Topic: Race at Rockingham Dragway- big bucks

[dragracer]

Looks like the Rock is having a race this weekend. Paying out a great purse in both street ET and Pro ET( no box) both days.

I'm leaning towards going up to compete.

Paging Billy Bling- whats the plan brother?? Its all go and no show at this event. No TV coverage- sorry. Just flat out racing if you can handle it!!! Come on man!!!

[Bill/BentON Racing]

Only got 1 out of 4 good cylinders.

[dragracer]

Only got 1 out of 4 good cylinders.

LEaking pass the valves or the rings?? Didn't you put new rings on the pistons?? Isn't that the newly built head??

Man I'm afraid to even check my leak down. I'm going to freshen up my top end over the winter anyway. Its been a year and a half since i rebuilt it and the mains on the crank were suspect then. 

Hopefully you don't find anything significant when you tear it down Bill. Let us know what you find.

[Bill/BentON Racing]

Oh, it's all 3 intakes on 1,2 and 3. Probably been hurt since Rockingham or Saturday's pass when it wouldn't shift. I set it up with tight on the intake side, @ .050. plenty if valves don't float or engine not over revved. I knew it was compromised Saturday night when I found #1 with .010 less plug gap than I set it at! Bill

[kmb69]

It was Rockingham in my opinion. That motor was flat on Friday.

[gschuld]

Man I'm afraid to even check my leak down. I'm going to freshen up my top end over the winter anyway. Its been a year and a half since i rebuilt it and the mains on the crank were suspect then. 

Frankie, any chance you can get a quick dyno run in on your motor before you tear into it?  It would be great to have the numbers for comparison sake.  I think I remember you not being close to a dyno shop, plus not being able to run your drag radial tire on the dyno. 

Billy,

Oh, you're in trouble now!  You hurt the 915 with Mike's beautiful head!  The man is having heart problems, we want him to get better .  Any chance you floated those valves on that serious high rpm "whoops" you had back in Rockingham?

George

[Jerry Rxman Griffin aka MuthaF'er]

Ouch! I knew you brought up that possibility. Did you scope the cylinders and look at the pistons yet? Good 1/4 numbers considering, except no 10's.

[dragracer]

Oh, it's all 3 intakes on 1,2 and 3. Probably been hurt since Rockingham or Saturday's pass when it wouldn't shift. I set it up with tight on the intake side, @ .050. plenty if valves don't float or engine not over revved. I knew it was compromised Saturday night when I found #1 with .010 less plug gap than I set it at! Bill

Oh crap man. Thats not good. At least the valves are off the shelf Kibblewhite items. You should be able to get someone local to cut the valves, and touch up the seats. The stems are really thin and unforgiving. At least now you have the rev limiter on the bike to save it from another catastrophic event. Maybe now you can get your 10 second pass out of the bike.

[Bill/BentON Racing]

 , I'll be ready. Another learning experience.  Yes, was probably hurt on 2nd run in Rockingham. It's getting fixed asap. Rev limiter will be tested at a lower rpm to make sure it's working. Mistakes costly.....and can be much worse. I'll never run a nice engine again without a limiter hooked up, was just stupid.  Knew it was hurt, not crisp and wouldn't pull high rpms. Good news is piston and rings sealed fine and no leakage on the exhaust side. I got lucky!  2016 should  be real interesting. Sorry Mike,  my bad, Frank, I'm coming!! Lol, Bill

[BPellerine]

too bad the engine has to come apart Bill.billp

[POPS 911]

GEORGE INQUIRING : Send FRANK in the 10'S about $200- $300 for gas to travel and pay for the bike pulls cost on the DYNO so you can get some numbers on a TIRED SOHC 750 ?? You could be the deep pockets $$$$$$$ FRANK needs to go in the 9's on NOS = send him cash and he will be more then happy to have YOU pay for your information. If the 10's bike was at my home in OHIO w/FRANK my man could DYNO that 750 SOHC for a whole day with information on your carb switching for a package price = SMOCK RACING MOTORS New Lexington Ohio 20-25 years [ his whole life ] spinning wrenches on bikes.

