[KarlNorman]

I have an oil leak, originally thought it was the valve cover gasket, but yesterday I noticed it is coming from the "flat head screw" up and right of the spark plug. Very slight leak and when I watched it, there almost seemed to be pressure building up and then it would release around the edges of that screw. Looked online for the exploded view of the head and valve cover and can't seem to find what the part is that it appears to be leaking from. Other than this the engine seems tight. Tried turning the screw, didn't budge, but I did not put much effort in as I do not know what it is or does and didn't want to damage anything. Any ideas of what it is or what to do about the leak would be greatly appreciated.

 

[alloutdoors]

I have an oil leak, originally thought it was the valve cover gasket, but yesterday I noticed it is coming from the "flat head screw" up and right of the spark plug. Very slight leak and when I watched it, there almost seemed to be pressure building up and then it would release around the edges of that screw. Looked online for the exploded view of the head and valve cover and can't seem to find what the part is that it appears to be leaking from. Other than this the engine seems tight. Tried turning the screw, didn't budge, but I did not put much effort in as I do not know what it is or does and didn't want to damage anything. Any ideas of what it is or what to do about the leak would be greatly appreciated.

I haven't pulled the service manual up for that model, but reasonably confident you can answer this question here, Honda ATV Schematics / Manual Help - Honda ATV Forum

 

[fishfiles]

My guess would be #18 o-ring on this print

https://www.partzilla.com/catalog/honda/atv/1989/trx350d-a/camshaft

 

[KarlNorman]

Thanks! That pointed me in the right direction, it is the EXHAUST VALVE ROCKER ARM SHAFT SPINDLE and the o-ring is likely gone, however it appears that it is major production number to change that o-ring so that will be for another time, I think I will just have to deal with a little leak for the short term.

 

[KarlNorman]

Thanks, but without knowing what the part is, hard to find it in there. I have both manuals for this bike and I have not been able to find it based on what I see there.

 

[shadetree]

well, your model is not a 1992 for starters, as they discontinued these in 1989 in the states. soooooooo, with that being said, you prob can't locate the part because your trying to find it for a 1992 model..that does not exists !..lol. 1989 is what you look for, and its located on the rocker shaft, it is an o-ring. both shafts have an o-ring just behind that screw slot, and yes, they are a royal pain to remove !.

 

[fishfiles]

Shade , I think he might know that as : " 1992 TRX350 (US 1989 TRX350D) Oil Leak " = is the thread title

Do you think he can pull the rocker shaft with the head still on the engine , change the o-ring and get the shaft back in ----- I doubt it , but don't really know 350D's

 

[shadetree]

Shade , I think he might know that as : " 1992 TRX350 (US 1989 TRX350D) Oil Leak " = is the thread title

Do you think he can pull the rocker shaft with the head still on the engine , change the o-ring and get the shaft back in ----- I doubt it , but don't really know 350D's

yeah, thanks for the heads up, sorry, been working my butt off lately, lots of hours, really sore and tired, missed his title all together, my bad. yes, you can pull the rocker box with the jug and cylinder left on the engine, this part is on the rocker box, a few bolts, and the rocker box comes right off, and undo the decompression cable if there is one on it ? .

 

[JPelletier]

I have a very very small leak too on my Rocker Arm, but the other one. It can't be removed in place there is a retainer pin

 

[shadetree]

I have a very very small leak too on my Rocker Arm, but the other one. It can't be removed in place there is a retainer pin

that pin CAN be removed, just takes a few curse words, an ex wife, a few cold ones, and yep..it will come out of the head !..lol.