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tat2dphreak
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?

realred914
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
Grelber
I've never had a bit of trouble with my hex bar setup.
tat2dphreak
ok, it's a brand new CB perf. linkage... probably still crap, but not old 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?
DBCooper
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.
yeahmag
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.
VaccaRabite
Use nylock nuts on the turnbuckles. I had the same problem until I went to nylocks.

Zach
Root_Werks
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.

driving.gif

I noticed on my carbs a slight inbalance at idle. I went to adjust and have only made it worse so far. headbang.gif

I need to find my sync tool and disconnect linkage, dail in etc. PITA, but once done, should be done.
tat2dphreak
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.


yeahmag
I thought the arm that uses an allen head set screw slipped... No?
tat2dphreak
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)
yeahmag
Is this a CB Performance piece? All the CB's I've owned held the arm to the hex bar with a set screw...
tat2dphreak
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 confused24.gif

I also thought about drilling into the hex bar a little to prevent the bar from sliding..
Jake Raby
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.
yeahmag
Odd... So it doesn't look like this anymore?

IPB Image
Root_Werks
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.
bandjoey
OT but applies: Hurry up Jake and get the new linkage perfected. 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.
dr914@autoatlanta.com
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?

yeahmag
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.
yeahmag
...and an LM-1 permanently mounted doesn't hurt either!
tat2dphreak
QUOTE
OT but applies: Hurry up Jake and get the new linkage perfected.

agree.gif

I was thinking the same thing last night, in between cussing at trying to work on a hot engine because of yet another linkage issue...

this isn't the first linkage issue... the first day I drove the car home after installing the new engine(and linkage) the throttle ear broke WTF.gif then it had been idling high until 2 weeks ago, when Wes and I finally figured out that tie angle of the springs was not letting my wron carbs close all the way, we used stronger springs, and changed the angle, and all was well for a few weeks, until this...

at this point if I knew (another) new linkage would really fix it(I.E. Jake's linkage) I'd pony up the $ ASAP.

my worry is hurting something else, of course after everything else that has gone on... I mean when one carb is running at part throttle and the other is closed, it CAN'T be good... essentially running WAY out of sync. I'm just glad I only had to go a little ways with the issue....

I had the tools in my car, but there was no where to pull off in that last little bit...
yeahmag
Shoot some pictures of your linkage: overall, left, right, throttle bracket

I bet you have something goofy in your geometry if you are having all of these problems. The linkage should work smooth and even.
Root_Werks
Don't know who makes this style, but I do like it. Every adjustement is a threaded rod with lock nut. Very precise and sturdy.
flipb
Here's my solution.

IPB Image

stirthepot.gif
SUNAB914
FI,
Blah, blah, blah
McMark
Don't waste your money on a VDO CHT setup. Read this thread.
tat2dphreak
QUOTE(McMark @ Apr 13 2010, 01:05 PM) *

Don't waste your money on a VDO CHT setup. Read this thread.



yea, I read that yesterday, I'll buy one of those and toss this VDO POS.

the spruce setup looks quite reliable and is even cheaper than a vdo kit smile.gif
yeahmag
I use one too... Love it.
VaccaRabite
agree.gif

I have one in my 914.
Mike saw it and liked it so much he bought one for the bus. The Dakota Digital CHT is the bomb.

Oops. Mine is different from the one in Marks thread. Mine is the digital gauge.
IPB Image

It does not look very 1970, but it is very easy to read. A trade off I was willing to make. If mine ever says 485, my engine is in trouble....

Zach
FourBlades

You probably know this, but just in case: your engine expands up to a half inch
in width as it gets hot, which can cause your cross bar to pop off. I think the
solution is to crank the bolts with the balls on the ends into the ends of the rods
until the springs in there are compressed completely, then tighten the nuts so
they don't gradually back off as the bar rotates.

You probably knew this already, but it was news to me lately.

John
tat2dphreak
no, I did not know the expansion was that great. I will check the spring tension when cold.

