Derbi GPR Track Bike

[toratora]

Ed and Alex went to Stockton. Alex took second on his KTM. Ed ended up racing a bunch of motards. I think he took second—he's number 14 in the photo (the white GPR). I'll have to find out who took first.

[toratora]

It turns out that the Sabac forks found on the 2002-2004 GPRs use 120mm of 10 weight! The inner top bolts should be torqued to 17Nm.

I'll go back and update the previous post...

[toratora]

I've been posting PWK info in some of the tech threads, but I thought it would be nice to have them around in the Track Bike thread since I run PWKs on most of my GPRs.

Here's a link to Duncan Racing's PWK tuning guide.

Here's an exploded diagram and parts list for the PWK, and a needle chart.

Here is a nice graph illustrating the effect of the various circuits, and their interaction on the PWK.

[toratora]

In accord with yesterday here are a couple more Derbi MotoGP Riders.

Yuichi Ui

Mike di Meglio

[toratora]

Today we went to the track. But Mikes bikes wasn't ready before we got there. We still had to fit different forks, bleed the front brake, add a new Res to the front brake, and tune the carb. All of this took me most of the day. Oh well. Didn't get much in the way of photos either. ¯ \_(ツ)_/¯

Lets start with the forks. Mike really liked how they were working. Once we got back I took a look at them. The left one seems to have leaked a bit, but the right one seemed to be okay. We will have to do some more testing.

The drive out to the track was beautiful.

It was time to work on my Track Bike. There wasn't much time left so I only got to tend to the reed. As you can see the old ones were tattered. The Malossi reeds look quite nice. And they worked nice too.

Pretty bikes.

[toratora]

Any line on a high flow petcock for a RS50 tank ?

Well then here's one! The Pingell Power Flow.

[toratora]

Found another one today, and since we've been going over them in this thread I figured I should post it here. Maxiscoot has a Bairikit Racing Digital CDI Unit that features variable timing. Now the pricing is high enough that you might as well get an HPI with a smaller flywheel, but if you want to keep the Ducati stator and flywheel here's another option.

I've looked for a graph of the curve, but I've not been able to find it.

It does come with that cool Domino switch I wrote about recently.

BRK (Barikit Racing Kit) CDI unit, digital racing version (with variable ignition timing), compatible with original ignitions. Note - make sure you order the right version for your ignition. Simply swap with OEM unit.
For Ducati ignition.

[toratora]

Tora, would you post a picture of a really well chamfered cylinder?

From my The Red Power thread:

[toratora]

So it seems that the AllBalls seals aren't a good enough fit for the newer GPR forks. So all of the Second Edition GPRs do have to have that off sized seal. I've got some coming from EZ Parts. Once that's going on MT Mike's bike should be in good shape. He picked up some jets, and the next time we get to the track we'll do some fine tuning.

[toratora]

It's been a while since I've done some track bike action. Today I headed over to MT Mike's place to get his bike into shape. Had to get the fork seals done, put on some plastics, test for leaks, and basically give it a once over. Everything went well. I also picked up my track bike for some wrenching action, but ran out of time to get any done today.