What Should I Be Trying For Jets Here

[LanceG60]

Ok here are my mods. Cool head, 19cc domes, Dyno Port 2-1 pipe, stock carbs and reeds. I run 117 50/50 with 94 mixed 32:1. I just pulled the carbs and my needle is down one slot from the center and I have 240 mains. Now I'm thinking 240's are way too small for what I have because I see people running 280's on stock bikes with just pipes. Plus the temp around here is getting cold, most days have been in the 20's. What should I start with? 300? Over 300? Should I put the needle back to stock? I just want to start over because the jetting hasnt been changed since the previous owner had it, and I already know more about this thing than he did and I'm brand new to Banshees so I don't trust his setup. I also did a tope end in the thing a couple weeks ago so I don' really wanna blow it up again.

[National Banshee]

Hi, The altitude you are riding at has a great deal to do with your jetting. 200 main is stock at sea level, At 20 degrees F you might need 220 mains, needles in the middle, with stock pipes. The 2 into one shouldn"t require very much more I don"t think. You might want to check with the pipe builder and see what they recomend, or learn how to read your plugs. There is a pretty good article at CT racings web site on how to read plugs. My guess would be around 240 you should be safe, but check your plugs carefully. What did the old pistons look like and what jetting wasn it then? Did it seize or melt the top of the pistons?

[LanceG60]

well I ran pump gas and I was told that is why I blew the last top end, plus it was the stock top end from a 90 so I guess it was due. The side of one of my pistons had a hole in it and that scared me. But the bike has been running rich from what I see because my plugs are pretty black. I'm wondering if I should just move the needle back and try these same mains again? But then again I could have just been running rich because my float is stuck. I was fixing that and that is when I checked the jets.

[National Banshee]

Once again it is important to know your elevation. 19cc domes at sea level would be a bit small in my opinion without 100% race gas. I am not a big fan of pushing the head volume that closley. If you burnt a hole in the top of the last piston, you were more than likely detonating, so I agree with whoever told you it was your fuel. Most people make the mistake of running to small a squish area and end up jetting it so rich to keep from blowing it up that there mods are worthless. If your altitude is less than 1500 ft, I would go to a 20cc dome set, then work safley on your jetting, but that is only my opinion. I assume your ignition timing is still stock?

[LanceG60]

Yes my ignition is stock, and I live at sea level. If I went to 20cc domes what would be a safe gas to run? What I'm running now or would I be going back to pump gas? This is starting to go off topic but oh well maybe that is the answer rather than messing with what my setup is now. I'm planning on switching the thing to 2 pipes and getting some carbs in a couple weeks...so if it would be better to pick up 20cc domes I'll do it all at the same time.

[lincster]

What air filter system are you running. This will play a HUGE factor in your jets.

 

I run 20cc domes and have T5s with the 2:1 air filter. I run 370 mains with 30 pilots and Toomey needles on the 4th clip position from the top.

I run 110 race mixed 50/50 with premium and 32:1.

I would jet way up if I were you, unless you are running the stock air box with a snorkel.

[LanceG60]

I have that pro-flow adapter with a foam fileter with no lid on the box. Not the way I'd want it but I just havent found an airbox yet. The guy hacked this one and it touched the exhaust pipe so its all messed up.

[lincster]

With no lid on the airbox, you are too lean on the mains. I would try around 270 or so.