I'm getting a late start tonight, decided to drink a few beers with a buddy instead of wrenching :beer:
FourBlades

Nothing wrong with a few beerchug.gif beerchug.gif beerchug.gif

I'd say tighten the ends into the cross bar with the engine stone cold until the
springs are just fully compressed but no more.

I think putting extra tension on it may fatigue and break off the arms on the carb
plates that the cross bar mounts on. You don't want to create a force trying
to spread the carbs apart by over tightening.

John
Mark Henry
If your engine expanded 1/2" that would be .250 per jug and your lets say 9.5Cr would now become about 5.5Cr...unless your saying that your rods also grow 1/4" at 200*F

6061 aluminum @600 degrees expands .010 (that's 10/1000 of an inch) per inch.
So the most expansion you would see is about .040 (.080 for both sides) and at 600 degrees you have way bigger problems to worry about.

And just in case someone wants to figure it out the math is 13 x 10^-6 inch per inch per degree.

Bottom line is it only grows by about .040-.050
Chris Hamilton
If you cant keep the arms from slipping put a couple hose clamps on the bar to keep it in place. It isn't perfect but at least it'll keep your throttle from sticking open until you can get some screws to stay.
VaccaRabite
mark is right. The engine expands when warms, but not 1/2 inch. A few Hundredths of an inch, sure. But 1/2 an inch expansion would lead to the engine eating itself for oil starvation at every bearing point. Folks using bell crank style synchros would have 3000 RPM idles when warm. Its crazy talk!



Jake Raby
I've found that TIV engines expand roughly 1/8" at 350F head temp with cast iron cylinders, a tad more with Nickies. The hotter the engine runs the more the engine expands.

I've had some second thoughts about bringing the Accu-Link system to the market. With all the horror stories of stuck throttles and etc I'd hate to end up in a big mess because someone didn't install the system correctly. I've been trying to reduce the amount of support that we have to offer with products by getting rid of the majority of our components that require extensive installations, set up and tuning. I could see hours being spent on the phone with installers of a system like this because they can't make it run perfectly.

Lots of people that currently have issues will buy a set up like this, because it is the best thing since sliced bread, they'll then find that their issues remain with this system just like the old system. That'll be because their issues weren't related to the linkage in the first place, they just didn't know that or believe that.

I may use the system on my turnkey engines that we can set up ourselves and then sell the idea and patent/ etc to someone else in the industry thats willing to deal with the support that I am not willing to.
DRPHIL914
chris-
I know you really hate the FI ?!?!?
I have had my share of carb problems too- 69 austin healy with dual webbers(back in h.s.-25 yrs ago+) i date myself. - but after struggling to return my 75 2.0 to good function f.i., i am ready to try the carbs!!!!
too.- i think it is the old ECU and vaccuum that cause most problems- the injectors etc are not the culprit, - but each to his own i guess!
biosurfer1
QUOTE(Jake Raby @ Apr 14 2010, 06:34 AM) *


I've had some second thoughts about bringing the Accu-Link system to the market.



Well that's not good news...I've been waiting months for this product. Guess I should have just gone with something else.
Jake Raby
QUOTE(biosurfer1 @ Apr 14 2010, 08:14 AM) *

QUOTE(Jake Raby @ Apr 14 2010, 06:34 AM) *


I've had some second thoughts about bringing the Accu-Link system to the market.



Well that's not good news...I've been waiting months for this product. Guess I should have just gone with something else.


Thats why I never recommend people waiting on a development, we may have issues making it work sufficiently or for some other reason it may not go to market.

The Accu-Link is a great product, but unfortunately it requires unconventional installation compared to other systems and the learning curves related to installation would surely create issues for us.

..and my insurance company flipped out when they caught wind that we were developing a throttle related product. Thanks Toyota, you bastards.
bandjoey
If it's that good, shoot a quick DVD of the install, and include that and then sell the linkage with a No Support clause in the legal paper we have to sign before shipping. idea.gif

If this isn't going to happen Jake, what's the alternative to hex bar that works and is easy for us nubes to adjust? Thanks for the help and info. biggrin.gif
DBCooper
Look, spend a few minutes with it and figure the CB hex linkage out. It's been used by thousands of people for decades and decades and is NOT that complicated! And it works just fine, tens of thousands of miles before you'll ever touch it again.

