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Post by carasdad on Apr 7, 2013 12:07:54 GMT -5
Thinking I have a possible Jet issue. Working on my Uncles scoot. Tao Tao cy50 t3. Put an 80BBK on it...got the tamper proof carb bowl screws out and put in a #  jet. Speed and power are awesome...runs like a champ and will GPS up to 46-47 mph. Once it runs a minute or two...warms up and I assume the enricher kicks off. Power and speed are down where as it will only hit about 39mph. Raised the needle one notch..still the same....raised it all the way...still the same. So my assumption since it runs best with the enricher on...is that the extra fuel it provides is telling me it needs a bigger jet?... Any ideas or suggestions?...  Thanks, Glenn....aka Yayiima benatigee |
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Post by alleyoop on Apr 7, 2013 12:43:55 GMT -5
If it starts up good and runs good after it is nice and hot up to 3/4 throttle you need a bigger MAIN JET. If it does not run quite as good after the motor is hot up to 3/4 throttle you need a bigger PILOT JET.
The PILOT JET feeds fuel all through the throttle range, not as much once the needle comes out far enough out of the diffuser to start feeding fuel from the main jet passage but contrary to what people think fuel is also being sucked out of the PILOT JET passage and tiny holes by the butterfly.
Alleyoop
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Post by carasdad on Apr 7, 2013 14:28:15 GMT -5
[replyingto=alleyoop]alleyoop[/replyingto]Alleyoop...That may be the issue then. In my 35+ years of working on Mopeds...Scooters and Dirtbikes..can't say I ever saw this issue. Once warmed up its rocket like take off has faded quite a bit and 3/4 to full throttle is virtually non existent. It just plugs along about 10 mph slower at WOT. Going out now to check the pilot jet...since it factory stock most likely it is not marked though....  That irritates me as many Chinese products I work on...neither jet is marked.  |
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Post by carasdad on Apr 7, 2013 14:53:04 GMT -5
Of course....the markings on the Pilot Jet are not legible....it appears to be stamped 40....does that seem to be in the ball park for a Minarelli 2T? Grrrr...nobody here can read the number and my gf has eyes like a Hawk....
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Post by alleyoop on Apr 7, 2013 15:25:58 GMT -5
No that seems to big, 150s run with a #35 or maybe a #38 but a #40 is huge not even a 250cc has a 40 size pilot jet.
If this is a 50cc and the pilot jet was not changed it probably has a #32 I would put in a #35 and give that a shot. A #35 pumps out a lot of fuel. I have 30 more ccs on my 150 is now a 182cc motor and It takes a #38 a #40 was to much fuel.
You can verify which way to go.
With the motor off turn the fuel ratio screw clockwise and count the turns it took to close.
Then turn it out counter clockwise the same amount of turns and start the motor. let it warm up so the enricher cuts off the extra fuel
at least 5 minutes.
Then turn the screw 1/4 at a time clockwise and see at what point it kills the motor. IF the screw is all the way closed and it does not kill the motor then you know the PILOT IS TO BIG.
If it kills the motor and you still have 2 turns or so left on the screw then you know the PILOT JET IS TO SMALL.
Alleyoop
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Post by carasdad on Apr 7, 2013 17:53:00 GMT -5
No that seems to big, 150s run with a #35 or maybe a #38 but a #40 is huge not even a 250cc has a 40 size pilot jet. If this is a 50cc and the pilot jet was not changed it probably has a #32 I would put in a #35 and give that a shot. A #35 pumps out a lot of fuel. I have 30 more ccs on my 150 is now a 182cc motor and It takes a #38 a #40 was to much fuel. You can verify which way to go. With the motor off turn the fuel ratio screw clockwise and count the turns it took to close. Then turn it out counter clockwise the same amount of turns and start the motor. let it warm up so the enricher cuts off the extra fuel at least 5 minutes. Then turn the screw 1/4 at a time clockwise and see at what point it kills the motor. IF the screw is all the way closed and it does not kill the motor then you know the PILOT IS TO BIG. If it kills the motor and you still have 2 turns or so left on the screw then you know the PILOT JET IS TO SMALL. Alleyoop Ok...bringing back memories a bit. Heard something similar to that when I was 16 working in a Harley shop. Harley used to make some really nice 2T rides. One of the best being their MotoCross bike...the MX250. It was monster of a ride and dominated Motocross.....then poof! I think their deal fell out with Italy and they stopped making them overnight. The shop had a dedicated Mech named Kort. I ran the parts shop...but hung out with him on repairs every second I got. I recall doing something similar with Harley Moped....the Leggerro. He would bore and stroke them for folks and make a real screaming moped. Anyway mine cuts off at about 1 3/4 turns out. So it must be small. My choices for the 19mm TK carb are #42 then #45 and I currently have a # 40. Thank gawd for 20 yo kids cause unlike we old folks...they can still see. My neighbor 1/2 mile down the road...ryan52 on here...looked and said..."Hey man..it's a 40" Smart @ss..how could he see it with a naked eye and my reading glasses would not work?... I am guessing 42 as 45 seems like a huge jump for those tiny Pilot jet orrifice's. Not sure which one.hmmm  |
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Post by millsc on Apr 7, 2013 18:01:14 GMT -5
40 is big ill take the tamper proof screws out of my stock carb i took off my t3 2011 i just upgraded to see whats in it, did the t3 you upgraded have a 44mm piston? mine did
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Post by carasdad on Apr 7, 2013 19:57:12 GMT -5
40 is big ill take the tamper proof screws out of my stock carb i took off my t3 2011 i just upgraded to see whats in it, did the t3 you upgraded have a 44mm piston? mine did Yes.44mm 63cc...and at 428 on the odometer the piston and plug look to have been over heated.. |
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Post by dude on Apr 7, 2013 21:31:06 GMT -5
I can't see myself, but I've learned to use my phone and take a picture then blow it up.
