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Post by pinkscoot on Sept 17, 2016 22:04:32 GMT -5
Threebond would be a lot neater then copper spray.
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Post by pinkscoot on Sept 18, 2016 10:32:02 GMT -5
I pulled the gasket out and while I was there took pictures: These are before I removed the gasket, the piston is right at the floor of the transfers.
This is the crown after I know torquing it down will tighten that up. So after I have a squish of .93. I have to go to work so I'll check the compression later. Here is the main jet. Its 8mm long and the head is 8 mm. The threads are 6mm and course. I think a Dellorto 6mm will work but I don't have one to try. I have the question out to Treatland. I found these that say the fit the predator but I'm sure they are available in the US.
Out of curiosity I started looking for rings and or 50cc cylinders, it would be easier to just go 70cc. I hope that I won't need to go that way.
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Post by 90GTVert on Sept 18, 2016 11:57:26 GMT -5
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Post by pinkscoot on Sept 18, 2016 14:02:28 GMT -5
Thank you Brent, that's the one. I'll get some on order.
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Post by pinkscoot on Sept 20, 2016 9:48:34 GMT -5
Yesterday I got the scoot back together and it started right up. I had 125 psi compression cold. The way that I've figured out how to burp it is to pull the hose off the top of the radiator since its the highest point. It does the job but is a pain to pull the front skirt off. I let it warm up and then took it for a ride, still sputtered at Wot under load. It came with a B10ES in it so I gave it a try. It was better but still sputtered to much. I did make it around the block and this thing handles sweet. Take of is strong but dies at about 3/4 throttle. I put the 9 plug back in and tried pulling the snorkel with the idea that if it was to rich I would see what giving more air would do, nothing it still sputters. I tried an open filter but it bogged, taped it over and it sputtered. Checked the compression and it was down to 110psi, I guess the oil from putting the piston back in was doing its job when I first checked and raised the compression. This will need a top end rebuild. I decided that since my plan was to eventually go to 70cc anyway I would go ahead and get it now. The only kit I found was this Malossi:
Scoot-tuning.ca had the best price and I got 10% off just for asking. Malossi doesn't list it on their site so I figure its no longer manufactured. Racing planet calls it a sport kit. I should know more when I get it. So the Predator is headed to the back of the garage until the new kit clears customs.
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Post by pinkscoot on Sept 30, 2016 19:00:04 GMT -5
The BBK came from Scoot-Tuning. Its very clean and looks good. The paperwork says it's only a 65cc kit. I guess the water jacket shrinks it down. Here are some pictures: The manual also suggested a plug with a shorter base than Derbi Specs. This is what the stock plug looks like in the Head: Correct me if I'm wrong that looks perfect. I have done a port Map of the cylinder and waiting until I install it to get durations. I'm still not convinced that my problem is Low compression but I have tried leaning the MJ down to 60. I put a 19mm Dellorto carb on with a 72 MJ and the problem was still there. I made sure all of the connections to the CDI were good and its still there. I tried running hotter and cooler plugs and it stayed. My next step will be the BBK and I hope it goes away. If not my final suspect will be the CDI. They aren't cheap and I only found them in the UK. Let me get this kit on and see what it does. My next full day off is in a week so It's going to take some time. One last thing The new head has the water outlet on the bottom but the stock head is on top, does it matter where it is?
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Post by ThomasTPFL on Oct 1, 2016 19:37:25 GMT -5
The difference in displacement is due to stroke. 47mm seems to be Malossi's standard piston size. The Derbi has a shorter stroke than Minarelli engines. Noticed that discrepancy when I put the BBK on my Morini based TGB.
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Post by ThomasTPFL on Oct 1, 2016 19:38:53 GMT -5
I'd want to check that plug clearance with some clay or something. Looks tight to me.
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Post by ryan_ott on Oct 1, 2016 19:58:37 GMT -5
Which plug number is that? Looks a bit too long.
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Post by pinkscoot on Oct 1, 2016 21:20:54 GMT -5
The plug is the a B9ES it has a 19mm reach. They spec a Denso plug with a 12.4mm reach. That would put the electrode in the hole. Is that what I want?
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Post by PIG on Oct 1, 2016 21:31:27 GMT -5
ES plugs are 19mm. NGK plugs that end in HS are 14mm. So a B9HS should do the trick.
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Post by PIG on Oct 1, 2016 21:33:38 GMT -5
I see you edited your post and it calls for 12.4mm plug? I don't know then. I would buy what the kit calls for then.
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Post by ryan_ott on Oct 2, 2016 12:34:30 GMT -5
The plug is the a B9ES it has a 19mm reach. They spec a Denso plug with a 12.4mm reach. That would put the electrode in the hole. Is that what I want? Cross the denso plug and see what you come up with. That looks the same as the Malossi cast lc I was running but I was using a B9HS.
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Post by 190mech on Oct 2, 2016 14:21:22 GMT -5
That pic of the plug in the head looks perfect to me,nice and flush with the combustion chamber..What is the depth of the spark plug hole??It looks like 3/4"(19mm) from here!
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Post by pinkscoot on Oct 2, 2016 14:29:30 GMT -5
I did some more research. The plug that Malossi the w27fs-zu for racing and the w24fs-zu for standard. I cross referenced the plug and the NGK plug it says matches is the B9HV that has the 12.4 reach. When I checked some other plugs like the champion they have the 19mm. The Denso plug they speced is no longer available and I found the replacement and ordered it. I also ordered the B9HS so I have an assortment to play with. Thanks for your help with this. This is going slow because I'm back to 60 hour work weeks with no days off.
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