YD100 jet size

[Marmalade1]

YD100 running great. Maybe 5 tanks in.

10/36T ratio. 1:40 oil ratio since new.

I'm using 67 size jet. Runs great, but almost seems like it's 4 stroking at midrange / full throttle.

Surely it can't be rich? I've not done a plug chop yet. I'd have thought a larger engine (vs my old 66cc) would've required more fuel.

Also, it requires brief choke and perhaps a full minute to gain power upon start up. Feels bogged down. My old 66cc was almost instant start and power. Could I be too rich on the low end?

 

[Chainlube]

Move the clip on the carb needle one notch closer to the end and try it.

 

[wolframore]

Do they come with an NT carb?

 

[Marmalade1]

Do they come with an NT carb?

No. Speed carb.

 

[wolframore]

I wonder if the 14.5 mm carb is too small for 100cc

 

[Marmalade1]

Move the clip on the carb needle one notch closer to the end and try it.

That sounds like it'll work for low/mid. I'll try.
Thx

 

[wolframore]

If you are indeed rich at idle but nowhere else increasing the slide cutaway will help. Start with small increments. But you need to do the work to determine what’s needed before you start hacking away at it. I still think the carb is too small.

 

[Marmalade1]

I wonder if the 14.5 mm carb is too small for 100cc

Well, "100cc", it's really 78cc. Vs the "80cc" that is really 66cc.

But, yes that was my concern.

 

[Karl Snarl]

I wonder if the 14.5 mm carb is too small for 100cc

Yep, way to small. 18-19mm would be way better. I run a yd100, they run great with a 18-20mm venturi.

 

[DAMIEN1307]

Yep, way to small. 18-19mm would be way better. I run a yd100, they run great with a 18-20mm venturi.

Dont think ya gonna get a reply from wolframore...lol...Last seen Nov 17, 2020...DAMIEN