gotta_goatsfast

What type of porting and what are your other supporting mods? A mid-top end 4mil might enjoy two 35mm carbs (good for you, since you only need to buy one carb!)

For my outdrive and clutch assembly these are the parts I run in my serval. Starting with stock ratio straight cut (spur gears) drive gears reduces the side loads that stock helical gears create. Then I opted for a magnum billet clutch basket (don't trust the stockers). Check your inner and outer hubs to ensure they are in spec or replace them as warped or worn hubs will create issues later. Mine were fine. If you do not have a pancake bearing pick that up as well. I use the clutch frictions and plates that FAST racing sells and it all holds together with stock pressure springs. Then the direct drive centrifugal assembly bolts to the top of the outer hub. I can get away with an allen machine screw and locknut on the fingers. Seams to be enough weight to hold the torque. Then I used a direct drive cast cover with 12 bolt window for reduced leakage potential. The chariot mega-flow impeller and machined waterpump cover went into the cover. Remember to swap the kicker idler gear bushing with a steel bushing. Mine had a lot of play and I was surprised it didn't shift and bind up with other gears.

Haha, I like how you give us an entire paragraph on how you are beating the hell out of your car running the tach up past your engines redline and then proceed to tell us you don't know what happened or what went wrong. So, here's what I assume happened. Since you stated you were only a couple of blocks out from your house, I can gather that the engine and all its fluids are not even close to operating temp. Then You ham on it all the way past redlilne with full boost and your aluminum pistons start to swell with heat. Unfortunately, the 302 block is Iron and it won't heat up as quick under these conditions. Your piston becomes bigger than the hole it reciprocates in (I hate it when that happens). If it is a stock block, I would first pull the intake manifold and inspect for hairline cracks (or gaps) in the casting running down the oil valley somewhere. A stock 5.0L roller block is the lightest (yay) but weakest (boo) of the FoMoCo small blocks as far as block strength. They are known to stress and fracture down the oil valley parallel with the camshaft. Anything over 450hp-to me- is considered a ticking time bomb on a stock roller 5.0L. Anyway, after inspection, I would proceed to pull the heads and any other heavy parts followed by disconnecting the engine from the car. Pulling the heads will reveal cylinder scoring and or broken parts. Check the heads over, a white valve indicates issues in its coresponding cylinder. Then pull the block and separate the oil pan to inspect your rods and crank. If this block is still able to be used, have it blueprinted and have your rotating assembly (if it is functional) balanced by a reputable shop.... and then invest in better tires/rear end/suspension components so you get traction instead of 4th gear spinning! haha, post up some pics of the carnage man. Also, even if the block still measures within spec, it would be real wise to step up to an aftermarket block (unless you already have an aftermarket block, then ignore me).

I cannot make a promise to you that Jeff is going to be the cheapest. But I will tell you that his prices are VERY competitive. For the Serval cylinder with a clean up port (cleans up any casting flaws/slag) will be very comparable to what Trinity quoted you for the cheetah. I do not know what the difference in cost is for polished (I'll get it dirty anyway lol). There are a few members on here that would give you a great price and they do awesome work. Most of the guys do it on the side so its not nearly expensive as a full time shop. But if money is a concern, I wouldn't worry about polishing the cylinder. If I remember right, the whole top end cost just shy of $1100. This included the serval block, two rear stud extenders, two small nuts to sneak onto the front inner studs, base gasket, piston kit, domes cut to your fuel requirements, and a cool head o-ring kit. I picked up much more than that, however. I picked up a modified shift shaft, shift star, and easy shift spring and new shift forks for smoother shifting, magnum clutch basket, fast racing clutch kit, direct drive lock up and cover,factory ratio spur style drive gears (straight cuts), pancake bearing, chariot mega-flow impeller and machined cover, dyna-tek CDI, chariot machined stator cover with bearing support, and a case saver. Used parts I picked up were the hotrods crank (I measured everything to ensure it was in spec with hotrods tech info and replaced bearings) 35mm pwk carbs (new cable, filters) billet intake manifold, and cut stock style trans (has some dogs removed) Parts I re-used from previous motor was the pro-design cool head, large capacity radiator, V-force 3 reeds, moose stator with plate, and solid motor mounts. I tried CPI pipes and then moved to R2s and wouldn't look back. As for suspension.... remember that even if the measurements are identical from a yfz to your banshee in the front, seat position, foot peg position, weight, rear suspension-to-front suspension, handlebar location, steering geometry, and even front suspension mounting points/spacing is different between the two. What works great on a yfz is probably going to be yfz specific. You may find that down the road upgrading to a proven aftermarket banshee specific suspension will make you worlds faster than what you are now... and yfzs. I've ridden 450 quads.... and I would never want my engine in one of them (talking stock here). Way too much power for even a new-tech 450 suspension off the show room floor. I do run yfz450 brakes and masters and it really is a cheap alternative to stop REALLY quick. Now I'm straying off topic, lol. What the moral of my story is you are better off spending a few extra bucks for a quality part from a reputable shop. Jeff WILL answer his phone and he will spend an hour on the phone providing help/assistance if you need it. He won't bullshit you into buying parts you don't need, and he'll give you insider tips to these engines should you choose to build it yourself too. Sometimes saving $30 or $40 going to a so-so company is going to kick you in the ass later.

