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Post by dexameth on Nov 9, 2021 13:09:49 GMT -5
I had weird running issues and swapped coils. Problem went away. I've swapped everything other than the stator.... Same results. Not many hours on the stator but it could be the problem. |
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Post by 65grendel on Nov 10, 2021 5:33:49 GMT -5
Buddy had an intermittent stator that drove him nuts for a summer
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Post by dexameth on Nov 10, 2021 7:06:12 GMT -5
I probably have mentioned it before, but the stator is the old Hoca Mini Alternator Kit, stupid light flywheel and an 8 pole AC stator with its own CDI. Less than 100 hours of use... I've even swapped to the stock CDI with same results.
I guess I could try the stock flywheel and stator 🙄
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Post by repherence2 on Nov 10, 2021 11:02:29 GMT -5
Are you running transparent fuel lines? So you can check for air bubbles in the fuel line after running WOT and it cuts out.
**edit. Seen that you eliminated vacuum. **
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Post by 808ministroke on Nov 12, 2021 5:15:08 GMT -5
I have Had very similar issues on one of my build it would do exactly as what you are describing I can't say for sure what your problem is I can only tell you what seemed to help mine was getting a completely different carburetor greater I was running a oko swapped polini pwk And it seemed to help a hell of a lot with that issue basically went away I think it was like an emotion tube issue not allowing enough fuel to dry in....
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Post by dexameth on Nov 12, 2021 7:11:51 GMT -5
I have Had very similar issues on one of my build it would do exactly as what you are describing I can't say for sure what your problem is I can only tell you what seemed to help mine was getting a completely different carburetor greater I was running a oko swapped polini pwk And it seemed to help a hell of a lot with that issue basically went away I think it was like an emotion tube issue not allowing enough fuel to dry in.... I took the 28mm OKO off and popped it on my 177cc Stella, upjetted to 120 main and it works amazing. I have even swapped to a smaller carb on the Minarelli clone and it stutters at high rpm still. I don't believe it's carb. I've swapped reeds as well. Pretty much swapped everything except that nice flywheel and stator... |
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Post by aeroxbud on Nov 12, 2021 17:53:59 GMT -5
So frustrating. But I guess the stator has got to be worth I shot.
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Post by broyager on Apr 26, 2022 23:40:23 GMT -5
Hi, I know this is an old thread, but a similar thing is possibly happening to me. New 70cc kit was going great for a few weeks, then I was getting concerned the compression was too high, or the pilot too small, off throttle, and after a high speed run it lost about 10% of it's power. I rode it gingerly home from that point. I had re-used the existing 50cc head, so the squish incorporates a flat section around the edge of the head, which used to butt down onto the old 50cc cylinder. I took the head off and could see some markings in the carbon where the piston had actually made contact with the head, though there are no marks after cleaning the carbon off. Basically my squish was the thickness of the head gasket........ I stuffed up the rings on my build initially too so both are right at the outside wear limit as they are, and will be replaced soon. Compression feels lower now after stacking another head gasket, and it sounds a lot less strained off throttle (pilot jet has been cleaned 3x, and will be replaced soon too), but has less power than it did, when it was on the edge of dying. Basically I'm saying it could be rings / compression related, ie I wonder if all that power I had was because the squish was incredibly tight, and compression very high. I may be able to confirm this when I replace the head and the rings in a couple of weeks, though the new head will match the cylinder so performance might not match what it was in any case. Can probably increase compression, tighten the squish though, once the shapes actually match....  |
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Post by Zino on Apr 27, 2022 0:14:57 GMT -5
broyager measure your squish .
1mm to 1.5 mm is what most lower end builds run
The race builds run lower than .7 but need higher octane gas to avoid detonation with the high compression.
When you lower compression you will lose performance .
The 50 cc heads can make compression a little on the high side it will help to get a head with a proper squish band .
Higher compression also leads to higher heat so you may need to look at upjetting to cool it down .
Your loss of power could because you were close to seizing.
I would buy a cylinder head tempature gauge to protect your hard work ,watch for temp spikes as you ride ,you want to have jetting that levels you off on high speed runs in the below 350 or low 300's .
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Post by broyager on Apr 27, 2022 1:45:35 GMT -5
Thanks for the details, yep have temp gauge incoming.
I did actually seize the kit the first time I put it together, only went up one size, from 75 to 78..... also had no oil in the tank (has a pump) and did the 2 heat cycles then 100% break in method.....
Only a bit of aluminum deposit lower down in the bore to take care of, and I had an extra piston (instead of the head..) so was able to make it work (after re-installing the original 50cc cylinder, not installing the circlips properly, which fell out and destroyed 50cc cylinder and piston....). I know a great deal more now..
Naraku 70cc kit, exhaust port smoothed and edges are off all edges inside. Running 85 main, 7g ish rollers, kevlar belt, intake and exhaust and everything else, are stock.
PGO Ligero (RS) / Genuine Buddy 50.
But re OP, could be compression / rings /squish related.
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Post by Zino on Apr 27, 2022 7:02:12 GMT -5
That Naraku Kit with stock head does push high compression and is quite spunky down low according to other users.
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Post by broyager on Apr 27, 2022 19:00:24 GMT -5
Yeah it doesn't need to rev for sure, like I wouldn't want to, or don't need to, change anything with the stock clutch for take off.
Just lacks that top end power now for accelerating up hills, which it was doing nicely.
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Post by terkauttaja on May 8, 2024 15:42:55 GMT -5
I have the exact same problem as heard in the video, nothing seems to help the cutting out at approx. 11000rpm when riding. I have a malossi cdi and have replaced all other electricals, stator etc. also sealed case well and checked for leaks. Also tested max revs with cvt not connected and it revved nicely. Still Nothing seems to help.
(My engine is minarelli horizontal ac)
On top of all the fuzz, i have tried many different rollers, variator pressure springs, 2 different clutches and front variator plates. Im pretty dumbfounded with this ghost problem.
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Post by billwill on May 19, 2024 9:03:49 GMT -5
I have the exact same problem as heard in the video, nothing seems to help the cutting out at approx. 11000rpm when riding. I have a malossi cdi and have replaced all other electricals, stator etc. also sealed case well and checked for leaks. Also tested max revs with cvt not connected and it revved nicely. Still Nothing seems to help. (My engine is minarelli horizontal ac) On top of all the fuzz, i have tried many different rollers, variator pressure springs, 2 different clutches and front variator plates. Im pretty dumbfounded with this ghost problem. Did you ever figure out your issue? I am dealing with something similar. |
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Post by billwill on May 19, 2024 20:17:33 GMT -5
I have Had very similar issues on one of my build it would do exactly as what you are describing I can't say for sure what your problem is I can only tell you what seemed to help mine was getting a completely different carburetor greater I was running a oko swapped polini pwk And it seemed to help a hell of a lot with that issue basically went away I think it was like an emotion tube issue not allowing enough fuel to dry in.... I took the 28mm OKO off and popped it on my 177cc Stella, upjetted to 120 main and it works amazing. I have even swapped to a smaller carb on the Minarelli clone and it stutters at high rpm still. I don't believe it's carb. I've swapped reeds as well. Pretty much swapped everything except that nice flywheel and stator... Hey man curious if you ever found the culprit to this issue? Having similar problems of my own and wondering if it ended up being electrical. |
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