backfire and new chain

[mattysigpi]

I was wondering if anyone knows a quick fix as to why the exhaust on my gz250 would backfire??? Everytime I shut it off, it sounds like I'm getting shot at....Also I was wondering if anyone had any links on where to get a decent chain relatively affordable. I just bought my GZ250 2 weeks ago. Its an 02 but only has 2000 miles on it. It sat in a shed though and I am in def. need of a new chain. Thanks for all your help! Also if your in daytona beach,fl hit me up...we'll go riding.

[Moedad]

Check to make sure your air filter is clean. That's all I know to do for the backfiring.

[mr. softie]

If you have been running rich that could cause backfire on shut down.

Try scrubbing your chain with wd40 and a nylon brush, followed with rags. If it is an O ring chain the links are probably ok even if it looks rusty on the outside surface.

I saw some non O ring chains on ebay for ~ $23 w/shipping, and some O ring chains for ~$50 w/shipping.

[Easy Rider]

If you have been running rich that could cause backfire on shut down.

Try scrubbing your chain with wd40 and a nylon brush, followed with rags. If it is an O ring chain the links are probably ok even if it looks rusty on the outside surface.



If it ONLY backfires on shutdown AND your gas mileage is good (60-70), I don't think I'd worry about it much. Might be able to stop it just by changing your shutdown habit a bit.

Just exactly what makes you think you need a new chain ?? A little external rust probably means nothing. Tires and chains are two things you should not get cheap with.

[jonathan180iq]

Has your carb jetting ever been adjusted? If not, have you added a new exhaust and or air filter that is not OEM?

IF you have done either of these adjustments, then they are they cause of your problem. Depending on what answer you give, the remedy will vary.

[Chris]

A new chain at 2000 miles??? Unless it is really rusted up try to brush it with a steel brush and lub it well.
Got a backfire problem?? I think the bike needs to run a lot on the highway. Just take it out for an afternoon and have lunch with your friend that is 100 miles away. I am betting she'll be purring like a kitten when you get home.
You've changed the oil and aired up the tires, right?

Chris in Atlanta

[mattysigpi]

I wanted to say thanks to anyone that replied...I really appreciate all the help...as far as the carb jetting, I have no clue what that is, but can assure you I have not changed it....I did do an oil change right away and made sure the tire pressures are ok....I have since wd40'd the chain and it looks great...I still can't figure out this damn backfire problem though...air filter is clean as a whistle too

[alanmcorcoran]

Matty,

I'm not a mechanical expert, but I think WD40 is a little too light for chain lubrication. It's certainly better than nothing, and will probably work okay if you re-apply it frequently, but I think there are other choices designed specifically for the purpose.

My experience with WD40 is it is good for penetrating and quick fixes, but I think it evaporates or something. Also, I think that there is some sort of "shock" or compression capacity for lubricants (not sure what this is called) and WD-40 is not designed for that. Do an Internet search on O-ring chains and I'm sure you'll find lots of suggestions.

Did you check for holes drilled in the exhaust? This is a popular internet mod for GZ's and could cause your problem if they didn't do the hard part (carb re-jetting.)

[Water Warrior 2]

WD-40 will not really lube a chain, just makes it look pretty for a while. Use a quality chain lube. DuPont with Teflon is a good one and stays quite clean as an added bonus. Costs less than M/C designated lubes. Available at Lowes, True Value and Ace Hardware stores. Not available in the GWN but I have sources.

As for cleaning a chain use kerosene and a small brush. Wipe dry and lube.

[Easy Rider]

As for cleaning a chain use kerosene and a small brush. Wipe dry and lube.

WD40 does a good job CLEANING a chain.....and is a LOT less repugnant than kero.
The recommended 90W chain lube is available everywhere !! :biggrin:

[music man]

Repugnant is about the nicest word that I think can be said for kerosene, that stuff sucks to work with, but.... it does get your chain looking brand new again, and doesn't take much elbow grease, except getting the smell of kerosene off of anything you got it on.

[patrick_777]

It's better than Old Spice.

[delgado3030]

Check your RPM's at idle. I had turned my idle control up when I first got my bike(I don't remember why) and soon after I'd get a backfire when I shut the bike off. I turned down my RPM's and it hasn't done it since