Shooting for 48HP

[bruce71198]

What do we know about bigger valves?

[RacinNinja]

48 HP out of a Ninja 250??? That is a pretty lofty goal....you're talking about adding 20 HP to a stock motor, almost double.

Bigger valves will need larger ports, larger carbs, and bore/stroke increase to be effective. Add a cam in there as well.

For the money it would cost, you could buy a 300 and get there much easier.....

[HoneyBadgerRy]

48hp is crazy, your looking at forced/chemical induction. A few people have put in +2mm valves into the newgens, I believe JE +4mm pistons are the ones that fit.

My guess on NA 48 would be a 300 crank, +4mm pistons, +2mm valves, ported head, 5 angle valves, and a whole lot of whishfull thinking on the dyno accuracy.

Edit: I forgot to add hot cams. Luckily these are easily available for the newgen.

[csmith12]

I wanna see this voodoo...

[RacinNinja]

Originally Posted by csmith12

I wanna see this voodoo...

Originally Posted by HoneyBadgerRy

48hp is crazy, your looking at forced/chemical induction. A few people have put in +2mm valves into the newgens, I believe JE +4mm pistons are the ones that fit.

My guess on NA 48 would be a 300 crank, +4mm pistons, +2mm valves, ported head, 5 angle valves, and a whole lot of whishfull thinking on the dyno accuracy.

Yup. Even with a small bottle I don't think @Racer x is hitting that number.

[APEmike]

Honeybadger has it right. You'll need to start with a 300 engine, Take a 250 block and put in bigger sleeves and +4 pistons. Some serious headwork with all the secret sauce. Custom camshaft, heavy valve springs, stainless steel valves, bronze valve seats (factory seats suck, ask @mgentz). Some sort of improvement in the factory oiling system, more pressure and volume.

Fact of the matter is some of the parts that are needed just dont exist. Stainless valves dont exist in the sizes needed to make valves for the 250/300. Oiling stuff like a high volume pump or pump gear and a high pressure oil relief valve aren't really out there either.

The sad truth is we are dealing with a sophisticated lawnmower engine. Oem parts are not designed for much more than a factory setup.

[crazymadbastard]

Doing a Ninja 500 motor swap?

[bruce71198]

This is my last engine in 250 cases, stock 250 head unported, cams, carbs. I think what I have up my sleeve may hit the mark.
[IMG][/IMG]

[RacinNinja]

Displacement? This will dictate, in part, how big of valves to go to.

[Z1R rider]

Originally Posted by bruce71198

[IMG][/IMG]

Glad to see that torque and HP meet at 5252 rpm, I laugh at the "dyno sheets" that meet at some other rpm. At 41+ HP.... you may get to 48 with some serious induction mods. Curious what you have done to it now. Best of luck!

[AwDang]

MR12!

[mgentz]

Originally Posted by bruce71198

This is my last engine in 250 cases, stock 250 head unported, cams, carbs. I think what I have up my sleeve may hit the mark.
[IMG][/IMG]

I don't see anything?

****EDIT*****NVM my phone didn't like it but my computer did...

[mgentz]

I am interested in what you have done or at least where your dyno is.

But seriously, I have more time and money tied up in this thing than I care to mention. My first dyno fell short of the mark, but the Pistons were hitting the head so that is to be expected.

From there, the more horsepower I have demanded, the quicker things failed. From disappearing valve seats, to cracked cams, to heating issues, I have had them all.

[Racer x]

48??? think about you clutch also.
I can get that with nitrous easily. But with out it I can not make 35. You will need real coils and a good clutch. After that it's an ignition and induction system that is properly tunes to the exhaust.
If I hit the lottery I would make a totally new cylinder head. The valves are way to small on the stock 250 engine. And the air injection is a very bad thing.
To get tat kind of power from a 249cc engine will require special attention to the cooling of the exhaust valve. And a giant pile of cash if you want it to last

[mgentz]

Back to the original topic. I have +1.5mm valves in my 250 head. Each one was custom made by APE for $60.00 each. If you want Ti, they are $150.00 each. I also recently talked to Jeff about SS exhaust valves. He said he could custom make those for $50.00 each or so.

After all that, know that I am not nay saying anything....hell I want to see what you can do. I just want you to share some of your secrets with me.

[mgentz]

Originally Posted by Racer x

48??? think about you clutch also.
I can get that with nitrous easily. But with out it I can not make 35. You will need real coils and a good clutch. After that it's an ignition and induction system that is properly tunes to the exhaust.
If I hit the lottery I would make a totally new cylinder head. The valves are way to small on the stock 250 engine. And the air injection is a very bad thing.
To get tat kind of power from a 249cc engine will require special attention to the cooling of the exhaust valve. And a giant pile of cash if you want it to last

The takai coils and true kevlar clutch with heavy springs are the way to go.

