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Wayward 2003 GPR

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al_pritchard
Posts: 46
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 7
x 60

Wayward 2003 GPR

Post by al_pritchard » Tue Feb 01, 2022 11:52 am

I managed to rescue a wayward 2003 GPR the other week. You know what they say, if you're cold there cold. And it looked so cute sitting in that garage. I found it in central NJ, and from the looks like it was registered in Virginia back in 2019. Anyone know the bike? If I understand correctly it's actually a 2002 with a VIN date of 3/2003.

Been poking around all the build threads - lots of good information here. So thanks for letting me join.

I haven't seen the bike fully assembled yet. It was a rolling chassis when I got it. So I'm sure we are going to be in for quite the adventure. The plan is to clean everything up, with some upgrades, and get it on the road - think spring is feasible?

How it came to the shop
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Got it all striped down, and started cleaning
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New bearings in the head tube. Wow were the originals rusty
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And started cleaning up the rear break
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Pro tip - when the break starts squealing it's time to replace the pad. This is one of the cylinders from the rear caliper. Does Treats carry these?
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And now a question for the group. How do you get the bolt out of the dampening tube on the Showa forks? ToraTora made reference to using an impact gun. But all it does for me is spin - even when I compress the fork.
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User avatar
al_pritchard
Posts: 46
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 7
x 60

Re: Wayward 2003 GPR

Post by al_pritchard » Mon Feb 07, 2022 7:08 am

These forks are going to be the death of me. Finally worked out how to get the bolt out of the top of the damper tube. I'll do my best to explain how I did it.

I modified a tool for removing a grinding disk from an angle grinder. It's thin enough that you can slide it into the spring, and use it to compress the spring a little. It helps to have to people to do this - once the spring is comprised a little slide two thin bars between the top of the spring, and the large washer on ether side of the now exposed damper tube. I also strapped the two rods together to help prevent them from sliding out. Now you can use the bars to further compress the spring, and your helper can pull up on the washer at the top of the damper tube. About 2 inches from the top of the tube you will find a 5/32" hole. Drop a hardened punch pin into the hole, and release pressure of the spring. Now the fun part, while holding the punch use an impact fence to brake free the bolt at the top of the dampening tube. You will most likely bend, or brake your punch - ask me how I know.

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I also now know the difference between hardened, and mild steal. :flushed:

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Did a little clean up of the headlight. Some one had been here before, and the assembly was riveted together. And both lens retaining rings were broke. Luckily I found a set on eBay for the Sachs MadAss, that is suppose to be the same part. We shall se.

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User avatar
benito brz
Posts: 120
Joined: Fri Sep 20, 2019 1:26 pm
Location: France
Replica: Derbi GPR 50 2003
Aprilia RS4 125 2014
x 89
x 78

Re: Wayward 2003 GPR

Post by benito brz » Mon Feb 07, 2022 1:07 pm

Thats some good work and an excellent project :sunglasses:
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User avatar
toratora
Posts: 3161
Joined: Wed Oct 11, 2017 1:05 am
Location: San Francisco
Replica: Derbi GPR
Cagiva Mito
Cobra CX65
Aprilia RS50
x 1756
x 1977
Contact:

Caliper Cylinders

Post by toratora » Mon Feb 07, 2022 9:40 pm

I don't know if Treats will have the cylinders for the calipers. I think I got some from either easy parts or Maxiscoot. Look in the Red Power thread, as I think I posted about them in 2018, or 2019.

I had to use a nematic driver to loosen up the fork bolts. Anything that was stuck in the pin hole either broke or bent.

:paw_prints:
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User avatar
al_pritchard
Posts: 46
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 7
x 60

Re: Wayward 2003 GPR

Post by al_pritchard » Thu Feb 10, 2022 11:19 am

Quick mid week update. ToraTora mentioned in another thread that the Sachs Madass uses the same headlight as the GPR (vertical light GPR). Found a pair on eBay and ordered them up. Looks like they are an exact match, although the Sachs headlamp has a bracket that needs to be removed. Stay tuned this weekend. Going to try to rebuild the headlight assembly, after a trip to the hardware store to find all the screws and standoffs the PO decided were not necessary. The buckets were pop-rivited to the headlight bucket.

Ebay link: https://www.ebay.com/itm/254530405587

Original on top, the Sachs on the bottom
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The bracket to be removed
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Part number if you don't like eBay
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User avatar
al_pritchard
Posts: 46
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 7
x 60

Re: Wayward 2003 GPR

Post by al_pritchard » Mon Feb 14, 2022 5:49 am

Didn't get to the forces this weekend. But did manage to make some progress. It was in the 60s on Saturday. So I took advantage of the warmth and busted out the polishing compound. The upper fairing looks to have been painted a couple of times - candy apple red at some point. A cut, and but brought it back to respectable condition.

The headlights were a perfect fit, and everything went back to tether nicely. Although if you look closely, the upper headlight is slightly off center with the faring. Once we get everything tightened down, we'll double check.

The original home is long on on the instrument cluster. So we used a bit of felted suede.
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VT78racer
Posts: 6
Joined: Tue Oct 22, 2019 6:27 pm
Location: Kentucky
Replica: 2003 Derbi GPR race bike - CR80 transplant
2000 Derbi GPR race/street
1999 Derbi GPR street
x 2

Re: Wayward 2003 GPR

Post by VT78racer » Mon Feb 14, 2022 7:39 am

Awesome work! I'm restoring a 2003 GPR as well. I'm curious to know if anyone has a source for the vinyl decals and paint for these bikes?
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User avatar
al_pritchard
Posts: 46
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 7
x 60

Re: Wayward 2003 GPR

Post by al_pritchard » Fri Feb 18, 2022 1:23 pm

VT78racer wrote:
Mon Feb 14, 2022 7:39 am
Awesome work! I'm restoring a 2003 GPR as well. I'm curious to know if anyone has a source for the vinyl decals and paint for these bikes?
I see some on eBay once in a while. Mostly out of Europe. What livery are you looking for?
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User avatar
al_pritchard
Posts: 46
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 7
x 60

Re: Wayward 2003 GPR

Post by al_pritchard » Fri Feb 18, 2022 1:28 pm

Who doesn't love parts day? Couple packages showed up for some weekend fun. Stay tuned

Domino throttle from Treats

Domino switch - needed for throttle upgrade, also from Treats

Brembo RCS14 from Kerveygirl

And brake pads from AF1

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VT78racer
Posts: 6
Joined: Tue Oct 22, 2019 6:27 pm
Location: Kentucky
Replica: 2003 Derbi GPR race bike - CR80 transplant
2000 Derbi GPR race/street
1999 Derbi GPR street
x 2

Re: Wayward 2003 GPR

Post by VT78racer » Sat Feb 19, 2022 4:59 pm

al_pritchard wrote:
Fri Feb 18, 2022 1:23 pm
VT78racer wrote:
Mon Feb 14, 2022 7:39 am
Awesome work! I'm restoring a 2003 GPR as well. I'm curious to know if anyone has a source for the vinyl decals and paint for these bikes?
I see some on eBay once in a while. Mostly out of Europe. What livery are you looking for?
It's the same livery that is shown in this thread. I've seen some of the other livery's on Ebay but not this one.
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