[POPS 911]

WHAT :  NOW you have the rev-limter on the bike ?? First thing you install on any drag bike =RIGHT ?  Those broken chains 530's with those stock OEM cheap stamped motor mounts turning that motor into a bind, loading side pressure on chain..... on KZ'S DOHC 630 RK HEAVY DUTY chain will last with little stretch , 101hp Dyno COBRA MOTOR might need a better chain. Shot more than a few 530 chains out the back off the Dyno and one thru the roof of the transporter on Joe Franco's son 1000cc Class SUZUKI  drag bike .... be careful that chain breaking wrapping into you rear wheel = your done.

[gschuld]

GEORGE INQUIRING : Send FRANK in the 10'S about $200- $300 for gas to travel and pay for the bike pulls cost on the DYNO so you can get some numbers on a TIRED SOHC 750 ?? You could be the deep pockets $$$$$$$ FRANK needs to go in the 9's on NOS = send him cash and he will be more then happy to have YOU pay for your information. If the 10's bike was at my home in OHIO w/FRANK my man could DYNO that 750 SOHC for a whole day with information on your carb switching for a package price = SMOCK RACING MOTORS New Lexington Ohio 20-25 years [ his whole life ] spinning wrenches on bikes.

Pops,

I believe there are many of us who would benefit from knowing where Franjie's 72mm motor stands power wise.  The engine requires no tuning, just a simple pull or two on a dyno.   The one who could benefit the most would be Frankie himself.  But with that said, I would be willing to "invest" toward having the reference.

I'm convinced Frankie is capable of running in the 9s next year if he decides he wants to, and without nitrous.  His engine building and tuning skills, along with his chassis set up and methodical approach to improving his combination are very impressive, regardless of budget.

George

[POPS 911]

Their you go FRANK as GEORGE said he will pay for the travel gas and DYNO PULLS on your tired ,worn out SOHC you are going to tear down and rebuild for 2016 = got you a deep pocket guy. Do the math BILLS fresh build COBRA ran 11.11et. w/101hp so your tired 750 SOHC ran 10.42et. you must have 110-120hp.  Weight of bike and rider could be a factor , but a DYNO PULL has no clue about that factor, could it be seat time at a track making many runs

[TurboD]

I too would be curious to see some dyno numbers on Frank's Bike, My guess is that they may be closer to Bill's than many might think.

If we simply compare 60 foot times, we will see that Bill's best is a 1.67(?) and Franks a 1.42ish. I was told many years ago with cars, that for every 1 tenth that you can shave off in 60' that you will lower the 1/4 time by 3 tenths. I have found this formula to hold somewhat true in many cases with vehicles in the 10-14 second range. I think that with motorcycles this formula might be slightly less at times, more around a 2.5 tenths gain per 1 tenth shaved. None the less.

If we take this formula and apply it here, a 1.67 vs a 1.42 we end up with a .25 difference. If we multiply this number, and using the age old formula (.25 for a bike) we now have a .625 reduction in 1/4 ET. This would bring Bill's 11.11 1/4 ET down to a 10.48. 

I keep saying 60 foot, 60 foot, 60 foot. As a drag racer we live and die by these numbers..Lol. With all respect to everyone, I read things on here almost daily that guys are doing or wanting to do to their bikes that will most certainly any chance of obtaining a good 60' time.

[dragracer]

You put it all in a nutshell Dave. Its all about the launch. But I also look at mph when the launch isn't where it should be. Consider the time and distance formula to understand where I'm coming from here. As I repeatedly stated, I'm not really concerned about dyno numbers, its "on track" numbers that I use as those are the only incremental that matters.

