Buddy 125and 150 Carburetor needle and ?shim

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PNWbuddy
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Buddy 125and 150 Carburetor needle and ?shim

Post by PNWbuddy »

I have been trying to get my Buddy 125 kitted to 161 with the Prima BBK tuned. It runs well but with very low top speed. 47ish GPS on flats and 53 absolute max running a half mile moderate downhill. Something must not be right. I did re-jet, cleaned the carb thoroughly, made sure the rubber diaphram wasn't damaged and was properly seated (checked that a few times). I did see that the carb needle didn't have any spacer or shim under it. When I looked at the scooter lounge carb diagram the needle drawing looks like it has a spacer. I know that the prior owner had the carb cleaned at a shop in Seattle so I wonder if they lost/omitted the spacer, if there is one. They did some sketchy things to this bike including leaving the exhaust gasket off, missing screw in air filter and wrong screw in the filter that cracked the plastic etc so I wouldn't put it past them to have left the spacer out. Scooter lounge lists the Buddy 125 needle for sale but not the needle for the 150 and according to Scooter West the 125 and 150 have the same carb but different needles "(Keihin 5mm round); 4HJBN Needle)
(Buddy 150 uses same carb but w/ different needle (4HlGL)"

So my question is if anyone knows for sure if there should be a spacer under the needle and if so what thickness it is. I could make my own nylon spacer or depending on thickness I could shim it with washers.

Thanks
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Stanza
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Post by Stanza »

What did you jet the carb to? And did you also increase the idle jet size? Is it bogging at any particular throttle position, or does it just feel down on power all around?
PNWbuddy
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Post by PNWbuddy »

I installed slightly larger pilot and main jets. I can't compare the numbers because the new jets have a different numbering system but I can say they are larger having used guitar string to compare them as well as visually. It runs well down low but runs out of steam 45 and above. I didn't do the BBK to add to the 125 top end reported variously from mid 50s to low 60s. Given that there is no shim under the needle in my carb that seems like the thing to correct. If I can't find the thickness of the stock shim I'll have to experiment but the diagram on Scooter Lounge makes it look like the shim is quite thick.
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JettaKnight
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Post by JettaKnight »

IIRC, my main jet is somewhere around 120. It's been a long time...


Is the CVT belt and rollers in good shape? IF that's worn, no amount of power will help.

I run a stiffer counterspring and 13 gram Dr. Pulley sliders.
PNWbuddy
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Post by PNWbuddy »

New Gates belt, new 12g rollers. I have some 13g sliders that I am going to try but I think it is a fueling issue at this point.
PNWbuddy
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Post by PNWbuddy »

As a clarification, there is no shim under the needle. Jettaknight, I don't see how you could get a 161 run on anything close to a 120 main jet. I got a new Keihin carb on Amazon, the listing didn't mention the brand of the carb but it is identical to the stock carb including markings on the body and jets same as the stock Keihin carb. The new carb came with a 38 pilot which is same as stock and a 118 main. The scooter would bog severely when given throttle, the bog resolved with a 96 jet and I was able to reach a GPS top speed on flats of 51mph. The stock main was 92, I might give a 94 a try. A "performance" unrestricted CDI made no difference in top speed. On to the Dr Pulley sliders, if that makes no difference then I am giving up on it.
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