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250kms and i got clutch slip

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Hi, i have a 2011 new old stock klx450r now done all the mods, FMF Powercore full system with the Powerbomb header, jd jet kit, air box mod, O ring mod on accel pump, and it now pulls like it should BUT since my first serious ride the clutch slips like a bitch!

Yes there is loads of free play at cable and i have loads of years in MX and road bikes and at 54 i have more years than i'd care to mention  as a mechanic so unless i'm losing the plot.

The oil is still original as it's only done 250kms and now drained ready for a new clutch and springs but the old clutch looks like NEW, has anyone had similar problems after the mods maybe the extra power is too much for standard clutch or is it possible that the oil is crap coz it feels like a 75w gear oil i use in cars.

I have a new KX450 clutch to slip in unless there is a heavier duty clutch to fit in place of the KX clutch.

I know there is a lot of threads on here but this thing is NEW and only 250kms old.

Any help would be great.

Edited by Derekj1563
typo errors

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The cables have a problem fraying down about 2 inches from the top and you would never know until it breaks.  You may be able to see some broken wires if you disconnect at the bottom and pull it out as far as u can.  Chased the same problem and that ended up being the problem ultimately.

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Well i wouldn't expect this from a brand new bike but as it has free play at the engine mounted cable adjuster so it woul not cause it to slip.

I will check it any way , love the bike and performance is now good but beginning to think of a 2017 CRF 450 as this is such an &%$#@! to get listings for parts.

Thanks for the info as i have read loads of clutch related threads on here but none with the same/similar circumstances.

Great forum just wish all the other forums gave such genuine advice rather that the usual if you don't know how it works don't try and fix it attitude.

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I have heard of some coming from the factory with an extra spacer washer in the clutch push rod / throwout bearing area.  There is a section in the service manual for checking that.  Good Luck and enjoy!

Edited by wielywilly-g
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All sorted with the new kxf clutch and springs, next step is to swap the head for a kx or if poss machine existing head to accommodate the larger valves and fit race cams.

Thanks for all the cotributions.

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Kx valves are able to be fitted,I have delwest KX valves but better to do the full head swap so you can take advantage of the better port design and size

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Thanks for that , i will keep an eye out for a head and i take it the exhaust header will fit ok?

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KX headers are a bolt on fit to KLX heads so what ever exhaust you have now will still work with a KX head,kx style header pipes are better than KLX style,what exhaust do you run now?

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FMF powerbomb header and power core 4 silencer, cant find a KX head in uk so may try a used KLX and have it modified with new cams.

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Try a local dealership,I was looking for a second hand head here in Australia and they go for about 5-800 and then you have to factor in servicing it and maybe new valves to be sure,I found a dealer who will order me a brand new KX cylinder head complete and ready to bolt on for around $1200  bit pricey but not much more than a second hand one with extra work done to rebuild it,and you know everything is new

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Off topic, is there much difference in the frame of the KLX to a later kx (2010 onwards) as i want to fit a decent aluminium skid plate and all i can find is plastic Acerbis ones in UK and postage from OZ or US with import charges for a good Ali one is a small fortune.

Been a mechanic all my life with own w/shop so a bit of modification is ok if a newer model kx will fit, have located a Ali one in spain but only list 2010 onwards.

Any help would be greatly appreciated.

Derek

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I have run a plastic acerbis for a few years and couldn't fault it,held up fine to the abuse and rocks etc,I only removed it as I had an oversized water pump cover and went back to an ali one so I could weld an extension on it to cover the water pump.I guess you could modify a KX one to fit but try find one that fits 06-08 KX  as for later model kx ones it all depends on the mounting system,the rear would be ok as you can just drill holes to suit your hole location but the front frame rails may be a different width on later KX ones so all depends on how they utilize mounts there

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Thanks again for the info i will look into the Ali gaurd and post my findings as most people start a thread and don't post a conclusion.

Cheers Derek

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The KX 450 Header is not compatible with the KLX muffler.  It is KX 250f diameter.  You would need to get the 450 muffler as well.  A 250 header will not work in either scenario. I like my Hyde Racing skid plate.  

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