If you want to try a bell crank type look on the VW sites for CSP (Custom and Speed Parts) which is a German aftermarket import. I don't know if they have a T4 version, but the T1 guys swear by them.
biosurfer1
I have spent HOURS with the hex linkage. I know exactly how it's supposed to work but for some reason, mine doesn't. I get everything sync'd perfectly with linkage disconnected and once I hook it up, everything is out of whack again. I try the smallest adjustment and it swings the other way out of sync.

Thousands and thousands of people used lead based paint for decades and decades...doesn't mean you would/should use it today. If there is something better out there, why wouldn't I use it instead?

Bellcrank it is
McMark
QUOTE
figure the CB hex linkage out. It's been used by thousands of people for decades and decades and is NOT that complicated! And it works just fine,


It works just fine. As in just barely. tongue.gif
tat2dphreak
QUOTE
It works just fine. As in just barely.

kinda the way I feel too... when it's working it's fine, it just seems to need tweaking from time to time, which is annoying as piss.

I've dated women that were less needy.
DBCooper
QUOTE(tat2dphreak @ Apr 14 2010, 11:35 AM) *

I've dated women that were less needy.


lol-2.gif Linkages are cheaper, at least!

.
Chris Hamilton
QUOTE(Philip W. @ Apr 14 2010, 07:52 AM) *

chris-
I know you really hate the FI ?!?!?
I have had my share of carb problems too- 69 austin healy with dual webbers(back in h.s.-25 yrs ago+) i date myself. - but after struggling to return my 75 2.0 to good function f.i., i am ready to try the carbs!!!!
too.- i think it is the old ECU and vaccuum that cause most problems- the injectors etc are not the culprit, - but each to his own i guess!


Me?

I don't hate EFI, I just hate L-Jet and D-Jet. You couldn't convince me to take the EFI off of my 94" Honda D16Z6 engine. But hey that's what 30 years of technology does for ya. If I had the money my 914 would have ITBs and a Haltech ECU instead of Dellortos.
Mark Henry
I'd tool up and make a HQ center pull linkage, but the joints I use are $13 each and I need 6 so right away they are over $78 in just joints.
I didn't worry about the cost as I only built linkages for complete engine jobs.
Jake Raby
QUOTE(bandjoey @ Apr 14 2010, 10:28 AM) *

If it's that good, shoot a quick DVD of the install, and include that and then sell the linkage with a No Support clause in the legal paper we have to sign before shipping. idea.gif


If it were only that easy....

Guess what happens when something is sold with a lack of support or disclaimers?? The support is still required, BUT the purchaser is forced to ask other people that generally know less than he does and then things are really fucked up. Its impossible to sell components that defy convention without support, otherwise the questions end up here and then the whining begins and I am forced to go tell someone to insert another tampon, take a Midol and figure the damn thing out themselves.. Then a pissing match begins because a couple of people had an issue and it didn't work PERFECTLY out of the box.

When something is expensive and well refined it is expected to work better than anything else, but something like this component system is heavily dependent upon installation and initial synchronization. I'd much rather not sale something as to have issues with something that is sold, luckily the money aspect of what makes this place tick isn't my primary concern.


QUOTE
If this isn't going to happen Jake, what's the alternative to hex bar that works and is easy for us nubes to adjust? Thanks for the help and info. biggrin.gif

Nothing is easy. Don't fool yourself into thinking it will be, common sense is the biggest requirement.


tat2dphreak
got down to the real root of the issue... the treads that keep that bar in place were boogered up and letting the nut loosen up... I tightened it up, synced everything, then went to double check and that nut was loose again... this time I tried wiggling it, and within a little bit it backed off just enough to let the bar move... I'll drill and re-tap that tomorrow.
McMark
Glad you found something wrong. It's nice to have something to fix, versus being stuck in troubleshooting hell. cool.gif
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