Dyno following rebuild and mods - Honda Motorcycles - FireBlades.org
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post #1 of 6 Old 05-01-2019, 6:37 AM Thread Starter
 
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Dyno following rebuild and mods

Hi

Here's my dyno sheet following a rebuild. The red line is the new one.

The bike isn't running perfectly - sometimes it hesitates at initial throttle opening above around 7000rpm and to be honest I expected more power. It's had:

Full engine rebuild with new cam chain and new bearings throughout
new piston rings
full s/s Hindle system and Ti end can (or muffler if you're not from around here )
K&N filter

I had it set up following this by HM Racing, who advised it just needed mixture screw adjustment. That surprised me but I'm far from an expert on this.

I've attached the before/after dyno sheet so I'd love to hear some opinions

Rob
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post #2 of 6 Old 05-01-2019, 10:38 AM
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Re: Dyno following rebuild and mods

Hi ~Rob.

If someone tells me: 'it just needs mixture screw adjustment' and then doesn't do it himself, it makes me wonder if he knows what he's talking about. Surely, if you take a bike to be dyno'd, you expect it to be returned with optimum output? It's not a cheap exercise as we know!
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post #3 of 6 Old 05-01-2019, 10:43 AM Thread Starter
 
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Re: Dyno following rebuild and mods

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Originally Posted by nigelrb View Post
Hi ~Rob.

If someone tells me: 'it just needs mixture screw adjustment' and then doesn't do it himself, it makes me wonder if he knows what he's talking about. Surely, if you take a bike to be dyno'd, you expect it to be returned with optimum output? It's not a cheap exercise as we know!
Thanks Nigel, to be fair I didn't make things that clear - they did actually do the mixture screw adjustment and this dyno chart is the result

I agree if they hadn't done it it would have been an expensive waste of time
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post #4 of 6 Old 05-01-2019, 11:00 AM
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Re: Dyno following rebuild and mods

Ah, right. I took it to be that the mixture was crook after the dyno.

Graph shows some marked improvement, but I must confess to not being overawed by output figures on paper. It can (and I don't imply anything) turn into a pissing contest among the boys, cos the next guy will want to post how HIS bike puts out 202 bhp at the rear wheel etc!

Don't get me wrong. I had my RR4 (with the 'modern fuel injection) done recently to correct a low down problem. Magic results and the rideability is so improved. However, the problem with these is that we can't do it ourselves, unless we fork out on Woolich or similar software. I come from the days of my CB750 K1, where we'd plug in a set of vacuum gauges, frig around for half an hour, and job's done.
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post #5 of 6 Old 05-01-2019, 11:27 AM Thread Starter
 
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Re: Dyno following rebuild and mods

Yep I do agree - I am a bit concerned that the dyno chap might have gone for the biggest figure he can get, believing that's what I wanted. I feel like it could do with being just a tad richer around 5-6k and obvs that will probably reduce top end a little but rideability is key
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post #6 of 6 Old 05-01-2019, 4:53 PM
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Re: Dyno following rebuild and mods

It does look a bit down on HP, a standard 929 should put out about 125 hp, and a Hindle system, with appropriate adjustments, should gain another 5-10. New bearings won't make the engine tight, how long has it run in for , and how did you run it in? did you do anything to the cylinder surfaces? I'd be very tempted to do a leakdown or compression test, maybe the rings haven't bedded in properly. First thing, check the airbox to see if oil/snot has been blowing in from the crankcase. I just rebored my 929 (to 954) and noticed signs of such snot from the crankcase when I checked it over after the first 30 miles. Now the rings are bedded in that doesn't happen. Did they give you a graphic of the air/fuel ratio? did you notice where it was at the interesting points? I presume you have a power commander fitted, if not that's your next step. And find another dyno operator.
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