Hi all.

Today my bike mc18 r5k went on a dyno and I thought I would post a pic of the graph and see what you guys all think of it.
The bike has new pistons and rings, the cylinders are in spec and the clearances are 0.047 and 0.046. The crank was rebuilt recently and
the seals have been checked with pressure and vacuum and they are perfect. The carbs have all new brass and gaskets and seals, airbox
standard as is all the brass, air screws 2 1/8 turns out. Standard pipes.

The dyno guy said there was some clutch slip and misfire, I was listening and did not hear any and the bike runs great on the road. I cannot
feel any misfire or clutch slip at any speed or throttle opening.

I have to say I was a bit disapointed at the results. Hopefully someone can read the graph and give me some advice, should I just accept
what i have and continue to enjoy ringing its neck or does it require some further work.
https://www.instagram.com/p/B_5Zph8lksj/

First things first, any dyno operator worth his salt is more than likely going to detect things like a slight misfire in a controlled environment that someone will on the road. Similar can probably be said about a tired clutch, or even a worn chain/sprocket(s). When the bike's not bouncing around on an uneven surface, and you're not having to concentrate on some idiot about to pull out on you from a side road, you can give a lot more attention to what's going on with the motor, so I would say it's well worth going through it all, just to check. He may well have expected more himself, and was just trying to let you down lightly though!

As for the power... that's pretty much what I'd expect with a standard airbox. If the crank's bot been done by someone competent, that can cause you issues too. Any fraction out of true, and it can affect the timing, which can very easily knock off a bit more power. Would've been handy to see all of the sheet to see the scale.

Here's a wire-spliced R5K [same bike in both graphs] with an unmodified and modified airbox lid [and reject to suit]. Stock exhausts and stock needles. They won't go unless they can breath!




Obviously you cannot directly compare numbers on two different bikes, on two different dynos, run by two different operators (even though both graphs are from a Dynojet 250), but you can compare the shape of the graphs, and get an idea of what to aim for.

At the end of the day though, I'm afraid you can't beat taking the bike to an NSR specialist. Even an RS specialist, or someone who does "loads of different 2-strokes", won't necessarily know all the little quirks of the NSR series, and what to expect from them.
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Andy.
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Thanks for the reply Andy.

The crank was done by chris applebee and I checked the runout myself when I got it back, it was perfect.
I forgot to mention the wire splice has been done. Also i measured the clutch plates and they were in spec but I suppose it could still slip.
The plugs are new as are the ignition coils and plug caps, the loom is in great condition so maybe pick ups although they read in spec. It will be
hard to find a miss when i cant even feel one even on top gear roll ons from 4 thousand revs.
Whe i work out how to do it i will post a better pic of the graph the air fuel looks all over the place to me but I dont really know what a good one
looks like.

Never personally seen a bad Applebee crank, and don't ever recall hearing anyone complaining about them.

If all the electrics check out, then you could have an air leak somewhere. Mind you, parts testing OK when static doesn't preclude them from failing when under load. As I say, maybe the operator was just speculating, given the low result. As I say, ultimately it's never going to go unless it can breathe. There's nothing wrong with OEM filters, but stock airboxes are too restrictive.

Kind of hard to offer any more than that remotely though.
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Andy.
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Thanks for your help Andy its much appreciated.
Just one more thing, how much does the airbox mod effect reliabillity if its done correctly by an nsr expert.

In my experience, all things being equal, none at all. The motor's designed to make way in excess of the stock 45hp, so long as the jetting is adjusted accordingly, 60hp isn't going to be detrimental in any way. There's no magic bullet for setup though, so please don't ask for one!
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Andy.
NSR-WORLD.COM

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Ok I wont ask, thanks again for your input.