Help figuring out what is wrong with my bike.

[blah]

Last couple of days I have been experiencing some problems with the handling of my bike. I noticed the back end felt a bit 'twitchy' and put it down to poor road conditions and continued to ride more cautiously.

Last night I did a 70 mile ride with a 52 litre top box on my bike and I noticed the handling became increasingly worse. Please note I always make sure my top box is loaded evenly and fitted securely as well as making sure it's not overloaded, but I was finding I was having to fight with the bike to get it go where I wanted it to.

The back end felt like it had a mind of its own and when ever I hit a bump the bike felt like it bottomed out. I even stopped to check the tyre wasn't low or there wasn't any obvious problems with the rear suspension. Also I have noticed the handle bars shaking from side to side and I had to hold them firmly to reduce the movement. (My arms are feeling it today as a result!)

I have been thinking about checking the wheel bearings and maybe the swingarm. Is there anything else you would recommend checking or has anyone else experienced something similar?

I am getting sick of riding super cautiously in case my bike tries to do something dangerous, it needs sorting asap.

[teejayexc]

Daft as it sounds I would check the front end. 'Specially with the 'wobble', head bearings, wheel bearings and even something as simple as a well worn front tyre can give the symptoms you describe.

Whaenever mine gets the 'shakes' I know it's time to replace front tyre, even if it looks half decent

[christhedivvy]

Tyre pressures checked with a proper gauge? (sorry if it sounds condescending) Also check swing arm, headstock and wheel bearings. I assume the wheel axle bolts are torqued up correctly and arent loose. You could also check the rear shocker out make sure its working ok

[blah]

I did consider head bearing initally but was told by a mate that it is more likely going to be the rear of the bike that is causing the problems. The bike is due to have new tyres after xmas, but I may get it booked in early now to get them changed. I don't fancy another ride like yesterday and the ride home tonight was just plain awkward. Doesn't feel like my bike at all.

Bit gutted really as I cleaned his breather pipes and changed his oil so he was running sweet again and then this happens. Ah well.

Looks like my day off will be spent tinkering again.

[blah]

Dec 15, 2010 23:16:52 GMT christhedivvy said:

Tyre pressures checked with a proper gauge? (sorry if it sounds condescending) Also check swing arm, headstock and wheel bearings. I assume the wheel axle bolts are torqued up correctly and arent loose. You could also check the rear shocker out make sure its working ok

Yes I am hot on with the tyres, pressure are checked once a week and I loom at the tyre for damage and wear every other day, ( I am a driver for a living so I have this drilled into to me to do it reguarly) Wheel axle bolts are torqued up correctly last time I checked, but I will check them again to be sure.

[christhedivvy]

in that case i'd definatly look into bearing and/or rear suspension, if new tyres dont cure it.

[blah]

Dec 15, 2010 23:28:45 GMT christhedivvy said:

in that case i'd definatly look into bearing and/or rear suspension, if new tyres dont cure it.

Cheers, thanks for the guidance.

[billywhizz]

rear wheel alignment??
check on the chain adjustments markers... rear shock siezed?? what about the linkage, sure it's not broken, seized or loose?

[m40man]

Dec 16, 2010 10:35:29 GMT billywhizz said:

rear wheel alignment??
check on the chain adjustments markers... rear shock siezed?? what about the linkage, sure it's not broken, seized or loose?

This is what I'm thinking too.

Do you have any play when you try to rock the rear wheel from side to side, bike on centrestand? Would point to probably either swingarm bearings or a broken shock mount. Also check the shock still has some rebound damping, by sitting astride & bouncing up & down - is the bounce more pronounced than you recall, is the bike sitting lower than you recall?, is there shock oil all over the spring & body? (are your feet flatter on the ground than previously?)

I'm usually amongst the least likely to suspect to a major failure, always taking the otimistic view, but I think you should give the shock area a really good look in case the shock mounts have cracked. (Be sure to check the top mount, not just the bottom.)
Get on your back with a torch & look & feel with your fingers for any evidence of a metal fracture where the shock mounts are, top & bottom.

[amorti]

Be sure to get BT45's for your next tyres, or at least to avoid Avon Roadriders. Hateful tyres with a really triangular profile that just doesn't suit a big barge like the divvy, promoting this sort of behaviour.

Mine was always a bit wonky with any weight in my 50-litre top box, I suspect the Divvy has a fundamental problem with weight distribution being too far back. There's not too much you can do about it, but a 1990ish FZR600 rear wheel takes a wider and thus taller tyre, and you could lower the front a little in the yokes. Replacing the front springs for hagon and fresh oil to hagon's spec helped handling a lot, too.

