250R NA Build - Ultimate

[JohnnyBravo]

Heal up an hit the dyno

[bruce71198]

Do any of you guys have old cylunder base gaskets laying around that you dont need? I could use a few.

[mgentz]

unfortunately all mine are in the trash. Out of curiosity, why? I thought you were just using gasket sealant or something?

[bruce71198]

My new engine config has the pistons protruding from the cylinders .25mm

[Racer x]

I don't have any. I re use mine and all my engines are together. Head gaskets. Com will make you a gasket that is any thickness you want. But you would have to send them your gasket as a pattern. And pay to have the pattern put into the computer. Just an expensive option. What sort of pistons did you get?

[cuong-nutz]

My guess he's trying out the 300 crank with 250 pistons. I wonder if Bruce has adjustable cams.

[bruce71198]

Wisco pistons. I talked to Cometic, $80 for them to make one. They're about $25 each from Kawi but until I get this setup dialed in I'm not going to order it. That's why I tried here. Cam sprockets are slotted.

[mgentz]

Working through a carb issue now. Jets are on their way. See other thread.

[cuong-nutz]

Did you get your valve guides off ebay? I am considering using the 300 head.

[mgentz]

I got my valve seals off eBay since no one had them.

[mgentz]

Working on my jetting still. Once I get her in the ball park she goes to the dyno.

[bruce71198]

My 66mm Wisco pistons hit the top of the combustion chamber. Has anyone used a carbide and die grinder to modify?

[Racer x]

I just used a die grinder with a scotch bright disc. You can see the little area that hits. It's just a triangle. I buzzed it off. No problem. Did you go with sleeves? My set came with the stock block bored out. That leaves the cylinder 50 thousands thicK. About half what I would like.

[mgentz]

The contact area can be sanded and blended real easy. However, I still prefer the flame area of the je pistons over the wiseco.

Sleeves would be a must for durability.
@Racer x , did you send me your final jetting specs? I wonder most about the float height and I am considering going to 14.3 mm.

[Racer x]

Originally Posted by mgentz

The contact area can be sanded and blended real easy. However, I still prefer the flame area of the je pistons over the wiseco.

Sleeves would be a must for durability.
@Racer x , did you send me your final jetting specs? I wonder most about the float height and I am considering going to 14.3 mm.

Yes I sent them
You said it looked fat. Float is 14 mm

[mgentz]

Going back from 13 to 14mm helped. Sudco had them over 15. Bike ran great before this with only the dying while stopping issue. Now she is rich everywhere. Has to be the float level. I think ill try 14.6 or so and see where that gets me.

[Racer x]

I have a fuel pump and a different needle and seat than you. I have a 3.2 seat in my collection so I think I have 2.8 in the carb.

[mgentz]

I have a 3.2 seat. What did the 2.8 seat do for you?

[Racer x]

Because I have a pump it reduced the volume.

[mgentz]

Ok. I figured as much. More playing to ensue....

[bruce71198]

Originally Posted by Racer x

I just used a die grinder with a scotch bright disc. You can see the little area that hits. It's just a triangle. I buzzed it off. No problem. Did you go with sleeves? My set came with the stock block bored out. That leaves the cylinder 50 thousands thicK. About half what I would like.

That's what I figured, thanks, just wanted a confirm. No sleeves, yes the cylinder looks thin, I have seen thinner. I remember you saying something about no bevel at the bottom of the cylinder and trying to get the rings in, I now feel your pain! I ended up making a ring compressor out of a section of a brake cleaner aerosol can and a hose clamp. Worked well.

[mgentz]

The 265 bevel is perfect. Either side of this and there are issues.

[mgentz]

Final jetting specs:

CR33 carbs
55 pilot
.5 turn out on the air screw
YY6 needles
5th clip
110 main
14 mm float height
230 airs
35 starter jets

Pulls like a bat out of hell and reads 13.0:1 on the a/f gauge.

[bruce71198]

Dyno time.....

[mgentz]

1-2 more tweaks then dyno. I figure I will do it in September so it's not so hot and humid.

[cuong-nutz]

Sweeet. I can't wait to fire mine up again!

[QuickSiR]

Originally Posted by mgentz

1-2 more tweaks then dyno. I figure I will do it in September so it's not so hot and humid.

Do it meow!!!!!

[mgentz]

Well...somehow now I have to beat Bruce with 335 cc to my 265.

