em down with my trusty screwdriver.
Bike instantly ran better RPM's dropped right away like they should after revving......

-----
Choke operates okay right?(look at it on the carbs visually as you play with the choke knob, make sure it's not hanging)
-----

What about your throttle cable?

Believe it or not, even moving or touching the cable can cause your RPM's to rise sporadically and hang there or slightly move as you turn the wheel or even not turn the wheel!
(this is common when changing handlebar styles, i've dealt with it myself)


Sometimes you may need to adjust the locknuts on the throttle cable too!
There are usually two, one at the handlebars, and one at the bottom near the carbs.

So if you just did the carbs and now your RPM's are hanging or revving, it's POSSIBLE you didn't install the cable locknut back on correctly or it got over-tightened!?
(i mean it could simply be holding your throttle wide open damn near.....so check it out!)


Just back-trace your footsteps of everything you did, check everything, then check it again and again....

There's no mysteries here....RPM problems are usually very simple and straight forward, usually just something stupid that was over-looked....we ALL do it sometimes!
------

don't be hard on yourself, i got my first bike ever last year, i've learned TONS about it......and I kind of got thrown to the wolves.....like usual.
My bike ran like complete **** when I first got it, I put so many hours into replacing and tweaking stuff, it's been quite a journey already!

But it's been totally worth it.....if you can work on an old GS, you can probably work on mostly anything.....(so i've heard)
Because I'm used to working on modern fuel injected stuff, so classic bikes are a first for me!

Learning is part of the fun.....it always sucks when you're doing it at the time, but when you complete it and look back, you're like "wow im glad that part broke, i learned a lot from that experience"

And it helps confidence with future mechanical problems and makes them a lot easier to tackle.....(like working on your buddies bikes or cars, or lawnmowers or whatever.....)

[drukin]

I have the same exact bike.
If your running lean it will cause the throttle to hunt at idle. i know mine was too lean from the factory. The only problem with that is to change the air/fuel mix you have to jet up or down accordingly. If no one has messed with it ever, i doubt its a problem.
also the single throttle cable setup doesnt help any, i know mine likes to stick now and again at very low RPM's.
If theres an air leak, it could only be coming from a few places. (intake manifolds or the carbs themselves seeing as theres no vacuum lines except for the one back to the petcock.)
My bike did the same thing when i got it. I used a ton of white lightning in the throttle cable housing to free it up but that single throttle cable is notorious for that kind of thing. Check to see if the airbox has a leak also.
(just to give an idea, if you remove the airbox like i did, you will have to go up 5 sizes on each jet and these 450 twins are very particular on how they want to run.)
My carbs were overflowing also when i got mine. I found a hair line crack in one of the floats after submerging it for 30 minutes, which was about the time i had to ride it for it to over flow. soldered it up and sanded it and works fine ever since.

All i can say is clean and inspect them, but do so very carefully. Make sure all the seals are tight when you reassemble (intake and boots to airbox), and most importantly dont over tighten any of the screws on the float bowls or diaphragm tops. Those threads in the carb will strip before the screws do. i found out the hard way. suzuki still makes all the rebuild kits, floats, and jets. And they are actually affordable.

hope that helps a little.

[Nessism]

Where are the pilot screws set? How many turns open?

[Nessism]

So what happened with this one? Lots of people trying to help but the thread has died? The idle will hang if the pilot screws are misadjusted so how about posting up where you set them? Since you said the seals were replaced we trust you removed the piliot screws and replaced the O-rings before reinstalling them. A wildly misadjusted carb sync will also cause the idle to hang so that's another thing that needs tending to.

[bellucci]

EJR,
Where do you live? Maybe you are close to a member that will swing by... I am not a carb guy, but my bike is running a little rough before the mains kick in. So if you are close I can experiment on your bike instead of mine I am in northern Illinois and Trippivot is close. If I break it, we can show upon his doorstep and suprise him.

[drukin]

unfortunately all the screws are sealed in on the 82 450.
only adjustment is jetting and idle screw.

[Nessism]

unfortunately all the screws are sealed in on the 82 450.
only adjustment is jetting and idle screw.

What do you mean sealed? There may be a cap over the pilot screw but it's easy to remove.