 $&%&*% carb linkage, does it ever stop needing? |
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| tat2dphreak |
 Apr 13 2010, 09:20 AM
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#1
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stoya, stoya, stoya  Group: Benefactors Posts: 8,797 Joined: 6-June 03 From: Wylie, TX Member No.: 792 Region Association: Southwest Region   |
ok, so I'm driving home last night 80 degrees, breezy... beautiful day, car is running GREAT!
clicking along at 65, everything is great... I go to make the second to last turn to get home( maybe 1 mile from home) and when I hit the clutch, the motor stays humming at 3500 rpms... like the throttle is stuck... there's no place to pull over at this point(ditch on one side of the road, and the other is a concrete barrier where they are doing construction... so the last mile, I cruise it as easily as possible home, using 3rd gear to keep it from accelerating too fast... my oil temps stayed below 185(my CHT still doesn't work, I think I flat got a bad gauge from VDO, I am going to break down and buy another whole gauge kit. once home I pop the engine lid, one side of the linkage bar had slipped down the hex bar, basically holding one carb open a little, which was the throttle problem. I tighten everything back up, re-set the springs(one had slipped out of the spring hole on the throttle shaft) re-sync, everything seems ok again... my question is this... should plan on this being the norm? hat I need to check and tweak the linkage every couple of weeks? also, since I was basically running very out of sync for a mile or so, should there be anything I need to check? any potential damage to watch for? |
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| realred914 |
Apr 13 2010, 09:23 AM
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#2
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Senior Member Group: Retired Members Posts: 1,086 Joined: 1-April 10 From: california Member No.: 11,541 Region Association: None |
QUOTE(tat2dphreak @ Apr 13 2010, 08:20 AM)  ok, so I'm driving home last night 80 degrees, breezy... beautiful day, car is running GREAT! clicking along at 65, everything is great... I go to make the second to last turn to get home( maybe 1 mile from home) and when I hit the clutch, the motor stays humming at 3500 rpms... like the throttle is stuck... there's no place to pull over at this point(ditch on one side of the road, and the other is a concrete barrier where they are doing construction... so the last mile, I cruise it as easily as possible home, using 3rd gear to keep it from accelerating too fast... my oil temps stayed below 185(my CHT still doesn't work, I think I flat got a bad gauge from VDO, I am going to break down and buy another whole gauge kit. once home I pop the engine lid, one side of the linkage bar had slipped down the hex bar, basically holding one carb open a little, which was the throttle problem. I tighten everything back up, re-set the springs(one had slipped out of the spring hole on the throttle shaft) re-sync, everything seems ok again... my question is this... should plan on this being the norm? hat I need to check and tweak the linkage every couple of weeks? also, since I was basically running very out of sync for a mile or so, should there be anything I need to check? any potential damage to watch for? not nrom unless you allow it to be norm. loose screw? get a new one, threads may be worn, still losse? new lock washers lock nuts, nylocks, etc are solutions, so is thread sealant, like lock tite. give that a go first, or maybe youhave a cheapo bendable linakge and need to upgrade no it dont need to be the norm. goood luck |
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| Grelber |
Apr 13 2010, 09:33 AM
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#3
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Insert favorite Don Rickles joke here. Group: Members Posts: 690 Joined: 30-May 06 From: McKinney, Texas Member No.: 6,107 Region Association: Southwest Region |
I've never had a bit of trouble with my hex bar setup.
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| tat2dphreak |
Apr 13 2010, 09:41 AM
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#4
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stoya, stoya, stoya Group: Benefactors Posts: 8,797 Joined: 6-June 03 From: Wylie, TX Member No.: 792 Region Association: Southwest Region |
ok, it's a brand new CB perf. linkage... probably still crap, but not old (IMG:style_emoticons/default/smile.gif)
it's not bending, thankfully, just one piece slid down the hex.. I'll put some loctite on that tonight, I didn't think about it last night, since I was too worried about something else being a problem.... would this situation?potentially cause any other issues? |
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| DBCooper |
Apr 13 2010, 10:07 AM
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#5
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14's in the 13's with ATTITUDE Group: Members Posts: 3,079 Joined: 25-August 04 From: Dazed and Confused Member No.: 2,618 Region Association: Northern California |
Nah, just fix it and you're done. People complain about the hex bars (heck, people complain about everything) but there are lots worse setups out there, believe me.
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| yeahmag |
Apr 13 2010, 10:11 AM
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#6
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Advanced Member Group: Members Posts: 2,443 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California 
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You need to give the set screws a good "omph!" when tightening them. If it still backs out you can try blue LocTite, but it's probably a defect or worn at that point.
I'd also suggest if you are using the stand off on the passenger side carb to double up on the lever arms that are attached to the carb. The will eventually fatigue and break. |
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| VaccaRabite |
Apr 13 2010, 10:12 AM
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#7
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En Garde! Group: Admin Posts: 13,628 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region
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Use nylock nuts on the turnbuckles. I had the same problem until I went to nylocks.
Zach |
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| Root_Werks |
Apr 13 2010, 10:15 AM
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#8
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Village Idiot Group: Members Posts: 8,520 Joined: 25-May 04 From: About 5NM from Canada Member No.: 2,105 Region Association: Pacific Northwest
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Everything on your linkage should be double nutted (to lock) or nylock only used a couple of times.
