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Discussion Starter · #1 ·
Hellow I'm having an issue with my fourtrax 300,I recently replaced the cam chain and timed the engine, after putting every thing back together I put oil in the bike and tryed to start it, it wouldn't start so I checked it for spark and it had no spark , so the problem with the spark was the cdi box, I bought a new one and put it on the bike and I have spark now and it still won't start,now I don't know much about spark plugs all I know is that it ignites the explosion in the cylinder ,so my spark plug is pretty old ,and yes Im going to replace it but just cause a spark plug has spark when you ground it out on the engine does that mean it's a good spark plug ? Any ways so I figured that the engine wasn't getting gas,so I cleaned all the jets out in the carb and It still won't start I mean its not even trying its just turning over so I'm stuck and I don't understand the problem any oppion could be helpful thank you
 

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Why did you replace the cam chain? Had it jumped time?

A spark plug can have spark and still be bad.

How much compression does it have? If it jumped time before you replaced the cam chain, there is a good chance you have a bent valve causing a loss of compression.
 

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Discussion Starter · #3 ·
I was riding it and it popped off and it was stretched so I put a new one on and timed it but I looked up how to time it and I did exactly what it said so I think the timing is fine , the engine has good compression and I just bought a new igniter wire today
 

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Discussion Starter · #5 ·
Well the timing was off I timed it last night I put it on the f notch when it's supposed to be on the t so now it's timed correctly but I'm still having a starting problem when I kick it over every other kick slips I don't know why but I need to get a new battery im just gonna hook it up to jumper cables today and maybe it will work today
 

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Now with that little bit of info, I can tell you; the battery has to be good for it to run properly. The CDI is battery excited and you kill the engine by removing battery voltage to the CDI unit - low voltage = weak or no spark.
 

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Discussion Starter · #8 ·
And also the spark seems week like I know if you put a screw driver in the spark plug boot and ground it that you should get a blue arc and a hardly get any thing doing that but all my other bikes arc a lot with the screw driver I have 3 other bikes a 98 big bear 350 a 05 rancher 350 and a 86 fourtrax 250 I know those don't matter at the moment but just thought they should be shared lol
 

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Yes, the spark will normally jump about 1/4 to 1/2 inch (and jumping with another battery (even a car battery) will not hurt anything as long as you get the polarity correct) - avoid using a booster battery charger - there's enough AC ripple in a battery charger to false trigger the CDI unit

It might be a bad plug cap causing the weak spark

Unscrew the cap from the wire and see how far the spark will jump - if it looks normal, hold the wire to the top of the plug and try starting it - if the spark is still weak replace either the or the CDI box

