Knock knock

[Urban_Legend]

Hi all.
I have a question that I feel I may know the answer too, but here goes. The old FJ11 is making a knocking noise at low speed/ revs under load. Most noticeably going up my driveway which is quite steep, but also from most stops. it is not the cam chain rattle as it does that all the time.  The knock is more like a small Japanese engineer wanting to get out. Sounds like it is coming from the front/ top of the motor. Could this be pinging?

I thought the bike was running rich, it certainly smells rich,and pinging is usually from being too lean. I have been told the bike sounds like it is a bit out of sync,  but I have no way of checking this at the moment.  Could that lean it out enough to ping? The answer bike is also hanging on the the last few hundred revs before returning to idle.
The issue is not affecting the performance of the bike, but it is disconcerting as I don't want it to go  bang.
Ta

Mark

[Urban_Legend]

Thought I should add some more information.  The bike is running pod filters with the needles raised to the 3Rd clip, 115  pilots, I can't remember mains size. 4-2-1 RPM exhaust,  timing in standard spot. ( not advanced yet). The knock is a reasonably new thing as it was fine before doing the 3000km round trip to the Aussie Fj rally,  but was doing in it on my return.

[Bones]

Is the sound anything like in this video Mark?  if it is it'd be the starter chain. It's a loud clacking sound when taking off from a start or accelerating from a slow speed in too high a gear but soon disappears as the revs rise. To test it out, put your bike on the centre stand put it in gear and hold the back brake on while letting the clutch out to load the engine up and have a listen. If it is the same sound, it's nothing to worry about, mine's done it for years and I know quite a few others that do it as well.

https://youtu.be/uCmiO-_lgKM

[Urban_Legend]

Yep. I think that could be it. I will give it another listen tomorrow to confirm.

Thanks Bones. Had me worried as it is a reasonably new sound.

[oldktmdude]

115  pilots, I can't remember mains size.

Mark, 115 is the main jet size. I think Bones may have pin-pointed your problem. Starter chains can make a very severe rattle when under load at low revs. Pinging usually wouldn't suddenly appear unless you have changed the timing or fuel rating recently. It's a symptom of the bikes age and milage. Don't worry about it, keep riding it like you stole it.
   Regards, Pete.
   

[Urban_Legend]

115  pilots, I can't remember mains size.

Mark, 115 is the main jet size. I think Bones may have pin-pointed your problem. Starter chains can make a very severe rattle when under load at low revs. Pinging usually wouldn't suddenly appear unless you have changed the timing or fuel rating recently. It's a symptom of the bikes age and milage. Don't worry about it, keep riding it like you stole it.
   Regards, Pete.
   

Thanks Pete. I always get the pilots and mains mixed up when describing them. Need to go for a good ride on her now I have fixed the oil leak from the crank seal.

[roverfj1200]

Mark. Run a 1/2 bottle of oil stabiliser in it with the next oil change and check your headers are tight. I had a top end rattle and turned out a header was loose.