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Post by proy on Oct 17, 2024 14:53:10 GMT -5
As far as carb tuning I like to start with the biggest main jet that allows the engine to idle without flooding. Then by one size at a time, lower the jet size and test ride. At some point you will notice an improvement to power.
I continue to lower the jet and test ride every time until I do not feel any more improvement. From there go back up one or two jet size.
Early on I did not rely on cylinder head temp sensor. It was a night and day differance in how easy it is to jet and fine tune your carb using cylinder head temp. I would highly suggest investing in a temp gague or even a well reviewed temp gun if your new to tuning.
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Post by proy on Oct 17, 2024 15:46:19 GMT -5
Also have you or do you plan to remove the restrictors in the yasuni pipe? Im not sure if its restricted the same as my eton beamer. When I first installed the yasuni pipe with the restrictor I could not get the engine to idle no matter what I did. Once I removed the restictor at the exhaust flange by grinding out the spot welds it started and idled a lot easier.
I have the yasuni z pipe and the only restrictor i had was in the exhaust flange but there are yasuni pipes with a second restrictor at the muffler side of the exhaust as well. Again not sure if your pipe will be restricted in the same way.
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Timmer
Scoot Enthusiast
Posts: 128
Location: Mechelen, Belgium
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Post by Timmer on Oct 18, 2024 16:30:57 GMT -5
Also have you or do you plan to remove the restrictors in the yasuni pipe? Im not sure if its restricted the same as my eton beamer. When I first installed the yasuni pipe with the restrictor I could not get the engine to idle no matter what I did. Once I removed the restictor at the exhaust flange by grinding out the spot welds it started and idled a lot easier. I have the yasuni z pipe and the only restrictor i had was in the exhaust flange but there are yasuni pipes with a second restrictor at the muffler side of the exhaust as well. Again not sure if your pipe will be restricted in the same way. If he wants the full potential, he’ll have to remove it. Those are restricted to get certified as street legal, and that’s for a 50cc. If he plans on running a 70, they have to go. It will probably have the restriction in the muffler too. |
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Post by proy on Oct 18, 2024 17:54:48 GMT -5
I drove my bemer on a polini sport 70cc cast iron kit for over a year with the knobby on road and off. I have the yasuni z (derestricted) so little lower reving but I loved the combination. Ill guess the stage 6 will be somewhat similar and more happy to rev with the yasuni R.
Be mindful of the rpm you use for extended periods. I over reved my polini sport for over a year but eventually the wrist pin bearing faild suddenly and whiped out the entire engine outside of the case and transmission. That was with a new naraku hpc crank and bearings. It lived mainly between 9k and 11k Rpm. Extended periods over 10k rpm is what killed it.
Love the build so far cant wait to see what you get out of it.
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Timmer
Scoot Enthusiast
Posts: 128
Location: Mechelen, Belgium
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Post by Timmer on Oct 19, 2024 5:08:38 GMT -5
Wrist pin bearing is the needle bearing i think? Mine held out for 2years+ on a 70 polini cast iron, with the bidalot s2 exhaust. I have no idea of the rpm’s it did, the scooter eventually died when i hit a wall coming down from ~70km/h, trying to avoid a schoolbus… long story, bad memories.
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Post by proy on Oct 19, 2024 13:50:25 GMT -5
Yeah im refering to the needle bearing at the top of the connecting rod.
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Post by yahnos on Oct 20, 2024 19:17:13 GMT -5
I bought a main jet kit with my carb and the largest size in the kit is a 110, would that be a good place to start? I did think about the temp gauge and will probably purchase a trailtech temp gauge as well as a rev gauge.
As far as the Yasuni goes, I removed the restrictor before I installed the pipe. I can't understand why that would be there in the first place?
The build is at a bit of a standstill now, i'm waiting on the angled carb adaptors and a pod filter, does anyone know where i migth be able to get and engine shroud from? most online shops seem to be out of stock.
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Post by proy on Oct 20, 2024 19:35:04 GMT -5
If it will idle with the 110 i would start there. Its gunna bog or die all togeather if its way to rich. My polini 70cc sport kit stareted at 108 and ended up at 98 until i get a good amount of miles on it. After about 2000 miles I dropped it to 88 and added a factory airbox.
Every engine setup likes slightly different jetting.
Cant say that will work for you but between 80 to 110 I think you should be able to get it running happy.
Also strong second on getting that fan shroud around the head. I have seen mopeds overheat idling on the stand with bad/missing shrouds.
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Post by proy on Oct 20, 2024 19:40:45 GMT -5
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Post by aeroxbud on Oct 21, 2024 4:38:25 GMT -5
The pipes come restricted so they can meet European legalisation. That's what the e mark on the pipe means.
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Post by yahnos on Oct 26, 2024 22:46:43 GMT -5
So the pod filter and angled carb adaptors arrived this week and I spent some time putting the bike back together this morning. I ended up removing the oild filter as well as the electric starter motor and blanked them both off. From what i've read 40:1 fuel to oil ratio is the way to go, anyone have any feedback on this?
I managed to get the carb on with the pod filter, throttle cable and choke and kicked the bike over a couple of times and eventually it started and idled fine after adjusting the idle screw. I started with a 98 main jet which seemed way to rich and worked my way down to an 88, the lowest I have which still seems to rich. the bike will start and idle but as soon as I twist the throttle it bogs down. I haven't changed anything else on the carb apart from the main jet. The needle is also on the lowest setting, do I need to purchase another jet kit and keep working my down until i find the right jet?
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Post by proy on Oct 28, 2024 5:48:02 GMT -5
More then likely unless you have a vaccume leak. Is it idling high? Or does it just die only when you apply throttle?
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Post by proy on Oct 28, 2024 5:57:29 GMT -5
When I first got my polini sport running I had a hard start/wouldn't rev issue. Ended up being a combination of bad crank seals and a minor intake leak. I now use an extrmely thin coat of gas safe sealent on all sealing surfaces for the intake.
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