Oversized Tanks, head stays, and what year frame?

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Brtp4
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Oversized Tanks, head stays, and what year frame?

Post by Brtp4 » 01:01 am Mar 20 2019

Hybrid Builders,

I am in the planning stages of a hybrid build, and have a question regarding what year frame to use. Have a 220 motor, rev pipe, bored carb, and a nicely set up 99 KX125 front end with wheel, I have access to an 03 roller, but have a 99 and a 94 option also. Each has some advantages, enough to not rule them out.

Anyway, the draw of the 03 is because it is newer. No matter what, whatever I build has to have an oversized tank for where I live. Have read that the rear headstay on the 03 interferes with the stock tank. Presumably, this would be worse on an aftermarket (probably Clarke). Does anyone have any feedback on this?

Thanks,

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Re: Oversized Tanks, head stays, and what year frame?

Post by rexemouse » 08:04 pm Mar 20 2019

I built an 03 kx hybrid. It's a fabulous bike. I have the Clarke tank and it required very little modification, 15 minuted with a heat gun and the blunt end of a screwdriver.

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Re: Oversized Tanks, head stays, and what year frame?

Post by bufftester » 08:43 pm Mar 20 2019

I have an 01 hybrid (same frame as the 99) and love it as well. Either of the newer ones is a good choice, little more aftermarket support for the 03 of course. Benefit of using the 99 is you already have a front end, the front changed between 02 and 03. But if the 03 is a roller then that's the way I'd go FWIW. Get it properly sprung and you'll wonder why it took you so long to build one!

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Re: Oversized Tanks, head stays, and what year frame?

Post by Brtp4 » 08:55 pm Mar 20 2019

bufftester wrote:
08:43 pm Mar 20 2019
I have an 01 hybrid (same frame as the 99) and love it as well. Either of the newer ones is a good choice, little more aftermarket support for the 03 of course. Benefit of using the 99 is you already have a front end, the front changed between 02 and 03. But if the 03 is a roller then that's the way I'd go FWIW. Get it properly sprung and you'll wonder why it took you so long to build one!
Bufftester,

You may have found a blind spot. I know the 99s are 46mm and the 03s are 48s, but I assumed I could bolt the 99 forks on as long as I had triples. Are there other differences between the 99 and 03 front ends?

Edit: The 99 forks have been revalved and rebuilt, and work well. Not practical to switch from them at this point.

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Re: Oversized Tanks, head stays, and what year frame?

Post by KDXGarage » 08:58 pm Mar 20 2019

The 2003 + stem is 6 mm taller.
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Re: Oversized Tanks, head stays, and what year frame?

Post by Brtp4 » 09:02 pm Mar 20 2019

KDXGarage wrote:
08:58 pm Mar 20 2019
The 2003 + stem is 6 mm taller.
You mean in length / spread between upper and lower, or the steering head sits 6mm higher?

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Re: Oversized Tanks, head stays, and what year frame?

Post by KDXGarage » 09:10 pm Mar 20 2019

The steering tube of the frame and the steering tube are 6 mm longer. If you want to use 2002 and older lower clamps, they will have to have a 2003 + stem installed.
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Re: Oversized Tanks, head stays, and what year frame?

Post by Brtp4 » 09:18 pm Mar 20 2019

KDXGarage wrote:
09:10 pm Mar 20 2019
The steering tube of the frame and the steering tube are 6 mm longer. If you want to use 2002 and older lower clamps, they will have to have a 2003 + stem installed.
Thanks a ton. Have to check uppr fork tubes, but I figure they will accept 6 mm more "spread".

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Re: Oversized Tanks, head stays, and what year frame?

Post by KDXGarage » 10:34 pm Mar 20 2019

You lost me.
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Re: Oversized Tanks, head stays, and what year frame?

Post by SS109 » 12:18 am Mar 21 2019

Brtp4 wrote:
09:18 pm Mar 20 2019
KDXGarage wrote:
09:10 pm Mar 20 2019
The steering tube of the frame and the steering tube are 6 mm longer. If you want to use 2002 and older lower clamps, they will have to have a 2003 + stem installed.
Thanks a ton. Have to check uppr fork tubes, but I figure they will accept 6 mm more "spread".

BP
Not spread but height. The fork legs have plenty of adjustment to handle it.
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Re: Oversized Tanks, head stays, and what year frame?

Post by bufftester » 03:07 am Mar 21 2019

The offset changed as well on the 03. If you have a roller thats still the better way to go IMO

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Re: Oversized Tanks, head stays, and what year frame?

Post by KDXGarage » 04:54 am Mar 21 2019

Read up on the differences in older posts. There are a lot of posts in the past decade or so on this site.
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Re: Oversized Tanks, head stays, and what year frame?

