Bike is a 2013 Fat Bob.

I have just returned from a big trip and the bike has developed a loud bang or knock when hitting really rough roads and pot holes.

I cant feel the knoc in the handle bars and when approaching a rough streach of raod have put my hand on top of each fork, steering head and the healight but cant feel anything. With the sound I would expect to feel something knocking. I an fairly certain the sound is coming from the front end.

Plans is to pull the front end down and check everything. Brake calipers, pads, wheel bearings, forks- replace seals and oil, stearing head bearing and light fittings. Will post results if I find anything.

Can anyone sugest anything else to look at to trouble shoot.

 

I've had somethings similar on my sporty. It kinda sounds like sheet metal hitting something. I'll be interested to see what you come up with!¡

check your tank bolts then can come loose and bounce on the frame .

might be a long shot..check the front engine mount.
mine was crook when i took a test ride,not nice clunk/bang when over big sharp bumps like rail lines,dealer had half a look ,got it home checked the mount and they sent me a new one ,noise gone....but every noise is different,just a thought

 

Check the front/rear engine mounts... easy for the riverts to pop.

Check the top stabliser mount... bolts motor to frame (under tank) tucked in behind the intake

Do you tave a stabaliser like the True-track... check the bolt on that as it may have closed so no or little gap. I can send pictures if you need more detail...

 

Could be any of the above or it could also be that the steering head needs adjustment. Check the fall away as per the workshop manual.
More often than not it is loose tank bolts, usually front but can also be the single rear bolt..

Check bearings in the neck too. Had similar thing happening riding over railway crossings or entering driveways from streets. Had bearings replaced, been good as gold since.

Any update......

Update, I've overseas on a holiday at the moment and didn't have much time to tinker before I left however I have
Tightened all fuel tank bolts
Tightened all engine mounts
Bought a 1 1/2" socket and tightened the steering to 100flb as recommended
No difference.
I haven't checked the steering bearing or fall away - didn't have time.

So I'm down to the steering bearing or the forks. If I jam on the front brake and push the front down hard I can hear the knock but its hard to isolate where its coming from.
My plan is to check the steering bearing and fall away adjustment and then do the forks. Disasemble and replace seals and oil, may as well if I have it apart.

I'm back at the end of October so will keep you all posted on my results.

On another note, I'm in Rome and there are scooters EVERYWHERE!! I think we have seen 3 Harleys so far. With the buildings so close together I would love to run through with my V&H pipes!!!

Check the little bolt/screws (Star head) underneath the forks, that hold the wheel axle in place n whatnot. If not get two people to hold the bike upright and a fat fucker to bounce his arse (whateva) on the front end (handle bars) while you listen. Then I'd be ripping apart the forks, but that's just me...

Thanks Bonkerz. Done that, we can hear the knock but cant pin point exactly where its coming from which is really annoying!!, but I'm leaning towards the forks, possibly the little nut at the bottom that you need to take the front wheel off to get to. I've done the seals before and have a jack so its not to much of a hassle so will tackle it when I get home . Atleast I can rule them out then if it continues.

check the internal bushings in the forks as well, the teflon coated sliders. if they have worn away the teflon coat there would be excess movement in the forks.

You might want to pack the spring a little by putting a couple of washers on the top of the springs. Been a problem particularly on Wide glide front ends for ever. my 9 had it and son does my 00

Found the bang!!

good job rapson,i suggested engine mounts a while back as had heard a "bang " on the test ride on my fxdl and suggested to the dealer that it may be head stem bearings,picked the bike up and "bang " was gone...but had a bad vibe in the r/h peg at 90-100 km's.with a small clunk now and a again.got home and checked the front engine mount and it was shot[shitty rwc i think ].replaced the mount and all was good.always felt the bike was a bit " tight ' to turn,especaily in roundabouts, put it down to me being rusty on the road after a long time off bikes and moved on.bought a bike lift and checked the stem bearings and wouldnt you know it, had to force the bars to move them....dealer had nipped up the bearings that tight that the worn rollers/races were locking up.top nut needed a metre long 3/4 " breaker bar to undo it...shit job by a large dealer of bikes. new bearings in,now "turns " good and is a pleasure to ride.enjoy your ride.cheers.[sorry for the long winded story.]

Thanks Bruce. Now I'm looking to replace my steering bearings, must be shot from being loose for so long. Did you replace yours yourself? After me experience with shopd I prefer to do most repairs myself. What bearings did you go with?

easy job to replace the bearings,but then i'm on the tools everyday.used hd bearings,didn't think they were that dear at about $45.00 each.could have bought them from a bearing company i deal with but went this way.originally the bike was fitted with a shield at the top and a seal on the bottom,looking closely the bottom seal fitted in to the recess same as the bottom one so i used 2 bottom seals. the top " shield " will not stop water getting in [ or dust].set the bearings to good a fall away and now rides/steers great.the bearing cups were that worn that rollers moving felt like detent,explaining the tight movement. while every thing was apart i polished a few bits as well so the job snowballed a bit.plenty of you tube videos on checking fall away,although i used a bit of long time experience and feel to set mine and think i got it pretty close.cheers