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CBR 170cc, DOHC and race cams


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Hello, have anyone here done the Honda CBR 170, dohc and race cams conversion? I have converted my CBR 125 to 170cc, DOCH and race cams. I have bought the PowerCommander V (PCV) and Autotune. Since the bike has a IACV (Idle Air Control Valve) I can't adjust the fuel at idle. The bikes runs at idle when its cold, so my theory is that ECU changes the fuel injection at different temperatures. Since my autotune runs perfectly at 2-5% throttle would it be possible to change the throttle so when its actually at 0 its at 5%? Do you think buying a CBR150 throttle body would help?

Have anyone done this conversion to the fuel injected models? And do anybody here have or know where to get premade fuel mappings for the PCV? If there are other brands let me know!

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I know this doesn't answer your question but why not throw the fuel injection away and go with a carburettor? Lots of flat slide jobies out there.

If throttle bodies has no "idle" screw, can you adjust the throttle cable so the bike idles a bit high?

150 throttle body is the one of choice for guys converting PCX 125 to 166 and up.

Edited by VocalNeal
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This mod has been done before on FI models heres a video The problem is that I can't find anyone to contact. Do you know where I should ask? And also, does the 150 throttle body fit and uses same cables etc? Don't I need to change the ECU when chaning throttle body?

Edited by 770
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In theory the ECU can stay same when changing thottle body because the flow meter automatically adjusts mixture.

However in your case, I'm not surprised at all about idle not working. Often, the maker of ECU mods of such don't even care about idle, assume everyone is happy using thorottle or removing cable play (that is a very bad and dangerous idea). They may have broken control of the idle air valve completely.

If you are looking for more power what I would do first and foremost would be a porting job of the head to perfectly match the throttle body, port the butterfly valve, these are the most important things. Then if too much trouble with FI, bin it and go carburetor.

Edited by paz
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In theory the ECU can stay same when changing thottle body because the flow meter automatically adjusts mixture.

However in your case, I'm not surprised at all about idle not working. Often, the maker of ECU mods of such don't even care about idle, assume everyone is happy using thorottle or removing cable play (that is a very bad and dangerous idea). They may have broken control of the idle air valve completely.

If you are looking for more power what I would do first and foremost would be a porting job of the head to perfectly match the throttle body, port the butterfly valve, these are the most important things. Then if too much trouble with FI, bin it and go carburetoI

I have a PowerCommander V and a Autotune, which can't adjust the fuel under 2000 rpm. I have talked with a Indonesian dyno shop and he means that it won't idle because of my race cams and that I need the original CBR150 cams. Do you think if I get the original cams it will run at idle? I can't adjust the idle since PCV cant adjust fuel under 2000 rpm..

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I have a PowerCommander V and a Autotune, which can't adjust the fuel under 2000 rpm. I have talked with a Indonesian dyno shop and he means that it won't idle because of my race cams and that I need the original CBR150 cams. Do you think if I get the original cams it will run at idle? I can't adjust the idle since PCV cant adjust fuel under 2000 rpm..

No, I don't think it will. Will be glad to say I was wrong if you find otherwise.

However if it idles so high most likely the PVC is kept open, at which point you can try blocking it.

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I've just read the manual, it appears that the CBR150 is about 200 rpm higher at idle than the CBR125. I am thinking of getting the CBR150 ECU and cbr150 injector. How much does those cost, and where should I get it?

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I've just read the manual, it appears that the CBR150 is about 200 rpm higher at idle than the CBR125. I am thinking of getting the CBR150 ECU and cbr150 injector. How much does those cost, and where should I get it?

Sorry, you may have took this forum for an Honda dealer or spares shop ?

You can search here for spare parts dealers and possibly someone with a parts manual can give you the P/Ns.

in any case these items bought new will be too expensive for just a blind try.

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what kind of exhaust, air filter and sparkplug are you using?

what are your valve shims set at ?

I don't know, they came pre-mounted by the dealer. I have a Danmoto performance exhaust, original CBR125 air filter and NGK iridium sparkplug. The bike starts but I have to give it a little throttle while holding in the electric starter. But it once I let it at idle, the bike stalls.

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  • 2 weeks later...

I have installed the CBR150 throttle body and 150 ECU now. When using the 150ECU it wouldn't start. I think we can now confirm it has to be something different with the wire harness since the 150 ECU wont work. When using the 125 ECU and and 150 throttle body, it runs at idle. But I'd still have to twist the throttle while holding in the electric starter to make it start.

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There is a white painted screw called a idle screw (in the manual) on the throttle body that adjusts how much the butterfly closes at 0% throttle. Since I have to give it a little throttle when starting it, do you think making the butterfly stay a little bit open at 0% throttle would work? Or would that make the rest of the injection system get weird? Here is a pic:

http://postimg.org/image/50rog0t73/

Edited by 770
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Now the bike starts sometimes and the first time I started it today the RPM went up and down, between 1500 to 2000 RPM (cold start). When giving it a little throttle it stalls, at around 4000 RPM even though the AFR was quite good. Later it idled precisely at 1500 RPM.

Video:



Im not sure if the CBR150 throttle body has a compatibility issue with CBR125 ECU. If that is true, I think it maybe will work with a adjusted idle on a CBR125 throttle body with CBR150 injector.

Or

Change to a CBR150 wire warness and use the CBR150 Throttle body and ECU. But i'm not sure if the PowerCommanderV is compatible, I've seen a Indonesian dyno shop use a Powercommander on their CBR150 but I'm not sure if they did some extensive modification to make it work. (Dynojet does not make PCV for CBR150).
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the carb model 125 and 150 CDI's were not compatible (i realize yours is Fi, ECU) it would start but thats about it...ive sent a few to the UK in the past to see if they were compatible,no one ever got the cdi's to work.

the stator part numbers were different, so its quite possible the magnetic flywheel is also different, which would probably mean different timing.

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