Smell like exhaust

[KoolBreeze 62]

Quick question on the older TRX350Ds. Everytime I ride my '88 I smell like exhaust when I get off of it and I can't figure out why. It's worse if I'm just putting around on it but still does it even if I maintain a constant speed. I've smoked tested the exhaust but didn't find any leaks. Seems like even if it was leaking, the wind would prevent it from getting on you at speed, but it doesn't. Do you other guys that ride these older machines have any issues with this?

 

I do need rebuild the carb (yeah, I know, still haven't done that) and adjust the valves, but the smell isn't really flooded, gas heavy smell. It's more of a raw exhaust smell. 

[_Wilson_™ 6,592]

no gas leeking down on the engine case ?? ... plugged blowby tube ?? next thought would be the valves might be out of adjustment ... because the intake for those is right there close (right and left) upper front fender.. 

[Fishfiles 20,147]

Maybe you need to ride faster , LOL 

[KoolBreeze 62]

19 minutes ago, _Wilson_™ said:

no gas leeking down on the engine case ?? ... plugged blowby tube ?? next thought would be the valves might be out of adjustment ... because the intake for those is right there close (right and left) upper front fender.. 

 

No gasoline leaks. Not sure about the blow-by tube, is that what's it called in the manual? I'll look into that, that very well could be the problem. Valves likely do need adjusting, but it doesn't rattle. Still going to do that soon though.

 

I've ordered a rebuild it for the carb also. But again, it's not really a gasoline/flooding smell. It's more of an raw exhaust vapor smell. It's almost as if the exhaust is blowing back on the the driver.

 

@FIshfiles Haha! Probably do! I just put around most of the time. It's so bad though that I have to take a shower after riding the thing to the mailbox and back (300 yard or so round trip). Should be walking no doubt.

Edited April 26, 2020 by KoolBreeze

[Fishfiles 20,147]

Yesterday a friend rode his 300 with us.  It set for a long time.  The burnt fuel coming out his muffler smelled like varnish.  You know that old gas smell.  

[KoolBreeze 62]

This one has been doing this for a while so I don't suspect the gas.

 

What about the crankcase breather tanks on these? Do they have some mechanical internals that go bad, anyway to check them out for proper function? I see they are no longer available. Haha, what a surprise.

[Fishfiles 20,147]

Shade and Goober are the 350 D gurus.  How’s is your plug burning.  

[_Wilson_™ 6,592]

plus ^^^ could be exhaust back pressure ....there should be a cover on the tail end of the exhauset bolted on by 2 bolts ... 

 

https://www.hondapartshouse.com/oemparts/a/hon/506bac6ef870023420a214d4/muffler

 

https://www.hondapartshouse.com/oemparts/a/hon/506bac6df870023420a214d3/air-cleaner

[KoolBreeze 62]

I took the crankcase breather hose loose from the engine and at the T under the seat, and blew out all 3 lines with compressed air. They were clear though. I didn't see the breather tank dohicky, so I'm guess the foreman doesn't have it.

 

The spark plug is definitely covered in dry black soot in short order. I changed it last year and it was no time time until it was covered in soot again. The carb has likely never been off and no telling how long it's been since the valves were adjusted. Dad parked this machine for the most part 6 or 8 years ago when he bought a new one. I brought it home last year and started fixing stuff on it. But then quit when I got busy with other things.

 

I took the cover off the exhaust last year and cleaned it per the manual, but I don't doubt there is some build up in causing some back pressure. I'm not sure how you'd check it though. I have an exhaust back pressure gauge but there isn't a test port on it. Suppose I could have my friend who owns a muffler shop weld one in. Probably easier to just replace the muffler though, can you still buy one that will work with it?

 

 

 

Edited April 26, 2020 by KoolBreeze

[Goober 1,555]

You might have an exhaust leak by the header/muffler joint.

but yeah sooty plug she’s running rich. Replace that choke valve $40

Edited April 26, 2020 by Goober

[Fishfiles 20,147]

Never seen mention of dumping the tank , cleaning the tank and the carb and  filling it with fresh fuel ---  6-8 years is a little while 

[LedFTed 1,135]

my 450es 2000, ran rich an backfired through the exhaust. in another forum, i got help to fix the problem. [y'all know, most have been there].

internet searches said it normally runs rich. well it dont, and was the carburetor. not the adjustments i think, just missing a part of two. one part i made myself, i dont know if this was to problem, i never found out for sure. it just ran better, an didn't backfire after that. never did get past 47mph. just as well.

[_Wilson_™ 6,592]

3 hours ago, KoolBreeze said:

I didn't see the breather tank dohicky, so I'm guess the foreman doesn't have it.

 

i believe those models all have this... if this part is what yout talking about ... but I'd take fishes advise ... and talk to shade, or goober

[shadetree 5,969]

21 minutes ago, _Wilson_™ said:

 

no, not all models have that part on them.

[shadetree 5,969]

my first thought is leaking gas cap ?, or seeing how you have not over hauled the carb ?, you might be smelling blow back from the air vents on the front fender ?.

[KoolBreeze 62]

3 hours ago, Fishfiles said:

Never seen mention of dumping the tank , cleaning the tank and the carb and  filling it with fresh fuel ---  6-8 years is a little while 

 

I should have elaborated more about that. He quit using it except for occasionally, but didn't let it sit with fuel all of those years. I've had for the last 2 years pretty much, probably ran 8 or 10 tanks of fuel through it. There isn't anything wrong with the fuel and there aren't any fuel leaks anywhere. It's not a gasoline smell that gets on you, it's an exhaust smell.

[retro 4,072]

Adjust the valves ASAP. Got a tight intake valve.

[KoolBreeze 62]

31 minutes ago, _Wilson_™ said:

 

 

That's the part I didn't see earlier when I was tinkering with it.

[retro 4,072]

Only 1985 TRX350A have those crankcase breathers that @_Wilson_™ showed ya. Your '88 don't have one, just has a hose that runs up the frame towards the front.

[KoolBreeze 62]

10 minutes ago, shadetree said:

my first thought is leaking gas cap ?, or seeing how you have not over hauled the carb ?, you might be smelling blow back from the air vents on the front fender ?.

 

Gas cap doesn't leak. But again, it's not a gasoline smell. More like raw exhaust. There aren't any signs of exhaust coming out of the vents up around the front fender, but still could be fumes coming from there I suppose.

[KoolBreeze 62]

3 minutes ago, retro said:

Adjust the valves ASAP. Got a tight intake valve.

 

Ok, I'll try that. Going to rebuild the carb also and I did order a new start valve for it as well.

[retro 4,072]

Did you buy a Shindy carb kit? China no work as you know....

[_Wilson_™ 6,592]

my 86 has one .... i don't think the 350 was turned out till 86  ...  before then it was 250a ... 

[retro 4,072]

Just now, _Wilson_™ said:

my 86 has one

 

Yup, they was on the 86 TRX350, one year only.

[KoolBreeze 62]

17 minutes ago, retro said:

Did you buy a Shindy carb kit? China no work as you know....

 

Yes sir I did and an OE start valve.