Author Topic: HELP! My throttle is sticking wide open... (Read 7064 times)

bullethead63 · **on:** November 02, 2009, 07:05:41 pm

I just bought a 2002 Classic,with 166 miles on the clock...it starts fine (electric or kick),but the damn throttle keeps sticking wide open...the piston valve in the carb is not moving in sync with the throttle...it seems to be hanging up,and despite repeated,cleaning,it won't function properly...any helpful tips out there?Do I need a stiffer spring?Cable lube?The "local" R.E. dealer is 100 miles away...

ShenandoahThumper · **Reply #1 on:** November 02, 2009, 07:16:05 pm

Try removing tank and checking the cable and re-route if bends are causing binding in the cable. Just an idea. Worked on one of mine.

bullethead63 · **Reply #2 on:** November 02, 2009, 07:20:18 pm

Thanks,Thumper...I'll give that a try...anyone else have an idea?

The Garbone · **Reply #3 on:** November 02, 2009, 07:21:50 pm

Congrats on the your purchase of an RE.

In addition to checking cable routing you might want to disassemble the throttle grip/ possibly put a little grease on the bar and lube the cable.

Personally, I would pull the carb and clean it real good as well as drain and clean the tank as the sucker has been sitting for 7 years...

rideOn · **Reply #4 on:** November 02, 2009, 07:23:24 pm

mine did that awhile back just after buying. the boot kept coming off and pulling the cable/piston up to reve up. i pushed it down, gave it a crank to make sure of normal idle. when idle was right, i zip tied the boot to the carb fitting.

bullethead63 · **Reply #5 on:** November 02, 2009, 07:29:00 pm

Quote from: The Garbone on November 02, 2009, 07:21:50 pm

Congrats on the your purchase of an RE.

In addition to checking cable routing you might want to disassemble the throttle grip/ possibly put a little grease on the bar and lube the cable.

Personally, I would pull the carb and clean it real good as well as drain and clean the tank as the sucker has been sitting for 7 years...

The first thing that I did was pour out the old gas,and put a couple gallons of fresh gas in it...when the throttle started sticking,I pulled the carb,and cleaned the slide...my first impression was that the spring was weaker than I thought it should be...should it be stiffer?

ace.cafe · **Reply #6 on:** November 02, 2009, 07:34:23 pm

Chances are good that it's the cable binding up at the bend over the carb, or is binding because it's stuck between the tank and the frame.

It's a very tight bend under the tank, over the carb, and playing around with the cable to route it to a place where it doesn't bind, usually works.
This is pretty common to happen to Bullet carbs, if the cable isn't routed in the best way.

bullethead63 · **Reply #7 on:** November 02, 2009, 07:43:07 pm

Thanks,guys...I'll go out and try to re-rout/adjust/lube the cable...and I'll pull the carb off and clean it (again),too...it's my day off,and I was just hoping to get in a few miles before dark...it's a beautiful sunny,cool day here in the Florida panhandle...just right for riding...or wrenching...(>_<)...grrrrr...this thing is starting to remind me of my old HD Sprint,already...at least I can get parts for the Bullet!

chumma7 · **Reply #8 on:** November 02, 2009, 07:47:42 pm

Another possibility is the cable is sheared and strands of it are getting stuck inside the sleeve. This has happened to me while driving and was almost a nightmare.
Check your cable for loose strands and replace if necessary.

bullethead63 · **Reply #9 on:** November 02, 2009, 07:50:40 pm

I'll check that out,too...but it's unlikely...the bike is really clean,and just like new...thanks for all of your help,men...I'll keep you posted...

The Garbone · **Reply #10 on:** November 02, 2009, 07:51:07 pm

Quote from: chumma7 on November 02, 2009, 07:47:42 pm

Another possibility is the cable is sheared and strands of it are getting stuck inside the sleeve. This has happened to me while driving and was almost a nightmare.
Check your cable for loose strands and replace is necessary.

Yup, my first throttle cable frayed on both ends like that, probably defective from the start, got 2k miles out of it.

ShenandoahThumper · **Reply #11 on:** November 02, 2009, 07:59:18 pm

I feel your pain as I too have a Aermacchi (HD Sprint 350) in my garden shed.

