Crashed GS550 this morning due to high rpm in throttle! Need some help...

[supergrafx]

This morning, I warmed up my bike like I normally do. After 10 to 15 minutes I started out for work. As I initiated the throttle in first, suddenly and unexpectantly, the rpms shot up past 9000 rpms, so I pushed the kill switch. I then started it up again, and same deal. I then got the idea that perhaps the grip was keeping the throttled rev'd, so I unclipped the rubber grip and pulled the grip off the thin plastic throttle. I started the bike up again and it went back to 1500 rpms. I thought, "cool, I'll just ride it without the grip, until I get some adhesive for the rubber and reclip it." As I pulled out of my driveway, and started up the street, and suddenly the rpms shot up again. I pulled the clutch lever in and applied the brake, but the rpms remained constant in the 9000 range. The bike sputtered out of control and down I went. The damage incurred was only the clutch lever broken off. Ofcourse, gas as well spilled from the carbs until I got the bike back up. With the clutch lever broken off, I pulled out a wrench from my back-pack, pulled on the clutch cable so I could set the gear back to neatral so I could roll the bike back to my backyard. That said and done, nothing was wrong yesterday with the throttle. This morning though, everything went wrong. So I'm wondering what might be the cause of this?

I have recently ordered a turn signal/horn universal switch from Bevel Heaven to replace my old one since it got banged up when I first got the bike. It was in pieces and the only way to get it working again was to glue the copper connections in place. Thus the headlight is always on, which makes my old electical problem on a continual drain on the battery that much more difficult to specify. Here is the switch I ordered and the link. Bevel Heaven's website said the switch is universal and would work with all street bikes, and I liked how it looked, so I went for it:

http://shop.bevelheaven.com/detail.aspx?ID=6

Now it seems, I will need a new throttle/kill switch/start up switch. At least if this is the problem. I don't know. I'm sure you guys will have some idea where my problem lies. So I am here to ask for help. If it is the throttle, could you guys tell me the best throttle I could mod my bike with? When parts on my bike go, I'd like to replace them with either new stuff or something cooler since my intention on this bike is to mod, not to keep it stock.

~Gabe

[doctorgonzo]

USUALLY, this is caused by the throttle cable being in a bind. The tank has it pinched against the frame.

[supergrafx]

USUALLY, this is caused by the throttle cable being in a bind. The tank has it pinched against the frame.

Thank you DoctorGonzo! Should I go ahead and replace the throttle cable then? By being in a bind, does this mean, the cable is not straight enough but bent due to being harnessed incorrectly under the the tank?

[Dave8338]

Could be that or a cable that has frayed and is about to break. I had something similar happen to me a year ago, after a long ride in the rain. Replaced tha cable and all was well.

[doctorgonzo]

Thank you DoctorGonzo! Should I go ahead and replace the throttle cable then? By being in a bind, does this mean, the cable is not straight enough but bent due to being harnessed incorrectly under the the tank?

Not necessarily. The cable has to be able to move freely. If it gets stuck between the tank and the frame, or of something else prevents it from moving freely you'll get this symptom. A sure sign is to sit on the bike (in neutral) with it running and move the handle bars right and left. If the cable is in a bind this will make the rpm go up and down. It's probably worth pulling the tank and having a look.

[supergrafx]

Not necessarily. The cable has to be able to move freely. If it gets stuck between the tank and the frame, or of something else prevents it from moving freely you'll get this symptom. A sure sign is to sit on the bike (in neutral) with it running and move the handle bars right and left. If the cable is in a bind this will make the rpm go up and down. It's probably worth pulling the tank and having a look.

Cool, I'll pull the tank off replace the cable just to be safe, making sure that it can move freely when I turn left and right. Do you know of the best quality throttle cable out there? Wish there was one that was less prone to this problem since it seems life threatening to a certain degree. Also, I never pulled the tank off before. I've heard just to keep the petcock in the on position and unbolt the bolt/bolts to the frame under the seat and lift it off. Is this right?

[Nessism]

Don’t go all willy nilly replacing parts until you figure out what the problem is. First thing to do is figure out if the carbs are hanging open.

Turn the throttle and then release the grip; the carb slides should drop and you should hear a “thunk” noise, which indicates the slides are dropping down to the throttle stop. The slides should drop with authority – not slowly return to the throttle stop.
VM carbs like you have should have TWO throttle cables; one to pull the slides open, and one to pull the slides closed. It is impossible for the slides to hang open as long as you turn the throttle to the closed position since the pull-closed cable will force the slides closed.

Verify what you find after you have a close look and report back.

[supergrafx]

Don’t go all willy nilly replacing parts until you figure out what the problem is. First thing to do is figure out if the carbs are hanging open.

