Rotax Long track info ??

[Brian Kay]

Anyone out there know much about setting a Max kart up for long track?

Gearing suggestions for tracks like Gingerman, Mid-Ohio, Grattan, IRP would be VERY much appreciated !!

Thanks guys and girls,

Brian K - www.t2racekarts.com

[John Bosanek]

The guy you need to talk to is Mike Moya. He should see this before too long.......

[Don Jones]

Brain.

Depending on the track you will need a 4-0 to 5-0 ratio we have 15 and 16 tooth drivers that go onto the drum. Great job on your pole at Rock Island!

Don Jones
Team Effort Motorsports/Omega Kart
330-940-2745

[Brian Kay]

Ahhh the internet,

Naked Women, Instant communication to anywhere on earth, and Go-Kart set up info. Did I miss anything?

On rear gears - What's the ideal range to have for sprint and long track?

Brian K - Shifter Guy and Rotax rookie

[Nick Weil]

aaahhh.... naked women... gear ratios....


75 tooth to 89 tooth should cover you in most situations Brian. Down here in FL you will want to have an 11T, 12T, & 13T engine driver. I don't think anything down here is long enough for the 16 & 17 except Daytona and maybe Savannah and possibly next year at the new North Florida track.

Hope this helps...

Nick

[Jeff Edwards]

Brian,

I'm sure Mike will have more specifics for you, but I'll pass along what I know now.

I can't speak to the specific tracks, (Gingerman, Mid-Ohio, Grattan, IRP), but I have raced my Max at Thunderhill and Sears Point in Northern California and at Portland at the IKF Grand Nationals, and it's an absolute BLAST!

I used to race KT-100 Limited (situp pipe) classes and ran a 15:75 or 5:1 ratio at Tunderhill. Now, in the Max, I run a 16:69 or 70. Thunderhill is a 3.0 mile track with elevation changes, a mile long straight and some very technical corners. Maybe this comparison will help you make the adjustment for your tracks.

Also, at the Portland GN's, I took 2nd place in the 125/150 Open class and was running a 16:66 and wishing I had a 17 tooth driver.

Incidentally, I used a used chain, used gear and no oiler and ran the one hour race just fine with some spray lube. I know that others have a problem with chewing up chains, but I haven't. (Of course, I've jinxed it now )

Send me a private note and I can connect you with my source for 15 and 16 tooth drivers if you need some.

Just remember, it has incredible torque in the midrange, and will pull up hills you never would have thought in a 'clutch' kart.

Happy Max'ing!

[Lyle Cline]

Just a question Jeff,

What times were you turning at Portland? What's a Max like to drive at Portland?

Thanks,

Lyle

[Jeff Edwards]

Lyle,

It was my first time at Portland and I enjoyed it immensely. The Max was smooth and fast. I know it would have been able to handle an even smaller ratio than the 16:66 which was the minimum I could provide at the time. So the times I ran were less than what is to come.

My times in practice were 1:26.3's. This was with my standard Max Challenge type setup (355 lbs).

In the race, I turned 1:27.3's. This was the 125/150 Open class, so I bolted on 35 lbs of lead to make the 390 weight limit. I also added a 2 1/2+ gallon enduro fuel tank in place of my left CIK sidepod to augment my nearly 2 1/2 gallon center fuel tank. I ran SL3's and other than the side tank, it was all standard CIK bodywork with the seat at 50 degrees. (I used just under 4 gallons for the hour long race.)

What is really interesting, is that I was going to tell the starter to put me at the back of the field since I was going to be real slow starting with that direct drive and the 5 gallons of fuel on a 390 pound kart. As it was, I peapicked a lousy number and was at the back of the 11 entries 'naturally'. At the start, I was about fourth going into the first turn. Of course, they all got by soon enough, but it sure amazed me. I think it only confirms my suspicion that I left some gearing 'on the table'.

Also of note: I took it out in the pouring rain during the morning practice and it was a real champ. It was my first time racing in the rain (uh, on the track, that is) and I was concerned that the mid-range torque would just spin the wheels. Well, the opposite happened: The rain tires had enough bite to prevent the spinning and the motor is so darn smooth that it put down power very efficiently - and a lot of fun at that. Where the gearboxes and clutch karts had to be careful about the balance, etc., the Max was SO-O-O SMO-O-O-O-TH that it was a pure joy.

I wish I lived a little closer to go run at Portland again!

Jeff

[ September 10, 2001: Message edited by: Jeff Edwards ]

[Brian Kay]

Jeff and all,

This is great info! I'll be sure to order gears 65 and up. Already have 15 and 16 tooth drivers on the way. (thanks Don)

Q: Have you played with jetting much? Power valve?

Oh yea, is there a decent tool available for changing front gears, or should I just buy a few more clutch drums and have them pre-installed.

Another Q: Is one chain length suitable for LT and Sprint, or will I need a selection?

Thanks again guys,

Brian K - T2 RaceKarts

[Jeff Edwards]

Brian,

Lots of questions - here comes lots of answers....

Jetting: I'm really new to this kind of jetting and have much to learn. (Only KT prior) I have been setting the needle to the second richest location for most instances, but treat it, more or less, like the old KT Low speed needle - jet based on performance off the slow corner and at the starting line.
Starts: don't floor it like the clutch karts! You'll just flood the thing and sit there. Use a VERY delicate touch on the throttle, feeding very slowly. Patience. Also, after the warmup lap, most of us, shut off our engines and just restart them barely before the flag drops - less likely to get carb flooding. The electric start makes this thrilling.

