Liquifire: 80-81 VS. 82-84?

[Checkmarks]

Kieth, and others:

I have read this thread and find it amazingly interesting.

Good news, I have the Polaris (P) 400 (84) Cdi and installed it in my invader motor. Had to order a new stock coil and was waiting but the snow was flying. I also used the (P) flywheel, stator/ coils and CDI. At first I was very nervous, the sled started right up.

When I installed the Polaris system, I got exceptionaly lucky. The first order of business was to adjust the timing so it would start hence the 'lucky' part. After drafting some timing marks on the clutch I grabbed for the timing light. Just a automobile timing light powered by a 12volt dewalt battery. As the engine reved to 3000rpm life the mark was right on 22˚BTDC. Now I just might be super lucky. All was going exceptional. The "curve" looks like @3000 22˚--@5500 11˚--@7000 5˚-- @8000 4˚. Without reference to where to start I guessed this was good. The throttle sounded very snappy. This curve is my eyeballs best I could do, running the throttle watching timing marks and the tachometer. Likely there is some error.

Best part:

What a great find yesterday. I picked up a 83 John Deere liquifire just to have a contingent motor for my Invader (my love). It ran yahoo! Electric start yahoo!

Knowing this had a 'special' CDI I was excited to see the ignition in action. It started with the twist of the key and some fuel in the carbs.

The Deere (LC Kaw 440 motor) at 3000rpm marked at 24° and finished 8000rpm at 8°. That makes for 16° of retard change which directly compares with Polaris's CDI. I was very worried a piston might melt down on my Vader and now I can sleep well at night. Deere engineers designed their Kaw's motors for long life at the expense of some horsepower so I know this swap is safe! This useful information does not gain any more horsepower on the top end, but I expect some magic in the lower rpm band...

The Polaris (P) swap is simple...
(P) stator/coil/pulser
(P) flywheel
(P) CDI
These items can come from likely all 84-98 Polaris liquid Fuji motors 400's, 500's even probally 600's. The only thing that is tricky is cutting the woodrift key down 1/16in or have the key way cut larger on the Polaris flywheel.

My endpoint is that now I can see the timing used on Deere's motor and adjust my Invader's up to these spec's. I have yet to see reference to timing other than 0.108 BTDC in books setting @6000rpm. There was a person on Kawitrax that said I would have no power @8000 with 4°. He said,"Most sleds including Kawi's finish around 14-16BTDC".

My question is where should I finish the timing 8° (Deere's finish point) is safe? Has there been someone on this site that has a 82-84 JD that has tried advancing with good results?

Mark

[Racemarty61]

The real world of kawasaki cdi ignitions, One was said to be heavy duty being separate coil & cdi box and one being light duty having the coil & cdi box built with-in it self, all kaw engines have the same 60mm stroke, the difference is timing for what kaw engine your using no matter what ignition system your using. I can use either or cdi set-up and get the exact same performance on any kawasaki engine.

[JD600]

I would have a tendency to disagree since we know that the HSR setup had a drastically different advancement curve built into it....

DE

[Racemarty61]

No real performance gains with many dyno tests through out kaws entire power band proves to us any noticeable or measurable performance gains pertaining to kawasaki's various ignition systems with un ported cylinders and stock cranks.

[That Girl Racing]

The timing retards on two stroke ignitions, not advances. Both ignitions end up with same finish timing. That is why there is no hp difference. The HSR has more start timing but that is gone over 5500 RPM.

[AirborneX4Special]

The timing retards on two stroke ignitions, not advances. Both ignitions end up with same finish timing. That is why there is no hp difference. The HSR has more start timing but that is gone over 5500 RPM.

Did some drag racing one evening many years ago, between an 80 and an 81 LF with standard gearing and clutches, but the 81 had a complete 83 engine under the hood. From a standing start, the 81 would waste the 80 every time off the line, and it was no contest. From a 10 mph rolling start, the 80 would roast the 81 every time, and again it was not even close. At top speed, one could never catch the other in either scenario because the top ends were nearly identical. This test was repeated several times both uphill and down on a snow packed road and the results never varied. We finally quit to go have an adult beverage and laugh about how much fun we had.

