Gore/Rohrich bigbore Breathes FIRE

[SFO]

Gorr/Rohrich bigbore Breathes FIRE

I finally finished my 97mm 426.
The power exceeds all of my expectations.
The HIT off of idle rips up through the midrange with startling aclarcity.
I cannot describe the way this thing pulls in accurate terms.
My buddies new 520 feels like a trail 70 in comparison.
The 97mm motor pulls away from the 520 easily.
I am going to Hollister this weekend to break it in more before I run it on the dyno.
The Arrow pipe has a mellow note that reduces the tinny yzf with a pipe sound.
I ran just straight b37 for fuel. Can't wait to see what the mtbe does.
I can't imagine this thing being faster.
I am really looking forward to running this thing on the dyno.
Thanks to Rich, Eric, and Mx-Tuner.
Bill
(rich, can you post some of those pictures I sent you?)

 

[Vic]

Why am I not surprised?:) Please let us in on the dyno results.

 

[nephron]

Sounds great. :)
My initially low-grade 4-stroke enthusiasm is growing with alarming "alacrity";)

 

[Rich Rohrich]

Originally posted by SFO
I ran just straight b37 for fuel. Can't wait to see what the mtbe does.
I can't imagine this thing being faster.

Glad to hear you're enjoying it Bill :) The response from pilot to needle transition should be much better once you add the MTBE. Straight B37 is really difficult to vaporize in these engines due to the high front end temps and short intake tracts so it's tough to get really good throttle response. The difference should be fairly pronounced once you lower the front end temps and add that extra oxygen to the fuel. Better invest in a really grippy seat cover :)

Originally posted by SFO

I am really looking forward to running this thing on the dyno.

ME TOO :)

 

[SFO]

There is a SLIGHT burble before the thing gets into/onto the needle.
Like I said, I can't imagine more.
It just hits and pulls, no matter what gear.
I was shaking after I rode it:scream: ...
I made Derrick get off of his 520 and he rode it.
He was pale when he got off of it too.:o
Look what you started, Rich.

 

[Rich Rohrich]

Originally posted by SFO
Look what you started, Rich.

Just a trouble-maker at heart I guess :)

The fuel screw might help some but it won't be very responsive on the straight B37. If you use the B32 straight it should run cleaner off the bottom than the straight 37.

 

[Rich Rohrich]

Here's the pics of the Arrow pipe Bill installed on his big bore YZF

 

[NVR FNSH]

Rich,
Do you have any dB #'s on the Arrow set-up? I heard they were long but OMG....

Brian

 

[Rich Rohrich]

Hopefully Bill can supply db numbers. All I have is second hand unreliable numbers at this point.

 

[SFO]

I am trying to hook up with Dale right now to schedule the dyno time.
At the point that he has it, I will use the db meter that he has.
Bear with me...

 

[BigBore]

Just curious......whats the displacement with a 97mm bore?

 

[SFO]

I think:think that a 97mm bore = 440cc displacement.
Forgive me Rich, I am not up to the math that you always make me do...
Did I mention that my bike RIPS ?:cool:

 

[Rich Rohrich]

It's 444cc :)

For those of you playing along at home it's easy.

Pi * ( (Bore /2) ^ 2) * Stroke / 1000

3.141592654 * ( (97/2) ^ 2 ) * 60.1 /1000
3.141592654 * 2352.25 * 60.1 /1000
444127.6603 / 1000
444.12 cc

For the record, Bill is a bad-ass machinist and does more math in a day than I do in a month :)

 

[rayovac]

Rich,

You are really scaring me now!!! :scream:

 

[SFO]

Bad ass machinist?