Less unsprung weight when properly fitted. But, it could be worse. They could have been installed sideways.

Powervalves are casted in to the cylinder. Unless there are provisions casted in and blocked off??? then no you can't run powervalves later. I wouldn't run a cheetah... let alone a ported cheetah in anything but wide open dunes and drag racing/hill climbs. The 421 (or even 392cc) serval will make a ton more usable power than that cheetah. Also consider, are you willing to risk your money with a company who has above average "mistakes" and failures? Some Trinity customers support Trinity, but I'd hit a shop where ALL of the customers rave about it. I chose the serval setup from FAST racing. Anyway, a cheetah cylinder is already way more aggressive (which means a powerband coming on later and narrower, while hitting a lot harder) than the serval. And Trinity is going to carve on it more??? Unless your race class mandates maximum cc or bore size, I'd go for the 68mm bore in whatever you choose. Its ultimately your decision, but I'm telling you the extra bit of horsepower from 9000-10500rpm gained from the cheetah isn't going to make you faster at the track or the trail than a serval which would pull harder anywhere under that 9000rpm (with trail specific pipes and intake setup). Also, understand that cylinder compression at kicking speed is vastly different from the cylinder pressure during peak torque (when the pipe is most efficient at stuffing fuel and air back into the cylinder). A super high exhaust port will show less kicking compression than a stock port (because the lower exhaust port traps more air at such a slow speed), yet at high rpm the high exhaust port (along with the rest of a quality port job) will have drawn in way more air and allowed more of said air back through the exhaust port before the piston covers it, meaning way more air and fuel molecules to be squeezed in the same space. Thus, the highly ported cylinder that shows lower psi while kicking will indeed require MORE resistant fuel than the higher psi stock port. There are a ton of other factors to consider when choosing the right fuel. Simply put, you want the lowest octane fuel you can run WITHOUT detonating. Anything more and you'll be wasting money and loosing power.

If funds allow, I would shoot for a 421 and you can always sell your stock stroke hotrods crank to off set the cost. CP industries is more known for producing the cheetah cubs, cheetahs, supercubs, ect. The serval line is simply a "torquey" version of the cheetah cub. It shares all the fine casting qualities, it shares the basic port technology as the cub to flow massive amounts of air. But the port timings have been altered to produce a wide, easy to ride-yet powerful as hell powerband. With my engine (look in my sig for specific parts) and 15/40 gearing with aggressive tires, I can lug the engine down to 3000rpm (well below the main powerband) and it still has enough nut to break the tires loose on tough grass... if I transfer my weight back for traction I can indeed do a wheelie with my +2 swinger at said rpm. What else is sweet? The powerband comes on smooth enough that the tires still grab (yet spin) when the powerband hits. An aggressive powerband is hard to manipulate in the terrain you and I ride in because the sudden rush of power leaves the tires spinning struggling for traction. This engine comes up on the pipe around 5000-5500rpm (with R2s) but does it smooth enough as to let the tires retain some grip. The result? Accelleration, not trenches. The powerband on my setup (I consider) very broad for a two stroke. Stay between 5500rpm and 10,500rpm and you have more power than you know what to do with. Believe me, you will cover ground very fast. When coming out of a corner onto a straight, its very easy to embarrass the 4 stroke guys. Passing a stock or lightly modified 4 stroke is like passing a scooter on the interstate. Just remember you are travelling way faster so you'll relearn your braking techniques and skills to compensate (I did). In long races, rider fatigue plays a big part. The banshee will kick your ass more than most quads. But being able to hold a gear through a corner and pinning the throttle exiting without chugging the motor really does help you more than trying to hunt for that gear to get you into the powerband and then shifting up quickly or risk overreving (and not accelerating anymore). If you weren't so far away I'd let you hop on mine. If you make it to Wisconsin, I'll gladly show you around. Just remember, with this much motor a proper suspension and brake setup is super important!

