Ltd ignition timing ?

[munkeystew]

Built a '81 LTD to oval race. I'm looking for timing specs. Everything that I found is rather vague. The sled is finally running, but runs horrific on bottom. I'm hoping that the timing is too far retarded. The motor was built out of three donors, so marking the stator was not an option. Also, I'm running 38'm round slides. Any jetting advice? Will not be running an airbox.

[Interceptor398]

Most likely jetting.

[Teherr]

here is what I found on this forum from someone else.     

"I ended up with 35 pilots,260 main jets 2.5 slides Q-0 needle jet and 6dh7 needle I ran it with 280s and k& n filters for awhile then changed to 260s with the stock airbox. i found the 2.5 slides worked best for me and the needle and needle jet is what i found to run the way i wanted it to. I put alot of miles on it like that and ran great. "

I too am building an oval racer - both a 80 4/6 and 81 LTD mono head.  putting 38's on both.  I raced an invader that last 3 years and do well in the corners but loose some distance to SRX only.  I am hoping one of the two LTD's gives me what I need in straits.  I think I will run invader ski's/springs and perhap invader rear suspension as well.  it sits about 1 " lower which is good for ovals.  Also, pull the front of the track up 1/2 to 3/4 for better cornering. 

[munkeystew]

Where do you race? I run USSA, PVR, Eagle River etc. I'm not new to the game. I run a john deere fanner, and have won Eagle a bunch. The  LTD has an R track, and 116 phazer skid. Stock stuff is long gone. Anyways, the sled has been a bear to build. It is somewhat rare. I'm currently at 45 pilots 350 mains. That's probably not helping. Ignition timing specs would be great, someone must know. Did you leave on the oil injection? I'm only using it to lube the center crank bearings. The other limes make a loop back to the feed line. I'm going to pre mix the fuel. Good luck.......

[gixxer6]

There's some info on the timing curves in here: 
 http://kawasakitrax.com/kawiforum/index.php?topic=336.0

[munkeystew]

The sled will be a Super stocker. Without ice time, jetting, and clutching are a guess. I'm certainly no stranger to racing, and having what it takes to win. Just looking for a little feedback on an unfamiliar sled. I chose the Kawi for something different at the races. I caught a lot of grief from people when I started racing my cyclone, until I started to win. I believe that this sled has what it takes to win at Eagle River, and other races. Just looking for some more educated answers than my own. I will be running pre mix, so jetting will have to be a little higher than stated. I just don't want to burn it down. I'm planning on running ironwood, so any info would be great.. Thank you..

[munkeystew]

Any idea on peak rpm? I've heard mixed results. 8300 was my guess. I'm running Polaris primary and secondary, Derby skis, phazer skid, 116 R track, juice brakes. 1 inch chromoly steering shaft, so an airbox is out of the question. Sprocket, I've heard that you are a pretty sharp guy, and are pretty familiar with the Kawi's, so any help would be greatly appreciated.

[Checkmarks]

Munk:

You have a slight flaw with your idea for premix.

K motors oil the main bearings with the oil pump, hence the three lines out of the pump.  Sounds cool to run premix but in application your motor screeches to a halt. Don't waste your time engineering the wheel.  Consider modern sleds use this pump idea still and once invented all sleds funnel to this system.

Saving some weight idea for you.  Delete the aluminum radiators from under the seat and the brass radiator.  Install Polaris cooling system that would only include the heat exchange in the front of the tunnel.  Just for racing I suspect that alone will get the coolant requirement satisfied. 

Airbox is for getting cool air to the carbs.  Pipe the radiator catch air flow into the airbox.  Deleting the box is like eating the hand off to feed yourself.  Hot air in the engine compartment is a constant change.

K primary clutch is better when it comes to the $$$'s getting satisfied.  Manipulation of the rpm is way easier.  Add an aluminum bolt, subtract one washer, bla, bla, bla.  The primary clutch manipulates the rpm.  Set for 8300 (stock pipes = stock hp = stock rpm).  Test the idea out.  Run a length of snow (WOT) measured with a stopwatch.  Change the rpm for a different run say 8500 (lighter weight system).  Same snow, same day, same temp just one track length over.  What was the time?  Faster = more power exposed hp.

