Welcome aboard BATS. And good news on the piston/cyl condition. Hope it is an easy fix. If the oil pump is blocked off pre-mix is the way to go. Another fellow you might want to ping is Rod, screen name ToraTora. Don't think he posts to BATS anymore, but, I think he is active on AF1 Aprillia racing forum group. Cheers, Jeff Another place you might like to check with: https://www.1977mopeds.com/Default.asp
Found my noises! They run right up the frame to the steering head. Chain running on a steel frame rail. Going to need a nice slider in there ASAP! I will visit KTM for a starting point. Ive used their forward bottom slider from the post 07 125-530 bikes on a few applications.
Thanks Jeff, and to all for the advice/resources. This is a lovely little engine, its a shame they don't have good support in the 075 series. I am going to drop some $$$ on bits now Im sure the engine is good.
If your would be interested. I have several .pdf files for the Derbi Senda. One is a shop manual and the others are parts lists with exploded views. Since Piagio bought Derbi they stopped supporting the importation of spare parts. Send me a PM with your email and I can get them to you. They are about 1.5 to 3.1mb each. Cheers, Jeff
PM sent, thank you! Messing with it today she has a sticky shifter shaft. Im guessing the shaft might be bent a tad or the return spring is weak. Half the time its fine, the other it drops into first gear (or a down shift) and the shifter hangs up on return just below its resting position. A tap and it resets right away. Upshifts its banging off fine. I will give it another good ATF change/bath and see if it improves at all. Ive put all of four KM on it.
Been doing some poking around and it looks like these ebe engines might have a sacrificial stopper stud and Im expecting my shifter shaft is boogered too. I will try to pull it out this week. Little video I found of a fella taking these out. (@andrewgore looks familiar?)
Used but good shaft stud, arm and spring assemblies are inbound from Sweden! Doesn't hurt to have a spare if by some chance mine is still OK. Im hoping this guy has a good shifter shaft too.
In for a dime, in for a dollar... Shifter shaft from the same seller. Hopefully in a few weeks these will resolve the shifter problems.
This poor thing. What has it been subjected to in its short little 126km life? Clutch post snapped off. It all looks brand new in here besides this and... The shifter shaft has been welded and a torx bolt is in place of the correct stop post. To run this bolt it had to be loose or the flange interferes with the shifter end, restricting full travel. So, it wobbles around like a drunk whirrrrrrrr on single track.
See how this all goes back with the correct stopper post/stud and a new shifter shaft. Used bikes. Not a fan!
New 21mm carby ready to plug in the rubber intake thats inbound from France. Nice when things just fit together. Getting the stock air box back in use will be nice.
Drat. Dug a little deeper, the shifter stopper bolt plate was a PO added mod to try to resolve the pic below. Cracked threaded boss on the case for the correct stopper pin. Shift lever was forced down and crack. See where it stands when I get the correct pin in hand next week or so. The plate he added was a botch job too. Almost a sheet metal screw thread just forced into a hole he drilled. Ugly.
Im speculating it got bought new, crashed within days, parked and eventually "this guy" bought it, eh-hem, fixed it and on to me. He claimed he put 30 miles on it. If so, it would have had under 50 when he attempted to save it. Shame its a rare engine in an already rare bike in the USA. It will get sorted. Im thinking epoxy first, then welding, then worst case, engine transplant. Detune a RM80/85 maybe and just enjoy the street tag and light weight trials hybrid thing I plan it to be.
Bummer such a low mileage bike is soooo buggered up. Looking forward to see how you solve the problems. Would be a shame to scrap such a low mile engine. You might be able to part it out to one of the other EBE75 owners around. I have always dreamed of stuffing a KX100 or CR85 motor in my Derbi SM. I have a couple of big bore kits for my 50 SM, but, I doubt they would fit your bike and it would do nothing for the damaged case. Best wishes and good luck.
Thanks, from everything Im finding, and another 075 owner, these are a dead end engine in this form. If I can save it I will, and the rest of it is going to live on regardless. Goose Racing is selling rebuilt 50cc versions of both D050 and AM6. Im guessing the mounting points are shared but that's just a guess right now. Even if they do, a tamed down RM80 might just end up in there, or even an air cooled DS/JR80. I dont want it to be a full blown screamer in the end.
My assorted parts arrived from Sweden. Much to my surprise the "shifter stopper pin" threaded in solidly to whats left of the boss. I cleaned it up and lock tited it in, then built a 360 degree hub around the existing piece in to the pin threads and up to the hex head of the pin in high strength epoxy. It felt good without the epoxy as I couldn't detect any play while levering it with the shifter... Will see tomorrow if it plays nice with the new shaft and clutch inner hub. Its assembled and Im letting the epoxy cure overnight before adding oil.