The Main jet, I'm treating like the High Speed KT needle - mid-range through top end performance. So far, I have simply followed the table in the book for jetting the main. HINT: when at home and it's quiet, do the metric conversions and write them in the book so you don't make a BIG mistake trackside.

I haven't raced Sprint yet with my Max (I WANT to, but haven't) so I don't know about chain length of sprint vs. long track. I have found that the limiting factor in chain length is how much fore and aft adjustbility you have in your particular Max installation. I re-did my exhaust brackets to give me more range and now only use one size of chain - six teeth less than standard new DID chain (?114-6=108?).

Oh, wow! I forgot one major item MOVE THE FUEL PUMP!! If you run it in the normal location beneath the carb, it works fine on short track, but on long track, long sweeping corners particularly, it'll starve. You simply need to mount it on the seat so that it sits higher than the carb bowl. Also, aim to shorten the pulse line as much as possible. My engineer hung my fuel pump from a zip tie from the seat side, with an inch slack, thus making a hinge or flexible connection. The pulse line ends up being less than two inches long, but it still gives me enough fore and aft movement to adjust for chain. No starvation or whatever that was.

I haven't made any adjustments with power valve. I did check to see that it was coming in at the proper RPM range, per the manual. I suspect there is more speed to be found there, also.

Drums: Changing doesn't take long at all, if you have the tools. The socket is a LARGE socket (I can't remember size! I'll try to remember to look later) and you don't need to spend $40 on the metric or sae set. Just buy the socket (the sae equivalent to the exact metric works fine) and an adapter to fit the drive of your your standard set. You probably already have a breaker handle of sufficient leverage, you don't need a 30" handle for this! At Orchard/Sears it was about $20 for both. The other tool is a two pronged clutch tool which is a specific item, but my buddy made his own. Basically you need a tool to hold the two holes, while you turn the nut. Think 'well attached and held' vise. On the other hand, multiple drums would be a lot handier at the track for quick changes.

Hint: If you take dusty off track excursions, be sure to check the inside of the clutch. Remember, it's really open and so collects dirt in these cases. (Not during normal use, however.) All you have to do is remove clutch drum from motor and spray down clutch with cleaner, re-oil bearing, and pop back together. Just takes a couple of minutes and works great.

By the way, the NCK Rotax Max class runs with the 80 shifters in two 20 minute heats (we start at the back). Although they roar off at the start, we hunt them down by the end of the race. Mike Moya is so good, he not only hunts down the 80's, but on a 15 second split start, he passed all of the FIRST group, too!

What a blast!

I better go, now.

Jeff

[Brian Kay]

Jeff,

THANK YOU!

Printed, and filed. Great info. Meant to take one of my Max karts to the track for serious testing this week. Crossing to / from Canada takes 3 hours thanks to yesterday's disaster so I'll have to wait.

I want to address the standing start bog if at all possible. At RIGP, we went from pole to DFL - live and learn.

Surprise - I have another question. What fuel are you guys using. Seems that finding something in the 98 octane range that will still pass tech (digitron) isn't so easy?

It seems a high octane UN-leaded would be best. Is this correct?

In closing, I would like to offer a "Tech Tip" of my own (if it's lame, dont tell me)

Maxima power valve cleaner. Used it in my Snowcross machine, which had a power valve very much like the Rotax. Huge difference. 1oz per 5 gal keeps em' working smooth.

Thanks again,

Brian K - www.t2racekarts.com

[Bill Wright]

Brian,

Before you go buying all the 219 stuff, if you want to run enduro or endurance I would suggest belt drive. Email me privately if you want more info.

Bill Wright
"Get on Course!" with FK www.formulakart.com

[Jeff Edwards]

Brian,

Thanks for the tech tip - I'll have to look into that.

In our series, NCK Rotax Max, we wrote the fuel spec to be "Fuel: Track gas, 98-octane maximum." Now, the practical matter is that the fuel available at Thunderhill and Sears Point is 92 and 100 in unleaded, and 110 leaded. A couple of guys tried to get fancy and mix the fuel to get more octane, but most of us find the 92 runs just fine. Besides, it's half the cost.

The oil spec is open.

However, this would preclude my adding your tech tip stuff during races...

As to 219 vs. belt: most of us think that belt would probably be the nicer alternative. Mike Moya ran a belt drive last time and it was fine. I know others will go to belt soon, also.

Most of the guys have had a problem with chewing up sprockets and the typical oil splatter mess, but I haven't. My sprockets and chains have been lasting incredibly long and I haven't been using an oiler. My secret: beats me . I have made sure that the alignment is perfect (between the sprockets) and I use Motul 'Off-Road Formula' Chain Lube and DID gold chain on a 1997 Trackmagic kart. The sprockets have been of differing brands, including Horstman split reds. Go figure.

Jeff www.NetKarts.com

[Brian Kay]

So where does one get ahold of these belts and "sprockets"(?)

A number of people have said that belt drive is the way to go for LT racing. One person said that the belt needed to be cut to a certain width, so we're talking about specialized stuff that I have no "source" for. (yet!)

In the meantime, anyone out there have a 17 tooth drive gear?

Mucho thanks, and PEACE ON EARTH!!

Brian K - www.T2racekarts.com

[ September 18, 2001: Message edited by: Brian Kay ]

[bird]

Sprockets are gears Brian