Once linkage is set, should pretty much be good like the old MFI set ups. If anything is coming loose, don't use locktite, get another nut to lock against it or a nylock nut. (IMG:style_emoticons/default/driving.gif) I noticed on my carbs a slight inbalance at idle. I went to adjust and have only made it worse so far. (IMG:style_emoticons/default/headbang.gif) I need to find my sync tool and disconnect linkage, dail in etc. PITA, but once done, should be done. |
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| tat2dphreak |
Apr 13 2010, 10:15 AM
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#9
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stoya, stoya, stoya Group: Benefactors Posts: 8,797 Joined: 6-June 03 From: Wylie, TX Member No.: 792 Region Association: Southwest Region |
happen to remember the size of nylock? I know it was a 11mm wrench I used to tighten it last night, I'll stop by tonight and get nylocks.
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| yeahmag |
Apr 13 2010, 10:16 AM
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#10
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Advanced Member Group: Members Posts: 2,443 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California
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I thought the arm that uses an allen head set screw slipped... No?
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| tat2dphreak |
Apr 13 2010, 10:20 AM
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#11
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stoya, stoya, stoya Group: Benefactors Posts: 8,797 Joined: 6-June 03 From: Wylie, TX Member No.: 792 Region Association: Southwest Region |
no. the arm piece that actuates the throttle slid down the hex bar... that piece is held by a set bolt and a jamb nut.... on mine at least.the hex bar was still tight between the carbs(spring loaded)
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| yeahmag |
Apr 13 2010, 10:22 AM
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#12
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Advanced Member Group: Members Posts: 2,443 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California
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Is this a CB Performance piece? All the CB's I've owned held the arm to the hex bar with a set screw...
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| tat2dphreak |
Apr 13 2010, 10:24 AM
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#13
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stoya, stoya, stoya Group: Benefactors Posts: 8,797 Joined: 6-June 03 From: Wylie, TX Member No.: 792 Region Association: Southwest Region |
QUOTE Is this a CB Performance piece? All the CB's I've owned held the arm to the hex bar with a set screw... yep CB perf. I bought it last year. it came with a 11mm hex bolt for that (IMG:style_emoticons/default/confused24.gif) I also thought about drilling into the hex bar a little to prevent the bar from sliding.. |
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| Jake Raby |
Apr 13 2010, 10:30 AM
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#14
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Engine Surgeon Group: Members Posts: 9,398 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
It is what you make of it..
Either you can get it right or you can't, either way you are right. Hexbar linkage works well, just as well as carburetors themselves. Neither are precision devices. |
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| yeahmag |
Apr 13 2010, 10:32 AM
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#15
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Advanced Member Group: Members Posts: 2,443 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California
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Odd... So it doesn't look like this anymore?
(IMG:http://www.cbperformance.com/catalogimages/3144.jpg) |
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| Root_Werks |
Apr 13 2010, 10:38 AM
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#16
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Village Idiot Group: Members Posts: 8,520 Joined: 25-May 04 From: About 5NM from Canada Member No.: 2,105 Region Association: Pacific Northwest
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Not sure if it helps, but the linkage on my carbs use a center pivot with arms to each carb. No cross-bar. I really like it, everything has a lock nut that tightens so once adjusted, it stays.
Very smooth operation as well. |
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| bandjoey |
Apr 13 2010, 10:53 AM
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#17
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bandjoey Group: Members Posts: 4,930 Joined: 26-September 07 From: Bedford Tx Member No.: 8,156 Region Association: Southwest Region |
OT but applies: Hurry up Jake and get the new linkage perfected. (IMG:style_emoticons/default/biggrin.gif)
My problem is always always getting the sync set on both sides, and then in tightening up everything, messing up one side slightly over the other. CB works, just not very friendly to me. I'm adding some metric nuts and set screws to my car tool box for the hex bar, after what Wayne just went through. |
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| dr914@autoatlanta.com |
Apr 13 2010, 11:01 AM
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#18
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914 Guru Group: Members Posts: 8,111 Joined: 3-January 07 From: atlanta georgia Member No.: 7,418 Region Association: None |
I feel your pain having to deal with the heartbreak of carburetion on a 914. Some crossbar linkage kits are far superior to others, that may be your problem. The ultimate solution (as I profess every day) is factory fuel injection!!!
. QUOTE(tat2dphreak @ Apr 13 2010, 08:20 AM) ok, so I'm driving home last night 80 degrees, breezy... beautiful day, car is running GREAT! clicking along at 65, everything is great... I go to make the second to last turn to get home( maybe 1 mile from home) and when I hit the clutch, the motor stays humming at 3500 rpms... like the throttle is stuck... there's no place to pull over at this point(ditch on one side of the road, and the other is a concrete barrier where they are doing construction... so the last mile, I cruise it as easily as possible home, using 3rd gear to keep it from accelerating too fast... my oil temps stayed below 185(my CHT still doesn't work, I think I flat got a bad gauge from VDO, I am going to break down and buy another whole gauge kit. once home I pop the engine lid, one side of the linkage bar had slipped down the hex bar, basically holding one carb open a little, which was the throttle problem. I tighten everything back up, re-set the springs(one had slipped out of the spring hole on the throttle shaft) re-sync, everything seems ok again... my question is this... should plan on this being the norm? hat I need to check and tweak the linkage every couple of weeks? also, since I was basically running very out of sync for a mile or so, should there be anything I need to check? any potential damage to watch for? |
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| yeahmag |
Apr 13 2010, 11:03 AM
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#19
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Advanced Member Group: Members Posts: 2,443 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California
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It just takes time. I've been setting up the CB linkage for probably 15 years now and have it dialed. My carbs are in perfect sync, it's reliable, and drives smooth as silk.
Carbs (and their linkages) are a bit of a black art. |
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| yeahmag |
Apr 13 2010, 11:04 AM
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#20
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Advanced Member Group: Members Posts: 2,443 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California
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...and an LM-1 permanently mounted doesn't hurt either!
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