Old gas / petrol - use by date? And other questions.

[Rob84KDX200]

Howdy all.

My '96 KDX200 has been in need of repair since last November, when my clutch gave way and needed replacing. Basket, plates and springs. The works. Oh and a new cable too.

That and other issues have since been rectified, and it's now fully running. But not to my full satisfaction (read on).

Managed to start it on the first kick after 6 months out of action! Now during this 6 month period, I've had about 15 litres of gas / petrol mixed at 40:1 with Castrol TTS. Stored in a plastic jerry can.

I vigorously mixed/shaked the jerry can, put a couple of litres into the fuel tank, and had no troubles starting the bike with this old gas.

However, I've noticed quite a bit of smoke bellowing out from the muffler. I used to run 160 main & 48 pilot at sea level. Made two changes - now running a 155 main. And the airbox snorkel removed.

I've yet to get my head around the pilot jet and air screws. I am just wondering, as a process of elimination, if it is at all possible that old gas could create such excessive smoke?

BTW, I'm running stock reeds, FMF Fat Boy K-30 (Rev) and FMF Turbine Core ISDE.

Many thanks in advance.

 

[sr5bidder]

if after fully warming up it still smokes alot. you'll need to get some new plugs and follow jetting protocall.

try removing the airbox lid, relocating the needle clip to the second ring from the top, and get a 45 and a 42 pilot to fine tune the low circuit.

fresh mix wouldn't hurt a bit.

 

[mudpack]

Howdy all.

it is at all possible that old gas could create such excessive smoke?

No. Stale gas will not cause smoke. Stale gas will clog tiny circuits in the carb and make your bike run like crap, if it will run at all.
Use Sta-bil if gas will not be used for more than one month.

 

[Dirtdame]

Maybe the primary side main seal has gotten sort of hard and brittle after all these years and you are now sucking a bit of tranny oil into the crank and that is creating the excess smoke.

 

[reepicheep]

Also consider temperature. My KDX was jetted spot on during the fall and winter, and is stupid rich right now... to the point where it fouled a plug for the first time when I tried to start it a couple weeks ago.

Jetting that is right for the winter will be way rich (and way smokey) for the summer.

 

[mathd]

Well, that is just my point of view.
But today's gas have ethanol in it. it loose octane really fast(and also is hygrogen because it is a polar solvent dissolving with water. wich petrol do not do(water in fuel not good that is why the use of gas sta-bil)).
Gas with less octane burn slower, that probably is making incomplete combustion with the current jetting causig it to smoke.

Put fresh gas and jet it correctly with fresh mix.
But that is just my guess.

 

[ecrum28]

I've got a question along the same lines. I restore and race vintage snowmobiles and i run 100LL aviation fuel in them because it has no ethanol. Will 104 octane leaded fuel be ok to run in my 80 KDX if mixed 40:1 with good oil?

 

[Rob84KDX200]

Just got 4 litres of fresh 98 octane gas / petrol, mixed with Castrol TTS at 40:1.

I made the following changes;

- 155 main jet (same as before)
- 45 pilot jet
- Air screw 2 turns out
- I left the needle and clip as is, untouched. 3rd from top.
- Airbox snorkel and lid intact
- Boyesen Power Reeds

And so far, it is far less smoky on idle. A lil spooge dripping from the tip of muffler, and there still is smoke. But nowhere near as bad as before. Yet to take it out for a ride, more to follow.

 

[Rob84KDX200]

Here's a lil video clip. I took the bike out again today, had it idling for about 5-10 minutes.

http://www.dailymotion.com/video/xdeogs_1996-kdx200-at-idle_auto

However, I'm a lil concerned with the smoke.

Why am I concerned? Well, as previously stated, I had put in about 800ml of Castrol MTX gearbox oil. After the idle session today, I proceeded to drain the engine oil. Wanting to refill with fresh oil. After a quick drain, I had measured only a touch under 700mls drained. "Where did that 100mls go?" - I'm wondering. Definitely not out through the crankcase vent tube. That's still as clean as a whistle, no oil exiting through there whatsoever.

I'm 'hoping' it's not due to bad crank seals. Would bad crank seals be evident at idle? In my case it doesn't seem to be. As you can see in the video, it is quite acceptable at idle. Very little smoke. It's only when opening up the throttle that the smoke is probably a bit too much.

What do you think? Your thoughts? Would the color of the smoke and/or sound of the engine indicate burning engine oil? Is it possible for the engine to retain 100mls of engine oil after draining? I had the bike on a lift stand when draining the oil, so it was vertical.

Or is it a simple case of leaning the main jet even more from where it's at now? (@ 155 - 152? - 150?)

Many thanks in advance.

 

[Rob84KDX200]

Moved this discussion to new thread, improving visibility. And a relevant thread title.

http://www.dirtrider.net/forums3/showthread.php?t=178898

 

[mudpack]

(water in fuel not good that is why the use of gas sta-bil).

Water in fuel certainly is not good, but Sta-bil does not remove water from fuel. Sta-bil prevents gasoline from breaking down into varnishes.
If you have water in your fuel, but some good water remover, e.g. Heet.