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Post by 190mech on Jul 8, 2018 15:16:54 GMT -5
Sure,smoothing the ducts and rounding the sharp corners has to help..You are on the right track,,base gasket back on and do your best to reduce the squish..
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Post by pinkscoot on Jul 10, 2018 10:42:32 GMT -5
I worked on the cylinder yesterday. I was able to get the ports perfect with a 1mm or so gasket. The problem was I had a 2mm squish. I started to sand the cylinder, I started with 100grit because I had no 80. I quickly switched to 60 grit and after 2 hours I got .1mm off. That is tough aluminum. I decided that it would be a great winter project and decided to see how it would work with no base gasket and a squish in the .9 range. I tried turning the reed block around and though it should work to do it I couldn't get the intake to seat right. I guess they knew what they were doing.
I may make a project of taking the Malossi cylinder down the 2mm. I spend a lot of time at work just sitting so I can make it a project during those times. I'll update this after I get the 50cc cylinder back on.
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Post by pinkscoot on Jul 11, 2018 10:14:27 GMT -5
I got it all together, Three Bond on the base and the O-rings on the head. I went to turn the piston and its hitting just a little on the head. That's no good. I pulled the head and started measuring closer and saw that the ring around the chamber is just a RCT smaller that the piston. Just enough that the piston won't go up past it and the piston is just a little proud of the cylinder. What's interesting was that when I was mocking it up it cleared fine but I only torqued the head to 8nm instead of the 10nm that the specs call for. I also found that I'll never have a squish greater than .91 because that's the distance from that ring to the combustion chamber. The solution for squish would be to take a little off the head and seal the head with Threebond. I went ahead and put a gasket in and all is good with a squish of 1.2mm. I'm going to check my compression and do a leak down. I may go ahead and run it and see what I have. I can always go with a thinner gasket if I need to.
I'll keep you posted.
Edit: While I was waiting for the Threebond to dry I looked at the motor mounts. They were a little old. I touched one and the rubber fell out. Oh that's why I had bought new ones a year ago. They got replaced and are nice and new and solid.
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Post by pinkscoot on Jul 13, 2018 10:26:10 GMT -5
I got the motor reinstalled. I put the needle in the carb back to W9 and the slide to 30. It started right up and idled okay. The only problem was O had an air leak I think. I did a leak down test and got a small leak on the intake but I fixed that. So its leaking somewhere near the carb. I sprayed carb cleaner and found nothing. The A/F screw is almost all the way in so I'll drop the pilot jet down by one size and see what that does. the engine did have a slight whine to it that sounded like it might be from the CVT. I'll pull the cover and see if it there. I'm hopeful for this scoot so I'm not giving up yet.
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Post by chadzilla1 on Dec 22, 2020 19:00:49 GMT -5
Hello I have a Derbi Predator 2001, can anyone help with an overheating issue. It just started, cant drive more then 200 yards and its over heats. There is no way to bleed to make sure there are no bubbles like my GP1 was able to. SO how do I flush the system? or check to see if the water pump is still working ??
THanks Chad
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Post by 808ministroke on Dec 24, 2020 22:30:50 GMT -5
I pulled the exhaust off of my parts bike and started cleaning it up. This is a picture of it: . After searching I discovered it is a Metrakit SP Exhaust. Of course if I had started here I would have found it right away, this forum has all of the information you need. I think I'll put it on and see how it works before I clean it up. I'll also do some more research on it. Does anyone have any experience with this pipe? they make good pipes
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Post by pinkscoot on Dec 25, 2020 10:45:49 GMT -5
Hello I have a Derbi Predator 2001, can anyone help with an overheating issue. It just started, cant drive more then 200 yards and its over heats. There is no way to bleed to make sure there are no bubbles like my GP1 was able to. SO how do I flush the system? or check to see if the water pump is still working ?? THanks Chad chadzilla1 If you look to your left you'll see a tab on the floating menu that has a link to the manuals. There is a generic one for the Derbi's its not great but better than nothing. The manual calls out a coolant drain plug. I was able to just squeeze coolant lines and keep the over flow cap off and eventually crack the thermostat housing and get it bled. Something I didn't do to begin with was open the thermostat housing and be sure it was clear. If the scoot has sat the coolant will clog up the passages and prevent flow. Thats what I had. After I got it clean and all bled I discovered that the water pump was leaking. There is a way to replace the gaskets and the pump but it takes a special tool that you can make or find. While starting down that road I stripped the screw so I ended up splitting the cases, replacing the gaskets and eliminating the internal pump with an electric one. I would start by checking that nothing is clogged before you do anything else. These are great scooters and handle like a dream. With the large tires and front and rear brakes they stop well too. Let me know how your adventures go.
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Post by noctis185 on Dec 26, 2020 15:16:05 GMT -5
Íve had a derbi predator and it was a nightmare it was fast but broke down fast and had overheating isues mine was air cooled I had to get another 2 derbi too fix it then I selled it fast it was getting costly and couldnt ride it long before a breakdown now I have a malaguti f10 and I have to do just reguláris maintanance thats all I hope you will have better luck then me
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Post by chadzilla1 on Jan 6, 2021 22:03:58 GMT -5
Íve had a derbi predator and it was a nightmare it was fast but broke down fast and had overheating isues mine was air cooled I had to get another 2 derbi too fix it then I selled it fast it was getting costly and couldnt ride it long before a breakdown now I have a malaguti f10 and I have to do just reguláris maintanance thats all I hope you will have better luck then me So I pulled my varaitor off and I noticed the water pump belt is off. But Im having major issue there is a large geared thing behind the variator. I cant get if off to get to the belt? it wont pull off
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Post by chadzilla1 on Jan 6, 2021 23:00:17 GMT -5
Ok I got it off, it took me 30 min of pulling. The belt is toast, now I hope I can find another one??
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Post by pinkscoot on Jan 7, 2021 1:50:45 GMT -5
I think I may have the one off of mine I replaced the water pump with an electric one. I'll poke around and see what I find.
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Post by chadzilla1 on Jan 7, 2021 8:26:31 GMT -5
I would love to do the same but Im not going to split the case so I'll live with what I have. Yeah let me know if you still have the water pump belt. Cant find any parts in America.
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Post by pinkscoot on Jan 7, 2021 9:23:55 GMT -5
I also have a spare ET2 oil pump belt, they may be the same belt.
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Post by chadzilla1 on Jan 7, 2021 13:43:55 GMT -5
I have no idea?
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Post by aeroxbud on Jan 7, 2021 19:40:13 GMT -5
Doesn't the belt that drives the oil pump, also drives the water pump?
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