Durability is key. At this point, I need to get mine back on the dyno but I am real certain it will show 40+HP at the rear wheel. With this setup, there have been some crazy issues that are being addressed now.

[Racer x]

I am definitely not saying it can't happen. I really want it to happen. And will share any knowledge I gain from using nitrous. The engine can handle it. But it has to be done right to last.

[Racer x]

Going for this much power is going to be tricky. I don't think this is going to work as a street bike.
What would the bike be used for is the first question. Second is what sort of fuel? I think methanol would be a good choice. Very high compression is going to require some serous thought at detonation control. Ceramic coatings would also be advised.

[spooph]

Very curious about this black magic...

[RacinNinja]

Originally Posted by Racer x

Going for this much power is going to be tricky. I don't think this is going to work as a street bike.
What would the bike be used for is the first question. Second is what sort of fuel? I think methanol would be a good choice. Very high compression is going to require some serous thought at detonation control. Ceramic coatings would also be advised.

We had this one ceramic coated on the skirts. Most certainly saved a botched cylinder wall for sure!

[Ghostt]

Buy an R6, CBR, etc..... If your on a quest for the major HP unicorn just remember that if you do find it, it's most likely gonna be unreliable.

Over the many years I have chased the unicorn, and while you'll find the HP, at a certain point it becomes unreliable. The trick is to stop at the point of the reliability becoming compromised.

I've always tried to balance the power, reliability, and cost, but I've always said "power, reliability, and cheap $, pick two, because your not gonna have all three".

In the end you have to weigh these, and decide if it's worth it.

[Racer x]

With land speed racing and drag racing at some point that is not even part of the equation. One or two passes and rebuild.
Each pass for me is a gallon of fuel 5.00 to 10.00 dollars , one pound of nitrous 7.00 dollars
Two spark plugs. 9.00 and the oil and clutch are done
110 dollars.
If it has a problem
300 for Pistons ,50 for an eBay block and cylinders 100 for gaskets and another 100 for valves.
I like my unicorn roasted on a spit. With fava beans and a nice Chianti

[bruce71198]

This is the start, the missing link (pun intended), to increasing the displacement above what I already have. Modifying a connecting rod to fit the 250 cases with the stroked crank and not have the piston protrude above the deck. Sorry about the photo, I was unable to rotate it ?

[IMG][/IMG]

[bruce71198]

I plan on road racing this engine. My last one held up very well aside from a few overheats, it was reliable. Upon dis-assembly this past month I have yet to find any adverse ware on the cams, valve springs, seats or valves. Piston and cylinder suffered some scoring from the overheat, the cylinder is still usable but the pistons are toast. The overheat was caused by the right angle pipe going into the water pump, it cracked around the weld on the pipe. This is the second time this has happened and will be addressed in the new build. The 300 head i will use is going to get ported and the combustion chamber polished. I think I will use the stock valves for the time being and count on super high port velocity to make power. Stock cams will be retained as well but I will degree them for maximum efficiency. To take advantage of the added CC's and port work I will run FCR carbs.I only need to find 6.75 HP. As far as durability is concerned I have already upgraded my clutch and the engine I borrowed the pistons and con rods from makes 30HP per cylinder reliably.

[RacinNinja]

I wouldn't go any bigger than +1 Mm valves if you do.

The throat will need to be increased as well as the carb size to optimize flow.

I'm assuming you already have a full exhaust on it. Depending on cam overlap, it may be worthwhile to go +1 MM on just the exhaust valves to create more scavenging and draw more fuel/air into the chamber.

[jkv45]

What oil are you planning to run? What did you run for the dyno pulls?

[HoneyBadgerRy]

If the bike had overheating problems may I suggest boring out the cylinders 2mm, it would help with your power goal, help reliability, and bring the bore x stroke closer to the stock ninja 250 ratio (which helps the shape of the power curve).

[bruce71198]

Originally Posted by RacinNinja

I wouldn't go any bigger than +1 Mm valves if you do.

The throat will need to be increased as well as the carb size to optimize flow.

I'm assuming you already have a full exhaust on it. Depending on cam overlap, it may be worthwhile to go +1 MM on just the exhaust valves to create more scavenging and draw more fuel/air into the chamber.

Ya, my thoughts too. The 300 head has a 1mm bigger valve than the 250. I'll concentrate on the exhaust side.

[bruce71198]

Originally Posted by jkv45

What oil are you planning to run? What did you run for the dyno pulls?

Rotella T6 I run it in all my bikes.