All your dazling of formulas leaves me verklempt...(Rich):scream:
My #'s and math habits are very pedestrian.
VERY.
2ND functions leave me weazing with mental dust bunnies...
What are the mtbe ratios, Rich?
I haven't recieved the B03 yet...
Mixing b32 and b37 50/50 subdued the burble on the needle/pilot transition.
Would the straight b37 create starting woes?
I still have to decipher the new starting ritual.
No more pump away and kick. It seems alot richer on the pilot with the 100 paj and 45 pilot.
So many changes so little time.
BTW, I am running the OBEKP needle middle clip, 175 main, and 45 pilot jet with the 100paj.

 

[Rich Rohrich]

Re: Bad ass machinist?

Originally posted by SFO
Would the straight b37 create starting woes?

ABSOLUTELY. On a cool SF night it would take an act of Congress to get it started on B37 :) I would start at ~ 5% on the MTBE and get a baseline on the jetting then work your way up. You may need a 48 pilot once the percentage gets above 10% and the weather cools off. Start with a 185 main on the dyno to play safe if you are going to go to high percentages of MTBE. 175 should be pretty close at 5% MTBE 29.5 psi, and about 60-75 degrees.

 

[SFO]

thanks for the b37 starting

update.
It seemed flooded, but didn't smell like gas and it wouldn't pop.
So I suspected the b37 and mixed it 50/50 with b32.
I had the air screw at one turn and turned it down to 3/4 turn.
The needle transition period gurggle got better.
Thanks for the heads up on the mtbe ratios.
Do you want me to blend by volume.
Could you describe your blending setup?
Going from a steel pail to a funnel/gas tank is really messy. Do you blend in 25 gallon drums and then pump into a, what do you do?...
Does the MTBE need to be measured in glass?
How much MTBE would be required to get .02% oxygen by weight with a 50/50 blend of b32 and B37?
Thanks, bill

 

[holeshot]

Compression ratio

.
What compression ratio are you running?

If you're running a Wiseco, do they offer both 12.5 and 13.5 versions?

 

[EricGorr]

Holeshot,
Wiseco offers 12.5:1 and 13.5 for compression ratios on their line of big bore pistons.
For any of you guys with older 400s looking to upgrade your bikes in the face of this recession, consider this, the stock connecting rod has been improved and the small end pin increased 2mm in diameter. The cylinder is also thicker to allow for overbores. I suggest starting with a 426 rod kit and cylinder. Those parts are dirt cheap, if you want to go the extra mile the cylinder can be overbored and plated like Bill's to 97mm.

 

[Rich Rohrich]

Re: thanks for the b37 starting

Originally posted by SFO
Do you want me to blend by volume.
Could you describe your blending setup?
How much MTBE would be required to get .02% oxygen by weight with a 50/50 blend of b32 and B37?

I blend by volume. 15% MTBE by volume would be approx 2% additional O2 by weight.

For mixing I use graduated plastic 1/2 gallon Rubbermaid containers and a Ratio Rite. I mix about 1 gallon at a time. It takes a little longer this way but I find I waste less and only end up mixing what I need. What ever is left over at the end of a ride gets drained back into a clean sealed steel can and stored in a cool place. I carry MTBE and whatever else I'm playing with in 1 liter nylon containers and keep them in a cooler.
I realize this all seems like too much trouble which is why I generally recommend people just buy B35 or MR2 premixed :)

 

[zio]

Originally posted by NVR FNSH
Rich,
...I heard they were long but OMG....

Brian

Yeah, I'm starting to develope a complex....:eek: (motion of the ocean, motion of the ocean, zio).

 

[NVR FNSH]

I figured that there would be somebody that just couldn't leave it alone.....


Brian

 

[Rich Rohrich]

Originally posted by zio


Yeah, I'm starting to develope a complex...

LMAO :)

 

[SFO]

Send me a pm if you are having size issues

Leave my pipe alone.
What twisted webs we weave...
The b30 didn't show today.
I am going to continue running the 50/50 b37/b32.
B

 

[Rich Rohrich]

Re: Send me a pm if you are having size issues

Originally posted by SFO
The b30 didn't show today.
I am going to continue running the 50/50 b37/b32.
B

Bill,

You'll probably be better off running the B32 straight.