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Classic Bike Trackdays

SDR 200 Front End Conversion

 
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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Tue Oct 05, 2021 8:29 pm    Post subject: SDR 200 Front End Conversion Reply with quote

Hi, my name is George and I am an SDR owner since 1992. This is how my SDR is now.
[img][/img]

I started to think about converting the front end when pitting appeared on forks. Despite the fact that I removed it, pitting came back again and again.
Also my disc thickness was almost over the limit.
[img][/img]

Initially, I wanted an SRX single disc front end but I couldn’t find it at that time, so I decided to buy a double disc 1JK front end knowing that I had to make some more changes.
Also I bought a TDR 250 320mm disc and a Sumitomo caliper. Many years ago I had bought a master cylinder from SRX.

[img]

[img][/img]


Last edited by george on Wed Oct 06, 2021 4:37 am; edited 1 time in total
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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Wed Oct 06, 2021 3:45 am    Post subject: SDR 200 Front End Conversion Reply with quote

The two front ends have differences to all their dimensions. 2TV have 33mm forks while 1JK 36mm.

[img][/img]

The 1JK steering stem is longer so I had to use the 2TV one.

[img][/img]

[img]

[/img]

[img][/img]
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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Wed Oct 06, 2021 3:57 am    Post subject: SDR 200 Front End Conversion Reply with quote

This is how the steering stem looks like with the new welding.

[img]

[/img]
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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Wed Oct 06, 2021 4:14 am    Post subject: SDR 200 Front End Conversion Reply with quote

An unexpected problem that I faced was that there was a difference between the front axles. 2TV’s axle is 12mm diameter and 1JK’s is 15mm.
So I had to change the wheel bearings. 2TV’s bearings are 12 37 12 but I needed 15 37 12 which are non standard and hard to find.

[img]

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[img]

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[img][/img]
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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Wed Oct 06, 2021 4:20 am    Post subject: SDR 200 Front End Conversion Reply with quote

I had to reduce the outer diameter of the bush collar to fit it in the seal.

[img]

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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Wed Oct 06, 2021 4:30 am    Post subject: SDR 200 Front End Conversion Reply with quote

The fork brace is smaller and I only used the piece with the curve.
I also made 2 new braces because the fender had to go nearer the wheel.
The braces in the photo aren’t ready yet.

[img]

[/img]

[img][/img]
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DSBBadmin
Site Admin


Joined: 13 Nov 2006
Posts: 682

PostPosted: Wed Oct 06, 2021 4:53 am    Post subject: Reply with quote

Welcome George !

Thanks for posting straight away, and especially with such a great first post. Clap

We know it's not easy posting photos on here, so thanks for going to the trouble of doing this. Some very useful info there for SDR owners.

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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Wed Oct 06, 2021 5:46 am    Post subject: SDR 200 Front End Conversion Reply with quote

Thanks.The 1JK’s discs are 267mm so the caliper hanging points had to be cut and welded to a new position.

[img]

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I disassembled the fork and then removed the hanging points.

[img]

[/img]


Last edited by george on Fri Oct 08, 2021 3:28 pm; edited 1 time in total
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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Wed Oct 06, 2021 5:52 am    Post subject: SDR 200 Front End Conversion Reply with quote

In this photo the hanging points have been welded to the correct places.

[img]

[/img]

The last thing that had to be done was the drilling of the clip-on
in order to make the hole bigger and reach 36mm.
I only had a 35mm drill twist and after that
I used files and sandpapers for fining.

[img][/img]
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James P



Joined: 31 Mar 2013
Posts: 164
Location: Sydney, Australia

PostPosted: Sat Oct 09, 2021 12:54 pm    Post subject: Reply with quote

Good work George - everything is a lot less difficult when you have your own machine tools and welder!

It is good to know that the steering column can be removed from the bottom fork yoke without too much trouble. From your photo, it looks like the steering stops on the SRX bottom yoke are in the correct place to suit the SDR - is that so?

You mentioned that the 15-37-12 wheel bearings were hard to find. If you have a lathe, would it not have been easier to make special bushes for the fork legs to suit the SDR 12mm axle? I am guessing that the SRX axle is probably a bit longer than the SDR axle, which is one reason why bushes may not have been the best solution. I'm not sure whether the threads on the end are different either.

I wanted to fit a 320mm disc to my own SDR, but the offset of the TZR/TDR/FZR disc made it a little too close to the fork leg for my liking. I didn't really want to change the forks, so I was lucky to find a 300mm zero-offset disc which did the job. I suppose you don't have that problem after changing the forks.

Does your Sumitomo caliper come from the same model SRX as the forks? Does it have 32mm or 34mm pistons?

Have you made any changes to the fork springs or damper rods in your new forks? Whatever the case, how do they compare to the SDR forks?

Please let us know what else you have done to your SDR. It looks like you have fitted a cable-driven tachometer - did you use the DT200R tacho-drive gears? Please let us know what else you might be planning!

Thanks & regards,
James
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RG(paul)



Joined: 10 Oct 2009
Posts: 43
Location: HAMPSHIRE

PostPosted: Sat Oct 09, 2021 9:27 pm    Post subject: Reply with quote

Well done... i love your work....

paul
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Top-shaggy
Show Star !
Show Star !


Joined: 05 Mar 2011
Posts: 1738
Location: Derbyshire

PostPosted: Sun Oct 10, 2021 7:13 pm    Post subject: Reply with quote

Great work. 👍
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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Mon Oct 11, 2021 5:58 am    Post subject: SDR 200 Front End Conversion Reply with quote

Thanks guys. Before I try to answer your questions James I have to say that I have read your posts many times and I think they are very helpful.
Yes I used the DT200 tacho-drive gears being inspired by you. The difference is that my tachometer is from SRX-6 and reaches only 9000 rpm.
In the photo you can see that the fork juts out from the clip-on because in order for my SDR to be in the same height as before.

[img][/img]

[img][/img]
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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Mon Oct 11, 2021 6:05 am    Post subject: SDR 200 Front End Conversion Reply with quote

The steering stops are in the correct place no problem with that.
I had the same idea making bushes in order to use a 12mm axle avoiding searching and waiting for 15 37 12 bearings.
I bought an axle (Yamaha x 135 rear) which is longer and I was planning to use it with a nut because the threads are different (smaller diameter) but I preferred not to do so.
Firstly, because I found the bearings and also, one of the bushes had to be too short (not reaching the leg threads), otherwise, it wouldn’t fit.
Nevertheless, I think it might be a good idea for the future if I need bearings and have problem finding them.

[img]

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george



Joined: 02 Oct 2021
Posts: 11

PostPosted: Mon Oct 11, 2021 6:09 am    Post subject: Reply with quote

The caliper is from TDM 850. By measuring the old seals, the pistons seemed to be 34mm and 30 or 31mm but I’m not quite sure about it.
I didn’t have any problem with the offset of the disk because the space between the fork legs is wider than the SDRs. But I had to make sure that the wheel would be in the center of the forks.
At the one side the bush collar is longer than the SDR one’s and at the other side I had to use washers.

[img]

The only change I made to the forks is that I removed 15mm from the spacer’s length. I used 10w fork oil.
I could say that the fork is harder than the SDR’s and softer than the Versys’s 650 that I used to drive in the past. And surely softer than the 125 Kymco’s scooter that I own now.
One thing I did to my SDR, that might be helpful for someone, is that I changed the sprockets and chain.
I could only find 46T rear sprocket so I decided to buy JTF1554 14T, Sunstar 3511 37T (or JTR846) and 520 108 links chain. The set works just fine.
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