Night Rider Liquifire

[liquifireguy]

I just picked up this 80 Liquifire Saturday. I bought it from the second owner, who had bought it used in 1986. The first owner pretty much immediately set it up as a race sled. The engine was sent into Aaen for porting and other modifications. At this time, I am not sure of what other modifications were done. The second owner, who I bought it from, put the clutching back to closer to stock and made it so that it was a very hot rider sled. Since he bought it in 86, he has put around 1000 miles on the sled and it ran fairly dependably. The custom paint job was done in 1980, as the airbrush guy signed and dated the hood 1980. The sled also came with an extra, NOS, hood that has never been on a sled, but was painted identical to the hood that is currently on it without the Night Rider name. I don't know if this was just an extra hood or what the deal was. I have ran the sled in the shop a little on the stand, but need to do a little more cleaning on the carbs before I get it in the snow. The crank seals have been changed in the last few years, as well as all of the outer bearings.
What do you guys thing about airbox/ no airbox on a performance sled. It currently has the Jegs foam filters on it. Would I get better performance if I got a gutted airbox so that I would get fresher air? I am used to stock sleds, so this is a whole new experience. It must be jetted for this setup because it has been ran for years this way.
Thanks, Jeff

[Horicon Joe]

Jeff ...... great looking sled. I would like to see more detailed pictures under the hood. Perhaps the most interesting thing I see is what looks to be added motor mount brackets?! I wonder if there was a different motor in it at one time. What is the serial # and could you post a picture of it?

As far as the air cleaners go .... I tried running them back in the day and they did not work for me on a stock sled. It started and ran fine until you got up to speed it lost power at times. I was told by engineering that they had to have the air box to normalize the air turbulence under the hood that could draw air away from the carbs at time??? Something like that anyway. I do remember seeing them on someone's sled recently and they said they had no problem? Maybe it was Brad Wheelocks sled?

Very interesting ....... Joe

[mfd1221]

Looks cool


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[liquifireguy]

I had some time to mess with the sled today. I took both carbs apart and soaked them. I don't think that they were dirty because it still runs about the same as it did before. It seems to be either running lean. The plugs are very light grey-- almost white. I did put new plugs in, so it is kind of hard to tell with the 15 min. of run time. Something is not right, I think in the carburetion. I can't get to go above about 5000 rpm before it bogs down-- barely enough to move the sled. Where should I start with fiddling with the carburetor? I have the drive belt on the loose side just to make sure that isn't the problem. According to the previous owner, the sled ran okay when he put it away a couple of years ago. In talking to him, he also said that he replaced the stator a few years ago. Ever since then, it has been harder to start and tried to backfire through the carburetors when starting. He said he thought Aaen changed the timing and he tried to get the new stator close, but he's not sure it is right on. Does anyone know the correct procedure?

The serial number of the sled is 128783. It was bought new around Farmer City, Illinois and the guy I bought it from lives near Monticello, Illinois. It came with the original John Deere cover and a ton of extra Liquifire parts, as well as another stock engine the was just rebuilt.

I am new to this performance sled stuff, so I am sure I will be asking a lot of questions, but man, the thing sounds cool when it fires up, so it is worth the fight. I am planning on keeping the sled just like this and not restoring it-- you don't come across a built performance sled everyday, so it has a lot of character. Does anyone on here know anything about this sled or remember seeing it back in the early 80's? I am very interested in more of the history.

Thanks, Jeff

[harleysportster]

One of the symptoms of a Kawasaki cdi box failure is what you are experiencing, engine will not rev over 5,000 or so rpms. Also could be the rev Limiter.
Just a thought.

[liquifireguy]

The rev limiter has been removed. I have a brand new aftermarket cdi that I will try. Thanks, Jeff

[liquifireguy]

This sled has me stumped. I have spent some time trying to eliminate possible problems, but the sled still will hardly pull itself with me running along side (I have gotten quite a workout). I have removed, taken apart, and soaked the carbs 3 times now, as well as taking apart and checking the fuel pump. I tried both bigger and smaller jets to make sure that the jetting wasn't a problem, I put a new CDI on, and put my brand new spare 102c clutch on. Compression is 120+ on each cylinder and is the same. I have had 3 different sets of plugs and 2 different coils on. A friend of mine stopped by and worked on it for a couple of hours last night. He was a Ski-Doo mechanic for a couple of years in the early 80's and he is at a loss. Has anyone here experienced a problem like this? Could it possibly be timing? It doesn't start real easily and, sometimes, will try to backfire through the carbs. It also seems like the warmer it gets, the worse it runs. The previous owner did replace the stator with a NOS one. I have the tech manual and it says to check timing, you have to use a timing light, which looks almost impossible to do on a Liquifire. From what I understand, with the Aaen modifications, you have to advance the timing something like 4 or 5 degrees, which adds to the complexity of this equation. I would like to know what others have done to set their timing and how well it has worked.

[Horicon Joe]

Put the air box on it and try .........

[liquifireguy]

Joe, unfortunately, I don't have the airbox, and it hasn't had one since the early 80's. I talked to Brad Wheelock about it the other night and we discussed the airbox. He said that one of Aaen's modifications was to set it up to run the small filters instead of the airbox. I thought that by trying different jetting yesterday-- both larger and smaller, I probably took the carburetion out of the equation. I will buy an airbox if I have to, but I hate to spend $50-$75 for an airbox that I don't need with this setup. Thanks, Jeff

[sledhead16]

How does it sound? Like to much fuel? Really smokey? Not enough fuel? It definitely sounds like a fuel delivery issue. Are your carbs syncd and both clearing the whole venturi on the motor side when given full throttle?

[sledhead16]

I'm thinking it's starving for fuel

[427cobra]

Id try setting the correct belt deflection. A slipping belt could cause problems.

But that wouldnt cause issues with it starting easily..??

[MARK S]

Sounds like they maybe used the later style stator assy in it but used the old flywheel.?? I had this happen before back in the day at the shop..Good spark, sometimes?? would start good and idle perfect all day but give it some throttle and it would fall on its face, sometimes you would pull your arse off only to get a pop every 20 pulls,I will stop out at the shop and grab the old tech manual as I had alot of notes written in there..Memory not as good as it used to be??? Mark

[Danzig]

I had these problems and I had to do lots to get it right.

Dropped pilots down to 30's instead of 35's.

Make sure the secondary is shimmed correctly, belt should exceed the sheeves about 1/8 inch, and make sure the spring in the secondary is preloaded correctly.

Changed CDI

Stator has a mark on it that lines up with a mark on the case seam, I advanced mine a mm .

Whats piston wash look like ? What plugs you running ? What kinda fuel filter you running ?

Airbox has to be on it in order for the venture to work on the powerjet circuit, it works kinda like a vacuum box

[TASKY]

The carbs dont look like Power Jet carbs. If I remember right one of the performance mods of the day was to replace the power jet carbs with regular 38's.

There really is no telling what mods have been done to it through out its life. Best source for specs would be the previous owners.

Clean that fuel line shut off and make sure it is opening all the way. Stranger things have happened.

What kind of fuel are you running? You shouldnt need more than 92 octane?

Have you tried it below 20 degrees fahrenheit? I had a piped sled once that was jetted right on when it was 15 degrees or below. Ran crisp and pulled hard. Any warmer and it was just plain embarassing.

Seeing how it has been messed with. Timing could be a problem to.