Erbman02 wrote:
USAFRETIRED wrote:
If you have resistors plugged into the tps cable, then the actually tps cable end is missing that connects to the carb. Whoever did that must of known of that trick from back when we started adapting the S&S carbs. The resistors are suppose to fool the ecu into believing the tps was there. Here is a pic from way back when we did these.

http://i837.photobucket.com/albums/zz294/usafretired1997/TPS.jpg


It might stop the stock ecu from causing the blinks, but it also never allows the it to go into WOT timing curve, keeps it in CT curve regardless of throttle position. Without resistors, by default the ecu goes into wot curve, but you get the blinks. If you have the dyn3k, without resistors, it to by default goes into WOT curve, but no blinking of light.
I don't know enough about timing curves, but both Yamaha and Dyna use by default WOT curve and not the CT curve, there must be a reason tho to use WOT?? This resistor set-up over rides the default mode and keep it in the CT curve.
=====================================

I believe they use the WOT timing curve is because in most cases when at WOT it's best to back off/retartd timing a few deg to avoid possible damage from detonation when at WOT/full load.

But when not at WOT & at low load part throttle steady speed cruise a few deg additional timing can be very usefull.

Thats because it can increase fuel mileage/improves throttle responce making it cripser & motor more responsive/also makes the motor run a little cooler too(as long as timings not overadvanced for cam/compression/combustion chamber/head design)which is important for an air cooled bike motor/etc.

That's what the vacuum advance & mechnical advance did on the older cars running a distributor advacing and or retarding timing depending on load via engine-intake vacuum (vac adv) and or depending on engine rpm (spring loaded mech-centrifical adv in dist) . the older motors when at WOT the intake vacuum drop very low temporairyly deactivatreing the vac adv which then retarteds the timing when at WOT where only the mech adv in dist is still adding timing.

Then when you back of throttle back to steady stat cruise the intake vacuum increases again reactivating vac adv in turn adding timing/advacing it again .

On avg when at steady state low load cruise with distributors timing was roughly 50deg +- few deg but when ya went to WOT(deactivating vac adv due to lower int vac) just runing on mech adv in the dist that 50 deg steady state timing then went to 36-38 deg on avg when vac adv was temporarily removed when at WOT. Then whan ya backed off the gas that increased intake vac again reactivating vac adv for more timing again.

Scott

takehikes wrote:
"If I were going back to stock carb system. . . I would shoot myself!

Unbolt that carb and toss in trash (please god dont recycle it some other foolish motorcycle company might find it) then bolt on a Mikuni 42 and smile.


I wouldn't shoot myself but theres no way in h*** you could make me put the miserable stock carb back on .. A 2 year old could jet the HSR42 and it would still work lightyears better than stock. Please don't put that stocker back on you can find an HSR42 on ebay reasonable.

I do have to agree with you 3 UP. I love my 45's.

3 UP wrote:
takehikes wrote:
"If I were going back to stock carb system. . . I would shoot myself!

Unbolt that carb and toss in trash (please god dont recycle it some other foolish motorcycle company might find it) then bolt on a Mikuni 42 and smile.


I wouldn't shoot myself but theres no way in h*** you could make me put the miserable stock carb back on .. A 2 year old could jet the HSR42 and it would still work lightyears better than stock. Please don't put that stocker back on you can find an HSR42 on ebay reasonable.

Oh man, you guys are making me feel better already

I just want to get her to run right now, we can worry about making her fly later. Got low 80 degree days right now that won't last forever. Bout all I can do is look longingly at her when I get home.

scottw wrote:
Erbman02 wrote:
USAFRETIRED wrote:
If you have resistors plugged into the tps cable, then the actually tps cable end is missing that connects to the carb. Whoever did that must of known of that trick from back when we started adapting the S&S carbs. The resistors are suppose to fool the ecu into believing the tps was there. Here is a pic from way back when we did these.

http://i837.photobucket.com/albums/zz294/usafretired1997/TPS.jpg


It might stop the stock ecu from causing the blinks, but it also never allows the it to go into WOT timing curve, keeps it in CT curve regardless of throttle position. Without resistors, by default the ecu goes into wot curve, but you get the blinks. If you have the dyn3k, without resistors, it to by default goes into WOT curve, but no blinking of light.
I don't know enough about timing curves, but both Yamaha and Dyna use by default WOT curve and not the CT curve, there must be a reason tho to use WOT?? This resistor set-up over rides the default mode and keep it in the CT curve.
=====================================

I believe they use the WOT timing curve is because in most cases when at WOT it's best to back off/retartd timing a few deg to avoid possible damage from detonation when at WOT/full load.

