September 3, 2014 at 7:15 pm #33095
Has anyone with a Leopard played around with the exhaust flex length? I was about to buy some flex and cut a few with 5-10mm difference in length. Is it worth it or just stick with the suggested 410-415mm total length? I will be running a road race which is probably 80% top end at roughly 14,300 rpm.
Tony Kart / LeopardSeptember 4, 2014 at 8:01 am #33118
Give Russell Karting a call or an email. Jim Jr posted in 2010 “I like 16.25-16.5 for road racing. 16.0-16.25 for sprint racing.” For RR that works out to be 412.75mm to 419.1mm.
P.S. I might still have a flex cutting jig if you need it.
LAD Specialties customer / tony kart / rotax / kt100September 4, 2014 at 11:53 am #33129
Tony Kart / LeopardSeptember 16, 2014 at 4:29 pm #33913
I’ve been road racing an 07 leopard for the last couple of seasons and typically run about 16 inches from the header to the first weld on the expansion chamber. I’ve not noticed much additional pull going longer.
I would suggest trying a taller gear to drop some rpm though. Leopards make peak hp between 12.5 and 13k rpm. Spinning them much higher will actually lowers your straightaway speed. On big tracks, I typically gear for about 13k max rpm running alone. This can equate to about 13.5 or so in the draft. You will be amazed at how this can lower your lap times if you keep your cornering speed up.
Check out my videos at l8apex63 on YouTube. Some include engine rpm.
Bob WimmerSeptember 25, 2014 at 11:05 am #34422
Thanks Bob, that was an awesome video and great track. I was going to ask you since I notice it in your video also… so this is getting off topic from pipe flex. I ran a different ratio this year and I smoked my newer (sprint) clutch with only a few weekends on it. I know it was my fault at the start for getting overly excited and blipping the throttle, which just overheated the clutch (which probably does nothing besides load it up with fuel even more). Off the start it slipped twice pretty bad and it was the same slip/over rev that I heard in your video. Are you running the road racing clutch? I have mine on order, but I figured the sprint clutch would hold up for the weekend, just as it did all the other years. This track does have 1-2 tight corners vs the very long straight.
Is this slip normal for a taller ratio like you/we run? Have you tried both sprint and RR clutches? I’m trying to figure out if the main cause was just from me heating up the clutch at the start and not having a chance to cool for over 30 minutes, or if it’s due to the clutch slipping/heating up in the tighter corners. The clutch was chunked up and looks overheated.
Tony Kart / LeopardSeptember 26, 2014 at 6:26 am #34475
Clark Gaynor Sr.Participant
Sean, just a couple things. There is no need to start the motor that soon before the start. 15-20 seconds is plenty. DO NOT keep blipping the throttle!!! Just give it enough to keep it running- that’s it! One hard start a day! In other words, take it real easy on it leaving the pits for practice, and only hammer it at the starts of the race. After each event (we actually do it each day) remove the drum, sand the shoes and clean them and the drum with brake clean. grease the bearing and you’re good to good.
Clark Sr.September 30, 2014 at 8:54 am #34697
You burnt it up on the line. When sitting still, you have to stay ” off the clutch” with your throttle, or you can burn them up in a matter of seconds!! Also, if you have a habit of blipping a throttle while your on the brakes, cornering, that can burn one up to. If your touching the brakes, you have to be off the throttle!! I’ve never seen a weaker clutch than on a leopard.October 2, 2014 at 6:19 pm #34809
I have tried both road race and sprint clutches. If I’m running a 16/80+ gear I stick with a sprit clutch. For a 16/79- gear I’ll run a road race clutch. Both can take about 4 hard starts before the friction material is gone. This is with the daily maintenance routine Clark mentioned and babying the clutch in practice and on the grid. Also if you go off or spin and floor it to get back up to speed you will distoroy the clutch.
I also found that a worn drum can cause premature clutch failure. If the shoes break on the clutch before the friction material is gone try replacing the drum with the clutch. It will likely solve any problems.
Bottom line, I’ spend as much on the clutch, chain and gears during a season as the engine.
With the preventative maintenance, you should be fine.
BobOctober 23, 2014 at 9:56 am #35832
Are you guys measuring this 16-16.5 from the pipe side of the flange or the engine side of the flange?October 23, 2014 at 1:51 pm #35840
Contact the association that you race with and ask how they measure. I have two Leapard manuals, one shows the measurement from the gasket side of the flange and another showing the same measurement from the pipe side of the flange. And there are posts on EKN to support both sides of the argument.
LAD Specialties customer / tony kart / rotax / kt100October 23, 2014 at 2:05 pm #35845
Thanks, but question was for those who say they run like 16″, are they themselves measuring from pipe or engine side of the flange?
You must be logged in to reply to this topic.
EKN Editorial Search
EKN Editorial Directory
- EKN CANADA
- Briggs Racing
- Can-Am Karting Challenge
- Challenge Of The Americas
- Florida Winter Tour
- International Kart Federation
- Los Angeles Karting Championship
- Rock Island Grand Prix
- Rok Cup USA
- Route 66 Sprint Series
- Superkarts! USA
- Texas ProKart Challenge
- United States Pro Kart Series
- United States Rotax Max Challenge
- World Karting Association