GT750 Drag Bike

Suzukidave · Post by **Suzukidave** » Sat Sep 22, 2012 8:59 pm

Kevin , have you been keeping a running log of jetting , air temp etc ?

water cooled · Post by **water cooled** » Mon Sep 24, 2012 6:41 am

Dave, I started keeping records earlier this year. Just before the race at Indy, Scott Allen (one of the other racers) recognized that a log book would be useful to me. He sent me a really nice log book and a detailed explanation of air density and other conditions at it relates to jetting and I started recording all the data... We also have a record of the air during the half dozen dyno runs we made last week leading up to the race and we added an EGT setup to the pipes to keep a close eye on temps. One indication I found at the track that we are close on jetting is a melted iridium wire on the center cylinder plug. Im going to change out the iridiums and go back to Denso.

Old School · Post by **Old School** » Mon Sep 24, 2012 7:14 am

How did you end up doing? How was the turnout?

tz375 · Post by **tz375** » Mon Sep 24, 2012 7:15 am

How was the weekend?

Regular plugs tend to melt before Iridium tips because they hold more heat. What heat range were the plugs. I figure a 9 on the street is OK for a hard ridden motor and 10 on the track but I don't think that Iridium gores to a 10. What did the other plug tips look like and are they showing any sign of overheating?

water cooled · Post by **water cooled** » Mon Sep 24, 2012 11:33 am

Turnout was great. We had 22 bikes compete this weekend. There are several riders working on bikes this winter to join our group next Spring. It would be great to approach a 30 bike field by next Fall.

I went out in the first round against Gary Seeley. I figured I needed a perfect light and perfect pass to beat him, none of which happened. When youre running against Gary, any tiny mistake will cost you the race. A bad reaction and some tire spin off the line was more than enough to put me on the trailer. Gary went on to win in the Finals against Gary Connors. Connors won the Indy race back in June. These guys are tough...no doubt about it.

Although none of us ever want to loose, I am happy with the bike and current performance. Im sure I'll catch a few weekends with Smokin Joe up at Thompson's Dragway in Ohio and resolve the traction issue. When that happens, a 9.99 wont be far behind.

R, Im running NGK BR8-EIX. Only had an issue on the center cylinder wire. Left and Right looked about right. The heat range seems to be right too...just a little lean at the track. Doug had me take out a couple degrees of timing.

tz375 · Post by **tz375** » Mon Sep 24, 2012 2:11 pm

BR8 ! I'm running BR9EIX in my street bike just to be safe........

But at the state of tune that motor is at, it doesn't take much to push things over the edge.

With the tire spin, is that a function of too much power now for that tire ?

Suzukidave · Post by **Suzukidave** » Mon Sep 24, 2012 3:10 pm

Looking real mean there Kevin .. i see you put the EGT assembly back on , are you getting a proper reading with the probes pointed to the back of the pipe ? Is your temp around 1200 deg on the top end ?

water cooled · Post by **water cooled** » Mon Sep 24, 2012 6:47 pm

Dave, I wasnt getting all 3 to read right. The probes are perpendicular to the flow and initially I had them adjusted so the tip was in the middle of the pipe. Later, I moved the tips back to about 1/4" and have to confess, I didnt check them on that last pass. I did checked the wiring tonight and found one of the thermocouple wired backwards in the patch cable so I corrected that. Should read fine now but I'll test again at Thompsons. The middle cylinder did give a good reading of 1000-1100F during one of the dyno runs. Someone suggested i use one of those cameras and set it up to record the EGT adn RPMS during a pass. Sounds like a great idea.

One of the racers is looking to sell an RPM Pro Data Logger/w software. I am very interested and looking in to that a bit but will probably have the deal sealed by the end of the week.
http://rpmperf.com/index.php?option=com ... &Itemid=57

Suzukidave · Post by **Suzukidave** » Mon Sep 24, 2012 6:59 pm

A helmet mounted camera might be a very cool way to record both your pass and watch the readings , i do feel the egt probes do work best inserted thru the back of the bend like you had with the Jemco pipes as the hottest gas flow should flow along the outside of the bend .

tz375 · Post by **tz375** » Mon Sep 24, 2012 9:10 pm

Highest temps are in the center of the pipe and on a bend that moves out a little but skin temps are lower than the gas in the center of the flow.

This is where a datalogger would pay for itself really fast in setting things up. 1100 is quite low in conventional thinking but that depends to an extend upon the pipe design where peak temps are. A few inches either way can make a huge difference to temps. What's important is that if the dyno temp was say 1100, then at teh track you want to see that same number or close to it.

Dave's right about the bike and rider looking more serious and focused each time we see a picture.

Old School · Post by **Old School** » Wed Sep 26, 2012 4:50 pm

Thanks for the update and pics. I would have liked to have made it, but I just wasn't prepared and now it looks like my bike may have a bad crank seal. Maybe they will start next season with a race at Indy or even Muncie.

water cooled · Post by **water cooled** » Thu Sep 27, 2012 4:24 am

Dave (from Anderson),
If it turns out you have a bad seal, Bill Bune (Enterprise) is a good option. He did my crank and trimmed the oil slingers down to allow the premix to get into the crank bearings. Quality work at a very good price. The Indy race was well attended by S/E racers so I suspect we will be at Indy again but S/E committee sets the schedule and usually posts it in January. There are a few more TnTs at the local track in October so Ill be out there before they close for the season. Then, take everything apart and put it all back together again.

Hope to see you next year. Send me a message if you need anything.

D&D CHASSIS · Post by **D&D CHASSIS** » Sun Sep 30, 2012 1:14 pm

Old School(Dave) what part of Indiana are you from? We have a couple guys from the Lowell/Valpraiso area

David Derrick
DBCF on the Super Eliminator board.....

Old School · Post by **Old School** » Mon Oct 01, 2012 6:52 am

Kevin Thanks I'm sure I will need some tips. It would be nice if SE would have the spring race back at Indy or even Muncie, Muncie would make a nice place for it. Nhdro had a few events there this year.

D&D I am from Anderson, 20 miles Northeast of Indy.

water cooled · Post by **water cooled** » Sun Nov 11, 2012 2:19 pm

Took the bike to Thompsons to catch what will probably be the last race day of the year before closing. Tried out the new MT slick which is a little wider than the GY I had been using. Couldnt find the correct tire pressure and probably had the bars a little too high but here is a slo-motion clip of the launch.

http://www.youtube.com/watch?v=hFTyy69Qehc

Here is another pass. We had to run 1/8th due to track conditions on the other end. This one started to get away from me.... considering how far out of the groove I got, the 1/8th time wasnt as bad as I expected.

http://www.youtube.com/watch?v=FmDsTdBggJg

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