On an MC21 is the gear position sensor tied into the power curve via the PGMIII and power valves? I have read on another thread that it can be removed and set for third gear. Is there any advantage to removal of the GPS? Does the wire splice negate the operation of the GPS? Is the GPS there due to original restricting?

And related, on an MC18 track bike, can the neutral switch be eliminated?

I am in the process of building a track bike and want to eliminate as much wiring from the wiring harness as possible.
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MC21R9N track
MC18R2J track
CBR954
CR250

On an Mc18 the neutral switch does nothing other than light a light. Leave it off it you want or if you have ditched that half of the clocks.

On an MC21 the GPS is bypassed by doing the orange/blue splice I have no idea what gear it maps to.
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Does andybody make a blank to fill the hole? (Like Tyga makes a blank to fill 2T hole). Or do i just snip off the wires and put the old one back in?
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MC21R9N track
MC18R2J track
CBR954
CR250

That's what I did and that's what the bloke who built my mc18 racebike did.
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I think Tyga do a GPS blank plug and retainer too.
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After years of moaning about immigrants now i am one...

fontyyy wrote:On an MC21 the GPS is bypassed by doing the orange/blue splice I have no idea what gear it maps to.

Thought the orange/blue was the speed limiter, and the GPS splice was soldering 4/5/6 gears to third so it used third gear map for the higher gears?

I am getting old mind...
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

If you look at the wiring diagram, Dave Ett's interpretation is correct... well atleast I agree with what he said!

Wiring diagrams are my bane. Everything else seems doable.

Have ordered GPS blank, and many other parts, from Tyga. If you don't need it, get rid of it!

Thanks!
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MC21R9N track
MC18R2J track
CBR954
CR250

Once the orange and blue wire splice is done there is no need to mod' the GPS wiring.

The PGM then only uses the GPS as a neutral switch as the ignition curve is the same in all gears (hence no need to mod the GPS). The orange and blue splice not only alters the ign curve but also the power valve opening.
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If I have to take the carbs off once more...

StephenRC45 wrote:Once the orange and blue wire splice is done there is no need to mod' the GPS wiring.

The PGM then only uses the GPS as a neutral switch as the ignition curve is the same in all gears (hence no need to mod the GPS). The orange and blue splice not only alters the ign curve but also the power valve opening.

Well , this would have been nice to know before I did the GPS splice. Not that it is a lot of work, but it if it is unnecessary...

I followed Tyga website recommendations and not NSR World advice. Now I realize that "To gain full OEM power on the MC21 the "wire splice" needs to be performed. This disables the ignition limiter in 4th, 5th, and 6th gear. (tuning section, ignition)"

By the way, What happens if you manage to cut the Bk/W wire that should not be cut?
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javes wrote:I followed Tyga website recommendations and not NSR World advice.

Apologies.

This info is now very old and I should probably update it.

At first it was thought that the two things had to be done. Many years ago I spliced the GPS to 3rd, found an improvement, and then spliced the O/blue and found more, so figured it was the way to go.

Many things have passed across the table since then.

Hi, Matt

No need to apologize. Even slightly out of date, your information (and others') is realy valuable and appreciated. In any case, splicing the GPS doesn't hurt.

I am curious with the question in my last post: What happens if you manage to cut the Bk/W wire that should not be cut? The guy that spliced my O/blue wire did cut it. Is this the reason my bike randomly cuts ignition at hi revs?
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If you cut the 'don't cut' wire then it means you have to solder it up again....job done.

Concerning the random cutting out, what plugs are you using?

They are BR9ECM, and the bottom one looks like this:



I am not a good photographer either.

The engine sometimes goes into the red, sometimes sharply stops at 11-11.5. I've noticed this from 4th through 6th.
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I forgot. Gap is at 0.7 mm