Chaparral Firebird Wiring Diagram

Chaparral Thunderbird Wiring Diagram

Q: What is the correct way to hook up fuel lines on the SSX consumer model?llow the chart below:

A. The fuel lines are confusing.  The right side of each injector is an inlet and the left is an outlet.  The way the injectors work is the fuel is pumped in on the inlet side (the fuel pump is built into the base of the injector, but it is not the usual carburetor diaphragm setup) where it is sent in to an overflow area.  The fuel is picked up from that area for the engine and what is left over is actually "pumped" back to the tank.  That is why it does matter which side you hook your hoses up to.  There are three (3) hose connections on the outside of the reserve (side) fuel tank.  One is for fuel pickup and needs a fuel line on the inside of the tank that reaches to the  bottom to get the fuel, the second is for the return fuel, it does not need an inside line attached to it.    The main (center) tank is the first tank to be emptied.  It has one line that drops to the bottom of the tank.  Make sure to weight the line.  After the main tank is empty, the engine will start to stutter and you must press the "Press for Aux." button to close the main pickup line.  The line then draws only from the Aux. tank.

Q: What oil mixture should I run in my SSX?
A: The owners manual states in section

3.1 Gasoline: The choice of correct gasoline is important.  Use good quality regular gasoline of at least a ninety (90) octane rating.  DO NOT USE HIGH OCTANE (ETHYL OR PREMIUM GRADES) OR NON LEADED GASOLINE.

3.2 Mixing Ratio: Always mix the gasoline with a good two-cycle motor oil (not outboard oil).  Mix your fuel at a ratio of 20 to one, or one quart of oil to five gallons of gas.

Because I had plug fouling problems with the above recommendation, I use Premium fuel and synthetic oil at a ratio of 32:1 with SplitFire spark plugs.  This has worked wonderfully for many years now.  I recommend starting with the manual recommendations and work slowly towards my ratio stopping when the engine stops fouling plugs.  A happy engine will make spark plug electrodes look tan after use (black=too rich).
 

Q: My 440 SSX feels sluggish, is losing power, and/or stalls under full throttle take-off.  What is the problem?
A: This can be caused by several problems.  The two most popular causes rest in the intake and exhaust areas.

On the injector side, the diaphragms may be cracked which usually results in poor hard throttle responses or the loss of a/both cylinder('s) firing ability.  Often, the engine runs fine at middle rpms, but stalls if not revved constantly.  Dennis Kirk catalogs carry replacements for $8.99 per injector, part number 17-192 (see page 260 of '98 catalog).
Another injector-side problem may be in the intake reeds.  Remove the injectors (carbs) from the engine and inspect the reeds for cracks or other abnormalities.  Replace if necessary.  Dennis Kirk carries Boyesen Power Reeds (part no. 18-0176) for $54.99 per engine (3-petal reeds).  See page 257, '98 catalog.
Also check the high-speed and low-speed screws for proper adjustment.  The manual does not offer proper starting points for the adjustments, but says "if your engine is four-cycling [boggy] under full throttle, your mixture is too rich and requires turning your high speed adjusting screw in (clockwise).  Never turn high speed adjusting screw in more than an 1/8 turn at a time.  If your engine seems to slow down under full throttle or backfire, you are probably running too lean."  See picture below (coming soon, hopefully).  the high speed screw is the bottom T-shaped screw.  The round, slotted screw in the middle is the idle mix screw.

Exhaust side problems originate from loose mounting flanges, bent ball sockets, rusted and missing internals, and/or cracked exhaust parts.  Check all of the above.  I had a slight crack down the seam of my exhaust manifold that killed performance of my SSX and was evident from the oil spray accumulating under the hood and around the crack.  A simple weld by a local manufacturing company for about $20 fixed everything.  Stronger and/or additional springs at the ball coupler help minimize leaks from that area.

Q: What engine do I have?
A: Well, there are many answers to this question, but to clear up some confusion, Chaparral engines are Xenoah engines, formerly known as Fuji engines.  The SSX was aspirated with the G34BW (338cc Liquid-Cooled, 40hp) and the G44BW (432cc Liquid-Cooled, 50hp) models.  Both engines have been extremely reliable and powerful compared to sleds of the early 70's.  The 432cc actually puts out about as much power as the early '90s Arctic Cat 431cc engines (as in the Jag Special - dual carb, 55hp).  I out-perform a '91ish Arctic Cat Jag Sport Special more often than not (speed and acceleration, not handling).

Q: Why does my clutch keep freezing in the engaged position when I run over 80mph for more than a few seconds?  How do I fix it?
A: The Salisbury clutch on some Chaparrals would compress so tight some times that the weights actually over extended and locked the clutch in the closed position. A hammer blow would sometimes free the clutch, but is not recommended as it puts stress in areas not intended for hammer blows.  I had the clutch adjusted several times by a former Chaparral dealer and eventually replaced it with a Comet 102-C clutch that I purchased from Dennis Kirk.  I then had it installed and tuned by the former dealer as installation is not an easy task if you have never done it before or don't have the proper tools like a clutch remover.
Since replacing the clutch, my SSX's performance has increased slightly, but noticeably and now runs smoother and more reliably.  The clutch can also be adjusted easily with parts available everywhere.

Q: Can I run my engine without the clutch on?  Without a belt?  With the track off the ground?
A: Not recommended.  The engine is designed to run under load.  Do not run without a clutch and use caution when running with the track off the ground.  I do often run the track off the ground, however, for short periods when making track alignment adjustments or to clear the track of ice and snow before transport or storage.

Q: Can I replace my clutch with one from another snowmobile of the era?
A: Most likely, no.  If you want to try, use extreme caution and make sure to use the right weights, springs, and taper angles.

Q: What is the proper track tension for a Chaparral SSX?
A: According to the Chaparral 1974 Snowmobile Owner's Manual:
6.2.4 Track Adjustment:  A. Raise the back of the snowmobile so that the track is entirely off the ground.  B. When unloaded, the track should be under sufficient tension so that the track "sags" approximately one (1) inch below the slide rails as viewed from the side of the snowmobile and approximately at the lower center point of the slide rails.  C. Running in heavy deep snow usually requires the track to be somewhat tighter.  If you feel the track slipping teeth occasionally (rough vibration under heavy pull), your track is too loose.

Q: My Hirth 171R engine suddenly froze up when riding.  What happened?
A: The first thing to look for is the hose that connects the bottom/back of the Tillotsen carburetor to the engine.  Often the clamp on the hose loosens and the hose falls off one side.  The hose transfers engine pulsation to the carburetor which run the diaphragms that pump the fuel to the engine.  Reconnect and try again.

Q: My Hirth 171R engine suddenly "pops" and freezes.  After a few minutes, the engine unfreezes and works fine for a while longer.  Why?
A: My best answer is that the engine liked to overheat a lot and would seize from time to time.  I never found a solution.

Q: Where can I get more information on Chaparral snowmobiles, both history and mechanically?
A: I recommend the Intertec SNOWMOBILE Service Manual as a first source.  It contains engine info (specs, rebuild instructions, etc.), clutch info, brand info, tech tips, spark plug info, etc. etc.!  It can usually be found at your local library or in the Dennis Kirk catalog.
I also highly recommend joining the VSCA (Vintage Snowmobile Club of America).  The connections and resources are abundant and the club has a list of contact people for specific brands of sleds.  Sorry, I cannot divulge this info to nonmembers.  See the VSCA web site at www.vsca.com.
Visit my Link Page for other online sites.