Dyno'd L1 with 54bhp..

Who's zxr400 is kicking out the most BHP? show off your mods and your dyno printouts.

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Dyno'd L1 with 54bhp..

Post by Dextermckay »

Evening all, had the bike dyno'd today at Steve Jordan Motorcycles producing a max 54bhp at 12,350rpm. The previous owner claimed to have carried out a full engine rebuild not long ago, which now seems like it was either lies or a sub par job - no offence intended!
It's a decent enough curve up until around 10,500 where it gets very, very rough due to a slight fuelling issue getting a bit lean as seen in the A/F graph below. The previous owner also mentioned a dynojet stage 1 kit that had been fitted, and other than the aforementioned mods it has a yoshimura rs3 end can.
If anyone has any ideas as what I can change (carb balancing etc), please feel free to weigh in - any comments will be much appreciated.
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Re: Dyno'd L1 with 54bhp..

Post by banner001 »

it looks like its getting starved of fuel above 11k rpm, i would suggest that you need to go up 1-2 sizes on your main jets, so you need to remove the carbs and see what is in there.

i have used steve jordan in the past, if you dont know what the above text means ask them to sort out the bigger jets for you, they are pretty decent lads there.
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Re: Dyno'd L1 with 54bhp..

Post by mark400 »

Assuming a Standard Engine (L not SP) with a Standard Airbox, with a slightly richer mixture ( if it has a dynojet kit, you can raise the needles a click) it could be making 56/57 hp. There are many differing degrees of "Rebuild" so you need not necessarily feel short changed.

Kawasaki claimed 61 HP for this bike, which probably equates to 56/57 at the back tyre. The biggest difference to be made now is fit a ram airbox, and jet accordingly. This would probably give you 6 - 7 bhp, the next stage would be to skim the head and improve the cam timing, I would recommend Dynotec Basingstoke for this.

Banner is correct in saying that you need to look inside the carbs to check all is well. Take off the float bowls (three screws )and an impact driver might come in useful as they are quite soft = Now unscrew the main jets and you can see they also screw into a brass tube with holes in - These are the emulsifier tubes, and must be spotless, just as the jets should be too. You could get them cleaned ultrasonically to be double sure, but in my opinion this is probably overkill.
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Re: Dyno'd L1 with 54bhp..

Post by Tirpitz »

This is an L1, so Kawasaki claimed 65ps. They claimed 62 for the H. See tech specs on the home page. It should be making around 61-62 rwhp - several dyno runs on here of stock Ls making that sort of figure. 54 is poor.

This is an oldish post so not sure what the OP has done with the bike but I would have been looking to give it a full service, with valve clearances. And get the carbs off and bin the Dynojet shite. There is absolutely nothing wrong with the stock fuelling on a standard setup ZXR with OEM jets and needles, Dynojet stage 1 on a stock bike is fixing a problem that doesn't exist (and Dynojet stuff has its own issues).

Check the air filter too. If someone has fitted a K&N 'improvement' that will cause a whole host of lean issues unless jetted to compensate. Which again is introducing one problem just to fix it and get right back to square one with no more power than before.
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