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1987 Honda TRX350D

15795 Views 156 Replies 9 Participants Last post by  Goober
Hi all,
First post. Just got a 87 TRX350D for free from a guy who was gonna junk it. It hasn't been run for a couple years so wasn't disappointed when it didn't start, no spark. Took the CDI out and threw it in the freezer over night and reinstalled the next day. It started. WOOHOO! I let it run for about 15 min. At first it blew a little smoke but that stopped after a couple min and purred away. As it was running I looked it over and saw it was leaking oil between the head and the cover. Shut it off, then it wouldn't restart. No spark. CDI bad. Ordered a new one. While waiting for parts, took head cover off and no seal. Chain was tight. Checked valve lash before taking cover off and they were all in spec. Put the cover back on and rechecked lash, all good. Installed new CDI and it started right up, but is blowing smoke like crazy. What did I do wrong? It wasn't blowing smoke anywhere near what it's doing now.
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All 3 legs of the stator measure 0.9 ohms and not continuity to ground. Stator passes.
All 3 legs of the stator measure 0.9 ohms and not continuity to ground. Stator passes.
you need to pull the light switch apart, and inspect the kill switch. have you tested the fan control unit ?, replaced the fan control unit ?. if its bad ?, you will never get the spark plug to fire.
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When you disco the oil sensor wire and ground it to the foot peg, does oil light and fan come on?
The light switch and kill switch are both broken. Both work with a jump that I installed. I plan on rewiring and installing toggle switches in the plastic next to the lights. The jumper works because I get 12.8 volts at the CDI plug. Fan control works. This has nothing to do with the ignition circuit. Will probably get a chance today to do more trouble shooting.
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The fan control is supposed to inhibit ignition under overheating conditions—As Shadetree mentioned a faulty fan control unit could disable ignition
Page 20-2 Note. How to fully test I’m not Sure. Well the note does say “after ‘87”

hereis one test you can do on it
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I misunderstood the DC-CDI. Someone else had a better explanation but maybe you found it on page 22-4.
DC-CDI pulse doesn’t come from the stator but from the battery.
The signal from the pulse generator triggers the boosted voltage. So yes a signal from the pulse generator is necessary to signal the CDI to charge the coil

im glad to have a chance to revisit this topic. So the pulse generator is probably signaled by the flywheel magnet?
I started getting a spark. No reason other that I recharged the battery and hooked it up better. I was using jumper cables. Made a battery holder out of tywraps and connected directly to the battery cables on the ATV. Is it possible for the Stator to be wet? Is it in the oil? I think that this ATV was in water because when I drained the fuel tank and oil sump water came out of each.
Now it cranks and does not start. Tried Starter fluid. My compression gauge will not fit so will look for an alternative. Holding hand on exhaust while cranking shows it has compression.
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Cool! Yah the DC-CDI needs a very good battery for ignition i hope this gets you good fire. Anything you can do to improve spark is a good idea.

remember i asked you about clipping off a half inch of your spark plug wire? You couldn’t get the cap off or something Anyhoo here’s a diagram of the wire with cap removed. Lotsa times you get corrosion in the old wire And you can clip off a small piece to get clean connection

Yup stator is in direct contact with oil as is the pulse generator.
For starting purposes I have the intake manifold completely off. Fuel was leaking out the intake as I cranked. Not as I would have expected. Never even tried to start. I rechecked spark with everything installed and it was definitely pulsing to the spark plug. A dry finger check prior to the spark plug install gave a good shock.
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Ok good
Spark, hopefully your engine hasn’t jumped time.
Fuel. Is the plug wet with fuel? So I’m thinking carb is oversupplying fuel or just a lot of cranking got it that way. You cleaned the carb? Pilot jet set to two turns out from seated?
Compression. Have you set the valves? Doing a compression test might help assure that you don’t have one hung open.
So now the real deal—if you know it had water in it, then I would not want to run it until i got it all cleaned out—don’t wanna ruin the crank and bearings right? So now you’re left considering how to proceed if it fires.
maybe the compression test will show you that the previous owner already ruined it?
Compression test does not look good. Realized that the spark plug does not have a sealing washer so will buy a new spark plug tomorrow. All four valves appear to go up and down properly. Cannot locate the "index mark" on the case per picture on 3-6. I think the T mark looks like an F mark and aligned it in center of the hole. Felt for piston and it felt at TDC. Valves seem tight but then 0.08 mm is very thin. Never got the feeler guage in between but it felt close to going. My real question is how does this Decompressor work. I have never seen and I am suspicious of it. It seems to have the proper clearance but does it release each time? Does it cause a loss of compression.
Area where the spark plug seals is very dirty. Do you have a method to clean the sealing surface without getting crud into the cylinder?
The T will follow the F.
With spark plug out and valve access covers off. Rotate the engine with a socket and a breaker bar—more control than a ratchet. You’ll see the intake and exhaust valves open and shut — now start looking for the intake valve to open—when it getting ready to shut look for the T.

I clean my spark plug area with a plumbers flux brush and Deep Creep
Is there an "index mark"? Centered the T mark in the hole. Intakes seem good. Exhaust a little loos but not much. Will remove the engine hanger bracket tomorrow and remeasure. Not off by much. Decompressor is about 3 mm. Hard to tell where to measure from.
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I think book says 2-3mm? Your measurement sound good to me. too short and it will ride on the valve
I get about 70 psi for compression. Too little. I am open to suggestions?
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Tried to start today. It is close but no luck. Seems like the decompressor is all of the way down. Except when foot cranking.
70 psi is very low
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