Throttle return question
Thread Starter
|
Road Captain
Joined: Jun 2008
Posts: 640
Likes: 13
From: Hickory, NC area
Throttle return question
My '90 UC with a CV carb doesn't seem to have a throttle return spring. It comes back a little on it's own but mostly I have to twist it to go and twist it pretty good to bring down the rpm. When I come to a stop I have to "push" it back to get the rpm's down around 1k. I also have to be careful between gears to be sure it comes down a little between shifts.
Does anyone know if there should be a spring attaching the cable holder to something immoveable so the throttle snaps closed? Anyone have a pick of the linkage side of their CV that would show how the return works? My manual isn't clear at all.
Does anyone know if there should be a spring attaching the cable holder to something immoveable so the throttle snaps closed? Anyone have a pick of the linkage side of their CV that would show how the return works? My manual isn't clear at all.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
There are two cables, effectively one pulling the carb open, when you open the twistgrip, the other pulling it closed when you close it. There is (should be) a light spring on the side of the carb, but it is not very obvious.
If the twistgrip does not move freely there could be a few problems. The cables may be dry, or even one of them frayed (broken strands of wire) inside. The twistgrip itself could be dry or gummed up on the handlebar.
Also an optional extra (I have one on my 1990 FLHS) is a star-wheel friction device, underneath the twistgrip body, which prevents the twistgrip closing quickly. It can be used like a crude cruise control, to stop the twistgrip closing while driving on the highway, but be unscrewed a bit to free it off. If you have one it could be screwed up tight.
I suggest you may just need some simple maintenance. Dismantle the twistgrip drum, remove the cables from it and check each moves freely in the outer. You probably will find it is either all as dry as a bone, or full of horrible crud! Either condition could jam up the works.
If the cable does not move freely and you cannot get it to do so, replace it with a new one. Grease everything lightly, including the twistgrip on the handlebar, and hopefully all will be OK!
If the twistgrip does not move freely there could be a few problems. The cables may be dry, or even one of them frayed (broken strands of wire) inside. The twistgrip itself could be dry or gummed up on the handlebar.
Also an optional extra (I have one on my 1990 FLHS) is a star-wheel friction device, underneath the twistgrip body, which prevents the twistgrip closing quickly. It can be used like a crude cruise control, to stop the twistgrip closing while driving on the highway, but be unscrewed a bit to free it off. If you have one it could be screwed up tight.
I suggest you may just need some simple maintenance. Dismantle the twistgrip drum, remove the cables from it and check each moves freely in the outer. You probably will find it is either all as dry as a bone, or full of horrible crud! Either condition could jam up the works.
If the cable does not move freely and you cannot get it to do so, replace it with a new one. Grease everything lightly, including the twistgrip on the handlebar, and hopefully all will be OK!
Road Captain
Joined: Apr 2005
Posts: 535
Likes: 14
From: Highspire Pa
If all else fails:
The stock carb on our 1990 Ultra developed a problem with the return spring located on the side of the carb. Even with the cables unhooked from the carb, if you would turn the linkage fully open it would not snap back. In order to get it to return properly we had to loosen the nut that held the linkage on but this had a negative effect of creating a small vacuum leak. I purchased a used CV carb from an '06 Street Glide and have been using that for the last few months, although I nver got it set up propperly it works pretty good.
Recently I learned about a fellow that rebuilds cv carbs and I plan on sending my original carb to him to see if he can fix it.
http://www.harleydavcvcarbrebuild.com/
I have read Wally does a good job, but don't know if my old carb can be fixed for a resonable price, Wally said he would look at it and let me know for sure, but he felt pretty confident he could fix it.
The stock carb on our 1990 Ultra developed a problem with the return spring located on the side of the carb. Even with the cables unhooked from the carb, if you would turn the linkage fully open it would not snap back. In order to get it to return properly we had to loosen the nut that held the linkage on but this had a negative effect of creating a small vacuum leak. I purchased a used CV carb from an '06 Street Glide and have been using that for the last few months, although I nver got it set up propperly it works pretty good.
Recently I learned about a fellow that rebuilds cv carbs and I plan on sending my original carb to him to see if he can fix it.
http://www.harleydavcvcarbrebuild.com/
I have read Wally does a good job, but don't know if my old carb can be fixed for a resonable price, Wally said he would look at it and let me know for sure, but he felt pretty confident he could fix it.
Thread Starter
|
Road Captain
Joined: Jun 2008
Posts: 640
Likes: 13
From: Hickory, NC area
Thanks for the thoughts. My cables are fine and everything rotates well. It just doesn't snap closed. The result is that I can twist it closed lightly and knock it down around 1500 rpm or twist a bit harder and get around 1000 or twist even harder and get to 800 - but it is all guesswork. Seems like there should be a spring somewhere else - connecting the carb linkage to something immoveable - like in a car setup. Doesn't seem like that is the case though. I'll see about replacing the spring on the linkage with something better/newer.
Thread
Thread Starter
Forum
Replies
Last Post
houdinitattoo
Exhaust System Topics
1
Apr 9, 2008 01:36 AM
