My 2002 Derbi GP1 Scooter Project
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My 2002 Derbi GP1 Scooter Project
I bought this Derbi Gp1 that had a blown engine, I drove up to Seattle to pick it up. I've always wanted one but they rarely come up for sale, but it's kind of a gamble since it needs work. It's the first non Honda scooter I've owned and my first water cooled engine also. The previous owner claimed it did 55mph with a 70cc BBK before it popped. I've all ready got a new top end on order, hope that's all I need to get it running.
- Wheelman-111
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- Posts: 11321
- Joined: Wed Oct 22, 2008 5:09 pm
- Location: Deepinnaharta, Texas
Re: My 2002 Derbi GP1 Scooter Project
Greetings:
Nice find!
Did you wonder why the liquid-cooled aftermarket cylinder kit grenaded at 3400 KM?
Cleaning the shards is an excellent idea, but it won't help much if the bearing rollers are already notched.
Consider splitting the cases, measure the crank thoroughly and replace the bearings. You'll sleep better.
Nice find!
Did you wonder why the liquid-cooled aftermarket cylinder kit grenaded at 3400 KM?
Cleaning the shards is an excellent idea, but it won't help much if the bearing rollers are already notched.
Consider splitting the cases, measure the crank thoroughly and replace the bearings. You'll sleep better.
Wheelman-111
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
Re: My 2002 Derbi GP1 Scooter Project
The exact reason why it blew is unknown, looking at the old piston I'm guessing it was running lean and got too hot. This derbi also has a aftermarket exhaust pipe and little bigger carb. I'm thinking the previous owner took off the stock airbox and installed a high flow filter without re jetting. I'm avoiding splitting the cases, if I had to this project would probably go on the back burner until winter.
- Wheelman-111
- Moderator
- Posts: 11321
- Joined: Wed Oct 22, 2008 5:09 pm
- Location: Deepinnaharta, Texas
Re: My 2002 Derbi GP1 Scooter Project
Greetings:
I think you may be right about "got too hot"! Yikes!
I don't see the o-ring grooves in the new cylinder or the head. Is the O-ring just compressed by the flat surfaces, or are there ring channels I can't make out in the pics?
The outside top of the new head appears to be a better design. Hope it rocks!
I think you may be right about "got too hot"! Yikes!
I don't see the o-ring grooves in the new cylinder or the head. Is the O-ring just compressed by the flat surfaces, or are there ring channels I can't make out in the pics?
The outside top of the new head appears to be a better design. Hope it rocks!
Wheelman-111
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
Re: My 2002 Derbi GP1 Scooter Project
Yeah there is a o-ring groove on the head but the ring doesn't appear to seat in the groove well, hope it seals good.Wheelman-111 wrote:Greetings:
I think you may be right about "got too hot"! Yikes!
I don't see the o-ring grooves in the new cylinder or the head. Is the O-ring just compressed by the flat surfaces, or are there ring channels I can't make out in the pics?
The outside top of the new head appears to be a better design. Hope it rocks!
- Wheelman-111
- Moderator
- Posts: 11321
- Joined: Wed Oct 22, 2008 5:09 pm
- Location: Deepinnaharta, Texas
Re: My 2002 Derbi GP1 Scooter Project
Greetings:
Did the fuses blow BEFORE you started the engine, or only after it was running? In the former case, it sounds more like a grounded, short-circuited wire. In the latter, did a new regulator solve the fuses blowing? That's a LOT of fuses... Like, 21?
Did the fuses blow BEFORE you started the engine, or only after it was running? In the former case, it sounds more like a grounded, short-circuited wire. In the latter, did a new regulator solve the fuses blowing? That's a LOT of fuses... Like, 21?
Wheelman-111
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
Re: My 2002 Derbi GP1 Scooter Project
The fuse would pop 4 seconds after turning the key on without doing anything else, everything seemed to work for that 4 seconds. The engine started with the kick start even with a bad fuse, no lights or anything else worked. I went around and cleaned all the wiring contacts and light bulb sockets had corrosion I cleaned up, but none of that helped with the fuse problem.Wheelman-111 wrote:Greetings:
Did the fuses blow BEFORE you started the engine, or only after it was running? In the former case, it sounds more like a grounded, short-circuited wire. In the latter, did a new regulator solve the fuses blowing? That's a LOT of fuses... Like, 21?
A brand new rectifier solved the problem, $60 fix. At least I found a US seller, otherwise it would had been a 3 weeks wait from Europe. https://scooterpartsco.com/
- Wheelman-111
- Moderator
- Posts: 11321
- Joined: Wed Oct 22, 2008 5:09 pm
- Location: Deepinnaharta, Texas
Re: My 2002 Derbi GP1 Scooter Project
Greetings:
Good thinking on pointing straight to the problem. Usually we end up throwing the wrong parts at it until the problem stops... with the right one. $60 doesn't sound too bad. Are these rectifers made in Italy, Japan or elsewhere?
Good thinking on pointing straight to the problem. Usually we end up throwing the wrong parts at it until the problem stops... with the right one. $60 doesn't sound too bad. Are these rectifers made in Italy, Japan or elsewhere?
Wheelman-111
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
Re: My 2002 Derbi GP1 Scooter Project
Probably made somewhere in Europe, I think it was a common vespa or piaggio part used on a few different models.Wheelman-111 wrote:Greetings:
Good thinking on pointing straight to the problem. Usually we end up throwing the wrong parts at it until the problem stops... with the right one. $60 doesn't sound too bad. Are these rectifers made in Italy, Japan or elsewhere?