Timing: about all motors run best (peak Hp) at 10 degree BTDC.  Plus or minus a tiny.  Splitting hairs for advance retarding, or progressive timing.  Set it and forget it.  Nothing vague with timing.  Ltd's (mono) use advance retarding cdi and Ltd's (80) uses progressive just like the regular invader except with two more plugs.

[rminier]

  Hmmmm. The Invader shop manuals describe a very specific method for setting the ignition timing. Who has an LTD manual?....if munkeystew is using the stock ignition components?

[rminier]

 Some specs from a 1982 LTD shop manual...should be the same for 1981??
 Dynamic timing....21 degrees at 6500 RPM...engine cold.
 Static timing....0.102 inch (2.61 mm) BTDC.

[munkeystew]

I'm still using the oil injection, just not feeding the cylinders. It's only being used to supply the center bearings with a small amount. A very reputable crank guy recommended removing the plastic slingers, using crankcase pressure to lube the center. There are a few motors which use that principle. I chose the lesser risk at this point. This is to avoid someone using non mixed fuel in my other race sleds on accident. One fuel can to bring. As I have stated, I'm not the village idiot. Just looking for some simple answers. I own a dyno, but have not had time to run the motor on it. First race is next weekend, then on to Eagle River.  Anyone with clutch weight knowledge for a p-85 or comet 102c would be super helpful.I just need a starting point. Thank you..

[munkeystew]

Currently have the almond gold, with 10 mb Polaris weights. 48 grams. Too heavy I suspect? Is 8300 correct? Also, I have the 81 ltd. The entrance for the radiator is on the right front. It's a ways from the windshield area. Didn't think that it was super necessary. What should the engine temp be? I put a more accurate mechanical gauge on, and may tap into the cooling system with the mychron tach also. Currently have 21/39 1.86 for ironwood, maybe dropping a  tooth on top will work. Eagle River speeds are substantially less than other tracks, due to the tight corners. So the 20 top gear may better suit that track. I built camber into both spreaders, and welded a cross tie bar underneath the motor. The bulkhead seemed pretty flimsy. 38mm carbs 2.5 slides 35 pilots, 300 mains. There is no way that airbox  is going back in there. I tossed the goofy bent steering shaft and built a 1 inch chromoly straight shaft. I do own a lathe, so I built all new steering shafts out of 3/4 aluminium solid rod. I reamed out the stock steering bushings to 1 inch id. I used a Polaris TX  jackshaft and turned down a older cat brake rotor to fit. Which leads to my biggest worry which is the jackshaft pillow block. The LTD uses a goofy metric jackshaft, and bearing. I was having a hard time finding a 6205rs-1 bearing to use the 1 inch od jackshaft. I ended up using an invader pillow block which uses a more common 52mm by 1 inch id radiused bearing. The block is a lot less sturdy looking. Are they failure prone? I had to shim the chain case quite a bit to align the shafts, what a pain. The pivoting chaincase, and adjustable pillow block made everything very time consuming. Again, I am not familiar with Kawi's, so any help is greatly appreciated..

[Teherr]

The ignition curves for the 80 4/6 and mono head are different.  They both end up at about 16% at max rpm of 8500.  But the 4/6 (like the invader) advances from low rpm to max and the levels out.  The mono head advances to as high as 28% at 3000rpm and then retards back (downward curve) to end up at about the same place as 4/6 at 8500.

there is a thread on this forum that discusses the interchangeability of ignitions between the 4/6 and monohead but doesn't appear to work.

[Interceptor398]

See if this link will work for you.  http://kawasakitrax.com/kawiforum/index.php?topic=336.0

[munkeystew]

Jeff Schmidt, him and his brother Dick , and son Nathan Run a 80 liquifire, and a 80 something sportfire. I run #517 Cyclone. I use the wahl equation for gearing also. I'm geared for around 85. My fanner has been clocked at 75.9 on a big track, which using the equation and engine rpm worked out well. They must somehow equate 2 percent belt slip in. I know other factors are involved, so I tend to gear a little high. I'm really not sure on the class speed, so it's just a guess. Not really sure what mph the sled is capable of on the track. I'm assuming around 80mph ? I've never ridden, or seen an Ltd run.Horsepower, wind drag, track tension, etc. Too many factors. Ironwood is days away I'll see how it does I guess..