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Discussion Starter #1 (Edited)
Gents,

I took the bike out today for a good shake down post build and it's all good but for one thing, at around 7.5k + it feels rough and almost missing. The power definitely dips off the curve, it's still revving and pulling but definitely not pulling as well..

Thoughts?

My first port of call is probably plugs.. what do you guys think?

PCV with a LDB map installed but not specifically to my bike.

Any ideas?

Cheers fella's

Jay
 

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Who's map and for what region bike? A US Spec bike does not utilize the same mapping as a UK spec bike or a Japan Spec bike etc.

Iridium plugs need more frequent changing than conventional plugs, but that is only good for a couple hp mostly observed at around peak hp

As we discussed I'm thinking you are just feeling the effects of the stock gearing since the bike doesn't have enough hp to pull redline like that. You have to lower the gearing in order to be able to able to get the engine to rev out and use all the available rpms.
 

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Discussion Starter #3
OK fair point Mike. The map is for a EU bike so as a base should be ok.. well I would have thought so. I hear you on the gearing but it happens from 3rd onwards.. if it was 6th I would say gearing, but I certainly won't rule that out. I remember having my old bike flat out many times, it wouldnt hot the limiter in top but it was a quite a linear delivery.
 

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Hey what battery you running in that thing?

& tell me more about the exhaust. Is that a proper HRC Superbike exhaust fitted to an otherwise stock engine with Ladybird cans? The huge diameter exhausts from the SBK machines never worked properly on even mildly built production based engines.
 

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Discussion Starter #5
At the moment a stock battery (for now before I get a Speedcell)
the exhaust has reduced headers compared to the full factory HRC kit. I believe it should run fine with a stock motor unlike the full HRC kit which needs the engine build to go with it.
 

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Discussion Starter #7
That is distinctly likely but it won't put me off it. I was a little worried that the mods would take the character out of it but I needn't have worried. It's got it all in spades. :D
 

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Gents,

I took the bike out today for a good shake down post build and it's all good but for one thing, at around 7.5k + it feels rough and almost missing. The power definitely dips off the curve, it's still revving and pulling but definitely not pulling as well..

Thoughts?

My first port of call is probably plugs.. what do you guys think?

PCV with a LDB map installed but not specifically to my bike.

Any ideas?

Cheers fella's

Jay
Possible lean Air/Fuel situation at that rev range using that exhaust/map combo.
If the A/F gets too lean, you'll notice power fade and possible misfiring if too lean.

Happened to me right after I took delivery of my bike in 2008.
Prior owner installed a Jardine 2 to 1 and a PCIIIr, but I doubt he had it mapped on a dyno.
At around 5600 RPM, the power started to fade big time, and at 5800 RPM it began misfiring. If I pushed on past 6000 RPM, it picked itself up and ran fine.

All I did was have it mapped on a dyno and it ran just fine across the full rev range afterwards.
Plugs showed a nice amber/honey color and worked fine.
 

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I'd have a peek at the fuel line routing. a pinched fuel line will still move fuel when demand is low but may be starving the bike for fuel in the top end. it's easy enough to have a peek
 

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Power Commanders are not infallible... Assume it is the same one that was on the bike prior to the mods? The PCV in particular has something of a reputation for not playing well with the RC-51.

Are your mods too extreme to allow you to run the bike without the PCV connected? It may be worth a try to 'bypass' it briefly to see if the problem goes away (assuming you safely can).

r/
Dave
 

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Discussion Starter #14
I fitted the PCV with the other mods. I took Wibbly's advice and checked the fuel line, I couldn't see a kink but it was not routed correctly so maybe that was it.. I will try later. Hopefully another LBP map will be with me soon. I will run a zero map and see what happens, I have it booked in to be dyno'do and mapped in a few weeks when I return from a business trip, unfortunately I have a big ride with pals tomorrow so I will nurse it a bit.
 

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I have the full HRC race kit exhaust and the bike runs flawlessly with a map on a PC3r with a standard engine & carbon airbox. Had the bike now over 10 years. No flat spots, no hesitation, no problems at all. Perfect fueling everywhere.

Sounds to me as if the problem you are having is with fueling; as Sub says - possibly lean at higher rpm.
Perhaps the map is wrong. Easy way to check is kill the engine as it's misbehaving and check the colour of the front spark plug to indicate how fuel has been burning.

If it's an SP1 (Am I right in thinking it's only SP1's and not SP2's as well - I've never had a problem with a FPR on these?) check for small leaks & possibly change your fuel pressure regulator as a precaution as these are known to lead to fueling problems when the diaphragm fails.
 

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I replace those on every single Honda I own at least once every 5 years regardless if they need it or not. Had one fail many years ago and fill cylinders 1 & 2 on a CBR600 (leaned over on the side stand) full to the brim with fuel. It was pure coincidence that I happened to be removing the airbox to fit a Manual Cam Chain Tensioner and saw the ports filled with fuel before trying to crank it and hydrolocking the whole bloody thing.

 

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i wonder if fuel quality affects the fpr's, i am pretty sure it does, i replaced mine at 15 years old, not that it was leaking but as a precautionary measure, i have recently discovered alkylate petrol, and i will be putting it in the bike and everything else for the winter lay up
 

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Discussion Starter #20
Well I had it mapped yesterday and sure enough there was a sizable hole in.the power and torque at 8-9k. Not much though maybe only 5hp. Anyhow it's producing 135 at the wheel and running sweet now.

Loving this bike.
 
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