CFD: The Redevelopment of a Derbi GPR 50 R

[cfsandiego]

[toratora]

Some time ago Kelso asked me if I wanted to buy his bike. I didn't have the resources at the time. However, recently one of my friends wanted to pick up a GPR for GPR Camp. So we contacted Kelso, and bought his bike. I drove the Saab out to Sacto to pick it up. It was interesting seeing all my parts still on the bike—Kelso sheepishly admitted so.

The bike itself is really rough. Here are some photos, but over time it will become clear how much work has to go into this bike to bring it back.

[toratora]

Got a little bit of work done on these two today. It's kind of funny these two bikes started out as pretty much the same bike--one red and one silver. Over time they have diverged significantly. Another interesting point, they both have had the front forks swapped out to older style forks. Different reasons for both of them though.

On the bike we got from Kelso there was some sort of nasty grunge on the wheels. I got most of it off with some Motul cleaner, but it took quite a while. Because of this I was only able to get to the rear wheel today. Hopefully the front will clean up easier.

He had a totally wrong spacer on the rear wheel. It looks like it might work, but I don't trust it--so I replaced in with the proper one (the one on the right).

Pretty new tire.

[toratora]

Yesterday I did have enough time to pop off the top end on the CFD bike. I have another Metrakit SP top end (with a ProRace head) that I was thinking to fit to this bike. It had on it a kit that I let Kelso borrow (which didn't come back!), but I don't think that kit was viable. I never got to properly check it out because once fitted he took off.

Lets check out the barrel that was on the bike. It's hard to see in these photos, but there is a very small section of bare aluminum where the plating has been removed. Kelso didn't do this, it was done before I got the kit. I don't know for sure, but I suspect this was the issues with this kit.

Seems like yesterday was Metrakit prep day.

The SP kit that I have required some clean up. I started on it with the Swimming Pool Acid and made some good progress. It looks like it might be okay, but still needs more work. You can see in the third photo what it looks like before the acid removes the aluminum that has stuck on to the wall from a piston that got too hot. I think I got this top end from Calimari. Although it could have been on Tony/Gabes Senda as that was another non-working bike when I got it, and I know those cats rode the bike hard without enough care.

We might just go ahead and put a Gila on the CFD bike, but I'll have to get out the shaving cream again!

[toratora]

Today is suppose to be mostly working on Chris' Derbi. Lots to do. I started out with a visual inventory of what's going to have to occur before Wednesday morning...basically lets just say it's a lot!

I don't think the bike will be recognizable as the same bike in a few days--there is just that much work that's going to happen.

[toratora]

Had some more photos that I missed the last time around.

Lots to do tomorrow!

[toratora]

Some pre photos—this bike was in need of a lot of care, and man are there some jankey assed things the PO did to this bike. Hopefully, I can get them all sorted. People do some pretty fucked up things to bikes.

While I was out there wrenching UPS came by with the EasyParts order.

Da Fuk? This is one of the rear set bolts!

And the brake pedal is all missing parts and just wrong. I may not have the bits to fix this one...

Time for the shaving cream. This one came out okay. I would normally do a little more clean up, but I'm really short on time, and it tested okay. If it seems like there's going to be an issue I'll have to revisit it.

[toratora]

Some EasyParts came today. But mostly for Chris' bike.

[toratora]

Lots of new parts for the CFD:

Top end install, everything seems to fit swingingly, and no clearance issues at all.

Starting to look like a bike again!

Turns out I can't do a pressure check with the smaller carbs, so I had to get a new rubber freeze plug. When I got there it seemed like I might be out of luck because they were out of just about everything. Thankfully though the one they had in stock was the one that I needed today.

[toratora]

I've a bunch of photos to post but it seems that photobucket is doing some maintenance again. Got it running!