Turn the throttle and then release the grip; the carb slides should drop and you should hear a “thunk” noise, which indicates the slides are dropping down to the throttle stop. The slides should drop with authority – not slowly return to the throttle stop.
VM carbs like you have should have TWO throttle cables; one to pull the slides open, and one to pull the slides closed. It is impossible for the slides to hang open as long as you turn the throttle to the closed position since the pull-closed cable will force the slides closed.

Verify what you find after you have a close look and report back.

As usual, thank you for your help. As you know, this certain mechanic rebuilt some extra carbs I had for me, and that is where those mixture screws came into play with you and me. The guy never returned a guage of mine that came to around 80-90 bucks from Germany off of ebay, 4 carb kits that I believe were not used in the carb's assembly costing around 80 with shipping, some engine bolts from Burk's costing around 35 bucks, and a full print out from BassCliff's site of the GS550 service manual that costs alot just due to printing all of it out. I thought the carbs were done right at least since until this point the bike's been running, even though the electrical problem was never remedied. The guy said he did a full diagnostic and said everything was fine. However, my battery is still losing it's charge rapidly, so I might need to get a reg/rec from Duanage or someone. All this having gone down, it might be no suprise that the carbs were done incorrectly. Navi is in the process of trying to get my stuff or at least some of my stuff back since I've called the guy around 20 times and every time he acts like it is the first time he's heard me asking for the parts back. If the carbs weren't done right, that really ****es me off. Cost 400 for the work on the carbs and 265 for a tune-up that included a new battery. I started getting bad vibes when I checked the air filter put in and noticed that the screw that holds the airbox lid was missing and the lid open and ajar. Not even sure if he added the k&n oil that accompanied the filter. I guess one learns the hardway like crashing, by putting one's trust in another's supposable experience... I will try to learn more. Never heard a thunk noise as I recall. I will keep you posted. I thought there was just one throttle cable. Can two throttle cables be inter-twined in one cable? Thanks again Ed. I'm going to print this thread out to read over and over.

[doctorgonzo]

There are some guys on here I'd trust with my bike or bike parts, most of the usual suspects like Rapid Ray, Steve, Ed, Chef, etc... but I wouldn't let a local shade tree guy or a dealership anywhere near it on a bet.

[supergrafx]

There are some guys on here I'd trust with my bike or bike parts, most of the usual suspects like Rapid Ray, Steve, Ed, Chef, etc... but I wouldn't let a local shade tree guy or a dealership anywhere near it on a bet.

Never again! If it wasn't for my kids, I'd relocate near you all! Thank god though GSR exists. Without it and you guys, I would truly be lost.

[cloudbreakmd]

Gabe,
Twist the throttle. Does it snap back? It definitely sounds like it's binding. Peter (the guy yo got the bike from) had replaced the cable from a GS250. So actually it has the wrong cable on it already. he did that because of the clip ons. Sheesh...

Try the throttle with the gas tank on first and then off. Look for any binding.

[supergrafx]

Gabe,
Twist the throttle. Does it snap back? It definitely sounds like it's binding. Peter (the guy yo got the bike from) had replaced the cable from a GS250. So actually it has the wrong cable on it already. he did that because of the clip ons. Sheesh...

Try the throttle with the gas tank on first and then off. Look for any binding.

As far as I know, I don't think it snaps back, but could be wrong. It is my first bike... I do manually roll it back when I need to rev down, like for example when coming to a stop. The bike is now in neutral since I used the wrench to pull the clutch cable to change gears from first or second to neutral due to the clutch lever breaking off, so I'll check when I get home. If you know anymore parts on my bike that may pose a problem, I'd appreciate knowing about them. Going down due to a stupid cable was not a good way to find out this fact. As Ed suggested, do you remember there being two throttle cables on my bike with this gs250 throttle cable used. All I saw this morning was one. I did not do the carbs myself as you know so if and when you talk to J., could you ask if two throttle cables were used when installing the carbs. If not, the carb job seems wrong. I'm sure the gs550 service manual which I lent him and have not gotten back with the rest of my parts specified this fact.

[82Shafty]

If your bike is sporting aftermarket low-rise bars, you may also be in need of a shorter cable. I would remove the tank, and see if the cable moves freely in its sheath.

Then take cable off of the carbs and see how the clock spring is holding up on the carb assy. If the carbs snap just fine without a T-cable attached, replace cable and make sure you get the proper size and route it so that it does not bind or keep the plates open.

[Nessism]

Sounds like you don’t have a proper pull-pull throttle cable setup which is appropriate for VM carbs. Finding a set of cables that are short enough for use with clip-ons is going to be a challenge. Not sure but maybe the cables from a 1979 GS1000S could be used? That model has low bars and VM carbs so it should have a two cable setup like you need.

[doctorgonzo]

Never again! If it wasn't for my kids, I'd relocate near you all! Thank god though GSR exists. Without it and you guys, I would truly be lost.

My mechanical experience before this bike was having a 350 chevy down to the block once in high school. People here are patient (for the most part, ha) and pretty much anything that doesn't require a machine shop you can do yurself with the help of this crowd.