BigRed350x

I did the machining on the cases, but I did it prior to chase (the previous owner of the twister before greg) put it all together. I just had the cylinders and the top case half. I bored the case for the cylinder, and did the case port matching myself, and had some tips on where/how to match the ports from firehead that I followed. I used a pour-in epoxy that was recommended to me by firehead for filling the heat chambers around the cylinder bore prior to boring and case porting. It is made by 3M and requires a hazardous materials handing liscense, which I had to order through work to get. Firehead used the same stuff on my big block twister. I don't believe the epoxy to be an issue with what happened on gregs engine though. No, we do not have an engine stay on this particular bike. Do you think it would be a good idea to add one, even with the smaller size of the engine? Factory front and rear mounts were used on gregs setup. I can remove the mounts on the under-side and weld in some solid mounts, but I don't think he'd go for that since he has a really nice powdercoat job on that frame that came from the previous owners. I'd hate to ruin it too, but if its necessisary to keep the engine from destroying itself, we will do it. Its still together, but the cases are cracked from 1 side to the other across the top case half. Crack starts right at the 12-oclock position at the sprocket bearing and go across the top towards the clutch basket. In the shape its in right now, if we pull up on the chain, it will just lift the whole rear transmission shaft and opent he crack in the cases more. I'm sure you can picture what I'm saying in your head. Thanks for the ideas. A bearing support is definitely in gregs plans for this bike when he can afford it. I think the damage that happened already is going to take a little funds saving to get all fixed. I've got a set of cases I'm going to give to him to get it fixed, but I'm pretty sure we are going to need a transmission. =(

Very true on the power/torque thing. I might be confusing power with torque in how I'm thinking about it. Good call. I read on PS from a lot of guys who say the robinson's are clunky and stiff. I didn't think about the gear lash issue with the billet 2nd. That's good to keep in mind, and makes pretty good sense. I also didn't think about the case being worn that could be causing the problem. This might have also been the problem with greg's build. If the cases were worn, it would allow the transmission to wobble a little (talking thousands of an inch) but at high rpm and engine load, it doesn't take much like you said, to cause catastrophic problems. Does anyone happen to have the measurements for what teh bore should be on a brand new set of cases for where the bearings all ride in the trans section? Do you happen to have that info daj? The guy with the mushroomed wristpins on PS lives right over in nebraska, not to far from me and he and I have been talking a lot about his vibration issue, which we've pretty much narrowed down to a bad crank balance combined with the fact that its a spread bore that's causing his problems. I think greg's problem and maybe bada's are both in the transmission areas from the what I saw on gregs engine when he was taking it apart and from what bada is describing. Lets keep this going. This is good stuff, and definitely more informative for the other readers...

Have you tried any other billet 2nd gears, besides the robinson? I've heard of a couple guys on planetsand who don't like the robinson ones. Maybe try stealing 2nd gear out of another similar transmission (RZ, RD, etc) and see if it holds up better for you. Have you tried using blue loctite on the nut on the crank? Are you sure you have the spring washer the correct way? Its spring so it acts like a lock-washer. If you have it flipped over the wrong way, it will act like the opposite of a lockwasher and try and push the nut off all the time its running. Make sure the washer is the right way, and I'd try a little bit of blue loctite on clean threads and torque it down good. (I use an air impact on a lower setting for my flywheel nut, clutch basket nut, and the nut you are talking about. Have you tried a maxload bearing on the stator side? I read in a thread on planetsand that the TZ bearings and stock bearings are not the best to have on the stator side with higher HP/TQ engines. Maybe try a maxload if you haven't already. Maybe look into a complete billet trans if you're breaking more than 5th. Is your current trans cryo treated or hardened beyond what the factory does? I know firehead made the gears in my big block twister himself. They've held up good so far. Maybe buy a whole new transmission and start from scratch with cryo treating and new bearings all the way around, billet 2nd, etc and see what happens? When was the last time you had your crank trued and welded? What crank is it? If it vibrates excessively, it could be a balance problem. I've been talking to a guy in nebraska who has a 24mil twin saber setup that vibrates so bad its causing him problems with his upper rod bearings and wrist-pins. He even went as far as to have the crank balanced by falicon and it didn't help. Kim at K&T told me that his vibration problems were from the spread bore and the wrong bearings on the crank. Hope some of that helps, or gives you some ideas. - Jared

With all the rabble rabble aside, can you give any good solid suggestions for what greg can try or do to help it run better in the future? I know you have a lot of very informative knowledge that could help his build, and help the other readers on the forum learn from threads like this. Why don't both of you guys take the rest of the rabble rabble to the flames and fights section or whatever its called, and make this thread more informative for anyone who reads it. Help others learn from gregs mistakes and maybe help other do-it-your-selfers in the future. I know there are builders out there who can and would do a better job than the garage warriors of the world, but we all know there are a lot more of the garage warriors out there, and its sites like this that get them through each project. Daj, you've helped me with a lot of things in the past that I was totally stumped about. I know you could do the same here for greg, if you can both get past crap from the past, this thread could turn into a great resource for anyone who is trying to do a build like this at home, and who might not be able to afford to use a builder. I know I would love to send business to a lot of the builders out there, I just can't afford it, so I try and teach myself and learn from my mistakes. The guy who put this engine together (which was not greg or myself) made quite a few mistakes, which came out after the transmission exploded. Like the clutch basket missing cushions, the backing plate not being tightened down good, the spacer washer between the inner hub and basket missing, etc. So, why don't you guys take the rabble rabble to the other section and use the things that are wrong with this engine to help other people learn and maybe figure out their own problems? There are a lot of people out there who enjoy working on their own stuff and probably can't afford to use a professional builder. So why don't you put some of the effort you are putting into bashing on eachother into helping the other folks out there. You have helped me in the past daj, and I know you can help greg and the others reading this thread. - Jared

