DRP: Derbi Reactivation Project

[toratora]

It was sunny today so I needed to bring out the Umbrella Girl. Today I worked on two bikes. The Lorenzo-Ui replica and the Wicked. I kind of worked on both of them at the same time. The replica went fairly well in as much as I could do with what I had around. The Wicked however, well...


I didn't take many photos, but I had to do a lot of wrenching. It seemed that yesterday I had localized things to the connecting rod. That meant pulling the top end. I thought well what if I pulled the pipe, reached in and held the piston. That indicated that the rod was fine. But while doing that I had my head under the engine (I know!). From that point I noticed that the noise was coming from the clutch side of the engine. I drained the transmission oil, removed the clutch cover, and discovered what appears to be a failing basket. I replaced the basket and almost got things buttoned back up, but it got dark and cold so I had to pack it in for the day.

I do hope this solves the problem--I so want to be riding this bike! I did take the Replica for a spin tonight though—first time really with the current setup. It was fun. It scoots along nicely. These second edition second gen GPRs are great little bikes.

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[toratora]

I was making up the newest harness adaptor to power the MetraKit tach, and the Koso H2O gauge I decided to test out the Chinese EGT. I connected it to the 12 volt moto battery and poof smoke—the magic was released.

The little component next to the power connector fried.

[toratora]

Well the cats selling the temp gauge are going to refund me.

The next issue was the air box coupler. The new unit for the bike had the coupler for the 125 since I bought the 125 air box. But it seems to have split probably due to me not getting it placed properly on the carb. Things didn't quite fit and I had to make a slight mod to the coupler, which probably didn't help either. I got a piece of radiator hose, trimmed the coupler to fit and used tire patching rubber cement. Hopefully it will hold. If it does it will probably work even better than before because I was able to increase the length the tiny bit that was needed.

[toratora]

Wow this is so cool. Anyone that's fitted a larger carb to a Derbi engine knows the pain of the trans oil filer cap/plug. Voca, the makers of the very nice pipes, has a really nice solution. Heck I think I need at least a half dozen of these! CNC anodized aluminum. It comes in red or black. And they make them for the AM6 too.

Of course if you get one of those you'll have to get the matching auto luber block off plate.

[toratora]

Today was another wisdom day—wisdom is what you get when you don't get what you want. :/

I started out with the exhaust issue. I though well maybe that's causing the vibrations. It most certainly was making a mess and loud volume!

The Copper sealer I had totally dried out so I had to get a replacement. I bought a can version this time. I think I like this style way better, and the prices was about half too.


Here are the suspects. There is suppose to be a Viton O-ring used with this manifold. When I bought the pipe from Treats they lost it somewhere between the time they took the web photo, and me buying the pipe. I've never been able to find the proper O-ring for this pipe, and as you can see the wrong ones don't last.

The plan was to slather up these parts with copper sealer, and that's just what I did. This seems to be working quite well, so that's good for now. I really really really want to get the Voca pipe on this bike. It's depressing not being able to Voca!

Here's how the oil plug makes unhappy with the PWK. I modified it today, but you'll have to wait for a photo of that mod as I forgot to take one today!

And it would seem that I might still have a drain plug leak. Have to keep an eye on this one—probably have to source a new crush washer.

This one surprised me a little bit. I'm bottoming out the suspension! The rear wheel is making contact with the subframe. I tightened up the pre a bit on the spring. This is a stiffer spring than comes with these shocks since I'm a lot heavier than the little ruggers that employ this shock on the Cobras. Even still I don't think it's going to be enough so I may yet have to source another spring. <sigh>

The big discovery today was this little issue. Seems that I didn't get enough torque on the crank shaft sprocket. This is held on with a taper fit, and I believe this was the source of the vibrations. I reset it, but I'm thinking that I got the balancer off. So now I've got to go back in there again. <sigh>

[toratora]

