J-Madd

Unless the transmission was ran low on fluid, you usually don't have to replace the transmission bearings. You don't have to take the transmission apart to clean it (if it is even "dirty" - which it shouldn't be.) YOu could get by with spraying carb cleaner on it to get any dirt/grit off of it. I just pour whatever oil I'm gonna run over the trans before assembly. When you fill the crankcase up, the trans is gonna be in oil anyway, though. As said, make sure the clutch is engaging and set correctly before putting the side cover on and filling with oil. Its also a great idea to make sure the kick starter is working before filling it up. You can just tighten the bolt on the side cover closest to the kicker, and a couple more then test it by hand to make sure it's working right.

That looks more like my 10 mil graph with that low peak, except yours has about 5 more hp. Shouldn't it rev out a few hundred more rpms? Can you get these in a casting with port timings like the Serval? I'm thinking Wompus on a stock frame trail bike.

I can't find my post about the Snipers, so I'll post this here. I got to run them Saturday. On my 3rd pass I dropped a tooth in the back because I'm running about an inch less roll out than before. I ran a 3.84@82 mph at a track where my best time was a 3.83@80 mph. The air density was bad, and it was during the day. I rarely hit mid 3.8s in the daytime. From my math, these pipes are revving out to 9400 rpms on my 10 MIl Cub, whereas the dyno showed the SB Shearers to peak at 9600 rpms. The snipers don't (by the seat of the pants) have a lot of overrev. When they stop pulling that's it. But they feel like there is a broad curve and power that comes on quick. I think I could run even higher gearing. Hell I think they would pull me 85+ mph in 300 ft. Not sure the e.t would be better if I did that, though. I'm running 16/44 with 75 roll out staggered extremes and it never thought about trying to bog (I weigh 182-185 lbs). I'm ready to get this bike on a good hooking track, in good air. This was only a test and tune session and the track didn't get watered much.

Shave the head, advance the timing, and go up a few sizes on the mains. That will help.

Save the money and shave the stocker 0.20" - 0.30".

That's the way it should always be. The 450s are geared so low, even if they are making more power (not sayin they are or aren't) the (bolt on modded) Banshee always wins the race if you go far enough. If the YFZ has a 15t on front, put a 15t on the Banshee.

Shearers or RDZs for that exhaust duration, imo. I don' t know much about power pros.

Let me know if you can cut it and make it a paddle track. I'd have to regear everything to run pro wedges, and I really don't want to do that.

Depends on exhaust port duration.

WIll you have lights and guard beams? How much shutdown room? Is it a paddle track? I might be able to make that race.

x2. My stock port trail Banshee (T5s, shaved head, +5 timing, 350 mains, K&N, no lid) would beat a bolt on YFZ by a ton on pavement. It'd hand their asses to them in dirt if we ran far enough as well (bad spinning out of the hole).

Do you still have stock carbs? (Looks like it by your sig, but I thought I'd ask) How can you tell that they're not sticking? You can have 1 of them hang and the cable/thumb throttle will still have tension on it and you wouldn't necessarily notice. If you take off the box to look at the slides, they would probably unstick by what you're saying about the wet prefilter. Let me know if you've confirmed the carbs are not hanging. If it's not the carbs sticking, I'm lost. The water should actually increase the velocity of air in the carb by displacing space that would normally be occupied with air, leaving air to have to go through a narrower "tunnel" which should draw harder in the jets and pull more fuel and lead to a rich condition. Also (as you mentioned) by displacing air it should lead to a rich condition. Maybe the water on your filter is contaminated with nitromethane

The revving is from the stock carbs sticking open.

On my drag bikes I run 2 heat cycles (on gas) with no water in the radiator. THen I run another with water the next day or so just to make sure there are no coolant leaks. I don't run all the heat cycles the same day because I like the motor to be stone cold between cycles, and the neighbors probably get tired of hearing it. AFter that I consider it good to go at the track. May be different for a duner, though. Nothing wrong with riding it around to break in under load, I just can't do that with mine.

These aren't full ridgid bikes, just stock chassis with struts. You can still put shocks back on them, but don't know why you would for a track bike. As far as classes, you'll need to contact the track that you plan on running at and build closest to the upper cc limit for a particular class. Some tracks only bracket race, so that won't matter at all - a golf cart could run a top fuel dragster. SOme typical CC bases heads up classes are0-400cc, 0-475cc, 0-550cc, 0-650cc, 0-825cc, etc.

Lighten the stock chassis and strut it. Ditch the stock handlebar and steering stem and build/buy a chromoly drag stem. Buy/build a 4 mil or 10 mil Cub with lockup and override with 39 mm PWKs or 41 mm Packard Lectrons on alky. No sense in messing with gas for a "purpose built drag bike." Bolt up some drag a-arms (-2 width, +2 forward, etc) and some spindle mount wheels with smooth buff tires. Go with a +8 chromoly roundhouse swingarm and run a wheelie bar at least the wheelbase of the chassis. Get a jj&a drag axle and run 14 paddle staggered extremes (I prefer ~72 roll out for a stock chassis, but have had success with 75 roll out as well). If you can't find the staggereds, some 22x11x8, 14 paddle extremes on 8x9 wheels work pretty good, too. 15/43 or 15/44 gearing, depending on rider weight. That will get you started. That setup can run 4.0s all day long with a 160 lb rider, and low 4.1s almost irregardless of tuning (and some 4.1s all day long (and a few 4.0s) with a 190 lb rider.)

Not related to your issue, but are you running a dual pingel and modded the gas cap? If not, you need to do that before running it hard.

I'm building a drag bike for my niece, and we're gonna use a YZ80 motor. Does anyone have a gearing vs speed calculator so I can get an idea how to gear this thing? Stock it has a 14" tire, we're gonna run 19'' tires. I'm thinking we can just gear it to use 3 or 4 gears in 300 ft for now. Any help or suggestions?

I believe a stock pilot jet is good for SSTs.

I don't know if the TZ bearings wear out easily?? Are you running alky? The crank bearings last a while on gas, but I'm about to the point that I replace the mine (maxload style) just about anytime I have the bottom end apart.

He says it has 68 mm 795 series pistons.................no such thing. I'm sure he means 573 series. If this is Corbitt - don't buy anything from him, as mentioned. I know he had a 601 area code.

That's what I was gonna say. Just zip-tie the filters together or get some header wrap to keep them off the exhaust. I tried exactly what your doing on my first Banshee and the weight would actually pull a carb completely out of the intake if I hit a small bump.

So your running different domes this year....I thought you were running the same. All of my 421 Cubs have 180 - 185 PSI. I have 19.75 cc domes in one, and 19 or 20 cc domes in the others. PSI will differ based on the exhaust port height. Those 421 cubs are usually 197 *- 198*. I don' t know what the 350 Cubs usually are. I'm sure K&T will put the domes right where they need to be for ya.

They are mainly used to get a big carb to clear the clutch arm on the case. They can add crankcase volume, but I don't remember how that affect power output. I don' t think it's necessarily a good thing.

X2 on lowering the rear end. I had a stock stroke Cub on gas with a +6 and lowered, running those same tires. I could take off setting on the back of the seat and it wouldn't wheelie. However, it was poorly tuned and wasn't a very strong runner. Now its ported and on alky and would be a handful with that same setup, probably.