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1987 Honda TRX350D

19K views 156 replies 9 participants last post by  Goober 
#1 ·
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.
 
#9 ·
In my line of work , I hear similar responses to problem all week long ---- you say " Then why would it be blowing smoke now and not before? " ---- I'd say it has to break sometimes , so why not now ------ my favorite is " it ran till I turned it off at lunch and then it would not start back up , there can't be anything wrong with it " , Dude it don't start , so apparently something is wrong

----I am not saying it is your valve stem seals , it would be the most likely thing from my experiences , the rubber seals get brittle and deteriorate ----- could be your rings as they will get stuck to the piston on a long sleep , especially if the carb overflowed some good corn gas into the cylinder during it's nap -------- have you seen oil consumption on your dip stick - did you do a compression check

if it sat up , the carb could have stuck and over flowed into the cylinder and leaked down into the crankcase , diluting the oil , then the gas evaporates over time and the level on the stick goes back down some , you might have been low to start , it looks ok but the oil is diluted and it starts smoking

maybe the carb is extremely over fueling and your smoking unburned fuel
 
#4 ·
A little history before initial start up. The gas tank had no cap and inside had chicken soup and was somewhat rusty. Got a new tank {plastic}. Had a buddy rebuild the carb. when I had new carb and tank on {NON OX GAS} it fired up. No smoke. Now it smokes like santa smokin weed at a sammy hagar concert!
 
#8 ·
Don't throw your original CDI away... those 87 350D CDIs are one of a kind and they can usually be repaired. Cold/cracked solder joints is what makes them fail.

Another question... what type of sealer did you use on the the rocker cover? Any chance you partially blocked the oil drains leading toward the chain/sprocket end of the cam with silicone sealant? If so, oil can get forced past the valve seals and make it smoke like a train.
 
#15 ·
Ya thats it! I suspect that the valve springs are sacked (you can have them checked on a spring scale) and the valve retainer smacked that guide, breaking it. Most of the original valve springs in TRX350 motors are sacked after 30+ years of service so this is not uncommon. Luckily it didn't drop a valve.

You can still buy an oversize valve guide from Honda but the OEM valve springs are NLA. Shindy sells all four valve spring sets though. Check those retainers out closely and replace any that are damaged by contact with the guides. And check each valve for a bent stem, especially the one that was in that busted guide. If anything looks questionable, replace it. Shindy sells valves too, I think...

If you decide to swap a used head on it rather than fix that one you'll need a new set of valve springs and seals and make sure the cam journals are in good condition... with no rolled out aluminum in the journal oil dam areas.

Keep us posted if you can.
 
#20 ·
Hey all,
Been a while, lots of OT at work and couldn't work on wheeler. Anyway, got the head totally redone by a local guy and the thing looked brand new!! Put the engine back together and it was hesitant to start but gave it a shot of ether and it fired right up. Let it run for about 15 min to burn off the nasties and it purred like a kitten. However, it blows a little smoke and has gas dripping out the overflow from the carb. Does this mean its to rich and the carb needs adjustment?
 
#24 ·
Never heard of them, but I know what the consensus will be here...use an OEM or Shindy kit to rebuild. I have an ultrasonic cleaner specifically for parts cleaning and simple green mix works wonders on carbs. Unless your throttle rod is rusted and seized. Ask me how I know...
 
#25 ·
Ya. I ordered the kit before I did any research so I will order the shindy kit. Amazon has them for 18 bucks. I to have an ultrasonic and carb was cleaned in that. I did not polish the float valve seat as has been mentioned in other posts so I will do that also before throwing carb in ultrasonic.
 
#26 ·
Hi All,
Been a while, was busy at work. I took the carb apart again and it was dirty as ****. There was crap all over the jets and a chunk of something on the float seat. The guy I had rebuild it will be shot! LOL. Put the shindy kit in it after I cleaned the body and it fired right up! WOOHOO! It blows NO SMOKE and purrs like a kitten after I adjusted the carb. Gonna start putting it back together.
 
#27 ·
gas dripping from the overflow is most likely the carb overflowing , maybe from trash coming from the tank that is recontaminating your carb ---the smoke could be from oil that was in the muffler and needs to burn off , or maybe the rings have not set yet , give that some run time and it might clean up ---- if it were me , when I got it running 1/2 ass good , I would sell it off and get a better model atv , the 350 D and A are not a good riding atvs , the steering sucks , parts are hard to find , and finding someone for help who really knows that bike inside and out just got a lot harder with the crash of this forum
 
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