The same coil was used on these vehicles:
1983 XL600R A - WIRE HARNESS / IGNITION COIL
1983 XR500R A - WIRE HARNESS / C.D.I. UNIT / IGNITION COIL
1984 CH125 A - WIRE HARNESS
1984 CH125 AC - WIRE HARNESS
1984 NH125 A - WIRE HARNESS / IGNITION COIL
1984 XL250R A - WIRE HARNESS
1984 XL250R AC - WIRE HARNESS
1984 XL350R A - WIRE HARNESS / IGNITION COIL
1984 XL350R AC - WIRE HARNESS / IGNITION COIL
1984 XL600R A - WIRE HARNESS / IGNITION COIL
1984 XL600R AC - WIRE HARNESS / IGNITION COIL
1984 XR500R A - WIRE HARNESS / C.D.I. UNIT / IGNITION COIL
1985 CH150 A - WIRE HARNESS
1985 CH150 AC - WIRE HARNESS
1985 CH150D A - WIRE HARNESS
1985 CH150D AC - WIRE HARNESS
1985 CH80 A - WIRE HARNESS
1985 CH80 AC - WIRE HARNESS
1985 NH80 A - WIRE HARNESS / RECTIFIER / KEY SET
1985 XL250R A - WIRE HARNESS
1985 XL250R AC - WIRE HARNESS
1985 XL350R A - WIRE HARNESS / IGNITION COIL
1985 XL350R AC - WIRE HARNESS / IGNITION COIL
1985 XL600R A - WIRE HARNESS / IGNITION COIL
1985 XL600R AC - WIRE HARNESS / IGNITION COIL
1985 XR350R A - WIRE HARNESS / C.D.I. UNIT / IGNITION COIL
1985 XR600R A - WIRE HARNESS
1986 CH150D A - WIRE HARNESS
1986 CH150D AC - WIRE HARNESS
1986 CN250 A - WIRE HARNESS
1986 CN250 AC - WIRE HARNESS
1986 XL250R A - WIRE HARNESS
1986 XL250R AC - WIRE HARNESS
1986 XL600R A - WIRE HARNESS / IGNITION COIL
1986 XL600R AC - WIRE HARNESS / IGNITION COIL
1986 XR600R A - WIRE HARNESS
1987 CH150 A - WIRE HARNESS
1987 CH150 AC - WIRE HARNESS
1987 CN250 A - WIRE HARNESS
1987 CN250 AC - WIRE HARNESS
1987 SE50 A - WIRE HARNESS
1987 SE50P A - WIRE HARNESS
1987 SE50P AA - WIRE HARNESS
1987 XL250R A - WIRE HARNESS
1987 XL250R AC - WIRE HARNESS
1987 XL600R A - WIRE HARNESS / IGNITION COIL
1987 XL600R AC - WIRE HARNESS / IGNITION COIL
1987 XR600R A - WIRE HARNESS
1988 NX125 A - WIRE HARNESS
1988 NX125 AC - WIRE HARNESS
1988 SB50 A - WIRE HARNESS
1988 SB50P A - WIRE HARNESS
1988 TRX300 A - WIRE HARNESS
1988 TRX300FW A - WIRE HARNESS
1988 Z50R A - FRAME
1989 NX125 A - WIRE HARNESS
1989 NX125 AC - WIRE HARNESS
1989 SB50P A - WIRE HARNESS
1989 TRX300 A - WIRE HARNESS
1989 Z50R A - FRAME
1990 NX125 A - WIRE HARNESS
1990 NX125 AC - WIRE HARNESS
1990 SB50P A - WIRE HARNESS
1990 TRX200 A - WIRE HARNESS
1990 TRX300 A - WIRE HARNESS
1990 TRX300FW A - WIRE HARNESS
1991 TRX200 A - WIRE HARNESS
1991 TRX200 AN - WIRE HARNESS
1991 TRX200D A - WIRE HARNESS
1991 TRX200D AN - WIRE HARNESS
1991 TRX300 A - WIRE HARNESS
1991 TRX300 AN - WIRE HARNESS
1991 TRX300FW A - WIRE HARNESS
1991 TRX300FW AN - WIRE HARNESS
1991 Z50R A - FRAME
1992 CN250 A - WIRE HARNESS
1992 TRX200D A - WIRE HARNESS
1992 TRX200D AN - WIRE HARNESS
1992 TRX300 A - WIRE HARNESS
1992 TRX300 AN - WIRE HARNESS
1992 TRX300FW A - WIRE HARNESS
1992 TRX300FW AN - WIRE HARNESS
1992 Z50R A - FRAME
1993 CN250 A - WIRE HARNESS
1993 TRX200D A - WIRE HARNESS
1993 TRX200D AN - WIRE HARNESS
1993 TRX300EX A - WIRE HARNESS
1993 TRX300EX AN - WIRE HARNESS
1993 Z50R A - FRAME
1994 CN250 A - WIRE HARNESS
1994 TRX200D A - WIRE HARNESS
1994 TRX200D AN - WIRE HARNESS
1994 TRX300EX A - WIRE HARNESS
1994 TRX300EX AN - WIRE HARNESS
1994 Z50R A - WIRE HARNESS
1995 CN250 A - WIRE HARNESS
1995 TRX200D A - WIRE HARNESS
1995 TRX200D AN - WIRE HARNESS
1995 TRX300EX A - WIRE HARNESS
1995 TRX300EX AN - WIRE HARNESS
1995 Z50R A - WIRE HARNESS
1996 CN250 A - WIRE HARNESS
1996 TRX200D A - WIRE HARNESS
1996 TRX200D AN - WIRE HARNESS
1996 TRX300EX A - WIRE HARNESS
1996 TRX300EX AN - WIRE HARNESS
1996 Z50R A - WIRE HARNESS
1997 CN250 A - WIRE HARNESS
1997 TRX200D A - WIRE HARNESS
1997 TRX200D AN - WIRE HARNESS
1997 TRX300EX A - WIRE HARNESS
1997 TRX300EX AN - WIRE HARNESS
1997 XR70R A - WIRE HARNESS
1997 Z50R A - WIRE HARNESS
1998 CN250 A - WIRE HARNESS
1998 TRX300EX A - WIRE HARNESS
1998 TRX300EX AC - WIRE HARNESS
1998 TRX300EX AN - WIRE HARNESS
1998 XR70R A - WIRE HARNESS
1998 Z50R A - WIRE HARNESS
1999 CN250 A - WIRE HARNESS
1999 TRX300EX A - WIRE HARNESS
1999 XR70R A - WIRE HARNESS
1999 Z50R A - WIRE HARNESS
2000 CN250 A - WIRE HARNESS
2000 TRX300EX A - WIRE HARNESS
2001 CN250 A - WIRE HARNESS
2001 TRX300EX A - WIRE HARNESS (TRX300EX'01-'06)
2002 TRX300EX A - WIRE HARNESS (TRX300EX'01-'06)
2003 TRX300EX A - WIRE HARNESS (TRX300EX'01-'06)
2004 CN250 A - WIRE HARNESS
2004 NSR50R A - WIRE HARNESS
2004 TRX300EX A - WIRE HARNESS (TRX300EX'01-'06)
2005 CN250 A - WIRE HARNESS
2005 TRX300EX A - WIRE HARNESS (TRX300EX'01-'06)
2006 CN250 A - WIRE HARNESS
2006 TRX300EX A - WIRE HARNESS (TRX300EX'01-'06)
2007 CN250 A - WIRE HARNESS

