Honda ATV Forum banner

1 - 20 of 90 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #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.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #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!
 

·
Super Moderator
Joined
·
5,956 Posts
Have you changed the oil & filter? What do you have in it? Is it overfilled?

Also check the crankcase vent hose to make sure it isn't plugged up by mud daubers or something.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #6 (Edited)
Has new filter and oil, not over filled. Yes filter in in the right way. Have valvoline ATV oil in it for wet clutch system. Thing rocks when in reverse and forward. Will check vent line in morning and update.
 

·
Super Moderator
Joined
·
38,142 Posts
with it being an '87 ?, chances are..time for new rings, or new top end ?. prob why it was put away for so long.
 

·
Super Moderator
Joined
·
5,956 Posts
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.
 

·
Premium Member
Joined
·
12,522 Posts
Then why would it be blowing smoke now and not before? I never touched the valves.
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
 

·
Premium Member
Joined
·
3,990 Posts
Whattaya mean new carb?

You need to rebuild the OEM QA03A.

You might be running overly rich.

Is your plug oily or sooty?

Need a compression check.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #11 (Edited)
Meant the carb has a new rebuild kit. I checked the crankcase vent line and it has no obstructions. Think I'm just gonna go ahead and put new rings and valve seals in it.
 

·
Super Moderator
Joined
·
5,956 Posts
Unless you used OEM Honda carb parts or a genuine Shindy carb kit, you'll have to fix your carb too. Let us know how it goes with the compression test and bore measurement if you refresh the topend.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #14
Cylinder bore is 81.002mm. Can still see cross hatch pattern on cylinder wall and is not glazed at all. Valves all look good with minimal carbon
build up. This thing has either been gone thru recently or was hardly used.
 

·
Super Moderator
Joined
·
5,956 Posts
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.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #16
The intake valve that had the broken guide is bent. The other intake valve is questionable so will replace both with new retainers. Can't find the springs on Shindy's site. Exhaust valves are OK.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #18
Yep. Both outer springs were at 39.98mm Spec is 45.75mm. Exhaust were at 44.97 so they are OK. All the retainers looked good. Found set of springs on ebay. The guides, seals and valves are in stock at a local dealer so ordered those. Thanks retro for all your help so far!!!!
 

·
Registered
Joined
·
14 Posts
Discussion Starter #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?
 
1 - 20 of 90 Posts
Top