As above, tyre pressures and loose head bearings are your top culprits, closely followed by no damping in the rear shock or failed swingarm or wheel bearings.

[bobh]

Basically you need to do a chassis MoT, only takes 5-10 minutes:

Put bike on centre stand.

Grab back of rear wheel and push-pull sideways. If there's any play work out whether it's the wheel bearings or the swing arm bearings.

Try to lift back wheel. If any play, check whether it's top or bottom of shock (though my first D6 had some play in the top shock bearing and it didn't seem to affect the handling).

Inspect the shock for oil leaks and broken or damaged spring. Drop bike off stand and check for damped bounce, listening for any noises.

Spin the rear wheel to check truth of rim and tyre. Inspect wheel for damage to rims etc. and tyre for cuts, damage and lumps.

And that's it for the back end - no rocker linkage to worry about on the D6. It's a very good idea to take the shock and swing arm off regularly and grease the pivot bearings and the top and bottom shock bushes. The bolt through the bottom ones can seize if not greased regularly and it's an angle grinder job plus £40-worth of parts to put it right (unless you've got access to a lathe).

Put bike back on stand. Check fore and aft play in forks and for oil leakage. Check wheel bearings for play. Put weight on carrier to lift front wheel and check that steering head turns smoothly without notchiness. Spin front wheel and check as for rear. Drop bike off stand and check forks for damped bounce, again listen for any noises (Yamaha forks do clunk a bit, especially when they need new oil. The brake pads can also make a noise as they mover in the housing).

Good luck.

[biblebasher]

my bike's like a pogo stick at the mo. back shock knackered. bouncing on the bike gets it springing back sharply to the original position.

[blah]

I've been meaning to update this thread with what was wrong in the end. My rear shock was furbar. It became pretty uncomfortable to ride and was rediculous really so paid out for a new hagen shock which is LOADS better. You don't realise how bad things are until you fix them. Had to get a garage to do it as I'm snowed under with uni work and deadlines and didnt have the time to do it myself.

They checked the swingarm and bearings and said they seemed fine. They advised me on what to keep an eye on and pay attention to. Had some BT45s fitted as well as my tyres were getting low and they are brilliant. So much more responsive than the cheap things that were on them previously. Pretty happy.

[blah]

Dec 16, 2010 14:16:49 GMT bobh said:

Basically you need to do a chassis MoT, only takes 5-10 minutes:

Put bike on centre stand.

Grab back of rear wheel and push-pull sideways. If there's any play work out whether it's the wheel bearings or the swing arm bearings.

Try to lift back wheel. If any play, check whether it's top or bottom of shock (though my first D6 had some play in the top shock bearing and it didn't seem to affect the handling).

Inspect the shock for oil leaks and broken or damaged spring. Drop bike off stand and check for damped bounce, listening for any noises.

Spin the rear wheel to check truth of rim and tyre. Inspect wheel for damage to rims etc. and tyre for cuts, damage and lumps.

And that's it for the back end - no rocker linkage to worry about on the D6. It's a very good idea to take the shock and swing arm off regularly and grease the pivot bearings and the top and bottom shock bushes. The bolt through the bottom ones can seize if not greased regularly and it's an angle grinder job plus £40-worth of parts to put it right (unless you've got access to a lathe).

Put bike back on stand. Check fore and aft play in forks and for oil leakage. Check wheel bearings for play. Put weight on carrier to lift front wheel and check that steering head turns smoothly without notchiness. Spin front wheel and check as for rear. Drop bike off stand and check forks for damped bounce, again listen for any noises (Yamaha forks do clunk a bit, especially when they need new oil. The brake pads can also make a noise as they mover in the housing).

Good luck.

This is something I will be undertaking reguarly in the future. Thanks for posting this.

[amorti]

Jan 12, 2011 23:23:20 GMT blah said:

I've been meaning to update this thread with what was wrong in the end. My rear shock was furbar. It became pretty uncomfortable to ride and was rediculous really so paid out for a new hagen shock which is LOADS better. You don't realise how bad things are until you fix them. Had to get a garage to do it as I'm snowed under with uni work and deadlines and didnt have the time to do it myself.

They checked the swingarm and bearings and said they seemed fine. They advised me on what to keep an eye on and pay attention to. Had some BT45s fitted as well as my tyres were getting low and they are brilliant. So much more responsive than the cheap things that were on them previously. Pretty happy.

You can't go far wrong with BT-45's on most slower bikes. The set I put on were approx 1 million times better than the Avons they replaced.

