Support GPR Camp!!

Wayward 2003 GPR

Create a thread about your bike.
User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Mon Sep 19, 2022 11:29 am

jkv357 wrote:
Sun Sep 18, 2022 7:40 pm
This is what the bracket looks like -
Thanks for that. Now to start digging through the scrap pile for a little material.
1 x

User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Mon Sep 26, 2022 6:21 am

Got to spend a little time in the workshop this weekend. Starting with creating a plate to help secure the front mud guard. Couple scraps of aluminum, and we have a plate. The plan is to secure with some blue lock tight.

Image

Image

Image

Also got the side failings sorted. Still need to drill hols where the side fairing meets with the upper fairing.

Image

Image

Couldn't help myself. To help complete the race look, I added a brake guard. This one comes from racefoxx.com. It's the same one I use on the GP200 bike, sos pairs are available.

Image

I also finally broke down and bought a rear stand. And I am so glad I did! I will be converting the race bike over to spools as well. This stand is so sturdy, and the bike feels so secure on it. It's a [www.sportbiketrackgear.com/woodcraft-ad ... minibikes/]Woodcraft Mini Spool Stand[/url] It's perfect for the GPR, and the race bike. I picked it up at: Sportbike Track Gear
3 x

User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Tue Oct 25, 2022 5:59 am

Slow and steady progress

First up, the fabrication of an exhaust bracket. Nothing to complicated. Used a series of hole saws to remove a little material, and give it a more professional look. If you do this, go slow when cutting the bigger holes. The saws have a tendency to grab the metal and spin it.

Image

Image

Also did some brake work. Lets start with the parts. Goodridge makes some super brake lines, and fittings. This order came from Lowbrow Customers. I opted for black covered stainless lines. And black fittings. The banjo bolts came from KurvyGirl - splurged on titanium, they are so cool.

Image

Image

And I learned something I did not know. The thickness of the crush washer should be selected based on the thickness of the banjo

Image

I also found a potential replacement rear master cylinder. This is actually the reason I decided to make custom lines. The front line was kind of twisted to use the upgraded Brembo brake. And the potential rear master cylinder has the exit on the top, not the left. So I was not going to be able to re-use the original line.

The master cylinder is a Brembo PS13B. It was originally fitted to a Cagiva Mito. And if I understand correctly the Mito uses the same foot peg orientation as the GPR. The good news is it fits. So once I get it primed, and tested I'll update the brake thread.

Image

Image
1 x

User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Mon Nov 14, 2022 5:54 am

So I've not been super happy with the left hand controls, and clutch lever. I was never able to get it tight enough on the bar to prevent it from spinning. So instead of shining it, and leaving well enough alone. I went out and found a clutch lever and perches that match nicely with the Brembo. I originally went looking for the matching clutch cable version of the Brembo RCS. But they are impossible to find.

I found a nice lever in the TWM GP1 cable type lever. Not super cheep, but not no to expensive either. Next step will be to solve for the controls. We'll se how it works out, I have a 5 button pod on the way. But it's from eBay so ¯\_(ツ)_/¯. The real ones are a bit expensive, so my hope is this one will be workable. I'll keep you posted.

Image

Image

Image

Also did some work on the kick stand. Started by making a small bushing to support the bolt. The parts diagram shows it, but it was not included in my box of parts. And by the looks of the original bolt, it has not been present for some time. Probably should have made it from oil soaked bronze, but I don't have any laying around. So aluminum it is.


Image


Image[

Image

Image

Image
1 x

User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Fri Nov 18, 2022 11:43 am

Quick end of week updates - couldn't wait to find a place to mount it. Now let's hope it doesn't interfere with the button pod. Once we finalize the location I can make up a cable.

Remote Choke Switch from Stage6
Image
1 x

User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Mon Nov 28, 2022 7:31 am

Progress marches forward. Not a lot left to do:
  • New controls call for new control wires. Update on that next week. Making cables is actually kind of fun. We need a new clutch cable, throttle cable, and remote choke cable.
  • Wire up the new control pod. Shouldn't be to difficult, but I need to work out how the lights are wired.
  • Double check all the electrics - not my favorite part
  • Paint - I thin I'm going to farm this out. So if you know anyone in New Jersey that might be interested. Let me know.
Let's start with the carb. Goin got run an PHBG 21. Starting out with a 96 Main Jet, and a W7 needle with the clip second from the top (that was the way it was shipped). With a Polini filter. Should keep the big rocks out, but probably won't do much for fine dust. On the plus side, it breathes super well.

Image

Now for the geek bit. My plan is to mount the remote choke under the clutch lever. And it looks like I have enough room for everything.

Image

Image

Image

But the hex cap head looked a little out of place. So we put a 10° angle on it, to match the bolts that came with the clutch lever.

Before
Image

After
Image
1 x

User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Mon Dec 05, 2022 6:32 am

So I think nI have the controls sorted. Plenty of room between the button pod, and remote choke. And all new control cable fabricated.

Now we just need to wait for spring, or a warm snap to push it out and start tuning the carb. Can not wait!

Left controls, and remote choke
Image

Right controls, with Domino throttle, and Domino start / kill switch
Image

And full view of the cockpit
Image
2 x

User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Tue Jan 03, 2023 8:43 am

Did a little work over the holiday brake. First was finally finding a temperature sensor that I didn't need to have shipped from the EU. That was a nice way to end the year.

Image

Image

And the other project was creating some aluminum spacers for the rear sets. They are based off the ones that Team Calamari use to make. And replace the rubber grommets. With the intent of preventing the read set from twisting, and rubbing against the swing arm. Not sure if I will notice the difference, but it was a fun project non the less.

Image

Image

Image

Now what else can I fiddle with until spring?
2 x

User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Mon Jan 30, 2023 8:37 am

Still finding little things to tinker on over winter.

I wanted to get the GPR closer to the race bike in regards to the shift pattern. The Bridgestone uses a 5 down pattern. They have a super interesting gear box with a linear pattern. You can choose Neutral 1 2 3 4 5. Or Neutral 1 2 3 4 Neutral and back to 1st.

ToraTora has some good information on this here: viewtopic.php?t=303

I started looking for a Cagiva Mito linkage, as it's a simple conversion. But the only ones I could find are in Germany and super expensive. So the next option was an Aprilia linkage. Found one cheep! But it requires a little time on the lathe to make it all work.

When using the Apprilia lever you need to create both a sleeve for the lever to rotate on, and a spacer to move the lever outboard of the recessed shifter hole. So off to the lathe we went. I modeled the sleeve after the one used on the brake lever. With a shallow channel that can help hold grease and keep everything moving well. Don't worry, Im ordering a deeper screw.

Image

Image

Image

Then to drill out, and tap the hole to support the linkage

Image

Image

Image

Image
1 x

User avatar
al_pritchard
Posts: 65
Joined: Sun Jan 09, 2022 2:15 pm
Location: Atlantic Highlands, NJ
Replica: 2003 Derbi GPR 50cc
x 9
x 82

Re: Wayward 2003 GPR

Post by al_pritchard » Tue Jan 31, 2023 12:09 pm

And all buttoned up. It helps to have a lathe to build the parts and help thread the linkage.

Remember when doing this at home, you need a left and a right hand thread on the linkage. Makes it so much easier to set the pedal position.

Image

Image
2 x

Post Reply