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Post by alleyoop on Apr 7, 2013 21:37:48 GMT -5
Well personally I think your going the wrong way, a #40 on a 19mm carb on a 50 WOW!! Like I said mine has 120 more ccs than yours and a #40 is to big I have a #38.
Even Millsc thinks a #40 is to big and he mess's with 50s everyday and with bigger bbks than a 63cc.
If it is really a #40 I would go down to a #35 that should be more than enough for it.
Alleyoop
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Post by carasdad on Apr 7, 2013 21:56:19 GMT -5
Well personally I think your going the wrong way, a #40 on a 19mm carb on a 50 WOW!! Like I said mine has 120 more ccs than yours and a #40 is to big I have a #38. Even Millsc thinks a #40 is to big and he mess's with 50s everyday and with bigger bbks than a 63cc. Alleyoop I agree and just talked to few buddies with 4T scoots....not Tao Tao but a GY6 50..is a GY6 50..they gave numbers from theirs which are 22.5-24.0.... A buddy gave me one...it is not marked but that is irrelevant as the scoot runs like a champ now....  Now I have another carb issue. I replaced the stock fuel and vac lines...they were so HARD you could not pinch them...pulling them off and putting back on the elasticity was gone. So I bought all new tubing and while I was at it I thought it would be a good time to check and clean the carb. Had it all a part...went in to eat..hyper active brat kid next door went in and played with the parts. Now missing the main jet..pilot jet and slide assembly. Main jet and slide assembly I have from an unused parts carb we had at the shop. But no pilot jet or A/F screw. A/F screw I found on Ebay super cheap. But did you know....NOBODY sells pilot jets for the TK 19mm carbs our Minarelli engines come with? I found no resource..just a bunch of blogs where guys are saying they won't buy another Yamaha because they now use the TK carb and they can't get jets. The boys mother was a real b*tch about it..but said she would pay for the parts..however what is there to pay for if they can't be found... If you or ANYBODY here has resource for them..please let me know. Also I heard a rumor that other brands work...but the 2 fella's in the forum did not know what type or brand. Somebody here must have a resource as I have read where they increased or decreased the pilot jet size on their TK carbed Minarellil.... |
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Post by alleyoop on Apr 7, 2013 22:16:32 GMT -5
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Post by carasdad on Apr 8, 2013 14:16:17 GMT -5
[replyingto=alleyoop]alleyoop[/replyingto]Ok here is something odd. If I leave the enricher unplugged after engine has sat and is cold....it starts and runs great..really flies. Unlike before with enricher plugged in...where after 2 mins it would lose take off and power... with the enricher unplugged and on all the time...I can ride 20 mines or more without that power and top end loss and the idle remains smooth. Whereas with the enricher connected after a few mins I lose power and take off...and idle is really crappy.. Confused. |
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jet. Speed and power are awesome...runs like a champ and will GPS up to 46-47 mph. Once it runs a minute or two...warms up and I assume the enricher kicks off. Power and speed are down where as it will only hit about 39mph. Raised the needle one notch..still the same....raised it all the way...still the same. So my assumption since it runs best with the enricher on...is that the extra fuel it provides is telling me it needs a bigger jet?... Any ideas or suggestions?... 
..BAD TO THE BONE..