I have a Hagon on my little CB-1. You can get some real differences in ride quality by tweaking the damping screw at the bottom end of the shock. It's a simple case of sticking a 4mm allen key in and twiddling. 1/4 turn at a time! clockwise for more damping, anti-clockwise for a softer ride.

ps. if you like the difference that made you should try the Hagon fork springs, they make an incredible difference to the bike's handling - ie, they actually give it something you could call handling.

[blah]

Jan 13, 2011 14:55:22 GMT amorti said:

Jan 12, 2011 23:23:20 GMT blah said:

ps. if you like the difference that made you should try the Hagon fork springs, they make an incredible difference to the bike's handling - ie, they actually give it something you could call handling.

[thehermitage99]

Hi Blah,

I bought my 600N a few months back from a local dealer and immediately noticed the same kind of handlebar shaking that you describe.

My bike has a small non-standard fairing and a top box which was already fitted when I bought it so I was wondering if it was bearings or something similar or even wind buffetting on the fairing. I took it back to the dealer for an expert opinion and in their view it was the topbox causing the problem.

Apparently the top box can really throw the 600N out of balance; having said that I have also had a new front tyre fitted and the 'wobble' is much better now.

If I were you I would get it checked or try it without the topbox to see if it is any better.

Bryan

[blah]

Jan 14, 2011 10:25:04 GMT thehermitage99 said:

Hi Blah,

I bought my 600N a few months back from a local dealer and immediately noticed the same kind of handlebar shaking that you describe.

My bike has a small non-standard fairing and a top box which was already fitted when I bought it so I was wondering if it was bearings or something similar or even wind buffetting on the fairing. I took it back to the dealer for an expert opinion and in their view it was the topbox causing the problem.

Apparently the top box can really throw the 600N out of balance; having said that I have also had a new front tyre fitted and the 'wobble' is much better now.

If I were you I would get it checked or try it without the topbox to see if it is any better.

Bryan

Hi Bryan,

The ride is loads better now that I have a new rear shock and tyres. I have yet to test it with the topbox, but will be using it in the next couple of days so I will know for sure then. Fingers crossed the handling will be loads better as it was getting to be a nightmare on long journeys,

[stephenpevan650]

hi not that i have anything helpfull to add except that i'm suffering a similar problem.
i bought a 99 600n a while ago,and at first i thought the handling was just a little strange and abit vague, possibly under steer.
i changed the fork oil for 15w, fitted a new rear damper not OEM,new head races, swinging arm bearings , i checked wheel bearings, wheel alignment, etc etc.
then i read that the tire pressures in the owners hand book were now obsolete for modern tires so i tried the new pressures, the handling appeared worse, it was like riding on ball bearings, very light at the front end,i tried different pressures then the winter came and i lost interest.
the only thing left to change is the tires and they look to be quite new so i didn't want to change them unless i had to, due to lack of funds of course, by the way the tires fitted are Avon road riders, are they any good ??.
any ideas appreciated. :

[amorti]

Jan 29, 2011 19:14:35 GMT stephenpevan650 said:

hi not that i have anything helpfull to add except that i'm suffering a similar problem.
i bought a 99 600n a while ago,and at first i thought the handling was just a little strange and abit vague, possibly under steer.
i changed the fork oil for 15w, fitted a new rear damper not OEM,new head races, swinging arm bearings , i checked wheel bearings, wheel alignment, etc etc.
then i read that the tire pressures in the owners hand book were now obsolete for modern tires so i tried the new pressures, the handling appeared worse, it was like riding on ball bearings, very light at the front end,i tried different pressures then the winter came and i lost interest.
the only thing left to change is the tires and they look to be quite new so i didn't want to change them unless i had to, due to lack of funds of course, by the way the tires fitted are Avon road riders, are they any good ??.
any ideas appreciated. :

Roadriders are awful on the XJ600S, the profile is too triangular. Fit Bridgestone BT45's next time. If you like a project, you can fit a rear wheel from a 1990ish FZR 600, this will take a 150/18 rear safely, that helps a bit too. Just speak to the breaker and check it's an 18x4" rim.

This could be he puppy:
cgi.ebay.co.uk/Yamaha-FZR-600-18-rear-wheel-chopper-streetfighter-/110642947359?pt=UK_Motorcycle_Parts&hash=item19c2d5651f

If so, it fits 1:1 - use your disc, sprocket carrier, rubbers and sprocket, bearings are identical etc. No issues with tyre/chain clearance. The only difference is a wider rim, I did this mod shortly before flogging the Divvy on.

[blah]

Yeah I've been told to stay away from Avons, the BT45s are amazing and I would recommend them to anyone. Like I said bike felt like a different bike with them on the difference in handling was improved so much. It was as sketchy as fook before.