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Discussion Starter #1
Final update for anyone interested.

Airbox mod, full system.

Dyno result with recomended 140 keihin jets - 124.6hp at rear wheel. Dyno man said running rich come down 1-2 jets sizes.

Dyno result with dynojet 126 jets (roughly equivalent to keihin 135) - 126.1hp at wheel with improved power curve. Dyno man said still slightly rich with gains still to be had but a safe point to stop as better to be slightly rich then lean for sake of 1-2 hp.

Only thing bugging me is would a 135 keihin be better. Seems to be difference in design of the 2 jets with keihin being shorter and having different bevel into the jet hole and maybe offering a wider fuel spray pattern or atomising differently, this could of course be complete Bollocks. fitted dynojets because they arrive the day after you order and cost £12 delivered, original keihin were difficult to source or mega expensive.

The end.
 

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Not a bad result at all if you ask me!! 126 hp on basiclly a stock motor appart from jets and pipe. Having mine dyno'ed next week so will post up my results too. Want at least what your getting or I wont be happy with the engine work ive had done :)

I guess that is about 135 at the crank?? Do you have the graph you can scan and post?
 

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What were you getting before the mod?
 

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That's good going as standard is something like 110-115hp! Got the graph to post up?

Do you have a k&n filter or another brand? I noticed pipercross make a filter that would effectively mod your airbox anyway as its the full filter face of foam without the sealing part. Given that, I really hope they have a note that you need to rejet as this bolt on mod would require you to go from 120 to 135 on your mains!!

I'll get flamed but what's the low end performance and economy like with this mod?
 

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Discussion Starter #6
Yeah im happy with the outcome, not bad for an old girl.

Really wish I had it on dyno before system and mod but afraid i didn't, would have been I'm teresting.

Filter k&n, mod says can't use stock filter. Really not sure about economy yet as hardly had chance to ride it. Low end performance seems ok, slight dip in curve between 3500-4500k

Trying to workout how to put pic up but all my internet stuff is done from my smart phone which I spend lot of time bouncing off walls and floors, modern stuff really isnt for me just don't have the patience. Bare with me on this.
 

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Discussion Starter #8
Cheers man, hate this phone hate touch screens! One thing I will say about HTC is mine still works after being battered everyday :mad::nono::)
 

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I thought you had just gone back to stock Morti ;)
A boy can change his mind, can't he? ;) In fact it's all a bit too civilized-sounding now.

Anyway, we're talking about 10% more horsepower for the price of a set of jets. Not a bad deal, that. Puts the 918 carb engine up to the same sort of power as a 929.

I'd say 4,000rpm is probably where it's coming onto the needle, maybe the needle wants shimming up or down one setting / add or remove one washer. Did you get the air fuel line with the print out? Even so, it's probably less dip than you get on a standard exhaust can.
 

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A boy can change his mind, can't he? ;) In fact it's all a bit too civilized-sounding now.

Anyway, we're talking about 10% more horsepower for the price of a set of jets. Not a bad deal, that. Puts the 918 carb engine up to the same sort of power as a 929.

I'd say 4,000rpm is probably where it's coming onto the needle, maybe the needle wants shimming up or down one setting / add or remove one washer. Did you get the air fuel line with the print out? Even so, it's probably less dip than you get on a standard exhaust can.


And a full exhaust system Morti ;-)
 

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Discussion Starter #13
Many thanks to lambchops :thumb:

Didn't get a/f printout unfortunately, the dip hasn't had chance to bother me yet but I don't really commute or spend much time below 4k when riding.

Something needed to be said is that every bike is different, a while back someone posted on this forum they had 125hp with the mod + can using keihin 124s I think, which baffles the crap out of me but it worked for him.

Heard there's a bloke up the road in north Yorkshire supposed to be one of the last old school carb tuning geniuses. I'll be going to see him at somepoint just to get a second opinion and compare results with his dyno, plus the roads are belting up there.

Love to know how this mod compares to the factory pro Apk, image they did lot more r&d than the Swedes, maybe I'll get 1 next year and let you know :)
 

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Im quite tempted with that kit also Jack.. But would be disappointing to spend over £100 plus shipping from the US and it be the same or minimal improvements..

Mine is booked for the dyno next week so lets see what mine makes, I need to lower my needles today as took it out yesterday when it was a bit fogging with lots of moisture in the air and it felt very boggy. Raised these one notch a few weeks ago and wasnt sure there was an improvment after I did it and now im sure its too rich.. This is why I want the dyno run so I know for sure whats going on..

Did they need to connect the dyno to your coils for the RPM signal?
 

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Discussion Starter #15
Yeah I'd imagine the Apk to have more air flow and utilize the 140 jets properly maybe a 142 with full system, therefore making more poke. Don't think the kit comes with jets smaller than 140 so you'd think it would run there or there abouts.

Fingers crossed for your Dyno run! Imagine its more of a jet thing rather than needles but you had porting work done and your rrw/x runs bigger jets standard than my rrv. Time will tell :)

Really no idea about rpm signal, I was nervously smoking outside both times when he was setting it up.
 

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hehe no problem Jack I will be the same :) Im going to rig up my GoPro to record the event!! So will post it up hehe, will make sure the guy does a proper job then if he's being recorded :)

Ive just spent a couple of hours dropping my needles a clip back down to where they were before I played with it so its ready for the run now :)
 

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Ive just spent a couple of hours dropping my needles a clip back down to where they were before I played with it so its ready for the run now :)
Do you also find it a bastard of a job to put the carb springs in then? Normally this type of job should be 1 hour max, but with those stupid 50cm bendy springs :mad:
 

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Whats it cost y'all to run on the dyno? I'm curious to see what kind power My carbed 900rr makes?
Iv ran numerous newer liter bikes and they are Very much surprised how good she runs. Even asked how much my fuel injection setup was. Lol its carbed I tell them and their floored.
Maybe its my bike is so light and runs fantastic why I pull on them light to light a lot has rider ability but some these guys dragrace so I dunno. But everyone calls my fightered out blade a Sleeper and watch out.

Iv looked in doing Viking mod but read bad reviews don't wanna cut my air box just to buy another stock one. Maybe they had improper carb tuneing.?
Awaiting to see more info on power you feel and is useable not leaned out Max dyno numbers.
 

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Ive just spent a couple of hours dropping my needles a clip back down to where they were before I played with it so its ready for the run now :)
I'm going to save this post for the next person who says carbs are simpler to work on than FI :evilaugh:
 
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