Rabble Rabble Rabble Rabble! All I am doing with this twister build is offering a shop for greg to work in. He's doing the work himself, and building this bike on his own. I don't have any association with it daj. Just so you know... He's just using my shop as a place to work. Not all drag bikes have a narrow powrband though. The engine in the bike firehead built that I have does not have a narrow powerband at all. And a narrow powerband doesn't necessisarily make the most power, its area under the curve that gets the job done. Useable power. It just happens that these engines tend to make peak power in a narrow powerband from their two-stroke deisgns. BUT an engine can be designed to make the same peak power without the narrow powerband, which is what firehead did the engine he built in my twister bike.

PM me a pic of your frame (side view) and I an show you where I've always put gussets on the banshee frames. Primarily on the A-Pillar that holds your steering stem and back on the sub-frame where your grab-bar mounts are the weakest parts of the frame.

Another thing greg forgot to mention, that does play an important part in the wheelie comment is that when he has the FAST 4mil drag port, on top of the +10 swinger it had a marvin that jeff set up with 1200psi in it. It was almost like having a strut on the rear. The new twister setup has a normal spring/shock setup in the rear. Now, I'm not trying to get into any of this back and forth on here, just something that he forgot to mention. I don't know which would put more traction to the rear, or which setup would tend to wheelie or spin the tires more. I haven't tried to tune suspension for anything besides dune riding where I prefer everything to me nice and cushy for my fat ass. The old FAST setup ran good and was very impressive in the drags, but the powerband of the drag port was hard to deal with sometimes for the type of riding we do around here. I hope the twister cylinders work out better for what we do. They are definitely a cool design.

Rabble Rabble Rabble Rabble!

Hooah!

If you do drag racing, then you want a light rim and tire both front and back. If you can find a buffed set of mowhawks for the front on a .125 rim they are a good all around tire for play and drag racing. A bead to bead buff on .125 rim is good in the rear. Size and number of paddles depends on what your engine has done to it. 21x12x8 8-9 paddle haulers are good on the majority of the banshees out there for just play riding. If you do a lot of drag racing and have more power to push around I'd go with a 22x11x8 9-10 paddle hauler or extreme. List what your mods are and we can help you out better.

You need to change your sig honkey. Neither of your bikes are FAST. LOL

Its normal not to see smoke once the bike is warmed up. As long as you are mixing your gas and its not really cold (castor tends to seperate in cold temps) then you are fine. If it is cold, just shake your gas real well before topping off. Make sure the oil is mixed with the gas real well before you pour it in your tank. Also, if it is cold where you ride, shake your bike a lot before you start up for the first time in the cold, because the oil can seperate and sink to the bottom of your tank. Castor 927 is good oil. I run it in all my 2-strokes. If you are on gas your ratio is pretty good.

I've got some 22" 12 paddle haulers SLS I'd sell you. $385 shipped.

Carb cleaner and a little wire brush.

I'd do a 4mil short rod, low-end port job from a good builder. Herr Jugs, K&T, LC Performance, A&S, etc. 33mm PWK air strykers, vforce reeds, 175ish compression, and 4-7 degrees of timing. Keep stock width a-arms and axle, and a +4 to +6 swinger. Billet basket, and a new clutch.

Tusk clutch will do fine for you. No need to go spend more than the $40 or so that RMATV sells the tusk unit for. Don't get ripped off for tusk clutch copies from others. Just go to RMATV.

Don't get all carried away splitting your cases yet. Jut build/buy a leak-down tester and test your top end. That will tell you if your crank seals are leaking or not without splitting the cases.

Hey man, cruise over to planetsand.com and get a subscription over there. There are a lot of professional builders over there who throw around porting information a lot. Numbers, durations, specs, etc. You will find answers to a lot of your questions there. My advice would be to go get some stock cylinders and some ported cylinders from other builders and measure their cylinders and just start practicing on the stockers. That along with the books out there and you can figure out the basics and just build on up from there.

Sent ya an email...

You'd have to throw some cash in with the ktm for a nice banshee. those ktm's are slow. I ran two of them this past weekend at kp and both had big bore kits and all the little bolt-ons and my girlfriend on her 470yfz was kickin their ass.

How about a tire size? 21" 22" rollout? width? 11" 12" ???? We need a little more information about the tires to help people figure out if they are right for their setup or not. Good price for ULS though. Are the wheels .125, .160 or .190's??

Wish I had the $ on hand man, I'd buy it in a heartbeat. This thing runs awesome. Outran bonbon's FAST 4mil Cheetah. Great deal.

100hp on a +4 swingarm will be pretty fun in the dunes. LOL

Riding this time of year is great there. I usually do a trip to utah each year in october. Some of the best riding IMO is around this time of year. - Jared

What pins are you talking about? wrist-pins? The locator pins on the main bearings that line up with the notch in the cases or what? Maybe post some pics of what you're talking about. Without more detail about what your talking about no one will be able to help you since we don't know what exactly you're talking about.