Chasfield · **Reply #12 on:** November 02, 2009, 08:05:19 pm

After being horrified for a number of months by the sharp bend that the tank's right hand fuel lobe forced upon the throttle cable where it exits the carb, I worked out that there was actually sufficient clearance for the cable to pass between the inner surface of the tank lobe and the spine tube of the frame. It now rises straight up out of the carb, curving reasonable gently into the U section cavity of the tank underside. I don't know if this is a pukka Enfield routing but it works nicely for me. If your carb kicks out sideways some, maybe because of a pancake air filter, then it is probably not going to work, but with the stock filter set up, my carb sits tight into the bike, close to its centre line.

bullethead63 · **Reply #13 on:** November 02, 2009, 08:24:00 pm

Thanks,Chasfield...that's how mine's routed too...I just checked out the cable,next step is pulling and cleaning the carb again...I knew that she'd be a little cranky,after sitting for so long...I've had to replace the battery,battery strap,and some fuel lines and other rubber that was cracked/deteriorated...I'm sure this will all work out...apparently Enfield ownership is a ZEN thing...I wish that my own personal shortcomings and design flaws were as easy to fix...

Chasfield · **Reply #14 on:** November 02, 2009, 08:47:03 pm

I am assuming that we are talking about a standard Micarb instrument, and not an after market Amal Concentric. Those distort and make the slide stick if the two float bowl screws are done up too tight. The Micarb is much better in that respect because the float bowl is located by four screws - and the slide is weightier and made out of better material.

bullethead63 · **Reply #15 on:** November 02, 2009, 09:11:42 pm

Yes,it IS a Micarb,not the Amal...so far,I've managed to get the cable lubed up,and it's not sticking...the slide is moving freely,too,and in sync with the throttle..upon closer inspection,there was some gummy black gunk in the carb,and I think that's what was making the slide hang up...and this spring is a little stiffer than I'd thought...
everything seems to be working,yet the throttle is still wide-ass open...I'm half afraid it's going to blow up the next time that I start it... ???WTF???

bullethead63 · **Reply #16 on:** November 02, 2009, 11:11:58 pm

After a little head-scratching,and repeated re-assembly,I've got her purring like a panther...no sticking,and a nice low,thumpy idle...thanks again to Chasfield,Shenandoah Thumper,Garbone,Chumma7,AceCafe,and RideOn...you guys are the best...I wish I'd had a forum like this when I was trying to keep my '73 HD 350 SS Sprint running...I might still own that cantankerous little beast!

ShenandoahThumper · **Reply #17 on:** November 03, 2009, 12:40:23 pm

Quote from: bullethead63 on November 02, 2009, 11:11:58 pm

.I wish I'd had a forum like this when I was trying to keep my '73 HD 350 SS Sprint running...I might still own that cantankerous little beast!

I also have a 69 350... My sons couldn't believe anybody would have bought one back in the day after they rode it. I need shed space for our bullets and it might have to go. Gonna keep the other beast out there.. 69 441 Victor Special... for the time being.. getting to old to have it try and kick me much longer..

bullethead63 · **Reply #18 on:** November 03, 2009, 02:29:57 pm

HAH! The Sprint was a "special breed",that's for sure...you shouldn't have any trouble unloading it these days;for some reason they've become quite collectible...as for the Bullet,I put ten miles on it last night,putting around the 'hood,and another ten this morning,before work...but it feels like the throttle is getting sticky again...I'll have to clean the slide (again) tomorrow night after work...and add more fresh gas...and the second kickstand bolt,nut and washer must have fallen off somewhere...the Enfield nearly fell over when I put the 'stand down...SURPRISE!...note to self:buy blue Loctite,wrench/ride/repeat...all-in-alll,this is the most fun that I've had in years!

ianw · **Reply #19 on:** November 03, 2009, 09:28:27 pm

I had this happen to me last week just after I'd cleaned the slide and dropped alittle light oil on it. The reason was the O-ring in the carb top. I'd tightened it down just a little bit too far - it doesn't bottom out on anything - and the squeezed out O-ring was then catching hold of the top of the slide. I backed the top off half a turn and she runs perfectly again. At least that's what it seemed to be - can't think of any other explanation

baird4444 · **Reply #20 on:** November 03, 2009, 10:23:46 pm

Check where the cable enters the carby at the top.
Is the slack adjusted out of it?
It takes one heck of a turn... maybe it is binding... can you pull some of excess
back to the carby to lessen that angle?
just a thot... - Mike

bullethead63 · **Reply #21 on:** November 03, 2009, 11:24:34 pm

Thanks for your input...I'll check out both of those ideas...

bullethead63 · **Reply #22 on:** November 05, 2009, 02:27:47 am

Just an update...I cleaned the slide (again),filled 'er up with fresh gas,put another 25 miles on the clock,and not a hitch...no sticky throttle,runs GREAT,and the guys at the gas station thought that it sounded awesome...they also thought it was MUCH bigger (and much older) than it was...they thought that it was a restored classic...hee hee...I guess I'm going to have to keep running fresh gas through this thing,to wash all of the goo out of the fuel system...thanks again for all of your hints,and helpful suggestions...RE riders are the BEST!

