Tonight when I started the bike, it kept backfiring. I was playing around a little with the throttle -- not too much, just a little throttle to drive the revs up to maybe 3000 once it had idled for a few minutes. Whenever I let off the throttle, it'd backfire really bad and shoot black smoke out the left rear cylinder's exhaust pipe. None of my other bikes have ever exhibited this behavior.
I've been researching backfiring on deceleration online, and haven't gotten a definitive answer. I did read that worse-when-cold backfires are too lean and worse-when-hot backfires are too rich. There are instructions for adjusting the richness of the carbs -- but it looks like I have to pull the carbs to do this?
This was the bike that I couldn't get started recently until I drained the carbs and changed the plugs.
Any thoughts on backfiring?
Ted....um....have you RIDDEN this bike lately? I mean REALLY ridden it,
ReplyDeletenot just putting around to and fro.
I've never ridden it. I bought it in a snowstorm in February and there's
ReplyDeletebeen a foot of snow on the ground, and ice on the streets ever since.
It's most likely plugged mid-jets (the pressed in ones) in the
ReplyDeletecarbs. A carb cleaning should take care of it.
Also....What shape is your battery in..... In needs to be fully charged...
ReplyDeleteMy big Sabre back fired when the battery was getting low on charge... Come
to find out, i had a bad stater, replaced it, no more back fireing....
Q: Does your bike have aftermarket mufflers or modified stock mufflers?
ReplyDeleteA: 100% Bone Stock!
Q: If so, you would want to calibrate the jetting sizes for the increased flow. What condition are the carbs in?
A: Haven't pulled the carbs to look. I wouldn't doubt they need some attention, since the bike is a 1994 with 3900 miles on it. I was hoping to not have to pull and clean the carbs, however. But, if that's what it takes...
Q: If the low speeds are clogged,
it will have the symptoms you mention. Have the carbs been sync'd?
A: Nope. I do have a four-barrel guage for measuring it. (Bought in for the GL1100 but haven't gotten around to using it.) I could balance the carbs first to see if that fixed it before having to remove them.
Q: Is the airbox complete and in good condition? These bikes run lean if the snorkle on the top is removed.
A: Hmmm, snorkle huh? I really am wishing I already had my copy of the Honda service manual. I've looked at schematics at bike-bandit.com but haven't gotten as far as the air filter etc.
Thanks for your help!
If you can get her out, I'd say to put in a double or triple strength
ReplyDeletebatch of techron and give her an Italian Tuneup.
I'd bet that this issue is related to the carbs.