Tazland 44mm prefers 68 jet

[Lunytune]

My Elite E SB50 cratered last Fall, just at the end of riding season. Compression poor. Tore it down then, but just recently put it back together. Initial road test was good, a little noticeable better takeoff, which I was hoping for. So I figure I best swap out the 68 jet for a 78 I had. Performance faltered, top speed cut to 20mph. Put the 68 jet back in and performance improved, pulls good on takeoff and top speed 30mph.

Anybody experience this? No, I haven't done a plug chop yet. I might also add that oil pump is hooked up but I'm still running mix 1/50 in the tank. Between the two, I'm sure it's getting rich mix, which I like on break-in.

[Trafficjamz]

That does not seem right. 68 seems small to me. What sort of air intake are you using?
Is the stock air box hooked up, or do you have an open carb?

[bradthreee]

No, I haven't done a plug chop yet.

You need to do this ASAP

[odinxxix]

i have the stock air box but i drilled 5...1/2" holes on top. and i have like an 88 i believe, someone drilled it out for me. when i put in a 90 it was too much.

[Lunytune]

Weather has been miserable last couple of days. Spring came, but chilling rain and winds returned. Hope to get back on the project tomorrow.

Yeah, I do need to do the plug chop. I'm hesitant to drill holes in the box, but may be necessary. Exhaust seems to be breathing okay. I'm suspecting the 78 with stock box is too rich and hope opening up the box will get the air/fuel ratio back right for the 78. I have a 100 jet but really can't imagine it needing that much.

I'm hoping I don't have to do exhaust mods. Say what you may, but I do believe tuning a Spree or SB50 does approach rocket science. Makes me nervous to move away from stock. The AF16 is much easier to overbore without problems. I have one with 50mm bore and 100 jet, and no other mods. It's a screamer.

[Trafficjamz]

Double post

[Trafficjamz]

I'm hesitant to drill holes in the box, but may be necessary. Exhaust seems to be breathing okay. I'm suspecting the 78 with stock box is too rich and hope opening up the box will get the air/fuel ratio back right for the 78. I have a 100 jet but really can't imagine it needing that much.

Don't drill holes in the air box. I did not have any luck using the stock air box at all. Not even the little black tube that connects the box to the carb should be used (IMO). The 78 should work. Put in a brand new plug, take the spree for a short ride then shut it off(don't let it idle). Remove the plug and look at it. If your plug looks good then you just need some sort of free flowing filter.

[eliteguy50]

you just need some sort of free flowing filter.

That is what Taz told me to use.

[tazland001]

Jetting is an interesting topic. I will give you some example, My two boys race motocross and desert. When we go on the road to race if the altitude is high I re-jet. If the altitude is real low I rejet. If the track has no turns I use a taller sprocket set up and if the track has a lot of turns I use use shorter sprockets. This just illustrates how we need to adjust the jetting due to altitude sometimes. Another thing some scooters respond differently than others. I know it sounds crazy but this is true. One scooter might run better with a 90 while the same exaxt scooter your neighbor owns needs a 85. Some scooter just have there own characteristics. Thats weird but get use to it. So if you use this 44mm kit you need to find the jetting that is right for you. Usually a 85-90 is ideal for break in. That does not mean that a smaller jet will not work but the smaller jets are a bit lean for the break in procedure and have a tendency to overheat the cylinder. When I sell the 48mm kits for the spree the jets will be 100 to 105 for break in.

Taz

[Wheelman-111]

Greetings:

Wise counsel from the Taz. Don't forget hot/cold temps low/high humidity, and oil content of fuel, just to name a few other confounders. The best anyone can do is suggest a high starting point and then it's up to the user to jet down. The safest route is to jet so rich it barely runs for break-in. Of course break-in will take longer if it won't start...