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Post by gsx600racer on Nov 4, 2018 22:28:59 GMT -5
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Post by oldgeek on Nov 5, 2018 8:52:47 GMT -5
I am going to use stock parts, I just gotta find where I put them! I remember that thread now that you mention it.  I have seen the mini rotor iggy kits here and there, have you seen any inner rotor options anywhere? |
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Post by pitobread on Nov 5, 2018 15:32:43 GMT -5
Peugeot Speedfight is close but not a direct fit.
No real bolt on solutions.
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Post by oldgeek on Nov 6, 2018 6:17:31 GMT -5
Well I screwed up again. Now that I put the wheel and the CVT components on, I can tell there is considerable backlash in the gear box. It is precise that I can turn the clutch bell almost an inch either direction before the wheel will move. I used a mix of gears to rebuild this gearbox. The final gear on the wheel is original, but all others are from a set that I got from feebay. I assumed the feebay gears were identical to the original gears so I did not count teeth. Hopefully I can pull the gearbox apart and just replace the original gear on the wheel shaft with the one that came with the set from feebay and it will mesh up correctly.  |
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Post by oldgeek on Nov 6, 2018 21:55:15 GMT -5
Got the gearbox well drained, I'll open it tomorrow.
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Post by gsx600racer on Nov 6, 2018 22:34:24 GMT -5
Hopefully this will help.  |
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Post by oldgeek on Nov 10, 2018 21:34:43 GMT -5
I finally got to pull the gearbox apart and everything was fine. I guess I am getting old cause after checking the gearbox on my other motors they are exactly the same as this one. I dont know what I was thinking, but whatever, right? Today after I finished helping my buddy install a new seat on his harley I started working on my scoot. I slapped the gearbox back together,added gear oil and finished assembling the motor. I pulled the motor out of Naked Kymco, and put the new one in. I mounted the pipe to the motor for the first time ever. I thought it was gonna hit the tire but it ended up just right. I still have to extend the bracket but for now the front mount on the pipe will be enough.  I made sure the bowl on the carb filled with gas and lowered the lift down. I tried to kick the scoot once while it was still on the lift and compression was crazy. 1 more kick and it crackled a bit so I took it outside to start it up. It is pretty hard to kick and the e start will not even turn it over. After a few more kicks it roared to life. It sounded pretty good, so I took it down the side road, keeping a eye on the CHT. The carb is lean down low but not as bad up top. I ripped it a few times to break it in proper and I can hear some nasty knock when coming off of the throttle. All this was done without an airbox on it because as usual I could not make one fit at first. I have 93 octane in the can and it knocks bad so something will need to be done about that. I pulled it back into the shop and was able to make a doppler airbox fit but it is not much of an airbox IMO. The next ride I still had knock, and I think it was worse than without the airbox. It also got hot quicker so I shut it down and pushed it just a short way back to the shop. That is all I could do today, had to go home to take care of some non scoot stuff.  The CVT setup is pretty good. I used some really heavy weights, a lot heavier than I thought I would need but they will likely end up being just a tad heavy. The pipe hits nicely after the CVT overcomes the early shift. I was too busy smiling to notice what the RPM's were. Tomorrow I hope to get the carb better and hopefully reduce the knock by doing so. I guess the real solution will be to open up the combustion chamber a bit? A special thanks to those that have helped me on this build, and my other builds for that matter!  |
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Post by 90GTVert on Nov 11, 2018 6:22:07 GMT -5
Would be nice to do some checks to try to figure out compression before modding, though it does sound high based on the kick and electric starting. A compression test may give you some idea. That's kind of a quick and dirty way to check. Can't really get an exact target, but it may be clear if it's out of the ballpark. Better yet, but a bit of a PITA is an actual compression ratio check. Doing that you can learn where it is and eventually figure out roughly what ratio you like and modify the combustion chamber to a certain spec to get what you want. 49ccscoot.proboards.com/thread/5043/calculating-stroke-compression-ratiosThere's also a calc here that may make things easier if you do take measurements : www.49ccscoot.com/calculators.html |
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Post by PIG on Nov 11, 2018 11:50:01 GMT -5
What! No video of it running! What a rip off
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Post by oldgeek on Nov 11, 2018 11:52:56 GMT -5
Would be nice to do some checks to try to figure out compression before modding, though it does sound high based on the kick and electric starting. A compression test may give you some idea. That's kind of a quick and dirty way to check. Can't really get an exact target, but it may be clear if it's out of the ballpark. Better yet, but a bit of a PITA is an actual compression ratio check. Doing that you can learn where it is and eventually figure out roughly what ratio you like and modify the combustion chamber to a certain spec to get what you want. 49ccscoot.proboards.com/thread/5043/calculating-stroke-compression-ratiosThere's also a calc here that may make things easier if you do take measurements : www.49ccscoot.com/calculators.htmlI have read that tutorial many times, but I have always been hesitant to attempt the process you have laid out so well. Partly because I am lazy, and it looks a bit complicated. Seriously, math is a BIG hurdle for me. I guess when you take one of these "kits" and attempt to make it be all it can be, there are no shortcuts. I should be able to pull the motor and make the required calculations without tearing it down. What compression ratio range should I aim for? Also what range is acceptable using a compression tester? |
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Post by oldgeek on Nov 11, 2018 13:07:00 GMT -5
Would higher octane gas help reduce knock? And how high of an octane should I use?
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Post by gsx600racer on Nov 11, 2018 13:39:56 GMT -5
Would higher octane gas help reduce knock? And how high of an octane should I use? It would help some. I would check compression first. On 70cc I shoot for around 160. Most would probably say that's on the low side, but I can run pump gas without issues. My first build years ago I was running 190 psi, it lasted 2 tanks. |
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Post by 90GTVert on Nov 11, 2018 14:52:56 GMT -5
An octane increase may help. I never try to set anything up to run on higher than what I can get from pumps, so 91-93. Otherwise it's inconvenient or impossible to take on long rides and can be really expensive.
I've kept mine between 7:1 to 8:1 corrected compression ratio with little concern for what uncorrected ratio is. 7-7.5 usually to stay safe for my street stuff. Would be interesting to know what stuff like the hyper race kits are using. I believe stock Zumas were quoted at 7:1.
I like to see around 150psi on a gauge so I know it's going to be strong. Getting around 200 is high, even though one of the service manuals lists 198psi for a stock 49cc for some reason. I set up a 90cc once and it measured 240psi. So much torque... but spark knocked like crazy and it wouldn't shut off with the key after just a really quick test run.
If you want to try the compression ratio calculation and don't want to do the math, just post all of the measurements listed in that thread here and I or anyone else willing if they see it first will do it for you. None of it is hard math. You just have to follow the steps.
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Post by gsx600racer on Nov 11, 2018 15:37:07 GMT -5
I had the same problem @190 psi.
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Post by ryan_ott on Nov 11, 2018 21:14:39 GMT -5
Would be interesting to know what stuff like the hyper race kits are using. The booklets from cylinders I’ve had list compression between 14:1-16:1. Current Athena lists compression at 16:1 likely uncorrected. No knock though.  |
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I have seen the mini rotor iggy kits here and there, have you seen any inner rotor options anywhere?
