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Discussion Starter · #1 ·
You won't believe the difference in how the bikes runs. Blew me away
 

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we're waiting :hmmm:
 

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I've heard a lot of discussion on this regarding the Husky 610 but I've never heard it mentioned for the 625SMC.

Please do elaborate.... It's beyond me why a bike with a carb needs a TPS anyways, unless it's to retard the timing/iginition curve somehow.

Lastly, I imagine tracing down the TPS is easy enough, but if you would please do a write up and/or post some pics.

I wonder if the TPS could be causing the bobble/surging mine feels at constant throttle around 45MPH.

MotoWillis.. Please list your bike's setup... (Jetting/exhaust/airbox mods)
 

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Discussion Starter · #5 ·
rearviewmirror said:
I've heard a lot of discussion on this regarding the Husky 610 but I've never heard it mentioned for the 625SMC.

Please do elaborate.... It's beyond me why a bike with a carb needs a TPS anyways, unless it's to retard the timing/iginition curve somehow.

Lastly, I imagine tracing down the TPS is easy enough, but if you would please do a write up and/or post some pics.

I wonder if the TPS could be causing the bobble/surging mine feels at constant throttle around 45MPH.

MotoWillis.. Please list your bike's setup... (Jetting/exhaust/airbox mods)
Well just got back from a 60 mile run and man what a difference. The bike vibrates less, excellerates harder and I can cruise 5 mph lower than before. So yes it elimated bobble/surging at lower speeds. All the TPS does is retard the timing below 6000 rpm dissconnect it and you get full advance at all rpms.
Give it a try you'll love it. the bike even sounds better.

Take your seat off and you'll see hte TPS on the left side of the carb follow the wires and it has a 3 wire plug and dissconnect it
 

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MotoWillis said:
Well just got back from a 60 mile run and man what a difference. The bike vibrates less, excellerates harder and I can cruise 5 mph lower than before. So yes it elimated bobble/surging at lower speeds. All the TPS does is retard the timing below 6000 rpm dissconnect it and you get full advance at all rpms.
Give it a try you'll love it. the bike even sounds better.

Take your seat off and you'll see hte TPS on the left side of the carb follow the wires and it has a 3 wire plug and dissconnect it
Cool..I'll go disconnect mine now, I really do think it's useless on a bike w/ a carb. I hope this does sort out the surging at constant throttle because I was about to get really creative with the jetting and fuel mixture.
 

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Discussion Starter · #7 ·
you have to take the seat and tank off not just the seat sorry
 

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TPS disconnected. Pics included.

Done.... w/ pics. :D

TPS on left side of carb.



TPS and 3-pin connector.



Disconnected.



Disconnected and taped off.



Too bad I can't go test it out. It's cold and raining here today, but I'll know right away if it helped, because pretty much any time I ride 45 mph it stutters a bit, and going down hill with the throttle partially open was not fun either.
 

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Discussion Starter · #9 ·
you'll notice when you crank it and let it warm up that it also has better throttle response
 

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MotoWillis said:
you'll notice when you crank it and let it warm up that it also has better throttle response
It's makes sense that it should be disconnected considering our bikes have the same carb setup as the Husky. Well, I'll find out later. MotoWills, let me know how your bike is setup.. Exhaust and jetting wise...
 

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Discussion Starter · #11 ·
Got supermoto endcaps
KTM airbox screen
195 main jet
stock needle in the 5th position
48 pilot jet
air screw 1 3/4 out
16:38 gearing
 

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MotoWillis said:
Got supermoto endcaps
KTM airbox screen
195 main jet
stock needle in the 5th position
48 pilot jet
air screw 1 3/4 out
16:38 gearing
Wow.. Your's is quite different than mine.

KTM airbox
185 main jet
JD kit (blue needle 4th clip)
45 pilot jet
air screw 2 out
16:40 gearing

Actually though.. it kind of evens out. If you're running the stock needle then you'll need another clip position because it tapers less than the JD needles, same w/ the larger pilot. I might play with the airscrew a bit, especially if this doesn't sort out the mild surging.

What are your crusing speeds? 16:38 is some pretty low gearing!
 

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Why would KTM think it was necessary to put a TPS on in the first place? Emissions or noise at a certain rpm to pass DOT regs, maybe? :headscrat
 

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B. Roe said:
Why would KTM think it was necessary to put a TPS on in the first place? Emissions or noise at a certain rpm to pass DOT regs, maybe? :headscrat
Not sure of the thought process behind it, but it's definitely useless. I wonder if there is a cover plate you can put on the FCR to remove it permanently.
 

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I gave it a try ????

It does pull a little harder but I was getting pinging until 4,000rpm and it surges bad at constant throttle. But I will give you it does pull harder and longer into the upper rpm but I don't think the trade off is worth it (Pinging = new piston sooner than later) and yes I was running 91 octaine
 

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Discussion Starter · #17 ·
thats interesting about the pinging. I didn't notice any but I run 93 octane. I didn't have any surging either. Today was the smoothest my bike has ever run practically no vibration crusing at 60 mph
 

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i unplugged my tps and it felt a little more responsive thus more timming.... but what i dont get is my 2002 crf450 also has a tps???/ why would that have one i did not notice any pre detonation i even put a new plug took it for a hot lap and pulled the plug all is ok but then again all my bike are race gas whores......
 

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lawdawgYZ400FSM said:
It does pull a little harder but I was getting pinging until 4,000rpm and it surges bad at constant throttle. But I will give you it does pull harder and longer into the upper rpm but I don't think the trade off is worth it (Pinging = new piston sooner than later) and yes I was running 91 octaine
I hope this is not the case, even at higher revs you were feeling pinging? Or just constant throttle cruising?

All the Husky 610 guys disconnect their TPS on their FCR without issue, while they're different bikes you'd think the net effect would be the same. I think a TPS on this bike is more useless crap we have to endure for EPA reasons, the carb/pump are providing fuel, the CDI just needs to provide spark, it has no reason to know where the throttle position is. If mine pings during anything other than high load/low RPM then I will reconnect my TPS. If there is no pinging on pump gas and it's able to cruise smoothly at 45MPH then good riddens!
 

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Discussion Starter · #20 ·
Well with it connected you don't have full advance till 6000 rpm which is when the SMC starts to come alive. I think any pinging is probably the result of other factors like bad/low octane gas. The smc has 11:1 compression. I was under the impression that the SMC requires 93 octane fuel. My two 520s require premium fuel and they have the same compression ratio. I know that it will run on as low as 80 octane if you switch the igntion curves on the CDI
 
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