Why did HD get rid of the throttle cable?

[76shuvlinoff]

 My 76 has a single cable, when I bought the 09 and saw two cables I thought that was overkill but from what I read here.... life is good!

[CraigArizona85248]

There's a number of reasons for TBW.  
- reduces cost
- reduces build complexity
- reduces cost of ownership - less maintenance required.  No oil and adjustment on 2 cables.
- gives engineering more control of vehicle - they can now limit the rate of acceleration, etc.
- reduces clutter for better asthetics - same as when they got rid of the speedo cable some years ago
- state of the art technology.
- integrated cruise control - no more cruise module - again less cost and build complexity and much more
 dependable.  There should now be very few warranty claims on defective cruise control outside of bad
 switches.
- probably in an overall sense, somewhat more dependable than cables. I'm sure Engineering would be
 able to prove that statistically, whether its true or not.  
- could help reduce emissions by giving engineering control of throttle.   Software could limit speed,
 throttle opening, etc for emissions purposes.
jt

I don't buy that it reduces cost, build complexity or cost of ownership.  One replacement of a TBW will cost enough to supply you with throttle cables to outlast several bikes.

-Craig

[96flhpi]

My 76 has a single cable, when I bought the 09 and saw two cables I thought that was overkill but from what I read here.... life is good!

BTW, Yarddog - ya might wanna try lubing up the cables once in a while

[harleyjt]

You hear about DBW issues because the majority of users dont post about it working.  Only a very small number of owners actually experience DBW problems, not a majority, as you may beleive.  At least, that is what my dealer told me.

As for me, I am not worried to upgrade my 07 cable bike to DBW.  Its proven technology, just look at the 1,000's of commercial aircraft using it every day transporting millions of people around the globe.  That isnt to say MoCo hasnt done a perfect job of implementing it, but same can be said for pretty much every part on a HD bike--it aint perfect for sure.

menace

Exactly.  It's also been used in the railroad industry for many years as well. 

When I was working for Chrysler and we first introduced this technology on the new Hemi, I braced myself for a barrage of complaints and allegations about runaway cars and complaints that the throttle was the reason I had a wreck, etc etc.  It never happened.  In fact, the very few issues we had, generally dealt with the vehicle not wanting to accelerate.  Much the same as what some have posted here.  It really hasn't been a problem and for the most part is very reliable. 

I'm not scared of it at all. My only beef is that now they - engineering - can program in how they want the vehicle to respond - engineering now has the power to "make you" take you foot off the throttle.   They can limit how hard you hammer the throttle as well. This can be beneficial as it will help the automatic transmission's life expectancy.  It can help with engine life as well - just try matting the throttle in neutral now and see what happens.  She's only going to go so high, and thats it.   
jt

[hotroadking]

TBW is just one more natural progression in the advancement of the EFI systems at HD

remember MM? couldn't idle worth a crap, hot, cold, leaks, tps what a PIA, and everyone bitched
then delphi, better, better control, less idle problems single bore intake better design runs well

Now TBW - less parts ie cables and cruise control module and cable - gone.  

JMO TBW is part progressive tech, part EPA/Emissions control.

HD in order to give us our beloved air cooled engines must take as much control over the efi delivery and burn rates as well as exhaust in order to maintain the air cooled engine in production....

So far I havent' had any issues with the 09's TBW but I admit I let the 08 get on the road for the bugs to get worked out first, never , ever buy the first year of production, you're a beta owner....

Corvette has had TBW for years and you don't see them running out of control, Yamaha's liter bikes all have tbw the 600 might as well and those are 160 HP 180 MPH race bikes...

Also  if the mo co engineers can slow the rate of acceleration,  the aftermarket will figure out how to improve it....

[wavlovr1]

if you have ever tried to adjust the throttle plate opening to coincide with the twist at the throttle on a TBW bike the answer is obvious. At lower throttle positions TBW controls the amount of actual throttle plate opening. Now just consider that (1) the bike is set to run lean as hell to meet emmisions specs, (2) the TBW is used so far on only the heaviest harley models.

When the TBW is set to open the blade at the same rate as the throttle twist, you get major pinging. The timing is too advanced for the mixture of fuel provided on that heavy bike. Either you richen up the mixture or retard the timing to solve the problem. I believe that TBW is the only way HD could get decent performance with adaquate timing on the heavy bikes while still maintaining an EPA compliant exhaust. JMO, jimbob

[Ultrashovel]

if you have ever tried to adjust the throttle plate opening to coincide with the twist at the throttle on a TBW bike the answer is obvious. At lower throttle positions TBW controls the amount of actual throttle plate opening. Now just consider that (1) the bike is set to run lean as hell to meet emmisions specs, (2) the TBW is used so far on only the heaviest harley models.

When the TBW is set to open the blade at the same rate as the throttle twist, you get major pinging. The timing is too advanced for the mixture of fuel provided on that heavy bike. Either you richen up the mixture or retard the timing to solve the problem. I believe that TBW is the only way HD could get decent performance with adaquate timing on the heavy bikes while still maintaining an EPA compliant exhaust. JMO, jimbob

That's a very good explanation. It makes sense that under certain conditions a linear applicaton of throttle does not provide optimum performance.

