Not familiar with your model, but it should snap back. Is there a hang up at the carburetor spring area, or is it in the cable routing itself? Sometimes if the cable routing is too constricted, it binds up and freezes in place.

 

I think the A models are the same as the other 400s, it should definitely snap back and it's probably due to adjustment. There's adjustment at the carbs and there's an adjustment on the handlebars. The service manual should help with which direction to turn them. I recall turning the handlebar adjuster clockwise (or so less threads show) making it looser (allows it the slack to snap back). Try all the way in and see if it snaps back, if not you might need to adjust at the carbs. Also make sure it still snaps back with the bars fully turned in both directions.

 

Make sure your throttle isn't slid onto the handlebar too far. If the inside of the rubber hand grip is tight against the end of the handlebar, it will want to hang open and not snap back.

 

If cable adjustment doesn’t help, remove the cables from the throttle tube/grip and see if it moves freely. If there is any debris inside the throttle tube or oxidation on the handlebars, it will hang up.

 

What? You mean this model come standard with "cruise contrrol"??

 

I would suggest you change the cables unless you want to practice jumping off the bike when the throttle jams at high speed . Every throttle needs to return to idle after you let go.

 

In case you don't realize, his bike has push-pull throttle cables that can be rotated back to idle forcibly if necessary... plus the usual kill switch and ignition switch as well, so bailing isn't likely necessary. But it sounded dramatic.

 

I dont know how you ran your cables but I found on my A that if you remove the left top motor mount and run the cables between the top mounts they work a lot better. Going around the left mount puts them in a bind. Having worked on several As I KNOW its a lot of work but I would pull the carbs back off , put all the cables on and see how they work ,if ok I would reinstall the carbs with the cables in between the upper mounts.

Hope this helps.

Bill

 

I was thinking of doing that routing with my new cable. It doesn't bind but I have it routed thru the center of the trees and around the left side and when I turn the bars left it hangs up on the left riser mount bolt. I was thinking that a zip tie to center backbone of the frame would keep it from hanging up but through the top mount would center it better and look cleaner too. Thanks for that tip Bill

 

There needs to be a little bit of slack in the cables(1 mm or so) if they're pulling against each other things will bind.

 

The cables don't go thru the triples, they run over the front and around the left side

 

OOPS, well it does now. It doesn't bind at all and I put zip strips or cable ties around it and the clutch cable to hold them to the frame.

 

When I replace both of my throttle cables with ones from motion pro, they were VERY susceptable to becoming hung up with internal friction following the stock routing. I also pre lubed them with cable lube as instructed as well. I left the carb ends off and found a routing that provided the snap your looking for. I was not able to use the stock routing hanger as it comes off the handlebar, mine had to "go more forward" before sweeping back on the left side frame. I forget if I put them inside or outside of the engine top mount. I'll check and take a picture of what i did and post tomorrow if I remember before work. I do remember thinking to myself that the factory cables allowed for tighter bends in routing than the motion pre replacements...

 

Been a while since I got to this but I found the culprit! Heavy rust buildup in the end if the handle bar was making it stick. Works like a charm now!

Sent from my Pixel 2 using Tapatalk

 

Wow that is gross! Thanks for posting a "conclusion". Now we know of one more condition to check with a sticky throttle. Did you manage to get it cleaned up? Planning to sand it and coat it to mitigate re-buildup?

 

I sanded and sprayed with oil for now. I will keep an eye on it, but the bars are rusty to begin with so I will replace it eventually with a nicer one.

 

I thought this seemed like a logical place to post this question. If there's no follow-up, I may start another thread. Not sure what the protocol is.

Anyway, I'm having an issue with a sticky throttle as well. Is there a trick to pulling off the grip and throttle tube to check? I wouldn't be surprised if the end of my handlebar looks like the one in the pic, but I can't easily pry it off and I don't want to force it and end up breaking something. Is there some kind of spring that returns the throttle? When I'm riding and let go, the throttle definitely returns, but upon start up, I can easily make it stick to force a higher idle. Seems sticky more than anything else.

Thanks for your thoughts.