[subxero]

^ good luck with that one, once he gets the jetting dialed in and a bigger carb I feel like that set up is going to push some serious ponies

[garth285]

What we need to do is convince him to go fuel injected!!! :-D

[mgentz]

Originally Posted by subxero

^ good luck with that one, once he gets the jetting dialed in and a bigger carb I feel like that set up is going to push some serious ponies

yes, but I do not know how far he will take it. I have taken mine pretty far.

In the end, he will most likely win, but it will be fun trying.

[QuickSiR]

It's september... where is that dyno?

[choneofakind]

howdy! Any updates?

[subxero]

^ been wondering the same

[mgentz]

Not much and I have many reasons for it as posted elsewhere, plus its December in WI! It's cold.

I have been contemplating ordering 47T and 43T sprockets, and I have been tossing around ideas about how to get more cooling considering the issues with the made up 300's, but haven't pulled the trigger yet. Meanwhile, I am working on firming up the front suspension a little as I bottom out sometimes.

Before I put her up for the winter, I got the carb tuning pretty much spot on. However, I will need to tweak it again for the spring weather. I will get her on the dyno in spring and I am sure I will beat my previous 36.43HP. But as I think about it, 36 RWHP is 10 - 15 more than stock or a 50% improvement. Not too shabby, but I know I can get 40 out of her. The only issue with my setup and the dyno will be the low to mid HP as you simply cannot open up the CR carbs too fast because they will lean out the mix and the motor goes limp.

I know it has been disappointing for everyone that the thread kind of died off, but I will finish it.

[garth285]

Hey bud, I read threw part of the thread but is there anywhere where you have a list of everything you have done to the engine?

[mgentz]

Originally Posted by garth285

Hey bud, I read threw part of the thread but is there anywhere where you have a list of everything you have done to the engine?

let me look or else I will type it all out again...

BTW the 36.43 HP was with stock carbs, shrouded valves, and 12.5:1 pistons that were hitting the head!

[garth285]

Thanks, I am thinking after I run the bike with a turbo for a while to build a N/A motor.

When I get some free time today I'll go back and read everything, very interested in the piston to valve clearance issues. I'd love to build a 14:1 or 15:1 250 motor!

[mgentz]

Let's try this over:

Where am I today:

Suspension
Forks redone and optimized by Ed Sorbo of Lindemann Engineering (Ed also added fork drains at the bottom of the forks so I can do oil changes w/o removing the forks.)
Penske triple with LE valving and short reservoir hose (will mount to battery box)
springs front and rear are based on my weight and riding style.

Ignition
BRT-is
NGK CR9EIX plugs
Takai Racing Coils

Engine
APE Ported head with +1mm intake valves
APE custom springs
New guides, seals and retainers
Falicon ultra light crank mods
Falicon gram matched, shot peened and polished rods with bronze bushings
JE 13.5:1 pistons
WEB cams both intake and exhaust (special grind not listed on site)
ISF polished transmission
Worldwide ceramic transmission bearings
Custom SS oil line
New water pump and hoses
Lots of new seals, gaskets and consumables (engine basically new)

Fuel/Intake
CR33 carbs
K&N dual pod filter

Exhaust
Leo Vince carbon superbike exhaust with custom header flanges that perfectly match the head and pipe for superior flow (I don't need to use gaskets). Pics elsewhere.
NGK A/F ratio gauge installed

Other Fun Stuff
Motion Pro VR Throttle (50mm cam)
Motion Pro Right Cluster Switch
Alien Motion Battery (4 Cell, weighs about 1 lb)
Heated Grips
Pirelli Rosso II tires 110/140
MicroBlue Ceramic Wheel Bearings
@rojoracing53 modified rear brake rotor (shaved off 13 oz or so!!!)
@rojoracing53 modified rear brake hanger (captive)
Stainless bolts where I could easily replace
Repainted lower half of the engine case
New sprockets with a 520 non-oring chain (15/45)
LP high performance coolant (no mixing)
Fender eliminator
Fully safety wired past WERA/AMA specs
SSR preload caps
WC clip-ons
Secondary fuel filter
Braking full floating front rotor
Vesrah SJRL front pads
SS brake lines
DB windscreen

[garth285]

WOW thats a hand full of stuff!!!!

Hmmmm APE valve springs you say huh.... I may need some for the turbo!