[hotroadking]

That's a very good explanation. It makes sense that under certain conditions a linear applicaton of throttle does not provide optimum performance.

Does that mean that the CV carbs slide was a good idea to control air flow velocity  LOL

[Ultrashovel]

That's a very good explanation. It makes sense that under certain conditions a linear applicaton of throttle does not provide optimum performance.

Does that mean that the CV carbs slide was a good idea to control air flow velocity  LOL

Absolutely. That's one good reason why a bike with a CV will start much easier than a bike with a regular sidedraft carb. The air is nicely controlled until needed. That's also why drilling a larger hole in the slide and cutting the spring down so the slide will open faster is counter-productive. People do like to tinker with them but they are really just fine if left alone other than calibrating them to a particular bike with a different needle and jets if necessary.

My personal opinion is that the standard 42 mm CV Keihin is the best bike carburetor ever built. I ran one on my former Shovelhead for more than 10 years with never so much as a burp. They were widely used on the Japanese big four prior generation bikes to good adavantage.

One good example was the GL1500 Honda Goldwing (1988-2000 6 cylinder). They had two Keihin CV's side-by-side and that gave them a truly seamless performance - almost as good as fuel injection. Harley also made good use of them as we all know.

If I ever get another older HD, I will run another CV carb. They are great!

[truck]

I had a Harley with TBW back in the 60's (you know the kind). The wire broke, but I was able to ride home by working the carburetor linkage with my right hand by reaching down under the tank.
TBW is nothing new, it's come full circle, just like the secondary drive belt.

[wayzalot]

I just like dependabe equipment.  my throttle cable lasted ove 50,000 miles and when it broke (by the throttle) I took off the adjuster and grabed a handful of cable and made it home.  Simple is more dependable.  Now if you will excuse me I need to adjust the aluminum foil on my rabbit ears on my black and white zenith. 

[FLTRI]

That's a very good explanation. It makes sense that under certain conditions a linear applicaton of throttle does not provide optimum performance.

Does that mean that the CV carbs slide was a good idea to control air flow velocity  LOL

Absolutely. That's one good reason why a bike with a CV will start much easier than a bike with a regular sidedraft carb. The air is nicely controlled until needed. That's also why drilling a larger hole in the slide and cutting the spring down so the slide will open faster is counter-productive. People do like to tinker with them but they are really just fine if left alone other than calibrating them to a particular bike with a different needle and jets if necessary.

My personal opinion is that the standard 42 mm CV Keihin is the best bike carburetor ever built. I ran one on my former Shovelhead for more than 10 years with never so much as a burp. They were widely used on the Japanese big four prior generation bikes to good adavantage.

One good example was the GL1500 Honda Goldwing (1988-2000 6 cylinder). They had two Keihin CV's side-by-side and that gave them a truly seamless performance - almost as good as fuel injection. Harley also made good use of them as we all know.

If I ever get another older HD, I will run another CV carb. They are great!

I had a Harley with TBW back in the 60's (you know the kind). The wire broke, but I was able to ride home by working the carburetor linkage with my right hand by reaching down under the tank.
TBW is nothing new, it's come full circle, just like the secondary drive belt.

[04glide]

I just went back to a carb. When my 04 FI bike was totaled and I bought the 03 I was real happy to have a carb again. I just added pipes and tuned the carb myself. Cost me $17 and it is running great. 

[carolinayarddog]

"BTW, Yarddog - ya might wanna try lubing up the cables once in a while" 

Thanx 96, but I'm way ahead of you.  I even soaked one in a coffecan of oil overnight before I installed it.  I wash the bike regularly and I suppose all that extra moisture shortens the life

 

[wayzalot]

I just went back to a carb. When my 04 FI bike was totaled and I bought the 03 I was real happy to have a carb again. I just added pipes and tuned the carb myself. Cost me $17 and it is running great. 

Exactly how I feel.  I guess there are two kinds of motorcycle riders.  Those that like the new technowlagy (which is great when it works) and those that like the reliable, be able to pull over and adjust and go type.  Now I might get hammered for saying that but I think there are two kinds.  My buddy rides his 47 knuckle like he stole it.  Once in a while we have to stop and fix or adjust something but lots of fun.  

[CraigArizona85248]

I already did that.  It only took a second because my lawn is so small.  Damn hooligans!  And if I catch that kid up the street I'm gonna hold him down and cut his hair.  Damn hippies!

-Craig

[redrokit8]

I have an '09 w/TBW and never had a bike run better.
There is no 100% touble free product that is mass produced.
It's human nature to reject change. We're creatures of habit.
If you don't embrace new technologies, that's ok. Stay with what you've got.
If given the chance, you should experience the new tecnologies as a bases for your beliefs / objections. Then you'll know for sure if it's for you or not.