J-Madd

I'm at a total loss on this. I checked the radiator and it's completely full. I've ran a tank of gas through it since I filled the rad up. It can't be the gaskets. What should I even look for next? A crank seal leak on the right side would burn crankcase oil, so that's not it. Is it possible that the porting is not identical b/t the 2 cylinders, thus one requiring more or less fuel at 0-1/4 throttle? I may put some bigger pilots in there and see what happens, even though I know the carbs and jetting is not the exact problem, but may hide it with larger pilots. Again..this thing rips from 1/4 throttle on.

Looks like you've already got everything figured out. Prices look pretty good. I don't believe you can run any bigger than 30mm carbs with the airbox, the boots won't fit, hell they barely, barely will fit the 30mm. I don't know if you can buy some different boots or not. edit: You didn't say anything about advancing your timing. I'd definitely do that.

Yeah, I'm on YFZ Central too. This site seams to be friendlier. All ya get there is "search search search." Here iIve seen post after post on the same topic, and they always get answered in detail even if its been answered a thousand times.

What are the air screws set at? If they are turned in or out too far, it'll be difficult to start also.

Welcome to the HQ!! Your gonna love working on 2-strokes after having that YFZ. Jetting principles are the same on 2 strokes. If its hard to start the pilots are too lean or the airscrews need to be turned in to richen it up a bit. What jets are in them now?

I don't have a clue what a y-1 and y-2 head is. Never heard of them. Anyone else?

The main shouldn't have any effect at all while in neutral. I've had a main jet fall out and it runs fine up to about 3/4th throttle in all gears. But I agree w/ everything else you've mentioned.

I was thinking head o-rings or base gasket myself. Last time I checked the radiator it was a little low, but I don't have a reservoir so it could have spewed out a little. However, no steam or water vapor appears to exit the silencer, no water beaded on the spark plug..........I've seen that before. I forgot to mention that I checked compression. About 160 psi in each cylinder.

OK here's what I've tried and the problem always STAYS ON THE RIGHT CYL. - swapped carbs and plug wires left to right - gapped plugs at 0.020 - checked reeds on right cyl. Other than this problem, it runs great, Smoked a DS650 w/alleged 70 dynoed hp. I'm guessing I'd have at least 10 more hp on that dyno.

I thought the 87-89s were only 5 speeds? Not sure.

I don't think you can make a comparison between the jet sizes on the MIKUNI and KEIHN 30mms. I used to have some 30mm "PWKs" from carb parts warehouse. I've been told that 30mm Keihns don't exist also, so I guess they were bored out 28mm. I wish I could remember how mine were jetted. I sold them to a fellow member. Carb Parts warehouse will give you general jetting recommendations for their carbs.

My '99 Banshee smokes my YFZ on dirt or pavement. YFZ had LRD exhaust, cammod, crower gen 3 intake cam, stock gearing, dyna fs ignition. I now have a Ron Wood exhaust. The LRD can was busted a the mounts. The Banshee has whats listed in my sig and shaved head 0.020'' (about 150 psi now). We also polished the exhaust port last rebuild, nothing major, no porting. It got stock gearing now, but it pulls a 15t pretty easily.

same question I asked a while back..click to check it out

I've never ran the SSTs, but I had a buddy w/that setup, K&N w/lid (no snorkel). I think he ran 240 mains and stock pilots, 300 ft elev, all temps. Seems small, but it was set up for MX by Tom Miller Motorsports before he got it.

My CPIs do it too. I leaned out the main jet and they still build up oil. I don't know what else to try. I run Klotz 32:1.

Your jetting could be rich. You can run lean oil/fuel mix and still have oil on the pipes and you can run 32:1 and have no oil if your air/fuel is lean. BTW, mine has oil on the ends of the CPI pipes all of the time. I jetted the main leaner and I seemed to lose a little HP, so I went back up. It still collected oil even w/the leaner jetting. I run Klots 32:1. I have a friend w/ the 35mm single set up and his smokes like a freight train, but he's never tried to fix it.

Good call. Don't get a puller from your local auto parts store. You have to get the one for a Banshee from the dealer or magicracing.com or where ever. I ruined a flywheel way back when I didn't know sh#t about Banshees.

I got some from Fullerton Sand Sports. I called Skat Trak and they were backordered there as well and got Fullerton's number. They matched the rollout and idexed them. Good service.

If you buy a timing plate, it should include directions. You can mod your own timing plate for free. There are some pics somewhere on how to do it..........you'll have to search for precise instructions on that.

What he said

260 mains on 30 mm carbs?? What kind of carbs are those? Your description sounds like it's lean to me, maybe on the needles; you may check your new reeds also. Broken reeds can probably cause similar symptoms.

Unless you ride through deep water, you could go ahead and take the lid off and re-jet to get a little more hp out of it. I run w/out a lid through a very shallow creek bed and wheelie over mud puddles, etc., and haven't had a problem with the filter getting too wet.

I ran all stiff springs w/my Barnett and HATED it. However, I think my cable had a lot to do w/it. It was all corroded and shit, but I didn't know it. A new cable probably would have made it a lot easier. Also, when you install the clutch, don't forget to line up the arm with the arrow on the case. If you don't know what I'm talking about, find out before you install it. I (and some others) know from experience. You'll fry that sucker and couple days.