Misfire??

[StooL]

I need to know if my bike is normal or if I have discovered something worth investigating further.

Having just replaced a piston and cylinder I have become very aware of all noises, rumblings and other characteristics of my engine. I have balanced the throttle and set the TPS and now have the bike running pretty smooth on idle. However, I am aware that the engine seems to "miss a beat" every five seconds or so. This is very very slight and barely twitches the rev counter needle. It can't be felt out on the road and the bike seems to be running well. I have checked the timing with a strobe light thingy. This was just to see if each cylinder was doing the same thing and they appear to be alike.

Is this something to worry about? Could it be a faulty hall sensor or something else? Or is this symptom quite common? I'm aware that these are big lumps of machinery and aren't always expected to be perfectly smooth but I am still trying to fathom the reason behind my holed piston and wish to eliminate another potential cause.

Cheers

 

[ferguscawley]

Sounds like a dodgy hall sensor to me. Get it replaced or you'll worry yourself to death

 

[boxer]

My 11 has always idled like this to a greater or lesser extent. I've just put it down to how good the last throttle body balance was.

Hope I'm right.

Russ.

 

[(RIP) Kaister]

Did you replace the plugs ?
After a blow-up involving melted metal there's always the chance some can get in the plug, causing tracking or even the plug ceramic has been cracked around the inner centre electrode - again causing a misfire.
Change the plugs first and clean the caps thoroughly.
After that if its still misfiring, i'd say hall sensor.

Did you use a clip-on type strobe that fires with the plug still in ?

Does it -

a- miss with the plug ? or
b - flash when it misfires ?

If a - iits electrical
b - its fuel related



Phil

 

[Big Lad]

I had the same problem at idle on my 1100GS. It would idle ok for a few secs, then miss 'a beat' then idle normally again. I cured it by using the twinmax over and over again until I got it right. It idles ok now.

 

[StooL]

Thanks for the input guys.

I've changed the plugs and I've also tried it with two sets of old ones in to see if there was any difference and there wasn't.

The strobe was connected to the plug lead with the plugs in and the light didn't flash when the bike missed its beat. It did the same thing on both sides.

I phoned motorworks yesterday and spoke to a guy on the sales team. He seemed to know his stuff and thinks if the hall sensors were faulty the bike would be showing more severe symtoms than the one I've described. As I said this can't be felt when riding the bike and it requires a bit of concentration to spot it when the bike is idling. Perhaps I'm just being paranoid after all the problems I've had recently. The balancing and TPS have really smoothed the running but there is still this slight concern. I might try and get hold of another hall plate with the sensors and if it doesn't make any odds I'll send it back. Motorworks didn't have one though!

Cheers

 

[Kenny Rodkiss]

If you want to hear what mine sounds like to compare with yours just give me call.

 

[StooL]

Thanks Kenny, I think I'll take you up on the offer before I spend even more money that I aint got.

I don't think I've got your number so I've e-mailed you. Can't get the PM thing to work yet although I have now become a sponsor.

Cheers

Edit: PM is now working so I've PM'd you instead