KMX top end???

[Ridge Racer]

hi peeps, whats the top speed of the KMX?

iv just been out on mine and for the first time, booted it and it did 65 at about 7k rpm (the max i could get out of it in 5th) 5th grear seems very sluggish and even on a straight if in 5th it will loose speed???

do i have the restrcited learner legal model as this seems a little slow to me for a geared 125??

[yankeedoodle]

[alpine]

[lilredmachine]

Yes, it is probably restricted. However don't expect to get much more when it is derestricted. It's a 125 off road bike.
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Bikes: too many, too much for one man to maintain anyway.

[lukamon]

mine does 85 on a good day - almost 80 on a bad one.

1. take the front pipe off, if there is a washer in the manifold, drill / knock it out.

2. take off the little box on the right (from the back) of the cylinder, and rev the bike. if the little rod does'nt move in ir out, pull it out (not out of the bike, just pull it)

3. upjet it, because it'll be running lean now. my main jet is 104.

edit: on second thoughts, mine does 7.3k rpm @60mph in 6th, so it might not be the same? what year is it?
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killa wrote: Im an ass man myself

[stevo as b4]

[Finglonga]

Got my first speeding ticket on my KMX on the A500 going through Stoke. I was well chuffed 85MPH and that was a standard trim de-restricted version they used to sell(not sure if they still do).
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Andy Sez....
F.Y.Y.F.F.

[lilredmachine]

So how does an extra 15mph on top make my statement of 'don't expect to get much more' untrue? It's not like it pops 100 with a derestriction is it?
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Bikes: too many, too much for one man to maintain anyway.

[lukamon]

actually, i must admit i would call (if you bileve the official figures) doubling the bhp of a bike "much more"
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killa wrote: Im an ass man myself

[V twin eater]

Go down the steepest hill you can find on full chat! Your find your top speed that way.

Then, give it the beans on a flat road when it is not windy and if you don't get within 10mph of your top speed on the hill, there is a problem.


*You should preferably try this only on safe, 70 mph roads. I thought I'd mention that before an attack from a safety Nazi.

The next person to mention the words: Gravity, Aerodynamics, friction or any of Newton's laws gets stabbed in the eye!
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---> Hyabusa 1300
---> Intruder 1400
SOON ---> Intruder M1800R

[sieversrichie]

oh but what about newtons laws
jks

[lilredmachine]

[Zen Dog]

My old KMX did an indicated 75 (about 80 if you were willing to lie flat on the tank!). I suspect it may have been derestricted though, it had a DEP pipe on it.

Zen Dog
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Current - '94 VFR750FR (Dead), '00 VFR800FI, '11 600 Hornet - Previous - '11 CBF125, '10 Street Triple R, '92 MZ ETZ301, '05 TTR250, NSR125R, KMX125, "Honda" Win
My bike trip around S.E. Asia 2010/2011

[stevo as b4]

[lilredmachine]

Uh huh. about the same as my DR then. Only ever seen 90mph down a big hill on that. That'll be about 27hp at the rear wheel.
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Bikes: too many, too much for one man to maintain anyway.

[lukamon]

what is is "unrestrictive" airbox lid? do you cut a bit off the old one?
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killa wrote: Im an ass man myself

[Ridge Racer]

well mines a 2 stroke, kmx 200 frame with a 125 engine in it, its 1990 frame and 2002 engine, the air box has had some of it cut away so i assume this is the unrestrictive air box mod?

tbh im happy with what its doing i just want to be sure its not got anything wroung with it

[stevo as b4]

Yeah basically the air box lid on the 125 has a smaller opening than the 200cc version. It has been proven that a 200cc item, or a cut away std one with up-jetting gives about 1.5-2bhp more than std!

You need to make the entry to the air box lid the same size as the top of the filter frame, which has a rectangular shape to it. The carb needs re-jetting after this to match the increased airflow.

i don't know the exact settings required for the 125cc, as i've never owned one. However the main jet needs to be increased to around 107.5 or 110, which is 2-3sizes bigger than std.

It's best to do this mod at the same time as fitting a performance exhaust IMO.

The Gianelli expansion chamber along with a DEP silencer seems the best exhaust system for the KMX power wise. It adds about 1.5bhp from 7k rpm upwards. The sound is brilliant too, much more Moto Crosser like than the std system. It's also half the weight or less too!

[Ridge Racer]

i tthink my pipe is std but i do have a dep silencer on it