Have a 01 RS w/ supercharger and many up grades. Going with a Milkuni carb. but it dosen't have TPS on it. Can I run w/out it?

I saw your question a couple of days ago, and was waiting for someone more knowledgeable to reply. But, no one has so for now, your stuck with me. Just last week, I asked Pat (USAFRETIRED) basically the same question as I have a S&S Super E carb with no TPS on my '01 Road*. Pat suggested that for best results, the carb should have a TPS adapter installed. You'd send your carb and TPS (Which I don't have a TPS since I bought the bike used with the S&S already installed) to A-1 Sportcenter and they'd install the adapter for you. That is not finacially possible for me right now. Pat sent me an attachment that was on the Roadstar Riders Forum that diagrammed how to wire in a couple of Radio Shack resistors into the bikes harness that would basically tell the bike that the throttle was in the closed position all the time. Come to find out, that is how my bike was set up. I'm at work, so don't have the attachment available. I'll see if I can figure out how to post it here on the clinic, from my home computer. It might be a couple of days before I can get to it. Or, if Pat happens to see this, maybe he'll chime in for you.
Tom

Thank's Aceman,

Sence then I have been doing more research and living in the Baltimore area there is a lot of shops and tech people to ask. However one might come up with a lot of ansews as will. One of them seems like it my be a good way to go (V O switch). Basicly the TPS wire's are connected to a switch or what I think is a (reastat) and then that is connected by vaccume hose to the manifold. This is suppose to be even more accurate.

Thanks Again for your response, I will let ya know the end resalt.

P.S. E me some pic of your ride. (tomnorment@yahoo.com)

Tom

Hi Tom,
I just sent you an e-mail, but here's the TPS resistor document that I was telling you about in case anyone else is interested.
Tom

Post edited by: aceman, at: 2006/03/24 15:10<br><br>Post edited by: DocShadow, at: 2006/05/04 17:10

Blown*,

I'd suggest doing a search on the RSR forum for &quot;restoring TPS&quot;; it has a very lengthy &quot;development&quot; discussion on how I adpated a Harley VOES switch to a Dyna 3000 on a Roady. It's been done on my bikes and a few other Roadies with Mikunis and S&amp;S carbs. What it does is retard the timing on high load (low vacuum) conditions, enabling more agressive timing curves to be run, along with restoring the Dyna 3000's curve switching feature (WOT/CT curves).

Opinions vary, but I concluded that trying to adapt the stock TPS to an aftermarket Mikuni presented mechanical problems and would not deliver the best timing advance because the Dyna 3000 was developed using a stock Roady with a stock Carb. It was a mis-match.

The stock TPS tells the ECU how to adjust timing based on throttle position. Change air intake or carbs and that signal-- and the ECUs response-- no longer conform to factory tuning, much less performance needs. Add to that the emissions considerations of factory tuning and it becomes very difficult to see how one can adapt the TPS from a CV to an HSR to produce the best timing.

The HSRs (and S&amp;S carbs) perform very differently than the stock CV carb (direct control of slide/butterfly compared to velocity controlled slide). Vacuum readings would confirm this (slower vacuum changes in a CV versus rapid changes in an HSR or S&amp;S). Vacuum starts to emerge as a better indicator of engine load for timing control (common knowledge with auto engine tuners and consider that TPS really doesn't &quot;know&quot;, it makes an electronic guess based on original factory tuning and configuration).

All this was confirmed in several discussions with the designer of the Dyna 3000. He considered adaptation of the VOES to be a good idea for aftermarket carbs/modified intakes &amp; motors, and helped me with the wiring. Greg with Nemesis agreed.

The VOES can be modified to trip at different vacuum levels -- which coupled with curve selection in the Dyna 3000 -- offers a good range of tuning parameters, especially for modified motors. Additionally, the Dyna 3000 has a &quot;setback&quot; feature with programmable timing retard, which can be tripped by a VOES switch. This was designed with nitrous (and perhaps blower) applications in mind, which are very sensitive to excessive timing advance under load, providing a &quot;tripped timing retard of up to 6 degrees, I recall.

Parts Unlimited has started selling VOES switches (~$40) with different trip points, so you can order one pre-set for around 2.5 to 4&quot; hG. Or, in the RSR thread, there is a description with part#s on how to modify the spring in any VOES and set it at your desired trip point. There's also pics showing the wiring connection. The HSR has a vacuum port on the carb, which I suggest using.

Good luck amd post your results.

Jim<br><br>Post edited by: Bucardo, at: 2006/03/15 10:23

Blown,
If you go on to www.baronscustom.com and find the Mikuni carb kit, it has the install instructions that you can view and print out. It tells you exactly how to by pass the TPS. I did it with mine and have had no problems at all

geezer wrote:
Blown,
If you go on to www.baronscustom.com and find the Mikuni carb kit, it has the install instructions that you can view and print out. It tells you exactly how to by pass the TPS. I did it with mine and have had no problems at all

You know, I tried to do this on mine. Baron's site says that one of the TPS leads on the main wire harness is .5v, one is 1.5v and the third is the ground. I checked both the yellow and the blue on mine and they both tested the same voltage, I think it was something like 5v. Any clues why?

Tom<br><br>Post edited by: aceman, at: 2006/03/24 15:11

Jim,
Thanks for the replay, sounds like your well versed on the technical aspects of the RS or any bike for that matter. Well as for the TPS situation it doesn't look like it's going to be a clear one but you gave me some good in site.

Do you have an opinion on the ignition timing of my RS, like where the total advanced timing should be or even degreeing the cam as I'v head it done before and retard timing as well based on the set-up of my RoadStar.

Thanks Again

Tom

Post edited by: BlownStar, at: 2006/03/17 01:04<br><br>Post edited by: BlownStar, at: 2006/03/17 01:08

Tom,

Thanks for the compliment.

I would consult the blower manufacturer and ask their advice. The right questions may be:

--What change in timing do they recommend for a typical V-twin application for idle and slow throttle roll-on?

--With a rapid throttle twist (abrupt load), how much timing retard do they recommend?

--Can you use a vacuum switch to effectively control timing in light of any positive pressurization in the intake caused by the blower?

--When does the blower kick-in (RPM)? Is there a vacuum condition followed by positive pressure?

--What carb jetting considerations must be made?

I've seen blower setups before on Road*s and there's nothing like consulting with someone who's solved these problems. If you can establish contact, it's worth a try.

Re: degreeing the cam, I have no idea how to do it on a Road* or if it can be done without significant mechanical mods. I would expect it wouldn't be required on a mild blower setup and that you could solve everything with timing and jetting.

The Dyna 3000 is a very capable and flexible ignition control unit. It seems to me you should be able sort out a tuning solution with it.

Sounds like a fun project. Where are you located?

Jim

Hey Jim,
&quot;Very good questions&quot;
I would love to say that I'm an expert on the special tuning of a 110&quot; blown Road Star but I ain't.
Unfortionally these questions are going to be hard to find answers for and I'm sure I'll get a lot of opinions tho.

Perhaps it will just be my own R&amp;D and the seat of my paints dyno testing, It's just that I really wont to get the most advantage (performance wise) from this combination that I have and what a shame it would be to be just a tweak or two away but not even know it.

As for my 10-20. Stevensville Md. just across the stream from (Annapolis)

Thanks again for the good questions