And the same CDI unit was used on these:
1989 TRX300 A - WIRE HARNESS
1990 TRX300 A - WIRE HARNESS
1990 TRX300FW A - WIRE HARNESS
1991 TRX300 A - WIRE HARNESS
1991 TRX300 AN - WIRE HARNESS
1991 TRX300FW A - WIRE HARNESS
1991 TRX300FW AN - WIRE HARNESS
1992 TRX300 A - WIRE HARNESS
1992 TRX300 AN - WIRE HARNESS
1992 TRX300FW A - WIRE HARNESS
1992 TRX300FW AN - WIRE HARNESS
1993 TRX300 A - WIRE HARNESS
1993 TRX300 AN - WIRE HARNESS
1993 TRX300FW A - WIRE HARNESS
1993 TRX300FW AN - WIRE HARNESS

BTW - how much compression does the engine have?
 

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Discussion Starter · #10 ·
Well now I have my clutch cover off and I was looking at the the clutches when I try turning the engine over with the kick start
And the inner parts of the clutches are spinning and not turning the engine over so could that be nuts not torqued down all the way or somthing else I don't know but I know it's supposed to turn the engine over
 

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Since you had to remove the clutches to install the cam chain. you have obviously assembled something incorrectly on that side of the engine, however the electric starter turns things from the other side of the motor.

You might have to take the clutches out and re-install checking the manual each step of the way. But does the crankshaft turn when using the electric starter?
 

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Where did you get the cam chain? Is it the same length (number of pins) as the old one? If you got it from Honda, what was the part number? When you say the timing won't line up, how far off is it? The engine will run and run well a half tooth off in either direction. If the cam chain was longer than the original, it will go in and line up (reasonably close), but will be off 2 teeth every rotation of the crankshaft.

I am just trying to figure out how the timing is off and won't line up.
 

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Discussion Starter · #16 ·
Okay I got the cam chain from a parts engine it was another Honda fourtrax 300 only it was a 88 and mine is a 90 but I made sure they were the same but i took the head off today and put the parts bike head on cause I i know that the valves are good on that one and I wasn't sure with mine so after puting everything back on I timed it and now it lined up but was off like a half tooth but it started today finally do I think the the problem was the valves but I don't know. But can you tell me the torqu specs for the alen head bolts and the cap nuts cause Its leaking oil out the head and I don't know the torqu specs I thought I did but hugging but it leaking I might not
 

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Discussion Starter · #20 ·
Hey I got my bike runing and driving but when I rev like a little bit to were I drive slow it's fine but when I hrev like half throttle it bogs down and starts puffing a lot from the exaust what can that be ?
 
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