The other day GL and I went on a test ride. That's when the vibrations from the pinion gear started. I also noted the torn air box coupler, but I also noticed a dribble from the radiator. A new one is along the lines of 125€ plus shipping, and it wouldn't get here in time even if I ordered one today. I did some research and it turns out they make these zinc rods for brazing aluminum with just a propane torch. Well that's something I can due. About four bucks at HomeDepot—and I got the last one they had in stock. :happy:

I also picked up some spare propane (don't want to run out when midstream on a project like this one), a brass brush, some flux, and flux brushes. I wanted to get a brass wire wheel but they didn't have any. You don't want to clean the aluminum with steal because it will leave steal particles in the aluminum making it much harder to braze.

[toratora]

Had to take a break due to the heat. It's like 27°C out there! Even with the Umbrella Girl in service I'm getting roasted!

The list for today was get the balance right (yeah I'm a DM fan), get the silencer pipe couple to stop spewing all over the nice clean parts, and fix the leaks in the radiator.

The exhaust fix was pretty easy. Just slathered it up real nice. Works great too.

My old trick of dealing without having a clutch basket tool—16mm six point works great.

To get at the radiator I pretty much have to take most of the front plastics off—again.

Currently the balancer is set properly, the exhaust is now in good shape with no more leaks (well there is that little one where the EGT valve is hanging out so I'll probably attend that one too), the radiator is out, and it's time to do some prep work on it to get it ready for the brazing action.

[toratora]

This may have worked if the radiator was in better shape. It seems like it might be a bit too far gone. Fixing the holes was like a game of wack-a-mole. Just as I fixed one hole another would emerge.

Here's what It was looking like.

This seemed to be where the issues were located.

Cleaned up with the rotary tool.

After the first attempt.

Bubble test produced evidence of more effort would be required. This would become an endless loop. I'd fix a hole, and more weaknesses would be exposed. I'm going to try again tomorrow. It was getting way too cold out, and there's already the issues of a radiator cooling too fast to get things going. But I'm somewhat sure that the core of this radiator has failed. I'll have to see if there's a radiator shop in town that could replace the core.

[toratora]

I did some digging around last night. I thought I had an older GPR radiator in the boxes, but I couldn't find it. I did find a Dirt bike radiator, and a Senda radiator from the Senda Project. I also called around to radiator shops, but most are closed today. I decided to go with the Senda radiator. The core on the 05's radiator is just too far gone. As soon as I fix a hole another one pops up. The Senda radiator cools the same engine so it should be okay, but it is about a 1/4 smaller, and will have more obstruction mounted on the GPR. It also has some incompatibilities with the layout of the hose connectors.

Clearly the stock hoses weren't going to do it on the throttle side of the bike. Thankfully I had a bunch of other stuff. I ended up using one of the Dirt bike hoses because it has some bends that were pretty close. I tried heating up a hose to bend it and that didn't work at all.

So it's a temporary mounting with Zip ties. The hoses hold it mostly in place, and I make some rubber bumpers to keep it from bouncing into the engine cradle. I ran it for a while and everything seems to be pretty nice. No leaks, hotness in the areas where it should be hot. The gauges are all showing proper numbers. I think this will be serviceable for GPR Camp, and later when I can deal with it I get a proper replacement.

As promised a photo of the trimmed oil filler cap. Kind of hard to see in place. But even with it trimmed I still have to remove the carb to take it out. I'm very much looking forward to getting the Vaca plug for this bike.

One of the few things I still need to take care of before I button it all back up. There's a slight leak at the EGT sensor on the pipe—this is because I did the hose clamp rather than having it welded. A bit of copper sealer should get me by as it's working great in all of the other exhaust joints on the bike.

[toratora]

Was able to take care of a few more things before it got too could to wrench.

I was able to get the EGT sensor sealed up—didn't test it yet but hopefully it wont be leaking anymore.

Here's a shot of the pipe coupler.

As the bike starts to come together again.

And mostly buttoned up again. I also made some adjustments on the front fender mounting.