Bones25 Posted December 31, 2015 Report Share Posted December 31, 2015 Hi Guys I am a Land Speed racer and thinking of a new project. I would like to run in the 500 class with a 2stroke. So I think a Banshee/ RZ350 based engine would be a good option. I do all my own work-- fabricate frames, engines, pipes. I've messed around with TZ's on and off for a long time -- road racing and LSR I have found many combinations for bore and stroke to give close to 500cc but I like 68x68 . Have anyone had experience with this combination? Or something similar. What sort of HP can I expect with road racing port timing? Has anyone reversed the cylinders? I did this on a TZ350 (141mph, naked) and it worked very well and made the pipes much easier to make and package. Any help would be appreciated Bones25 Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted December 31, 2015 Report Share Posted December 31, 2015 Sent from my SAMSUNG-SM-G890A using Tapatalk Quote Link to comment Share on other sites More sharing options...
Deadbeat Posted December 31, 2015 Report Share Posted December 31, 2015 im not sure the gains really are worth the effort of spinning the jug around if drag guys dont bother with it Quote Link to comment Share on other sites More sharing options...
BANSHEE HP Posted December 31, 2015 Report Share Posted December 31, 2015 Id choose a combo with the shortest stroke. 72/58 would probably be it. You dont need the the tq of a +14mm(68mm) stroke. Ive spun my 4mm's to 10,800-11,000 with over rev and theyve survived, all be it in a much shorter distance. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted December 31, 2015 Report Share Posted December 31, 2015 I don't know much, but don't you want the tq to pull the gear? To hit 150 160 or whatever your after, the gearing must be crazy. What's the distance you get? Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted December 31, 2015 Report Share Posted December 31, 2015 That's a lot of stroke to keep revved out that long. God speec and good luck. Quote Link to comment Share on other sites More sharing options...
Bones25 Posted December 31, 2015 Author Report Share Posted December 31, 2015 Thanks Guys The reversed cylinder is not to make any more HP it is for packaging in the bike. The chassis has 4" ground clearance and the steering head is only 2'6''. Frontal area is everything in Land Speed I was thinking of a 68x68 engine but it looks like a 68 stroke will not go into Yamaha cases. Rules say motorcycle engine- not sure if the billet cases are legal or I want to spend that much. I can use ANY fuel I like- race gas-- gas class. Nitro,methanol-- fuel class. I will start with gas. Torque is very important. If the gearbox does not suite the power band the change into top gear may be useless. It will still have a road type gearbox and if the powerband is narrow the revs will drop too far and not pull. I'm chasing 170mph naked. I think the record was set on a TZ750 with 250 cylinders 10000rpm is a lot for a long stroke especially for 3 miles at full throttle. My experience is with early TZ's-- similar crank to banshees-- is that 10500 is enough for road racing. My mate logs his bike at Bonneville and it is WOT for over 1 minuite. Its a turbo GSXR 750--- 235mph Land Speed Racing is HARD on engines cheers Bones Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted December 31, 2015 Report Share Posted December 31, 2015 1- You can put a 14 in stock cases 2- You will have a VERY hard and expensive time getting a 68 stroke cub. 3- Good luck trying to race competitively with a budget. Quote Link to comment Share on other sites More sharing options...
m671054 Posted January 2, 2016 Report Share Posted January 2, 2016 Pretty sure a 68 stroke cub uses a 10mil casting. Your other 2 statements are correct. I have one on my bench right now. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted January 2, 2016 Report Share Posted January 2, 2016 No way a 14 mil stays together at 10,000 rpm for a minute in top gear. Theres a formula somewhere for piston speed, and that is too much. Back when the two stroke books were written 30 or so yrs ago that piston speed would've been off the chart. I don't know if you've ever heard of Jason Menz, but he was kicking around the idea of trying land speed racing at one time. He would likely have some excellent ideas if he would share them. Not sure if he would though. Quote Link to comment Share on other sites More sharing options...