bullethead63 · **Reply #23 on:** November 15, 2009, 02:56:59 am

OK...here's the latest...at 275 miles,it's started sticking again...on the advice of a good friend (with considerable experience in Brit bike maintainance),I've put a few drops of Royal Purple synthetic motor oil in the throttle cable,and I've been cleaning the slide with denatured alcohol...and works INSTANTLY...instead of using WD 40,and rubbing a blister on my thumb...I've been careful not to get any on the O-ring,but if gas won't hurt it,denatured alcohol probably wont,either...am I just pissing in the wind here,or should I just replace this throttle cable?Or maybe the carb,too?I deas?Hints?Suggestions?Thanks,Bullethead63~

1Blackwolf1 · **Reply #24 on:** November 15, 2009, 03:40:41 am

At the rate you are lubing the cable I'd probably go ahead and replace it. Sounds like you may have pieces of the cable wearing away from the inside out. Or disassemble the whole thing and see if you can clean out the housing and then reinstall the cable in to the sheath and go from there.

Of course there maybe another vriable in the equation. The throttle control itself may have gunk inside it. If it's the original control they are only two plastic sleeves that rotate on each other. And if the control has any gunk/wear it could cause the problem you have mentioned. Carbs are fairly bullet proof..have disassembled mine a bunch and haven't had any problems there.

I would look at the throttle control and cable as the culprit here. Will.

mrunderhill1975a · **Reply #25 on:** November 15, 2009, 03:54:44 am

,or should I just replace this throttle cable?Or maybe the carb,too?I deas?

I have a couple ideas, .........you should have a spare throttle cable in the tool box at all times anyway, so you won't be stranded in East Shelbyville or the outskirts of Capitol City.

So, get a new cable, keep the old one as a spare in the tool box, and see if it makes any difference. If the new cable doesn't help, look elsewhere. One thought is that if the top of the carb has ever been tightened too tight, the carb body may have been distorted slightly and the throttle slide may bind up. If that is the case, the only solution is to keep using the throttle until it eventually wears into fitment (or get a new carb, but that is a bit extreme). Don't tighten the top of the carb with any tools (just hand tighten) as the tools encourage over tightening.

The only other thing to consider is a weak carb spring but that seems unlikely since it is relatively new.

One more thing just occurred to me,...... old gas varnish may have coated the inside of the needle jet which would cause the needle to bind up in the jet. Take out the needle jet and clean it thouroghly.

bullethead63 · **Reply #26 on:** November 15, 2009, 04:12:39 am

Thanks,all...after working the throtlle for a few minutes (with the fuel turned off,and the bike not running,of course) the Royal Purple seems to have done the trick...I'll take her for a spin tonight or tomorrow,and report back...RE riders are the most helpful that I've met yet!

bullethead63 · **Reply #27 on:** November 15, 2009, 05:44:14 am

WOO-HOO! That did it...20 miles later,and not a hitch...smooth as silk...that Royal Purple really did it...I'll put another 20 on it tomorrow,just to be sure...

bullethead63 · **Reply #28 on:** November 17, 2009, 06:10:52 pm

323 miles on the clock now,without a hitch...YEE-HAH!!!

GBBullet · **Reply #29 on:** November 17, 2009, 11:36:11 pm

i had a similar problem with the stock cable and it was cause by fraying inside the twist grip mechanism. It came and went at first but over time the fraying became worse and It eventually stuck permanently wide open. In my case the stop lug on the end of the cable was not well manufactured in the first place.

apex · **Reply #30 on:** November 18, 2009, 03:38:07 am

Same bit of info, my cable on my 99 is directly under the tank with little clearance. I had a high rev problem and couldn't adjust it out of the idle screw. Then I noticed that the carb had shifted a quarter inch letting the cable come out of the carb housing and catching.
I'd start there if you have gone through the slide.

bullethead63 · **Reply #31 on:** November 22, 2009, 11:13:59 pm

Just another update...386 miles,and no more trouble with the throttle...I took the tank off,leaned the carb (stock Micarb) as far inboard toward the center spine as I could,taped the cable sheath to the frame with black electrical tape (and a zip-tie,just to be safe),pulled the slack forward,out through the casquette,for a nice smooth loop towards the grip,and it's smooth a silk...no sticking,no lag...I'm still cleaning the throttle slide with denatured alcohol every 20-30 miles,as it's really sticky to the touch,but I'm writing that off to old varnish residue in the system...it should clear up sooner or later...today I had the most relaxed ride yet!

bullethead63 · **Reply #32 on:** December 04, 2009, 06:09:09 am

This just in:I just turned over 600 miles on the clock...no more troubles! Haven't had to clean the carb for the last 200 miles...and I'm one happy camper...

Ice · **Reply #33 on:** December 04, 2009, 06:44:28 am

That is good news.