I should add that the particular serval I mentioned is 392cc, has more aluminum (much more solid than two single jugs carved out) and a nikasil bore vs. steel sleeves in the oems. And yes, your head will bolt on, the reeds and intake from a stock cylinder will bolt right on, and the pipes will match right up. Good luck!

I understand not wanting to pull a good crank and replace it. If you are interested in a monoblock cylinder, look into the 68mmX54mm serval. It is the same 68mm bore with all the same technology that is in a 68x58 serval, only for use with a stock stroke crank. I built a 421 serval and it really does have a wide and smooth powerband. Its incredibly predictable and very forgiving. It can be lugged down and still pull gear upto and into the powerband and with the right pipes will provide a screaming 10K+ overrev. I spank the 4 strokes at the tracks and cross country courses. From what I understand you ride in similar terrain.

Time to seriously consider a 4 mil with an mx style port. You'll have more power up top AND way more balls down lower. Get with a reputable site sponsor. The extra stroke and port would be WELL worth the money.

Sit farther back. lol. also, a lot of idiots drag race by revving it to peak power and just snapping the clutch which usually always results in a slow take off. The holeshots work great in digging and still let me kick ass at the mx tracks and cross country/hair scramble situations.

Low 40s is an honest number to the wheels if tuned right.

Honestly, I wouldn't even bother. Jeff has gotten everything I've ever needed right the first time. I wouldn't mess aroud letting a company "experiment" with my toys on my dime and on my time. Go to someone who already has their marbles in order and enjoy your toys.

I use 20x11" holeshot HDs and they dig. It will completely remove grass and vegetation and dig 2-3 inches into the dirt for 30-35 feet when I launch from second gear. Those tires seem to be the best for my setup and the terrain I ride in.

Hard to tell, my serval already overpowered the tires in anything I ride. Throttle is crisper with the right dip switches set (I like curve 3) and it seems healthier but how do you judge more power when the tires are struggling to hold in either situation. lol

Since the install is pretty straight forward, I would assume you have a faulty unit. Throw the stock CDI back on and if it runs, then I think you found your answer. Since I installed mine, with the switch off I can kick it and it will fire one maybe two revolutions before ignition fails. I'm guessing it has a healthy capacitor which provides the few sparks without having power. Which leads me to the next piece of advice, use dielectric grease on all connections. Anyway, hope you have some sort of warranty or return because it sounds you might have a faulty CDI (if it runs with the factory CDI again)

Sometimes its best to just accept your losses and move on. Jeff has never steered me wrong. He's a straight up honest guy who will tell you what he can and can't make happen and what it takes to get there (all while telling you what parts you don't need to waste your cash on). With Jeff and Nick, you will be riding. And that benefits EVERYBODY. Jeff has a new customer, you got a head turning setup, and Trinity won't have posts all over cuz you'll be busy riding!

....I feel dumb for even stating it (because it is fairly obvious) your clutch is slipping? Just a wild, outragious guess. Time to repack your clutch with new frictions and steels. Maybe upgrade your clutch springs. And definatly pick up a pancake bearing.

Your carbs are working great with a dune ported 4mil. A 30mm carburetor might be crisper in the low end (but if you're putting, you don't need it) and you'll lose a little of what counts in the meat and overrev. Dial them in as close to perfect as you can and ride. Use the cash on something else.

You'll have more luck here. BHQ "wanted" section Generally, people search the for sale section in search of purchasing parts from the original poster. If you have a flywheel for sale-for instance-then post said topic in the for sale section. The BHQ gods in their almighty wisdom forseen the future and created the wanted section just for folks like you in search of parts like flywheels. Generally I'm just a jerk to guys but some get all butt-hurt so I took the nice and thorough aproach. We'll see the results shortly...

#186

To properly read a plug you must do a plug chop. Observing the ground strap and edge of the porcelain will tell you if your engine is detonating (black or aluminum specs) if you are oil fouled (hmmm, its wet) or if your heat range is too high or too low (ground strap color should transition at the elbow). The air/fuel ratio requires the plug chop, though. There's a "how to" stuck on the top in the forums. Check it out.

I've got neither

turn the carb upside down and you'll get more fuel (which surely means power) out of it.

Do you have enough motor for two 39mm carbs? I only ask because either you are severely limiting a hot engine with a single carb or you are running a mild motor and the 39s will simply be too much. And a single 39 probably won't do any better on top as the split intake manifold is the top end power robber... not the carb.