| Author | Message | ||
     Ingemar |
I don't know what's going on with my bike. Recently it started seriously backfiring when taking off from idle or very slow speed. And I mean LOUD! Occasionally the engine dies. It has always had a little trouble getting up in revs from idle, so I've made a habit of giving 1 or 2 small throttle twitches to prepare it for a launch, but now when I do that, it backfires. Next to that, shifting is getting very rough. It regularly doesn't get into 1st shifting down. It's sits in neutral without the light on, and sometimes need an extra kick to get into 1st. It helps to disengage and engage the clutch when this happens. Also, it regularly won't shift down from 3rd or 4th without disengaging and engaging the clutch inbetween shifts. When it is stuck, I disengage the clutch and I hear a click. I can then shift down again. Otherwise its stuck. Any thoughts? Thanx, Ingemar. | ||
| M1combat |
You should engage and disengage the clutch when you down shift anyway. You can also let the clutch out just to where it starts to engage and shft there too, but I try to make sure each downshift is acompanied be a pull of the lever. As far as the backfiring... I would think it way be getting colder where you live and it probably only does it when it's cold? If not, what is your idle set to? | ||
| Kowpow225 |
I definitely clutch on every shift, up or down. But not when coming to a complete stop, I pull in the clutch and gradually go down through the gears. Ingemar, I have had some problems as well with shifting irregularities. Mine would "bind up" on me when stopping hard. (It didn't want to go into 1st to take off again. Similar to what you're describing.) I adjusted my clutch as per the service manual. This made all aspects of shifting much better. Do you have the service manual? Also try some Syn 3 in the gearbox. | ||
| Bud |
did you check the header bolts (front and rear) en primairy tension grtz. | ||
| Moboy516 |
Mine had that problem (shifting) and the primary chain was very loose. Had it tightened to spec and problem went away. | ||
| Xb9er |
It isn't necessary to blip the throttle at all to prepare for a launch from a stop since it's fuel injected. In fact when I stopped blipping the throttle, my Firebolt stopped backfiring. Overfilling primary/trans fluid by only a few ounces will also contribute to difficulties finding Neutral in one try. Mike. | ||
| Johnk3 |
mine was backfiring when coming off the throttle and when getting on it. It was also stalling a bit too. That went on for about 3 days and then my spark plug was blown out of the hole. | ||
| Ingemar |
Thanx guys. I'm nearing the next service, I'm not gonna wait for it and go ahead and do it. I'll change the oils and check primary chain tension, as well as redo the clutch as the service manual instructs. Johnk3, how tight did you tighten your plugs? And how did you end up fixing it? Ingemar. | ||
| Ingemar |
m1, The backfires started last week and is getting worse. Is has gotton a bit colder, but only a few degrees celcius. Temps are still above 15 degrees celcius. Idle is set around 1000. | ||
| Wyckedflesh |
Is the idle hunting around or staying consistent? | ||
| Ingemar |
I woudn't say its hunting around. 95% of the time it sits at 1000. Sometimes though I notice it stays a little above (a small twitch of the throttle and it will fall back to a 1000) and rarely it will idle just below 1000. I never really bothered about the idle tho ... should I? | ||
| Wyckedflesh |
If the idle was hunting I would suspect the problem I had with an intake leak for the back firing. Its the only time mine would backfire, other then when I would blip the throttle like a carbed bike. | ||
| Ted |
I agree with Moboy, I think a loose timing chain could cause bad shifting and backfiring. | ||
| Henrik |
Intake leak ... combined with colder air will make the bike run leaner. Check it out. Henrik | ||
| Lazyme21 |
Mine back fires, but it only happens when I am at high RPM and down shifting. Any clue on this one? Plus, it is doing it more since I put on the Jardine Exhaust. (Message edited by lazyme21 on October 04, 2004) | ||
| Captainplanet |
Lazyme21, That pop is caused by closing the throttle while engine braking. It is pretty normal on a straight flow through pipe. Using a techlusion to richen up the idle circuit will get rid of a lot of it. The other thing that will help get rid of it is to not completely closing the throttle upon deceleration will downshifting. | ||
| Lazyme21 |
ok cool, I will give that a shot, thanks man! | ||
| Ingemar |
