Author Topic: throttle cables (Read 2260 times)

egar · « **on:** May 17, 2009, 06:34:43 AM »

Okay, so I've spent the morning reading every thread possible about throttle cable problems. Here's mine. I began rebuilding my 77 550k from the frame up in sept.
The only thing keeping me from hearing the engine run is the installation of the new throttle cables. I first went with drag bars but the pull cable was waaay to long. So I put the stock bars back on the bike and installed the cables. There is too much cable still. And even if I configure the cable different ways to take in the slack, that means the black cover with the adjustment screws is too far away to be mounted on the holder thingy on the carb. I bought the stock cables as recommended by one of you guys a couple of weeks ago from Motion Pro. I'm really a a loss at this point and cannot figure out why this problem exists now that I'm back to the stock bars. Any suggestions?

Gordon · « **Reply #1 on:** May 17, 2009, 06:42:18 AM »

Quote from: egar on May 17, 2009, 06:34:43 AM

There is too much cable still. And even if I configure the cable different ways to take in the slack, that means the black cover with the adjustment screws is too far away to be mounted on the holder thingy on the carb.

I'm confused by this part... $:-\$

egar · « **Reply #2 on:** May 17, 2009, 06:56:54 AM »

I'll try to describe better (and post a picture later after running errands) but basically if I lock the black sheathed art of the cable by using the adjustment screws, there is way too much cable. The cable itself hangs way past the butterfly/wheel thing that opens and closes the carbs. Which means if I hook the carb end of the cable up to the carb, the black portion of the cable with the adjustment screws is too far away to anchor on and lock in place witht the cable adjustment screws.

Gordon · « **Reply #3 on:** May 17, 2009, 07:53:39 AM »

Quote from: egar on May 17, 2009, 06:56:54 AM

I'll try to describe better (and post a picture later after running errands) but basically if I lock the black sheathed art of the cable by using the adjustment screws, there is way too much cable. The cable itself hangs way past the butterfly/wheel thing that opens and closes the carbs. Which means if I hook the carb end of the cable up to the carb, the black portion of the cable with the adjustment screws is too far away to anchor on and lock in place witht the cable adjustment screws.

Do you have the top end of the cable attached to the throttle grip when experiencing this problem?

egar · « **Reply #4 on:** May 17, 2009, 08:50:44 AM »

Yes. The throttle cables are both attached at the throttle grip end of the deal.

Gordon · « **Reply #5 on:** May 17, 2009, 01:40:06 PM »

Got that picture yet?

egar · « **Reply #6 on:** May 17, 2009, 03:57:24 PM »

You guys post better pictures than I.
Here's the other thing I noticed. Even if I could lose some throttle play to get the pull cable on and not have slack, it leaves hardly any cable to wrap around the bottom of the butterfly wheel (what it resembles to me) to attach the push cable. It's almost as if the cables were backwards, but as we all know, they thread in differently at the throttle end. Plus I checked the catalogue number with motion pro....

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egar · « **Reply #7 on:** May 17, 2009, 04:00:43 PM »

The last picture was the wrong one, obviously. I suck at posting pix.

OldSchool_IsCool · « **Reply #8 on:** May 17, 2009, 04:42:31 PM »

I think you might have your cables reversed. The "pull" cable (the one that retracts when you twist your throttle) should thread under the throttle cam and slip into the hool-like structure you see there in your first pic. The "push" cable clamps on tom and grabs into the hole just above the screw head in pic #1.

egar · « **Reply #9 on:** May 17, 2009, 06:00:39 PM »

Old school,

The length would make much more sense, since the pull is too long for the top and the push is too short to wrap around the bottom of the wheel and hook in, but the wheel (I forgot what you just called it - the correct name - turns forward to open the carbs, so wouldn't the pull cable have to be at the top and the push wrap around the bottom? At the throttle end, the pull cable is the front cable and the push is at the back, correct? I would love to switch them around at the throttle end but they are threaded differently. The front cable screws right in and the rear has a metal tube that is seated up inside the throttle before you can tighten the outer screw up into the throttle. Does that make sense?

OldSchool_IsCool · « **Reply #10 on:** May 18, 2009, 08:07:58 PM »

Egar,

I looked over my cables (sorry no pics, my cam SUX!) and can tell you this. The cable with the long tail should mount to the throttle grip in FRONT socket such that the cable is PULLED when you accelerate. The tail end threads UNDER the throttle cam on top of the carbs. This cable pulls AGAINST the return spring. The short tailed cable fits to the REAR of the grip and the TOP of the throttle cam and is pushed by the return spring.

Does this make sense with what you are seeing?

egar · « **Reply #11 on:** May 21, 2009, 11:30:43 AM »

Old school,
If I can get them to thread in at the throttle end the way you described, it should work. If it works, I will kiss you! Will try it as soon as I get home.

OldSchool_IsCool · « **Reply #12 on:** May 21, 2009, 12:23:51 PM »

Well now I have mixed hopes that it will work for you!!

egar · « **Reply #13 on:** May 21, 2009, 03:07:36 PM »

Old school,
The throttle cables cannot be switched at the throttle end as they are threaded differently. So I had that part right (it matched what I ordered). So I am stuck with a pull that is too long and a push that is too short. The thing is that the butterly wheel thingy that you attach the cables to at the carb turns forward (or counterclockwise if you are looking at the left side of the bike). It springs back clockwise. I don't know what to do with the bike at this point unless I order custom cable. I'm at a loss, since I ordered them to the year specified at Motion pro.....

OldSchool_IsCool · « **Reply #14 on:** May 21, 2009, 05:49:03 PM »

It's a '77 550K with PD carbs, right? There is a thumb screw to adjust the idle between carb 3&4. The return spring is there also, right?

egar · « **Reply #15 on:** May 22, 2009, 04:36:00 AM »

Oldschool,

I will take a photo this weekend. I swear the carbs don't look the same as my last 550k. There's something strange about the thumb screw. It's not even touchng the part that's supposed to spring against it.

jordanp · « **Reply #16 on:** June 06, 2009, 10:00:50 AM »

Hi, first post here.... Lovin the forum so far... any news on this? I just picked up a 78 750k and cant get the stock throttle pull to work right either.... stock bars and everything... curious to know your solution as I just went down to motionpro headquarters and bought new cables that still dont work

goon 1492 · « **Reply #17 on:** June 06, 2009, 12:04:30 PM »

There wouldn't be a case of the P.O's going on here, previous owners can make mysteries for us to figure out. It at first sounds like the cables are switched around but you say that's not the case, almost sounds like different parts mixed together, could you talk to motion pro about your problem and maybe they can find cables that are the right legnth to adjust for the changes?
Then take the first cables you bought and let them go for sale for that year make and model and hope the next guy/gal has that setup and will be able to use them.

Joel · « **Reply #18 on:** June 06, 2009, 12:07:37 PM »

Does Motion Pro make all their cables to order? Perhaps they got some of the parts mixed around during construction and made the cables the opposite lengths.

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Author Topic: throttle cables (Read 2260 times)