Found this oddball close to home and here she sits. Street titled, all the papers flew thru DMV. 126KM on it! Oil inj pump had been run dry (hoses cut) and was making an awful noise so the drive gear was deleted. Its got a (possible) YZ80 carb thats gotta go. Its on a home made manifold thats about as cheesy as Ive ever seen. Which is pretty cheesy. Rides around but has a bit of a rattle in there, gotta search around a bit more. Its either 50 or 75cc, looking for the engine number tomorrow. If anyone has a Derbi or some lead on "stuff" please share!
Join this forum: http://www.bayareatwostroke.com/forum/forumdisplay.php?f=7 The guys at BATS know as much about Derbi as anyone in the USA. And these folks sell, or can find just about anything you need: https://www.treatland.tv/ Plastics are not available in the US as far as I know. If the PO ran it out of oil...??? Time for a new top end. Hope the bottom end is still good. the engine serial # should tell you if it is an EB50 or 70. Nice looking bike. Cheers, Jeff I have a 2002 SM50.
Somewhere along the way they cut the oil lines and ditched the carb so guessing the original gummed up, the YZ80 carb was kinda fitted and had no oil line port... It looks new besides what they did. Im pulling the carb out soon to be able to see the engine numbers. Its huge, jammed in and hitting everything at all points. Thank you Jeff!
With some help from the Derbi FB group I found the engine ID numbers under the very wrong 28mm Mikuni carb that had been butchered into place by a previous owner. This has the nice but rare EBE075 (75cc) engine. Kinda a stroker version of the EBE050 which has parts aplenty both stock and performance cylinders, pistons, etc. The suspected air leak was most probably the home brewed manifold plate. Darn shame as this bike is otherwise in great condition. Going to start searching for a piston n gasket kit.
Stock manifold (19.5mm) was with the bike, along with the carb to air box snorkel so hopefully i can get her closer to OEM and breathing clean air. The stock 8-10 HP is fine for me if a piston is found... maybe a custom batch will have to be popped out.
check out 50cc.nl for all sorts of cylinder/piston/carb options. might have to use a spacer under an EBE50 cylinder kit to make up the stroke/deck height difference.
Im not sure if I can even get to the stage 1 bucket on this lil fella! So far Im drawing a blank on piston kits and top end gaskets for the 75 series engines and the very available 50cc stuff isnt an easy option. Ive sent inquiries to a few suppliers in Europe. I hate to do it as its so darn fresh but I might need to swap in another engine if I cant get the top end sorted. The typical 60/65/80/85cc MX engines seem to drop in the frame with room to spare. I even found a horizontal cylinder pit bike engine in one. Blech! The carb stuff is easy if I get that far on the original engine.
http://www.bayareatwostroke.com/forum/showthread.php?t=3611&page=2 this has a lot of info in it. its hard to keep track of, but i think it might be doable to put the ebe050 75cc big bore kit on the ebe075 with a 5mm spacer.
I followed a build if that set up on another forum (find the link in a minute) and the guy hit it to work but it wasnt very good in the end. His words, its "better than a non running 075" basically but a stock 75 or built 50 is nicer with less troubles.
http://gprcamp.com/foro/viewtopic.php?f=15&t=19&sid=d04e368238af6e537baf05448988b636&start=220#p3710 075 with EBE50 perf cylinder kit.
I used to have a 99 gpr50 with a mk pipe and it ripped to about 60, with my fat ass on it. it was fun. Tons of shifting tho
Have you checked the crank yet? Is there a GPX 2 stroke that would fit in there? If you can find a piston kit. Way back when, I used these folks to fill deep scars and re-plate a YZ125 cylinder. I didn't have any issues with their work. If you can give them a piston and the tolerances... https://www.uschrome.com/locations/wisconsin I was in France this past summer. Kids blast around on 50cc versions of this bike, no license required. Someone must have a parts stash someplace. Heck, you can still find parts for Bridgestone motorcycles. Derbi's are rare in California. Every so often one pops up. They usually ask 3K+. I have no Idea what they get for them, because asking and getting are two different things.
Did you contact the guys on BATS? Send a PM to "twinturba", "dankerson", "Four_Ari" or one of the folks that post in the derbi forum. also a call to these folks: https://www.teamcalamari.com/ if they are still in business might get you some leads or contacts for parts. I would think Treatland.tv could also provide links.... Some reading in this thread: http://www.bayareatwostroke.com/forum/showthread.php?t=3611 Good hunting. Jeff
Im pretty sure the TSE250R would shoehorn in it but thats huge... no smaller 2T engines from GPX are available yet. Id not want it as a 4T cause Id just get a Beta 125 in that case. If the EBE075 is a dead end, a KTM built Beta 80cc engine would be my first choice. 6 gears, no power valve, throw a set of trials tires on it and its a street legal hybrid thing-a-ma-bob. Gonna pull the pipe off and eyeball it thru the exhaust port. TBC... I have a lead on what might be engine gaskets on a shelf in France and and one in Italy.
Im registered on BATS just waiting for final approval from a mod. Things look less grim at the moment. Pulled the plug (which looks surprisingly OK) and the plug cap had fallen apart. Needless to say, the cap wasn't really on the plug and bare conductor was obvious so Im hoping my top end noise was sparks bouncing around under the hood. Doesn't explain why it was only obvious under any load though.
And then theres the top end view with the pipe off. It looks brand new, no carbon on the chamber in the head, cross hatch in the cylinder and rolling it back n forth in gear with my finger on the piston I feel zero pin bearing play.