yeah, mine does that too, especially when I'm racing a bit. It's popping really nice. I love that sound. I don't wanna get rid of that! What I have now is what someone else called 'sneezing', the moment you open the throttle to get away it 'sneezes' real loud and kills the engine (most of the time). Concerning the intake leak ...There has been another thread on how to check. Someone suggested using gas, so I used a butane-propane mix gas for soldering puposes etc (not lit, hehe  ). My problem was I couldn't really get to the manyfold without removing the complete airbox assembly. Maybe I should and use brakedisc cleaner too to be certain. I'll check this weekend. Thanx guys. Ingemar. | ||
| Wyckedflesh |
Ingemar if you check the service manual you will find how to make a hose adapter that you can push in from underneath on the intake side of the frame after you take the scoop off. | ||
| Roygbiv |
I had that same problem but it mysteriously stopped! | ||
| Ingemar |
Wycked.. i feel kinda stupid. The solution is laying right there in front of me on page 4-117. maybe I should read it more often ...  Thanx man! | ||
| Wyckedflesh |
RTFM  | ||
| Ingemar |
Could ignition have to do with it? (Message edited by ingemar on October 07, 2004) | ||
| Glitch |
It could have everything to do with backfiring. To set your static timing yourself instead of taking it to the dealer. Read this. | ||
| Ingemar |
Thanx Glitch, excellent stuff. I printed it out and will check it this weekend. Primary tension is good and so is the oil level in there. ps. how did you link to a specific post in a thread? | ||
| Dj_rider |
check your o2 sensor wire...could be grounding out | ||
| Ingemar |
I'll check the 02 wire. Is it a common problem? If so, approximately where would it happen? Thanx, Ingemar. | ||
| Dj_rider |
it is a common problem...the damn o2 wire is a small enuf gauge and the plastic insulation around it is so thin, that it rubs on the top of the engine, the side of the frame, and the side of the 02 sensor...because of the vibrations, it wears down to the wire causing a short...it happened to me 2 times already, the first time it did it so bad the engine light came on because it fried the 02 sensor, this time i noticed my bike was only backfiring alot and acting funny 1/4 the time, true enuf i checked the damn o2 wire and there it was, just barely rubbing on the side of the o2 sensor again...the good fellas at the drummer factory (those damn rednecks) said to get yourself a few lengths of shrink wrap...slit it down the side, put it over the wire...super glue it back together, then heat the SOB...i did it with 3 layers, i betcha that mof0 wont rub thru again...at least not for the next few years | ||
| Hogs |
Dj_rider hey thanks for the heads up on that GooD to KNOW...! | ||
| Ingemar |
Thanx! | ||
| Martin |
I just had very similar problems with my XB9 for the second time. The first time I changed the plugs and affected a temporary cure. This time I found that the front plug was loose and so tightened that up but to no avail. I then found that the rear HT lead had nearly fallen out of the coil! My broken thumb (Another story)made pushing the HT connections back on the plug very difficult but I eventually managed-it.I really must invest in some of those lead plier things. | ||
| Ingemar |
Martin, what is a rear HT lead? As dumb as it may sound, I don't know what HT stands for. Coil ... rear ... spark plug wire maybe? Thanx! | ||
| Ingemar |
O2 wire is fine. Ignition is advanced by 0.5 - 1 mm max. Darn that was tough, turning the rear wheel, watch the DMM to change to 5v and see if the marker is in the middle of the hole at the same time!! The bikelift was in the way prying my ribs too while I was leaning over and tried to look straight into the hole for the marker. Anyway, I left the ignition as it is. I don't think half a mm is giving me the probs I have now, is it? Besides, wouldn't a retarded ignition give backfires instead of advanced? I dunno really ..  Oke, the rear sparkplug .... what does this tell you guys?   | ||
| Odie |
Ingemar, he means the plug wires (high tension). And your plugs look very good in my opinion....Odie | ||
| Wyckedflesh |
It looks to me like your running rich. I know its weird seeing one of us claim a bike is running rich, but compare your plug coloring to mine that were running lean...  Look at the electrode more then the base of the plug. | ||
| Ingemar |
I know sparks can look very different depending on how you've ridden. The pic I made was after a very short ride and it wasn't up to temp. I'll check again today. It's buelltiful outside so I'm outta here! | ||
| Ingemar |
I have set the idle a little higher this morning, and had a ~100 mile ride today. No backfires at all. Not once... Does that really make that much of a difference? I can't believe that was the cause ...  Btw, ya think I need a new tire?  I was hoping to get away with it until next season, but after seeing this I'm getting some Pirelli Diablo's next weekend. It scared the $#@! outta me when I saw it! |
