2001 Derbi GP1 OVERHEATING!!

[dominick]

Okay... Got a 2001 Derbi GP1 off craigslist for 600$ It ran good, but about four miles later on the way home it shakes and dies. drive belt came off. The thing was recently serviced and they put the wrong size belt on it. got the new correct size belt and put it on. First try to start..nothing. Electric start not even making a sound. So I kick started it and it ran but died every several yards because the battery was dead-ish. installed new battery and the electric start still doesnt work, but it runs well when i kick start it. BUT after about 10-15 minutes of idling or actual running it overheats! I added more antifreeze, and noticed there was nearly nothing in the coolant tank to begin with! Just some thick green/gray sludge! I wanna get this thing running, starting with the overheating problems. I do not know very much about 2-stroke scooters. Any help is greatly appreciated.

[bigdorkfoot]

might wanna flush out the system, could be sludgy and not doing what it needs to be,

[D-cat]

Flush the system, water is fine for that part. Use your standard 50/50 mix for the fill.

Keep an eye on the system for a while. If it leaks or continues to overheat, have the system pressure and flow tested.

[yowster]

You got air bubbles in the line is why it's overheating. There real fun if you haven't ever done one. Certified motorcycle mechanics don't even know how to do it right. It doesn't matter if its the spanish engine or the piaggio you bleed them the same. Just filling it up will not do!!! First fill it up and on the very front of the head is a 13mm bolt just opposite of the water line, or just on the other side. You got to undo it to let the air out and wait till it's a steady flow of water, then screw it back in real quick. The hard part is you have to take off all the back half body panels to get to it because the bucket is in the way. Well it might not be on the piaggio engine because it's been a while since I done one of them. I have the Predator's and Hunters. The gp1 took the predators place with the piaggio engine and suppose to be the fastest 50cc 2 stroke in the world. They have used it for yrs on gileria's and most recently on the Aprillia. Piaiggio bought them out. I've sold a few gp1's when I was a derbi dealer. The biggest restrictor on this scooter and the same on the atlantis is the muffler. It is a catalytic convertor because of euoropean emmisions. You put on a good exhaust and remove the brass plate with five holes in it on the carb air filter side and it will run, ( the air inlet and remove the nozzle inside the air box while your at it. It will run 60 stock without anything else. I have a air cooled atlantis same but air cooled and it will do 55. Water cooled is 1 hp difference and that's a big difference on a scooter. You can't do that or get 8-9 hp out of a yamaha minerrili engine without having to add a lot of after mkt parts. They won't out run it and I don't care what any body says. Racing parts are everywhere for these scooters but for the piaggio engine I would go with malossi all the way because they work with piaggio very close with their race engines and their in the same country. Them engines can turn up towards 24,000 rpms on the race circuit and yamaha well 17,000 but that's still fast. Around 80mph, maybe 85. On your anti freeze mix it is 70/30 by the book but you can do 50/50. I've done them 80/20 but winter time I'd go 50/50 or 70-30 just get the bubbles out because you will blow it up. A word to the wise, If a mechanic has never worked on this type of engine do not let him because they will be experimenting with it and that's probably why it is overheating they didn't know what they were doing. it' best to use a certified Piaggio mechanic but I had to learn because I sold them and after every rebuild they have to be bleed first no questions asked or it will blow. I learned how to do it on dirt bikes in the early 80's. You can also do it by squeezing the water line while the water cap is off but it's not the best way if you have never done it. I do it as a quick fix or when I'm on the road riding it and can tell it is overheating because it will be sluggish.