registered user Posted January 2, 2016 Report Share Posted January 2, 2016 250 singles go to 10k and even a bit further without trouble. their stroke is longer and thus higher piston speeds than a +14 banshee. so mechanically speaking, a +14 banshee shouldn't have much trouble at 10k if quality parts were used but thats probly about the limit where it would run out of breath and whether or not it would go a couple miles is hard to say Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted January 2, 2016 Report Share Posted January 2, 2016 I know someone that had custom sleeves made to fit in a smaller class with a banshee based engine and stock cylinders. You might be able to talk to driveline about small bore aftermarket cylinders . I built the engine for his daughters race bike with these cylinders they were real thick but ported up real nice . He did pay a pretty penny for sleeving but she dominated her class using all regular shee components just smaller bores stock stroke . Maybe another route to consider . Does it have to be normally aspirated , these turbo bikes are pulling big mph in short distances 1/8 mile . The biggest problem to sort out might be limits on tranny gear ratio Quote Link to comment Share on other sites More sharing options...
SlowerThanYou Posted January 2, 2016 Report Share Posted January 2, 2016 This peaked my interest in the past using a quad, but not much luck with the sanctioning organizations. No one wanted to bother with the quad & yes I tried all of them. I have actually been fortunate enough to run Speed Week at the Bonneville Salt Flats from 89-96 with a car. I would like to return with a new car, but the condition of the Salt Flats is not good. 2015 Speed Week was cancelled & the future is in limbo, based on the salt condition. Anyway, our experience is with asphalt drag racing a Banshee (1/4 mile). We have been close to 130 mph in the 1/4. This was with a 443cc Cub, 68 bore X 61 stroke on race gas & Methanol. This combo worked really well & pulled great rpm. The vast majority of the run was between 9,500 - 10,900 rpm. We also looked at doing Pikes Peak & they are very quad friendly. The have a 500cc engine size limit. We looked at keeping the same stroke & going to a 72mm bore with a Cheetah Super Cub or the original Cheetah cylinder. That would put the motor at 496cc. Quote Link to comment Share on other sites More sharing options...
registered user Posted January 2, 2016 Report Share Posted January 2, 2016 sleeving is fairly cheap as theres a guy up north that machines them on a lathe to any application then etches and cuts the windows to where you want but im not seeing the reason to use a sleeve. if one the crank works billet +10 would fit in stock cases then just use either a 66 or 68 cylinder from driveline or cpi. blam youll be pretty close to the 500cc mark and no added weight and expense of billet cases. then again I don't know if the crankworks +10 fit in stock cases square is regarded as the best compromise but going slightly over wont have significant consequences. testing and papers have all been written on this. of course this applies to engines with logical thinking and design. banshee roots go back some 35+ years ago so it doesn't exactly fall into the logical thinking and design category so maybe the larger over square doesn't have the same affects as it would on another engine. hell I don't know. still on these old engines it doesn't make sense to me going hugely over square as conventional wisdom says it shouldn't run as well Quote Link to comment Share on other sites More sharing options...
Bones25 Posted January 2, 2016 Author Report Share Posted January 2, 2016 250 singles go to 10k and even a bit further without trouble. their stroke is longer and thus higher piston speeds than a +14 banshee. so mechanically speaking, a +14 banshee shouldn't have much trouble at 10k if quality parts were used but thats probly about the limit where it would run out of breath and whether or not it would go a couple miles is hard to say Yes, 250 singles will go 10000 but they have been designed as a 250-- crank life would not be like a MXer. Remember a banshee engine was designed I know someone that had custom sleeves made to fit in a smaller class with a banshee based engine and stock cylinders. You might be able to talk to driveline about small bore aftermarket cylinders . I built the engine for his daughters race bike with these cylinders they were real thick but ported up real nice . He did pay a pretty penny for sleeving but she dominated her class using all regular shee components just smaller bores stock stroke . Maybe another route to consider . Does it have to be normally aspirated , these turbo bikes are pulling big mph in short distances 1/8 mile . The biggest problem to sort out might be limits on tranny gear ratio No point going smaller with a banshee. I have a TZ250 I can do that with. I have read they make 90hp-- I think Japanese ones :-) How often do you drag race guys need to replace the pistons and rings and cranks When the GP sidecars ran 2strokes at one stage they would put in cranks EVERY meeting. Practice on the last meeting's race cranks and fit new ones for the race. I would like to get a few meetings out of an engine. cheers Bones Quote Link to comment Share on other sites More sharing options...
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