 

Remove the screws holding the housing together and pull it apart. Remove the end of the cable from the plastic throttle sleeve, and then the sleeve should slide right off the bar. The return spring is on the carb.

 

Thanks for that info. I might as well try to lube the cables once I get that housing apart, too. Wondering if I should just get new grips and throttle tube. I guess it will depend on the condition of the existing.

 

Throttle tube probably needs to be cleaned. Do not lube it with grease! Use a silicone spray on it and the handle bars. I'll suggest replacing the 38 year old cables that have never seen lube in their entire lifespan. Fairly cheap and once done you'll never need to again, lube before installing.

 

Thanks. I have no problem spending a little on new cables, but I don't know if I really trust myself replacing them. It may be fairly simple, but it doesn't look that easy. Is it a costly job to have a shop deal with it if it comes to that? Also, once I expose the end of the cable(s) at the throttle end, would lubing the cables at that point help at all or just be a waste of time?

 

It'll take @1 hour to change them out, current labor rate around here averages $100/hr.
You can lube them once they're exposed at the top. Thin oil like sewing machine oil is used. Some people use WD40. You'll know it's properly lubed when it starts to drip out the bottom of the cable at the carbs, takes awhile to get there.

 

Good to know. Thanks. I'll try to clean the bar and tube and lube first. May be my Saturday project.

 

Hi again. Quick follow-up to the suggestions here. First of all, I do have silicone lubricant, so I'll use that on the bars and throttle tube as suggested.

As for the actual cable...man, there are a gazillion products out there and everyone swears by the one they happen to use. Here are my most practical options (in that I already have them):

• WD-40 (mixed reviews; people love it or hate it)
• Kroil (not really a lubricant)
• Silicone spray
• Lock-Eze (liquid graphite)
• Maxima Chain Wax
• plain old motor oil

I guess as important as what to use is how to use it. At this point in my experience I'd prefer not to remove the cable from the bike, so I'll do what I can after disconnecting them from the throttle grip end. My question has to do with how much stuff to use. All the methods I've seen say to put lube in until it comes out the other end. I can see that maybe for a clutch cable, but that can't apply to the throttle cable, can it? I wouldn't want excess going into the carb. I'm thinking I'll just apply a little bit judiciously and work the cable by hand until it makes its way at least most of way through the length of the cable. Or is that even worth the effort?

Thanks.

 

WD40 and Kroil are great for cleaning and rust removal which may be a good part of the cables sticking if they are. They're not a lube though. If those are used them Silicone spray is worthless, incompatible. Motor oil is too thick to use. Chain wax would only work if the entire cable was exposed, Graphite spray will work IF the 1st 2 are not used.
I'd suggest this product https://www.3inone.com/products/multi-purpose-oil/. It's a thin oil that will travel the length of the cable.

 

I have a feeling I shouldn't have started this little project. I separated the two halves of the housing and can see the cables wrapped around the tubing, but I can't get enough slack to remove them to slide the grip and tube off the bar. There seems to be some important step I'm missing. What is it?

 

You should be able to pull the housing halves apart enough to rotate the throttle sleeve past the stop so the cable isn't wrapped around the sleeve. Then just push the end of the cable out of its spot in the sleeve and slide the sleeve off.

 

They're apart enough that the halves are being held together only by the electrical connection for the kill switch (I think that's what it is). Not sure what you meant by "rotate the throttle sleeve past the stop".

 

Or rotate the throttle, grab the cable with needle nose pliers to hold it in place and then turn the tube back giving lots of slack to pop it out.

 

And I tried that, too. I imagine once I get one out, the other will get enough slack, but right now they seem to be fighting each other.

Am I supposed to do anything with those other two nuts underneath that feed the cables into the housing?

 

There should be a nut on one of the cables, if you turn it as far as it can go in one direction it will get looser. The other direction will make the cable tighter (sorry I don't remember which direction). Loosen it fully and see if you can get it off.

Those nuts will eventually have to come off to get the cables out

 

You may have to slack off the cable adjustments, either at the carbs or at the handlebar housing to get enough slack to remove them from the sleeve.