[gixxer6]

Peter, I bet you are correct. I was struggling with it after I put it on line, and wondering about a power loss with the HSR at only some 8 degrees advance at 8000 RPM, per the comparison graph in the above post. EDIT: THAT GRAPH WAS INCORRECT AND I DELETED IT. I made the assumption that each vertical division was one degree on the service manual graph for the LTD 4/6 HSR. If you make the assumption that each division is 2 degrees, the graph looks something like the one below, which is the point I believe you made. I had previously looked at 2 degree divisions which results in some 30 degrees advance at about 3000 RPM. That seems huge? The 4/6 service manual graph also leaves some RPM up to interpretation. Probably the best we can make from all of this is an indication of what the Liquifire curves may have looked like (note next paragraph).

Keith / Norton: There may be other factors in relating the Kawasaki advance curves to the Liquifires. The Gordon Jennings Two Stroke Tuners Handbook lists several engine parameters that effect the determination of an optimum advance curve, such as combustion chamber shape, spark plug location, distance from plug to remote area of combustion chamber, etc., some of which are different Kawasaki vs. Liquifire. The question is were the Liquifire curves unique (?),……or were the engine differences not sufficient to warrant Liquifire specific advance curves? Peter, your thoughts would be appreciated. I think I am finished with this before I do any more damage!

Guy

advance comparision 2_001 (Small).jpg

I dug through my Kawasaki manuals, and it looks like the first graph marked "Standard Invader" is the graph for the 4/6 LTD, and the second graph is that of the 81-82 LTD/82 Interceptor (8 port motors). I can't find a graph for an Invader. But the manuals show that the Invader is set to 22 degrees at 6500 RPM, while the 4/6 LTD is to be set at 18 degrees at 6500 RPM.

I am planning on installing the 81-82 LTD CDI on my Invader this winter. I am hoping to get a little better low-end/mid range power from this Invader. It is an 81' (so it has the larger improved pipe). It is unmodified other than I had the heads shaved.

[That Girl Racing]

The difference in timing comes from were the static timing is set not the box. The CDI box (HSR style box) retards the timing a pretermined amount. It has no idea where the trigger is. Adding 4 degrees of timing at 6500 especially if you spend a lot of time cruising at that RPM could prove expensive. Peter

[kenwaters]

This thread helped me to understand/solve a problem I had been having with my race sled. Thank you Peter and all for the wealth of education here. I used a Sprintfire flywheel on my race sled, because it was a perfect match dimensionally, and it did not have the added mass of a ring gear. After reading this thread, I came to understand that the Sprintfire flywheel, although dimensionally perfect, has a very different trigger point with the magnets. The magnets are rotated about 5-10 degrees off, which was letting the motor run, but it sure was hard starting.

[webman]

Has anyone tried running a sled with the polaris parts installed on the kawasaki motor?

[vader]

Why did certain invader heads have dual spark plugs. Any gain in performance

[Grumpy]

I seems that now days a lot of the racers are going to the Skidoo Electronics, I'm not sure which Sled/Engine there taking these parts from?? Stator, Flywheel, Electronics Box/CDI but then they install them on there race sleds.. ( Flywheels have to be modified to fit there certain engine make )
Just FYI,

Peter do you have any input on this?? or anyone??

Grumpy

[JDT]

Cat did the same thing back in the early-mid 70's with the Kawwy engines.

They may have thought that if one system failed the other would keep it running.

Kind of like airplane engines.

But then came along indexing washers and the world was never the same again.

[JDXpowered]

as a side note to this conversation, I picked up an 80 liquifire that had been converted to the 82-84 ignition. it does not bolt to the engine housing correctly, but runs fine. And finding a parts for the 82-84 is very very difficult. I did find that Kokusan ignition on the indy and noted it looks similar; looking a little more I found one that looks the same when searching for Kawasaki 650 coil cid. Good part about the Kawasaki version is wiring looks a little easier to modify.

I will be buying one and trying it, will let folks know.