how to raise max RPM's

nads.com wrote:

What would happen if you stuffed the biggest piston in there u could get then added alot of weight to the crank and turbo'd the assembly. Wouldn't it launch like a rocket and have the momentum at shift points to carry on like one? It seems obvious torque is the quickest way to the finish line once again. Are we doing all wrong here? We already know these engines won't turn the rpm of newer desighns. Is the flywheel affect only for the Harley's? Why would the engine need time to spin up when the bike is revved before the clutch is engaged? Ok I hereby challenge anyone and everyone out there to cut this theory to PIECES. To me it's all about how can one make the wheel turn harder. More weight in motion vs more motion. I don't think the answer is taking an itty bitty motor to 20,000 then only having to squeeze the crank between your fingers to stop it instantly.

I would say the "more motion" part of the theory can only come from one place...RPM, when you're launching the bike... IF the 60' is no good, the rest probably won't matter anyway...

I understand the question that has been posed, I understand that we are just bench racing.

I like a guy that thinks outside of the box. But if you don't have a real big pile of money, stay in the box.

Steel gave the best answer, months ago $$$$$$$$$!

It's all about building 10 motors or 50 motors. You would be the luckiest guy in the world, if you could do it with only one motor. No one else can do it! (Not even with the newest motors)

It's all about R&D, not pencil math or online calulaters or he said, she said. It's MONEY.

Since the start of time, race shops have battled over witch is best, horsepower or torque. Both have proved good results over the years.

I see alot of limits in the whole deal.

1) Design and build a new head.

2) Bore size is limited, now you must design and build, cases, cyl., pistons, crank and rods.

Not one of each part, maybe 10 or 50? (at this point build your own motor, and put your name on it)

Now lets talk about the transmissions. Newer bikes have closer gear ratios or a sixth gear so they can keep the motor in the higher rpm range. Old bikes are designed to reduce rpms, with every higher gear.

I guess we should add, building a whole new tranny, to the list. What is the cost for that and the R&D?

Then I think about the basics, what would the bore clearance be on a motor turning those high rpms? Valve cl., deck height, valve to piston cl. etc, ect.(one wrong choice, and you lose one or ten of your R&D motors)

I like pro stock bikes because they are the fastest bikes, with carbs and gasoline. If you use VHR as an example. Their V-rods turn the same rpms as their pro stock Z1 did. The power, torque and everything else is done, over, finished before 10,500 rpms.

So other then fun or a design project, why would you want to rev it any higher?

Maybe by using stronger rods and flat top pistons, some pro head work for nitrous, with heavy springs and a long duration cam that has intake lobe center around 112 youd have a top end screamer with the cylinder filling with a supercharge effect. Bring the redline up to around 9 with it peaked out there. If the intake was tuned for this as well as the collector being closer to the exaust ports? I'm thinking larry's facts and theorys have to be used here, it's the only hard evidence there is and it's tried and true. Just never on a small motor or this one at least. Isn't about cylinder pressure for hp? Would it not be 100hp with this set up?? it would have to be. With everything jiving up top carbs intake ex, cams heads, good fuel? It would be one I would love to build if I had the money just to be unique. I think larry could work some math on this around 9 or 9.5 for rpm and come up with a more than less real world figure for hp. The key would be the tuning and the head work. How would it hold up? No idea accept it might help to brace the crank and add stronger studs it would go a long way toward holding together. Cylinder volume is limited so I'd work on stuffing as much charge in as I can, and we all know how it gets in there. It's obvious it's not going to happen at low rpms but inducing a large amount of charge at high rpm without having it shut off early by a closing intake valve Believe would make some serious power. I'd guess at this point intake and exhaust tuning would take on new roles also and one would take advantage of these to maximize on power output. It really comes down to how much you can stuff in the cylinder and how much pressure the motor can handle. It might fall short of hp goals but would not fail to put a smile on ones face. I think in the end ignition timing lead and fuel demand are big temp. controllers and engine life regulators.

I rev my 810 to 10k, which is the redline on a 750 turbo. It won't rev much beyond that anyway because the (stock) ignition breaks down. Well at 30psi it does anyway. It was completely reliable at 10k though.

My old 760cc race bike used to rev to 11k+ because it ran less boost and an aftermarket ECU, but that was for race use only.

The Harris F1 GPz750s (non-turbo) and the Muzzy GPz750 superbikes used to rev to 11,500-11,750 but they had reliability problems and regularly broke valve springs. They also had all manner of tweaky bits inside and made around 130hp.

Well said...

just can't leave folks alone can ya willy boy....will61310 wrote:

Well said...

Wow, 100+ replies now. :ohmy:

I've read every post here front to back, and there really isn't much that I can contribute that hasn't already been said.

I am however still puzzled by one thing in particular. What's with the obsession with the 650 motor? :huh:

I'm pretty open minded, and I can understand that for nostalgic, or inherited reasons you might want to restore one. But why make one into a practically non-streetable, b low itself apart, slower that just about everything out there money pit?

Boredom? ... I know you've said for some reasons why, but... Why not just put one of thousands of superior motors in there and just plain have a better bike?

You could just run without a tach, and tell everyone it pulls 15k. :laugh:

Cheers.

trianglelaguna wrote:

just can't leave folks alone can ya willy boy....will61310 wrote:

Well said...

I wasnt aware i was offending anyone, only complimenting Lorcan for putting it all into perspective...CRAIGGY POO

well there are plenty offended ...really can't the knig see he has no clothes.....thinner oil raises rpm's....remove a oil scraping ring will toowill61310 wrote:

trianglelaguna wrote:

just can't leave folks alone can ya willy boy....will61310 wrote:

Well said...

I wasnt aware i was offending anyone, only complimenting Lorcan for putting it all into perspective...CRAIGGY POO

trianglelaguna wrote:

well there are plenty offended ...really can't the knig see he has no clothes.....thinner oil raises rpm's....remove a oil scraping ring will toowill61310 wrote:

trianglelaguna wrote:

just can't leave folks alone can ya willy boy....will61310 wrote:

Well said...

I wasnt aware i was offending anyone, only complimenting Lorcan for putting it all into perspective...CRAIGGY POO

craig, you are just being foolish now....you are better than this....put that thing out and call it a roach and quit drinking the kool-aid out of the helmeted one's helmet..
he's not doing you any justice....then again, he is not doing anyone else any justice on here either...

I would like to think Mr. Lorcan knows quite a bit about the limitations of these engines,and i thanked him for his input by saying "well said" if you take offense in that, then you must have issues that need attention..By the way, who , or what is a knig? - Remember to keep it on topic,

piston speeds in these first kawi fours bikes was not "the" goal in itself ...rather a usable curve for real world riding and some steady building power was on deck then....the japanese were well aware of rpm's and had ran small cc four stroke gp engines a decade before kz's that reached rpm's not to be soon seen again on a production unit.... if they had intended for a 12000 rpm street kz then one would have been built ...and no offense to the hero's that achieve giant numbers with these old engines....but a 5000 $ c-list bike with some suspension mods and minor engine work will walk on those bikes and be able to run to the store with a passenger or cruise the highways on pump gas....3500 on a good day on e-bat will pay off quicker than a catalog motor and shipped out work..........knock knock