KX Fork Conversion / Required Knurling?

Questions and comments about converting to beefier forks..

KX Years on required knurling (Only vote if "YES")

90-91
4
11%
92
0
No votes
93
0
No votes
94
1
3%
95
2
5%
96
5
14%
97
5
14%
98
2
5%
99
6
16%
00
1
3%
01
2
5%
02
0
No votes
03
4
11%
04
1
3%
05
4
11%
 
Total votes: 37

kevfort19
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Post by kevfort19 »

ksx 220 2001 with kx 125 2000 pressed in with no knurling
KDX 220 2001 =)

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Post by KDXsg »

2003 kdx200 stem onto a 2005 KX125 triple do not require knurling. bottom stem bearing is the same too.
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Post by Mr. Wibbens »

So has anyone done an "E" Series stem?

Does anyone know if they are any different than an "H" stem?
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Post by KDXsg »

H series triple tree can be fitted onto e series kdx. because they use the same top and bottom bearing and of the same stem length. i do not know the stem bottom diameter if both are the same. but h series stem can be pressed out to fit 2004 and 2005 kx125 triple without any mod done.

I will bet that the e and h series stem is of the same diameter at the bottom because they use the same bearing.
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Post by Rcrx21 »

2002 KDX220 stem into 2003 KX250 triple did not need any machining or knurling. The whole process went smoothly.
Thank you to everyone that took the time to cover all the variables. I would have never attempted this myself if it wasnt for all the information provided on this site.
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Post by heckler »

2006 KX450F stem pressed into a 2005 KDX

No knurling required, although I am making a 30.1 mm ID X 38 mm OD x 1.9 mm thick washer to fit between the lower bearing and the bottom crown.

The KDX stem has 1.8 mm of material that has not been ground that sticks out from the lower KX crown and will slightly lengthen the KDX stem fit into the headtube. Not sure if I need it, but my machinist works for cheap.

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Post by joshxr650r »

97 220 stem needed knurled to fit 2003 kx125 tt. added 3mm washer to lower assembly to keep from having clearance issues with top threads and fatbars.
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KX Fork Conversion / Required Knurling?

Post by jgear19 »

01 kdx 200 to 08 kx 250f requires knurling.
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Re: KX Fork Conversion / Required Knurling?

Post by carts69 »

99 KDX stem pressed out, 9 tonne pressure & some heat required, pressed straight into 2001 KX250 lower clamp. No knurling needed!
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KX Fork Conversion / Required Knurling?

Post by argclh6670 »

Sorry. For the dumb question. But, what the heck do you guys mean when you say knurling?
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KX Fork Conversion / Required Knurling?

Post by SS109 »

This pic below is knurling. It is used on some swaps to make the KDX stem fit tighter into the KX triple.

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Re: KX Fork Conversion / Required Knurling?

Post by CoronasAndChips »

RB did my stem swap a 2002 KDX stem to 1997 KX 250 clamps so I don't know if he knurled it but I DID need to use the spacer and did not need to make any mods to the stops.
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KX Fork Conversion / Required Knurling?

Post by KDXohio »

Are 89-92 kx 125/250 forks not worth the conversion?

Are they just not much of an improvement over stock?
Or if one could do a rather cheap conversion with them would it be worth while? (By cheap i don't mean cut corners or install junk)

I have a 90 kdx200 I weigh 145lbs I have found an 89-92 250 front end complete for 90$ Piecing together a newer front end is looking like a 300-500$ investment machine work included
So with that being said I have a 1999 kx125 for the track but I'd like my kdx to be track capable as well but mostly going to be woods riding.

Any help is much appreciated be honest I'm new to suspension work so I need all the advise I can get. I'm more than capable of rebuilding, revalving, adjusting....etc but just because someone can do something doesn't mean they know what they are doing.
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KX Fork Conversion / Required Knurling?

Post by James_09 »

Nice post!
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Re: KX Fork Conversion / Required Knurling?

Post by 6 Riders »

I put 97 KX forks on my 95, no knurling needed......every bike is different, even between KDXs, so take it for WIW. I recommend, when doing the fork swap, be ready to need some sort of machining done.....when you do this, there is no surprises or set backs.
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KX Fork Conversion / Required Knurling?

Post by TheGriz »

99 KDX 220 Stem
2001 KX Triples (EDIT 2001 KX 125 Triples)

No knurling needed.
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KX Fork Conversion / Required Knurling?

Post by Gotanubike »

I am in the process of swapping over '97 RM125 showa dual chamber conventional forks to my '90 kdx200.

I could not [/i ]convince my brother(who is doing the press fitting and machining for me where he works) that knurling might be necessary to fit the kdx stem to the rm125. He said knurling will not cause any change to the diameter of the kdx stem post, or may possible make the diameter even smaller :? . Is he just plain wrong or is the purpose of knurling for something other than increasing the diameter on the stem post? Thanks
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Re: KX Fork Conversion / Required Knurling?

Post by 6 Riders »

Gota, The machinist that I'm going through is going to cut the hole in the lower triple a bit bigger and then make a bushing, he will then press all 3 pieces together. He also believes that knurling is not a great idea.
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Re: KX Fork Conversion / Required Knurling?

Post by TheGriz »

Before I cut more material out of the triple, I think that I'd rather build up some weld on the stem and turn it down on the lathe to get the tight press fit.


Edit: nevermind... my brain wasn't on straight. Cutting the triple and building up the stem do the opposite from each other. What was I thinking.
Last edited by TheGriz on 07:43 am Dec 30 2014, edited 1 time in total.
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Re: KX Fork Conversion / Required Knurling?

Post by ohgood »

Gotanubike wrote:I am in the process of swapping over '97 RM125 showa dual chamber conventional forks to my '90 kdx200.

I could not [/i ]convince my brother(who is doing the press fitting and machining for me where he works) that knurling might be necessary to fit the kdx stem to the rm125. He said knurling will not cause any change to the diameter of the kdx stem post, or may possible make the diameter even smaller :? . Is he just plain wrong or is the purpose of knurling for something other than increasing the diameter on the stem post? Thanks

knurling, done right, can increase the diameter of a shaft by .005-.050", which is a pretty good amount. it's in the machinist handbook, which is a great resource to have on hand when working wIth metals, maths, or machinery. [emoji2]

personally, I would rather have a sleeve to make everything properly tight.

putting punch marks on a shaft is what we used to refer to as "Chinese knurling" which is both a derogatory term and explanation of its quality. it will swell the area around the punch mark, but also introduces stress risers to metals that have been stress relieved (heat treatment) previously.
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