Possible timing issue, help needed please.

MattR · Sep 21, 2012

Hi, The machine is a 1987 TRX350D. Anyways I started it on my trailer, ran fine. Backed it off and proceeded to drive it to the flat grassy area to check front diff lube level. Got it there, and it wouldn't idle when I had it parked. Was rough starting too. A few times I heard a popping noise that not sure how to explain. Kinda like a small scale backfire, yet from the front of the engine. Now it wont start at all.

I checked for spark, and has good spark. Fuel is going to the carb, removed the carb and everything looked fine with the exception of a few small pieces of dirt at the bottom of the bowl. Held my hand over the carb opening to make sure if it didn't need to be choked (waiting on a part to fix that). Well, instead of it wanting to suck my hand in, it tried to push it back away from the carb. I removed the spark plug and sprayed a bit of ether in and replaced plug. Turned it over and nothing except the motor cranking over.

To backup my diagnosis, I am wondering if this sounds like a timing issue to you as well? If so, without tearing the whole thing apart, is there a way to check timing? I do have a manual, service and owner's, yet neither seem to refer to the timing at all. I have worked on 2 strokes, yet this will be my first 4 stroke atv project.

Any help is appreciated.

Thanks,
Matt

MattR · Sep 21, 2012

OFF TOPIC...Yet the mods and admins might like this info. I just googled "1987 TRX350d Engine Timing" and it is front page on search results already.

toodeep · Sep 21, 2012

The forum is very active on the search engines. The reason why some will post "x amount of views and no help", most of the views are search engines.

To the problem though.. Was there a rattle in the motor? The only timing to set is the cam to the crank so if the timing chain was really loose it could have jumped time. What do you have for the choke valve now? Have you tried a different spark plug?

MattR · Sep 21, 2012

I didnt notice any rattle before it died. As far as the choke valve, there is a plastic piece that threads into the carb body to hold the cable in place, and the cable has just been resting in there loosely. That threaded piece is the part I am waiting on, should be here either today or tomorrow. Spark is very strong with the current plug, even compared it to a new plug and spark was the same between the two plugs.

Why would it be pumping air/gas back out the carb opening?

MattR · Sep 21, 2012

New choke parts arrived today, Installed them and also a new spark plug. Tried to start it to basically amuse myself and hope for some strange reason it fixed itself, and as I figured, no fire just as stated in original post. Also took carb apart again to mainly clean it again, gas in fuel bowl as should be and no dirt this time. All jets and passages are clean also.

Soooo, without tearing the whole thing apart, is there a way to check timing? Or doesn't this seem like the possible problem??

toodeep · Sep 21, 2012

You might be able to remove the intake side valve inspection cover and with a flash light see the timing marks on the cam sprocket. I can't remember for sure if you can or not on these machines. Other than that the head cover would have to be removed to check the timing.

MattR · Sep 21, 2012

ok, ty. I will have to work on it tomorrow. It is getting dark out and a bit cold too. Talking about a chance of snow flurries here tonight. No garage at the house.

Possible timing issue, help needed please.

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