Overboring block

Cbx, you do get around you "old dog".
I'm at 1 1/2mm on my intake valves. Looks like thats about as far as you could go to be on the safe side.
The YOSH cam has a good grind. You might want somebody to grind you something close to what they have if you don't want to pay all that money.

PAY ALOT OF ATTENTION TO YOUR VALVE SPRINGS!
You should do alot of research on your springs Chris! Trust Me....

TurboTim: Seems like with a 200+ Hp motor and a low 1.60's short time, that bike should have been in the high 8's. But on the other hand if this was thier first time out thats a start.
Here is one to proud of...
135pd rider(Johnny?)(North carolina)
1 tooth down
airbox mod
pipe and pw2...9.35 at 153mph(stock motor!)

Tinhead: You said it yourself, reliability.
 
Stock motor???? Maybe stock CC's. 153 mph seems awful fast for just those mods. Has anyone else out there gotten 150+ mph out of their stock(no motor mods) busa in the quarter?

Frank,what MPH dod you run stock?
 
Frank, who makes good(big) valve springs for the busa? Point me in the right direction. A buddy of mine has a modified intake cam, port and polish with micron and pc2 and is making 190 hp. he runs 9.8's at 140 150mph and he weighs about 220 lbs
 
i don,t care if it,s a stock . the motor couldn,t be stock to run that kind of mph.that is on an average 5/7 more mph than anyone else in the nation and it takes horsepower to make mph. not b.s. that bike must make at least 190/200hp.and how does frank know if the motor was stock if he doesn,t even know the guys name that has the bike.there could have been nos on the bike that no one saw. sounds like crap to me.

[This message has been edited by A Daddy Busa (edited 29 December 1999).]
 
APE is running retainers now that replace the stock aluminum retainers and work with stock springs. Under $200 per set. The retainers for the race springs will be slightly different.

Jay
 
Jay: Have you had the chance to work with any Busa motors yet?

If you have, what combonations have you been using for Valve Springs? (springs/retainers)

And what Lifts and Durations on Cam's have you been using? And why?(your findings)

....Frank
 
One other thing, the reason rod-ratio is so important is because of the leverage the rod has on the crank. Optimum rod ratios have the most leverage (at the proper crank angle), which results in optimal (efficient) power. I'm no expert on this, and this is only my opinion, but if I am wrong or if anyone has opinions on this please let me know. I am ALWAYS learning....Thomas Gafa
 
Thomas, Could you give a little more detail to what Topic on Dragbike.com the info you were talking about comes from?

I'm just like you are, Learning every day!

Thanks Frank
 
Sure Frank, it was in the Engine Building 101 section (APE) with the title of Compression Ratio and Copper Gasket Use. I hope Jay doesn't mind me using his response, but it was so good that I'll include it:

By Jay Eshbach (Jay) on Saturday, December 25, 1999 - 04:46 pm:

Lonnie;

When you stroke a crank, you have to compensate for the piston coming up too high at tdc. There are only
four ways to do this;
1. Taller block
2. Spacer plate
3. Shorter rods
4. Move pin hole up in the piston.

#1 is the best choice if possible. #2 is the most common and works very well. Not sure what problems you
had with it. #3.. when you stroke the crank you are shortening the rod ratio in the engine. If you use a
shorter rod, you are REALLY shortening the rod ratio. Not a good idea unless the head / cam combo has
been designed for a short rod engine.
#4. This is done in many automotive stroker applications, however the modern import motorcycle engine
simply has no room to do this effectly.

So.. The stroker kits with spacer plates are not "junk". We sell plates with all of our stroker cranks that we
do for engines with removable cylinders.

Jay
 
Guys, the person quoted above also posts here as Jay. You cannot go wrong with his advice, he has done more than most of us combined, and his business IS motorcycles. I have much admiration for him, I've been following his advice at dragbike.com for awhile and he is knowledgable in every facet of engine building. If any of you modify your engines, chances are you will have APE parts in them. They are busy enough that they don't need my "advertising", but if any of you have questions or need parts then Jay is the man. I just hope I'm not stepping on any toes here, and the last thing I wan't to do is start sounding like "Jason".
 
Tinhead, I'll try to answer your question. A large part of the reason you may not want to stroke an engine is rod-ratio. When you stroke a crank, you effectively change the rod ratio to one that compares to using a shorter rod. With the increased stroke, you must now either run a taller block or shorten the rod, again worsening the rod ratio even further. The thing most people use in this situation is a spacer plate to raise the block. There was an excellent discussion about this in dragbike.com forums.
 
Frank;

We have been so busy we couldn't jump on the 'busa stuff right away. We ordered all the stock valve train stuf from Suzuki and just got it in. We will be running retainers next week. We see where the stock aluminum retainer does not fit the stock spring very tight. This is exactly the same thing Suzuki did on the 750, and that has been part of the 750s retainer problem. Our titanium retainers will fit the springs tightly so they don't walk around and help contribute to the harmonics. If jessie is doig your stuff, tell him we will have these next week. He buys from us.

I see where the stock springs are not interference fit, but are progressivly wound.

We will have to set them up in a head to see how close to coil bind they are with Webs biggest cams.

We sell the Web stuff, their biggest cam is .395 lift. We have a spring that gives about 10 more pounds on the seat than the stock ones, but until we set a head up, I don't know if they will need it. I can not imagine this head needing over 50 lbs on the seat in a race application.

We will wind up giving someone springs and retainers to get our hands on a head.

Jay
 
Turbo;

Thanks for the kind words. Hope you have had success using our parts.

Chris;
The stroker question would be a wide open one. The Hawabusa is a stroker when compared to a GSXR1100 and is OK for the street.

In most cases, the problem with a stroker is the rod ratio thing. In certain drag racing applications, especially automotive, short rod ratios work well. With a short ratio, the piston spends less time at TDC and BDC. This allows some very agressive cam timing as the piston is not in the way as much. I have seen pro stock cars with the blocks milled down so far, they were almost into the water pump bolt holes.

This doesn't work so well in high rpm engines, because the time it takes to ignite the mixture is constant, even when the time the piston remains at TDC decreases with rpm. If the piston snaps over TDC too quick at very high rpm, it could actually start to run away from the charge.

A longer rod ratio lets the piston dwell longer at TDC while the burn takes place.

With the correct rod ratio, the rod would be at 90° to the crank throw exactly when the most power is being made in the combustion process.

I am not sure this answered your question.

Jay
 
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