HONDA CT125 Big Bore Kit

[m in sc]

no, i never had to do a 'reset'.

trim the unit voltage down till you get it where you want it. its that simple, really .

 

[Happy Campa]

As of now, you have only the S cam and injector?

For connectors, consider some single-wire weatherpacks. Amazon sells them pretty cheap, and they are pretty easy to set up

Yes, only a Clipping Point camshaft and just added a PCX150 injector. Thanks for the connector advice.

 

[Happy Campa]

I'm still getting rich running readouts on my Koso narrow band AFR despite trimming the EFIE down to 205mv. I'm running the Heihin PCX150 injector sold by Yuminashi as the new 8 hole version of the classic 6 hole 140cc minimum, they say "on steroids". Am I right thinking the 6 hole and 8 hole is the same if its delivering the same 140cc? I've run out of ideas. I'm sure I'm hearing a tappet sound when getting on the throttle and it goes away off throttle. I've checked the valve gaps a couple times and all is good, any ideas ? Running stock cam, throttle body, intake, modded air filter in stock airbox, Takegawa sports exhaust and the Yuminashi 143cc kit. I'm planning a long moutainous trip from South Wales UK up to the North Coast in 2 weeks and I'm getting a bit concerned that the CT won't be dialed in for the trip.....

You could try bypassing the oxygen sensor mod completely and try running it. If it runs too lean, just plug it back in. Can you post a picture of the fouling on your spark plug? The community can give you good input then on how rich it's running.

 

[selly]

You could try bypassing the oxygen sensor mod completely and try running it. If it runs too lean, just plug it back in. Can you post a picture of the fouling on your spark plug? The community can give you good input then on how rich it's running.

Funny thing is the plug isn't looking fouled at all. Makes wonder if the AFR is reading right, I only see any numbers when off the throttle to change gear etc then briefly see 12.5 to 14 then as I get back on the throttle the number drops out of scale which is 12.2 and reports A - too rich.

 

[selly]

no, i never had to do a 'reset'.

trim the unit voltage down till you get it where you want it. its that simple, really .

I'm going to brave it and do what you recommend I guess I'm a bit wary of blowing this thing up before I go on a planned 2 week trip on the little CT......Thanks for your input.

 

[m in sc]

i would def take a narrow band afr gauge reading with a grain of salt personally. better to be safe than sorry IMHO.

 

[selly]

i would def take a narrow band afr gauge reading with a grain of salt personally. better to be safe than sorry IMHO.

I guess it give an indication how it's running at wot when most overheating problems seem to occur. Is there another way to know other than running a new plug at wot for a few miles then pulling it ?

 

[m in sc]

a plug chop is a solid method, do it on 2 strokes all the time. or head temp. I did my initial setup using a wide band to monitor, that's how i came to the MV settings i used on the trail. once the target is set, its always going to aim for it. its pretty well documented in the grom community what these settings are w a narrow band O2, and when i 1st did it, i checked it and it followed the same results, so went w that. I knew from my past experiences that a genuine pcx150 injector would handle the 143/cam/intake/exhaust mods I have. .02

 

[selly]

Yeah I guess I had 250mv for the efie in mind and was a bit reluctant to deviate from that not having much experience with tuning and hearing about quite a few overheating issues others are having. Are you running your efie at 250mv? Looking at you setup you're running a way more aggressive state of tune compared to mine so its a bit surprising why I'm running so rich, perhaps lack of air due to stock intake and throttle body? Anyway thanks for your help it's appreciated.

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[m in sc]

the intake made a difference. prior to that i was at 21 but didn't really notice that much of a difference. ON MINE, 21 put it in the 13 afr range wot which is 'ok', but the .25 lets it drop into the 12.5~12.8 range in the very top end. I mean, if its not fouling the plug or just black, i wouldn't sweat it too much.

 

[Happy Campa]

Funny thing is the plug isn't looking fouled at all. Makes wonder if the AFR is reading right, I only see any numbers when off the throttle to change gear etc then briefly see 12.5 to 14 then as I get back on the throttle the number drops out of scale which is 12.2 and reports A - too rich.

That is weird. I'd trust how your plug looks over the reading. As long as gunk isn't building up on the plug, I think you are probably in the sweet spot for reliability/ not overheating.

 

[RustyRodder]

Yes, only a Clipping Point camshaft and just added a PCX150 injector. Thanks for the connector advice.

Hows it running for you? Any issues leaning out?

 

[Happy Campa]

Hows it running for you? Any issues leaning out?

It was running hot/lean and started to stumble while running wide open at high ambient temps, but I think that was due to the takegawa air filter I put on at the same time. I pulled it apart check the piston and cylinder. It still looks good. Now I'm waiting for new gaskets. Other than that, it really likes the higher rev range and seems to want to climb higher. Low end isn't as snappy but is still ok.

I also ordered some finned valve and camshaft covers from Webike to increase heat dissipation. Extra cooling is always welcome when pushing things.

QuantiQualification ran into the same issue with his engine running lean while using the takegawa filter. He is on this forum, but I forget his handle.

 

[RustyRodder]

The stock ratios don't seem to like anything other than a stock air filter- putting an efie on now? Or just back to stock filter?

 

[Happy Campa]

The stock ratios don't seem to like anything other than a stock air filter- putting an efie on now? Or just back to stock filter?

I actually tried the efie, but it started running awful. Yes I dialed it in. I'm bypassing the efie for now, going back to the stock air filter and starting again with less variables. I ordered an A/F ratio meter as well so I'm not just making educated guesses.

 

[m in sc]

sure you had it wired in 'backwards' from the original instructions.?

 

[Happy Campa]

sure you had it wired in 'backwards' from the original instructions.?

Yes. I checked the voltage shift too. What was being fed back to the ecu was telling it the engine was in a leaner condition an actual. (Add fuel) That's definitely something to good to double check. Any advice on resetting the ecu? I assume disconnecting the battery for a while will make it remap to fuel tables.

 

[dmonkey]

@x29Saab put together a video on resetting the ECU

 

[selly]

As an update on my woes getting a reading on my Koso AFR with it only showing either rich running with an "A" or no reading which I assumed was the signal being outside of the range it reads. I've been trying my best not to run too lean and burn up the piston but without a reading it was guesswork. I had the AFR meter wired up via the EFIE but decided to drill the exhaust and add a bung to run the Koso O2 sensor direct. Now I'm getting good clear signals running the EFIE at 200mv gives me 12.7 on the AFR at WOT and mid 12's once I'm up to 30 mph on so. I think I'm happy with that and I've gained a bit of confidence for my forthcoming trip. Thanks for your help if you've chipped in.

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[QuantiQualification]

Be careful taking the KOSO AFR values as actual, they are more relative. With mine, 250mV set on the EFIE results in the ECM targeting 13.0-13.1:1 on my KOSO Mini3 AFR meter. My understanding is that the ECM is actually targeting closer to 13.5:1 at 250mV. I would be very careful if your reading is mid 12's with 200mV (which is leaner than I run under closed loop) to accept anything over that, like 12.7:1 at WOT. You might cook something. Watch for stuttering or detonation. If you have even the thought that you felt something, immediately back off the throttle and allow the piston and cylinder to cool.