Post by rexemouse » 07:33 am Mar 21 2019

The 03 has a lot of unique parts, like the swing arm and linkage system. The roller I started with was really rough, and I had to replace some on these unique parts. They were a struggle to source, and extra not cheap when I found them.

Regarding forks, one advantage of the 03-05 is that kxf forks and triple bolt right up. Assuming you like showa TCs.

Definitively take a look at the builds on this site. I referenced these daily when building my two hybrids.

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Re: Oversized Tanks, head stays, and what year frame?

Post by Brtp4 » 11:01 am Mar 21 2019

Brtp4 wrote:
09:18 pm Mar 20 2019

....I figure they will accept 6 mm more "spread".

BP
KDXGarage wrote:
10:34 pm Mar 20 2019
You lost me.
It's OK, I understood you.

Not spread but height. The fork legs have plenty of adjustment to handle it.
[/quote]

Thanks for the comment. I think that was explained by KDXGarage, but to clarify.....do you mean the steering head sits 6mm higher than the previous gen, or the steering stem tube and stem are 6mm longer? I understand your comment about the forks having enough length to compensate.
rexemouse wrote:
07:33 am Mar 21 2019
The 03 has a lot of unique parts, like the swing arm and linkage system. The roller I started with was really rough, and I had to replace some on these unique parts. They were a struggle to source, and extra not cheap when I found them.

Regarding forks, one advantage of the 03-05 is that kxf forks and triple bolt right up. Assuming you like showa TCs.

Definitively take a look at the builds on this site. I referenced these daily when building my two hybrids.
Thanks. I have read everything on here and TT about hybrids, have a bunch of notes, part #s, etc. The remaining questions I have are all about interchangeability, mostly for the reason you gave. After my post last night, I looked up parts on EBay and 03 stuff is as you say.

On the forks, I would prefer Showas, am familiar with them from my Hondas. But I have a nicely set up set of 99 KYBs that I just rebuilt. I am going to stick with those for now, just in the interest of this build somewhat in control.

Thanks,

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Re: Oversized Tanks, head stays, and what year frame?

Post by SS109 » 07:33 pm Mar 21 2019

Brtp4 wrote:
11:01 am Mar 21 2019
Not spread but height. The fork legs have plenty of adjustment to handle it.
[/quote

Thanks for the comment. I think that was explained by KDXGarage, but to clarify.....do you mean the steering head sits 6mm higher than the previous gen, or the steering stem tube and stem are 6mm longer? I understand your comment about the forks having enough length to compensate.
The stem is longer hence the steering head also sits higher. Learned this when swapping '02 triples (22mm offset) on to an '03 KX250 (stock 25mm offset) which is the same basic setup as the KX125. Had to swap the '03 stem in to the '02 triples to makes it work.
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Re: Oversized Tanks, head stays, and what year frame?

Post by Brtp4 » 09:29 pm Mar 21 2019

SS109 wrote:
07:33 pm Mar 21 2019

The stem is longer hence the steering head also sits higher. Learned this when swapping '02 triples (22mm offset) on to an '03 KX250 (stock 25mm offset) which is the same basic setup as the KX125. Had to swap the '03 stem in to the '02 triples to makes it work.
That is great info. Do any of the 46mm compatible triples have 20mm offset? I would add as much trail as I can.

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Re: Oversized Tanks, head stays, and what year frame?

Post by KDXGarage » 11:36 pm Mar 21 2019

They are not 20 mm offset. You might find the offset in some old Motocross Action magazine website articles.

I want to say they are 22 or 23.

The outer fork tube diameter changed a few times even though the inner tube was 46 mm.

There were three upper KX125 / KX250 clamps for 46 mm forks, (1996 - 1998 , 1999 - 2000 and 2001).

There were three lower clamps (1996 - 1997), then 1998 - 2000, then 2001 with the tapered stem.
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Re: Oversized Tanks, head stays, and what year frame?

Post by Brtp4 » 05:28 pm Mar 22 2019

KDXGarage wrote:
11:36 pm Mar 21 2019
They are not 20 mm offset. You might find the offset in some old Motocross Action magazine website articles.

I want to say they are 22 or 23.

The outer fork tube diameter changed a few times even though the inner tube was 46 mm.

There were three upper KX125 / KX250 clamps for 46 mm forks, (1996 - 1998 , 1999 - 2000 and 2001).

There were three lower clamps (1996 - 1997), then 1998 - 2000, then 2001 with the tapered stem.
Brilliant, thanks KDXGarage. Super helpful. Going to grab some 99 KX250 triples, the rubber mounting will help my battered wrist. I know I may have to grab an 03 lower for the stem at some point if I go with the 03 frame.

Thanks,

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Re: Oversized Tanks, head stays, and what year frame?

Post by KDXGarage » 06:09 pm Mar 22 2019

You're welcome.

Good luck with it.
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