Pops said it best once when he wrote that we're not racing dynos. In the end, I'm not going out of my way to strap my bike to a machine to tell me how it performs on the dragstrip but if I can make it to one it'll be for the purpose of checking my afr as I think I've still a little too lean somewhere in my run and don't want to hurt my engine. I'd rather spend the dyno money towards the purchase of a Wego to get data from every run. Not just when its sitting on a table in someone's shop making noise.

[Jerry Rxman Griffin aka MuthaF'er]

Borrow Bill's new Wego. Can you guy's share? I'm not familiar with the system.

[dragracer]

Borrow Bill's new Wego. Can you guy's share? I'm not familiar with the system.

Jerry, the wego is used to display and log your air fuel ratio. It gets its input from an egr sensor place on the exhaust pipe as close to the merge of the collector as possible. It can be downloaded from the wego to a lap top to get real time information on the afr through an entire run. It helps to determine exactly how the carbs are performing so you can make adjustments without putting the bike on a dyno. Daily weather conditions change so  making jet changes from a one time dyno pull really isn't indicative of actual, on track runs. That's why most racers don't put much stock in a dyno run.

[TurboD]

I have been using a Fast system from one of my race cars.

[gschuld]

Pops,

I have plenty of respect for your skills and experience, but you tend to dive into a condescending tone at times.  I don't understand why exactly...  but it's getting OLD!

George

Sorry this is off topic

[scottly]

Borrow Bill's new Wego. Can you guy's share? I'm not familiar with the system.

Jerry, the wego is used to display and log your air fuel ratio. It gets its input from an egr sensor place on the exhaust pipe as close to the merge of the collector as possible. It can be downloaded from the wego to a lap top to get real time information on the afr through an entire run. It helps to determine exactly how the carbs are performing so you can make adjustments without putting the bike on a dyno. Daily weather conditions change so  making jet changes from a one time dyno pull really isn't indicative of actual, on track runs. That's why most racers don't put much stock in a dyno run.

Frank, does the Wego also log RPMS? In any case, slight weather changes shouldn't require jet changes. Get your bike jetted so even in "cold" temps it doesn't hurt the motor from being too lean, and leave it alone, unless you are talking altitude variations of greater than 3000' or temp variations greater than 30*. There is too much difference in fuel flow between main jet sizes to justify re-jetting during the day, IMHO, and it won't do anything for consistency.
Invest your money in one of Pop's ET predictors instead. The fact is that if the temp goes up, HP goes down, and no amount of fiddling with the carbs will change it. If the barometric pressure goes down, HP goes down, and again, no amount of fiddling will change the laws of thermodynamics. The weather station on a dyno provides the data to the program to correct for atmospheric conditions to a standard, such as SAE. Pop's magic box appears to use the same data to directly predict the change in ET with changing conditions.

[dragracer]

Scottly, weather station/et predictors are a drag racers most important tool from what I have observed in my limited years of racing. Its one of the devices that been on my long list of wants since I was introduced to one in the later 90's. For some reason, I always spent my money on more pressing things like engine parts, race fuel and tow vehicle gas. I'll get one eventually as I know the importance of how the weather directly affects each run.

As to jetting, I now have a baseline on hit and cold weather jetting to work from next season for better consistency. The mains are easy to change on the bike. I have no intentions of doing a daytime, night time jet change for bracket racing. If it was heads up racing, yes.

[scottly]

Frank, the point I'm trying to make about jetting is that the jets don't come in small enough increments to justify small atmospheric changes. Which style Mikuni jets are you using, the hex head or the round-head reverse flow?

[gschuld]

http://www.altronicsinc.com/racing-weather-stations/handheld-racing-weather-stations/performaire-predictor-1.html

Frankie,

Regarding weather stations/predictors, what do you think would make the most sense?   There are several versions of handheld systems(like the link above) and bigger trailer wired, laptop/processor type systems.

George

[dragracer]

George, the altronics unit is the most widely used. Its what I will eventually buy.