1985 Honda Flamethrower???

[MudBug]

Hey guys, its not a problem I have here, I just know its not right. After I have my bike warmed up and drive it a few miles (km's here) and shut it off, it shoots a blue flame out of the exhaust about 5 inches long. It sometimes does it when coming down off a high rev. I thought valve adjustment immediately, but I switched the rocker cover (unrelated issue) and double checked the valves, and they are spot on at 0.004. I can post a video if you would like. It does this every time I shut it off, so it isn't just a 'once in a blue moon' thing. Thanks for any help!

[kasey200x]

What kind of atc is it? the s and m series is supposed to be at .002 i believe. And it sounds like your running really rich.

[MudBug]

Its a 1985 Big Red 250ES. Plug color says rich, but not really rich

[MTS]

You have a stock exhaust on it??

[factoryX]

LOL. my 200x did that with cobra exhaust.

[kasey200x]

If you have a really open or free flowing exhaust, like without a spark arrestor, it's probably running rich. That's why you have to run spark arrestors in public places, so that if your bike's running rich it won't catch any trees or anything on fire. I say drop you jet's a small amount. Or first try raising your clip, since that is the easiest.

[factoryX]

which is kind of BS in that(If I remember correctly) there is not one recorded event of a atv or dirtbike starting a forest fire.

[inv3ctiv3]

which is kind of BS in that(If I remember correctly) there is not one recorded event of a atv or dirtbike starting a forest fire.

Better safe then sorry, we have had our forrests and town ravaged by fires in the past 3 years and I couldn't imagine being the cause of one....

[factoryX]

true, but its pushed off as a cause for nature destruction. For example:
http://www.wnd.com/?pageId=70904
I wish I could find the clip but this is just as good.

And as for two strokes being required as well? they don't even produce the heat required to produce a spark out the exhaust.
Anyway lets not kill this thread of back firing silencers.

[kasey200x]

Luckily for me, we don't have anykind of active tree huggers lol there is literally no restricitions, and i have never even had a friend of a friend be tested for noise levels. So i think i'm going to miss the freedom once i move up north.

[200XMichigan]

Guess it just depends where north you go. Here no one cares, you could run no exhaust if you wanted, not that your valves would like it. But pretty much you can ride anything with an ORV sticker down the road. You could take a piped 250R down the road to the store and get gas and groceries if you felt like it. Take your 3 wheeler anywhere you want as long as its not the highway or freeway. I wish I could take the 250ES across the Mackinaw Bridge and hit some trails in the UP.

[MudBug]

Stock exhaust, to anyone who's still interested in the original topic :lol:

[Thorpe]

I have been told that it can be valves out of adjustment (never hurts to double check your work) or timing chain could be stretched (allowing timing to be off from where it should be)

Keeping in mind, I am no expert... Maybe Dirtcrasher will chime in, he is an expert at the ES/SX motors!

[MudBug]

Thanks thorpe! This engine has A LOTTTTT of miles on it, And the cam chain is slack (up and down play on sprocket) so that makes sense!

[kasey200x]

Double check to assure timing is still correct. After that, readjust the tensioner. If it does not use the same method as a 200x, then ignore this. But start it, let it idle, unscrew the large size bolt under the rubber cap(will be on the left side cranks case behind the cylinder). Unscrew almost all the way, then re-tighten after you let it sit for a few seconds.

[pirate122]

for a 250es your valves must be adjust at 0.003 in

[MudBug]

I know that 0.03 is factory, but I remember seeing on here that going one size up doesn't hurt.

[kasey200x]

I guess that would be someones opinion. One thing you can't go wrong with, and thats factory. Put it to factory, and continue to eleminate options as you go.

[factoryX]

or fab something to work.