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Post by spaz12 on Jul 26, 2015 13:12:57 GMT -5
I can't really remember, but I don't think that the needle is adjustable on that carb. It's been a while since I've messed with one.
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Post by spaz12 on Jul 26, 2015 13:40:20 GMT -5
This video is for the Zuma but it's the same carb as yours.
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Post by birdman on Jul 26, 2015 18:29:05 GMT -5
Lol maybe an upgrade to a 19mm carb could be a good investment at this point
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Post by tsimi on Jul 26, 2015 19:21:35 GMT -5
Thanks for the help guys! Really appreciated and very welcome. spaz12I'll be damned that looks like to be the same carburetor. At least the upper part is same. Here a video that shows that carb closer and except for the mixture screw all is same. youtu.be/LJpTgCWuGc8Thanks for the video I haven't looked at my Carb to compare yet but sure an interesting mod there. And I think you are right the Needle might not be adjustable. I found a Japanese Blog entry where someone is talking about that Carb and that he replaced the Needle with this one (Yamaha Part No. 4LV-1490J-10). Unfortunately he doesn't "show" how to take apart that stock Carb Needle thing. Lucass2TAs spaz12 mentioned I don't think the Needle is adjustable so I need to get a replacement that can be adjusted first. And of course after I removed the Snorkel and found the right MJ first. But to be really sure that the stock Needle can't be adjusted I need to take apart that thing so any guide is very welcome. Positioning the Needle down means what exactly? Rich or Lean? birdmanDon't put such ideas into my head....that won't end well with the house president.  UPDATE:found a guide with pictures in the Zuma forum. Needle Removal Guideand here the Japanese version  which show the exact same Carb as mine since it is from the same scooter. Japanese Guide |
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Post by spaz12 on Jul 26, 2015 20:27:03 GMT -5
Good find tsimi. It'd been so long since I've torn into one that I couldn't remember if that need was adjustable or not. BTW, raising the clip puts the needle further down, which makes it leaner. Lowering the clip makes it richer. |
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Post by Lucass2T on Jul 27, 2015 4:39:42 GMT -5
Oh totally missed that part about the fixed needle clip! Yeah i know some carbs have a needle that can't be adjusted.
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Post by tsimi on Aug 1, 2015 5:34:33 GMT -5
I received the needle this week and today we had nice weather(a bit too hot for my taste) so I did what niz76 and birdman said and removed the Snorkel. Because it is the first try I thought I go high with the MJ from #80 to #88 and I think i hit the jackpot. It's like the beast was caged in before and now it has been released. Brutal acceleration at WOT and the sound of the air box without Snorkel is awesome. Max rpm that I reached before I shit my pants was 9600rpm. Top speed... can't tell my speedo goes until 60kph and the needle went as far it could. Next time I'll use a GPS to get more accurate info. The other positive thing was up hill, everything runs great now. I even slowed down up hill and checked if it would respond once I cranked it to WOT and it was beautiful.... Tomorrow I will try and see how a #90 MJ behaves. I should have listen to niz76 in the first place when he told to remove the Snorkel. He was right with the roller weights when I was tuning the CVT and he was right again. From now on I will listen to everything he says. If he tells me to jump out of the window then I'll do that without questioning it. There was no bogging or sputtering at any stage of throttle. Even if I crank it quickly from stand still to WOT it accelerates smoothly. So I might not need to adjust the needle after all. But I guess it's good to have a spare needle that can be adjusted just in case. I can't do wheelies yet since the clutch engages way too early. I can't get enough rpms to have a powerful take off so that will be the next mission once I get the MJ thing done. All in all, it seems that I am on the right track now thanks to you guys. |
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Post by birdman on Aug 1, 2015 7:58:55 GMT -5
now the real fun begins lol
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Post by tsimi on Aug 2, 2015 19:15:05 GMT -5
Went for a ride with the 90 MJ in it and ran very well. I couldn't tell the difference between the 88 and 90 MJ. Rpms at WOT are same, around 9600rpm. Top speed according GPS with both MJ was 70kph (42mph) with the stock variator and i think i still might have the additional shim washer in it from the time when i was tuning the CVT for the 50cc engine.
I already put in the 92 MJ to see how it will perform but didn't test drive it yet.
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Post by niz76 on Aug 2, 2015 19:17:35 GMT -5
The bigger main jet is a lil' safer if you can't feel a difference in performance. Go as large as possible b4 performance drops off! BTW thanks for the kind words Tsimi! lol. A couple scoots I've dealt with were only happy with the snorkel in, but those were (probably) stock 49cc scoots...
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Post by tsimi on Aug 2, 2015 21:55:47 GMT -5
Yeah, will do. Going higher until it starts to loose performance and then i know which will be the winner.
I am so glad that i bought the MJ set that is a life savor.
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Post by niz76 on Aug 2, 2015 21:57:57 GMT -5
Upjet in winter time!
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Post by tsimi on Aug 4, 2015 6:12:22 GMT -5
Test drive with MJ #92 completed. 9,4 km long drive. Felt very powerful and strong more then with #88 and #90. No bogging or trouble at all. WOT was steady and strong. First rpms stayed steady at 9000 and then slowly climbed to 9400rpms max. Top speed reached was "almost" same as with the previous 2 Jets, 69kph (approx. 42mph) So the top speed is not a BBK issue but a CVT issue. Later I'll pull the spark plug and see how it looks. Here as screenshot of the GPS.  So the current winner is #92. ...let's see next what #94 does. |
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Post by tsimi on Aug 5, 2015 6:53:49 GMT -5
Test drive #94...man oh man...just beautiful, can't say more then that.
Brutal, brutal acceleration at any throttle stage. At WOT no bogging or struggle at all. Nice power. Max rpm was same as with the #92 around 9000-9400rpm. Top Speed, here again around 69/70kph.
Just so fast acceleration and so much torque and I haven't even started to touch the CVT yet. I can drive uphill nearly the same top speed as on a flat road.
Man I was way off then thinking that an #88 would be enough to start with. So I was way too lean then if a #94 performs that good. So now I am facing a problem, I hope that the next MJ #96 will work fine or even bog because I am running out of Jets here. I have #70-#96 and I didn't really intend to buy the bigger set that starts from #98-#124 if not necessary.
Next MJ #96....stay tuned...
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Post by niz76 on Aug 5, 2015 18:18:54 GMT -5
lol The idea is to start pig rich and work your way down, but I kinda tuned my Mikuni TM the same way you are...
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which show the exact same Carb as mine since it is from the same scooter.
