Topic: CB750A Street ET bracket drag bike. A year to build it.

[Bill/BentON Racing]

Dennis, he really is! The $$$$ came out of his winnings the week before! Class act!  Bill

[Bill/BentON Racing]

Carbs on Calendar Girl right now.....STOCK, Haha just rejetted. But stay tuned, have some options in the cave! Webers, RC George's stockers bored out to 30-31mm.Might try them next. 127.5 mains, Honda stock air boots,40 or 42 pilot, needle 3-4th don't recall is what's on there! So mo power coming from that angle, but I got a 915 kit calling me and a Mike Rieck head Stage III. Have a Stage IV, but's it's got the older 915 you have to open the block for! So might go Kenny's 915 already bored with the Stage III head for now and a  Megacycle 125/75 or Dynoman 315. Or could use the Yosh B grind still. Gotta think ....and that hurts!!! WE will run 11's with Calendar Girl in November!  Bill May have a 327!

[dragracer]

Bill, just curious as to what rpms you're launching Calendar girl??? I feel that bike could very well already be high 11 second capable.

[Bill/BentON Racing]

Frank, probably is. Launching around 4000 rpms. Tach needle at launch won't stay stable, gets to 3-4000 rpms starts to swing wildly, settles down after launch. I've been increasing launch rpm by ear. 60 fts show the difference, all 3 passes Sunday 60 fts in 1.8xx. Best was 1.828. Before Sunday best was 1.863. Ran a 1.861 and 1.828 and one in the middle. Plan on going to Commerce to race on 24th. Will try to keep increasing launch rpm until it becomes detrimental. But may/ probably have a 915 in by Valdosta! Any input appreciated. Thanks to all, Bill

[dragracer]

Frank, probably is. Launching around 4000 rpms. Tach needle at launch won't stay stable, gets to 3-4000 rpms starts to swing wildly, settles down after launch. I've been increasing launch rpm by ear. 60 fts show the difference, all 3 passes Sunday 60 fts in 1.8xx. Best was 1.828. Before Sunday best was 1.863. Ran a 1.861 and 1.828 and one in the middle. Plan on going to Commerce to race on 24th. Will try to keep increasing launch rpm until it becomes detrimental. But may/ probably have a 915 in by Valdosta! Any input appreciated. Thanks to all, Bill

Did you resolve the shifting issue also??

Wow, only 4000 rpm?? Yes my friend, you are leaving a lot on the table but for a short wheel base bike, i can understand your caution in taching it up more. To combat the wheelies at higher launch rpm's, you'll need to do a lot of clutch management but it can be done with consistency if you practice more. Heck, at 4000rpm, i personally wouldn't even waste my time ( or the tire) doing a burnout because its unlikely on a properly prepped track that you'll ever break the tire loose.

[Bill/BentON Racing]

OK, then must be launching a little higher, spun like crazy on 2nd round Saturday. 60ft was 2.213 because of it!  Here's the time tickets for Sat and Sunday.we had big fun, a big shout out to Larry Romig, superman he was! Thanks, Larry...now how's 'bout some videos, tire spinning one?
Frank, stay tuned last 4 passes as rpm's went up 60 ft came down! Duh!  all 4 1.8's. Last 4 R/T's .000, .084,.085,..078. We're getting there. I lost 3 races I should have won...but I learned! Two of them bike let me down, one on perfect light I backed off! No more! Breakout or win or lose! Haha.
Shifting resolved...I shifted to 5th manually!  Thanks, Bill

[dragracer]

Not sure what i'm thinking about on the burn out deal. You've only got an 18" tire on the bike and no good choice for a sticky compound so i can see the smaller tire spinning. Still a respectable 60' but until you really get that down lower, the ET's will not drop. The higher rpm you leave, the bike could become less consistent due to the possibility of wheelying. Goes back to the argument, do you want to put up a number or turn on the win light. Sometimes you have to decide on one or the other. I'll be picking at my SOHC over the weekend. Found a bad shift drum  and a bent center shift fork. I've got parts this time so we'll see if this resolves the issue. New air cylinder, shift solenoid and air kill going on too once i get them ordered up. We will be ready for the Man Cup finals- i hope. 