But when not at WOT & at low load part throttle steady speed cruise a few deg additional timing can be very usefull.

Thats because it can increase fuel mileage/improves throttle responce making it cripser & motor more responsive/also makes the motor run a little cooler too(as long as timings not overadvanced for cam/compression/combustion chamber/head design)which is important for an air cooled bike motor/etc.

That's what the vacuum advance & mechnical advance did on the older cars running a distributor advacing and or retarding timing depending on load via engine-intake vacuum (vac adv) and or depending on engine rpm (spring loaded mech-centrifical adv in dist) . the older motors when at WOT the intake vacuum drop very low temporairyly deactivatreing the vac adv which then retarteds the timing when at WOT where only the mech adv in dist is still adding timing.

Then when you back of throttle back to steady stat cruise the intake vacuum increases again reactivating vac adv in turn adding timing/advacing it again .

On avg when at steady state low load cruise with distributors timing was roughly 50deg +- few deg but when ya went to WOT(deactivating vac adv due to lower int vac) just runing on mech adv in the dist that 50 deg steady state timing then went to 36-38 deg on avg when vac adv was temporarily removed when at WOT. Then whan ya backed off the gas that increased intake vac again reactivating vac adv for more timing again.

Scott

When I first did the 42, I had no mods, no TPS , no VOES. Then I did the VOES, was just a hair better. Bout a yr later did the TPS mod, and my city mpg's picked up about 4mpg, so I got much better mpg with CT curve than what you say would be better than WOT in low throttle riding. Not only did I get the mpg's in the low throttle, but crisper acceleration than the VOES mod or no mod. There are multiple timing changes while in CT curve till the voltage put the ecu into WOT curve. There are about 20, 25 timing changes that occur while in CT curve, at approx every .2 volt there is a change to timing. Another thing I noticed with no mods to the 42 carb, my jetting was just a hair richer on the pilot ckt, maybe about a 1/4 to 1/3 turn on the pilot screw than with the TPS. If I would have known the attributes of the TPS, I never would have bothered to do the VOES. The TPS mod was a night and day difference.

Okay, I am back at it - got an inexpensive 03 stock carb, factory airbox, and throttle cables off of ebay to replace the S&S carb on my 01. I got the S&S off the bike and setting on the bench. The AIS and about everything else has already been stripped from the bike by the PO. I think I have most everything figured out (so far - I'm sure more questions to follow) other than the hose from the vacuum chamber duct. (right side of the picture). Is it suppose to go to something already removed from the bike or am I missing something? What should I be doing with it? Does anyone see anything else I am missing on this carb? The Choke cable has a nasty bend in it right below the knob that I did not notice before purchase. In case I do not get this one straightend out, if anyone has upgraded and has one for sale, I would be interesed.

I am have and am working out of both Factory Service Manual and the Clymer Manual if anyone thinks to point me to a page I am overlooking.

link to carb pic. http://www.hunt101.com/data/500/medium/carb_0021.JPG

Thanks again, Mike

Mike, are you referring to the long hose on the right? I dont remember what that hooked to. Maybe someone will chime in soon on it.

Yes sir, that is the hose in question. The manuals refer to it attaching to the "Vacuum Chamber Air Duct" on the carb not decent pictures of the other end of the hose that I can find.

leave that open to air, nothing attaches to it, it's a vent. Same with the hose for the float bowl, vented to air. There are no vacuum ports on this carb so nothing that gets plugged. And there are no hoses that get attached from anywhere on the bike

Erb, the hose has a clamp on it so you would think it was connected to something before it was pulled off the bike? Been to long for me on a stock carb.

I can pull my tank tomorrow on the sidecar unit if needed.