Originally Posted by HoneyBadgerRy

If the bike had overheating problems may I suggest boring out the cylinders 2mm, it would help with your power goal, help reliability, and bring the bore x stroke closer to the stock ninja 250 ratio (which helps the shape of the power curve).

To late, I went the other direction. I am kind of happy with the torque curve, actually I would be happier with more of a torque increase over HP.

[jkv45]

Originally Posted by bruce71198

Rotella T6 I run it in all my bikes.

T6 is fine, but it's a Group III synthetic. You might want to consider moving to an Ester-based oil like Redline or Motul (Group V).

Going to an Ester 30 wt oil may even give you a touch more HP, but because of the level of performance you are reaching for an Ester oil would give you an added level of lubrication and protection.

[mgentz]

One of the largest issues that you run into is that nobody has a lot of experience trying to make these bikes go faster. I have dealt with all the top guys in America and they may have done 1 or 2.

The good news here is that APE and their workers have great relationships with the racers on the west coast and they can use this. Just today I talked to Jeff @APEmike and he gave me the below tips on the motor in roadracing conditions:

1) the oiling system sux. Everyone recommended doing the oil pressure mod.
2) the crank and rods are weak links. Many times this leads to premature bearing wear from flexing.

The point is: As we try for more HP, we expose more weak links in the chain. Now I'm not sure if I got the bike built on a Friday 10 min before quitting time, after a Thursday night drinking binge, but I have seen many durability issues as I have pushed the HP limits of the stock components.

[Racer x]

I use a larger bearing clearance. Still in spec. Just more clearance on the rod and crank bearings. Then I am going to put a shim washer in the oil pressure relief valve to increase pressure.what else do you recommend?

[mgentz]

I am running my balance shaft and main journal bearings in the middle of the spec. I run the rod bearings at the loose end of the spec.

I had the rods shot peened, hardened, and bronze bushings with additional oiling holes.

I run the exhaust valve clearances at the loose end of the spec to help with cooling.

Currently, I am plating the cylinder for better oil retention, seal, and durability.

I have a true Kevlar clutch with HD springs. I have also polished the transmission and put in ceramic bearings. Undercuts are nice here too. I have also done the shift spring mod for more preload and a better shift.

The cylinder head is a toss up. But for me, the extra heat killed the intake seats. I now have nickel bronze intake seats. Exhaust seats have been ok.

The ignition has been upgraded as I had experienced issues with the stock system.

Do the oil pressure mod. I will do this now.

For extra hp, change the water pump to electric.

Use a good synthetic oil. Your choice, I am not starting that.

[Racer x]

What exactly is the "oil pressure mod"?

[HoneyBadgerRy]

/S Obviously its when you mod the oil pressure to be faster, Duh.







Seriously, if you didn't get the sarcasm you have a problem. Also I am curious of the oil pressure mod. I have heard of reliving one of the holes and the newgen drain housing swap, thats about it.

[mgentz]

Originally Posted by Racer x

What exactly is the "oil pressure mod"?

you know.

The exact description is shimming the oil pressure relief to open at a higher pressure. The relief can be found behind the clutch cover near the front of the engine on the 2008-2012. The shim is a thicker or additional washer that has the same OD and ID of the original. This increases the oil pressure by not bleeding off pressure too early. You should also know that the oil pump is only capable of about 100 pounds of pressure. You @Racer x have also toyed with the idea of using a ZX12 relief but I never did get you to tell me what year.....

http://forums.ninja250.org/posting.p...&t=78763&tro=1 (the pictures are missing due to how old this thread is)

https://www.youtube.com/watch?v=zBVs1XnSVpE

[Racer x]

I thought so but wanted to be sure.
I never did anything because I am now at the point of doing it. I made a pressure guage setup. And looked at the relief valve. I thought the stock 250 relief valve was not made with a C clip and the zx12 was. But now I realize the stock valve can be adjusted. So now I am going to assemble the engine and measure the pressure. The make the adjustment to get 70 psi at 3500 rpm .
The pressure is not really controlled by the valve. The pressure will be determined by bearing clearance. Then regulated by the valve.

It was fun to revisit the 250. Org webpage. That was a nasty angry group. They hated on everything I did.

[mgentz]

Originally Posted by Racer x

The pressure is not really controlled by the valve. The pressure will be determined by bearing clearance. Then regulated by the valve.

It was fun to revisit the 250. Org webpage. That was a nasty angry group. They hated on everything I did.

1) yep. That is a better way to explain.

2) I cannot imagine what they would say about me.

[Racer x]

They would say you should get a 600. Or you should ride the bike like it is and not ruin it with useless modifications.
Or in the case of turbocharging. Why would you build somthing that will kill you when you try to start it?

[cbinker]

with what you got now, use a dyno in New Orleans?