[Bill/BentON Racing]

Frank, you nailed it, launched the 1.863 a long time ago, higher rpm , but was wheeling and wasn't as consistent. So right now with this setup may just try a little more, lift wheel a few inches! 1.7's would be in the 11's, Bill

[scottly]

Thanks Billy! Sounds like we need to fix the tach issue; I recall a thread about fitting resistors and/or capacitors to help settle an electronic tach. I know using the secondary pick-up on my dyno tach when testing the FT500 caused the tach to jump all over the place when revved in neutral, but operated normally under load. Evidently it has to do with the wasted spark, and the voltage developed on the non-firing stroke? 

[Bill/BentON Racing]

Scottly, that sounds right, under load ok, Bill

[scottly]

What tach ya runnin on the girl? Also, you mentioned re-jetting; a lean mix seemed to confuse the dyno tach/computer even under load.

[Bill/BentON Racing]

This one!

[trueblue]

Bill, I have a Speedhut electronic tach on my 650 and it is steady as a rock.  The only time it falters is when I turn the indicator on when the engine isn't running.  It causes the needle to flicker but doesn't worry it when it is running.  They do all sorts of tachs, might be worth a look. 

[Bill/BentON Racing]

true blue, thanks for the info. Bill

[Jim F]

why not go back to the stock cable driven tach

[Bill/BentON Racing]

Always a possibility! 

[bwaller]

The Krober's a good tach Bill. And tough too, it flew 150 feet, rolled a bit & still works like gangbusters!

[Jerry Rxman Griffin aka MuthaF'er]

why not go back to the stock cable driven tach

Cool factor 

[Leino]

I don't use a tach.

[Jim F]

or use just a shift light

[Fastbike]

Jim,

Only problem is most street bike classes don't allow the use a 2-step for starting line rpm, therefore he would need a tach for that unless he has a real good ear for rpms (WHAT! WHAT DID YOU SAY?) lol.  If Bill can't get the electronic tach to calm down, I would reinstall a mechanical tach just for the starting line rpm and install a shift light for shifting purposes.  Why try to stare at a tach going down the track and see where the needle is?  Hard to look at that needle when you need to be looking back at me running your a$$ down like a dog!!

[Bill/BentON Racing]

That be right! 

[POPS 911]

One shift light to come on when you crank throttle to launch RPM [ ADJUSTABLE w/green cover ] the second shift light to be set at shift RPM'S[ adjustable w/red cover ]  slam bike on the ground and wire in a BUSA TIP OVER SWITCH turned front to rear mounted on a fixed plate with nuts and bolts to move up or down that you can adjust for kill to 12v coil side by pulling up front of bike with a engine hoist = 6-8-10-12 inches your choice. Why would you look at a tach ? see that light popping on in JEGS face going down the track in his PRO-STOCK CAR = real racer use shift lights.......... dead on their set number. You need to be looking down the track and not at a needle on a tach as bad things can happen fast by taking your eyes off the lane. Happen to me over past 25 year : Deer, raccoon, skunk and a rabbit running across the track in front of you, that was two deers at a Friday night race.
The launch shift light could be adjusted just to pick up the front wheel a little out of the hole = your bike is not a 1500cc no bar bike and I watched a guy from Green Bay, Wi. race a no-bar bike in the 8.60 SUPER COMP class and was the Champion at IDBA. his name was Ken Naef and how did he control the no bar bike to run 8.60 no wheeling

[Leino]

a real good ear for rpms

That's how I do it. Why else would I be using a Murray sidewinder  ?

[Bill/BentON Racing]

Thanks, I'm thinking it out, I have a. Dyna shift minder so that can be set at whatever rpm to shift, wouldn't need light, though I have A Dyna one.Lots of possibilities. 98 days and counting, POPS, c'mon down!  Bike has to run under 16.00 though. 15.99 or better, Bill