Unstable rear end

On the suspension, you have to assume the previous rider has set it up for their needs not yours, so I would typically revert the whole bike to stock and then spend time exploring what changes make things better/worse. Only change one thing at a time, and in small increments - then test and see how it pans out on a ride around a fixed circuit of nearby roads so you know what to expect. Your weight suggests you may find that aiming for a bit harder than the standard settings it will work best - but its a personal thing so make your own call on that.

The fact you have installed lowering triangles and dropped the rear of the bike by 35mm should not greatly affect the handling/steering PROVIDED you also brought the front down - by a roughly similar amount. If the front is still stock that could make for weird handling.

Ideally you want to ensure the forks came down by the same amount - but I don't know how much scope there is on a 750 and in practice you may run out of room and won't be able to get the front down 35mm. So if you have not already dropped the forks through the triple clamps then its probably the first thing to consider. Just don't go mad! You must ensure the steering moves freely from lock to lock and the cables and brake and clutch lines are not snagged or over stressed at any point. Also make sure there is still clearance around the forks for the suspension to compress. Make sure the bolts are properly torqued.

Once the bike is levelled off, you may find the handling a lot more predictable/acceptable. (PS you may need to shorten the side stand and possibly ditch the centre stand if it grounds out on bends with the bike tipped over).

As for tyres - the wear you report on those BT020s sounds unusual - any chance of some photos?

It suggests the previous owner did a lot of motorway trips and the tyres are now squared off so rather then enjoying the bike smoothly tipping into corners, you find its all or nothing - in which case new tyres is the way to go.

I don't know what sort of riding you have planned on your VFR - but don't assume the best choice for you is to fit the same tyre again.

Its well worth discussing with a tyre fitter what options are suited to you taking into account your likely use of the bike..

If you plan on doing lots of touring especially mega long motorway runs, then a dual compound tyre (DCT) like the 022 or 023s (or Pirelli equivalent) is the way to go. These have a very long lasting central wear tread section and with super sticky sides giving great confidence if you occasionally hit the twisties. The 020's are cheaper for a reason. If you do loads of track days then you really want a super grippy tyre like the 016's but they won't last half as long as the 022/023s.

Finally if you bought the bike recently from a dealership, then it may be worth saying the handling seems off and asking if their technician can help you get it set up for you.

Good luck - Let us know how you get on.




SkiMad

 

Took the bike round to a friend today who has a lot of experience...He had a look at the tyres and assures me that there is nothing wrong in that department. He also took it for a ride and says he could find nothing wrong in regards to the handling apart from the front preload could do with stiffening up a bit maybe..
He wonders if the first time the back slid on me was down to diesel/oil on the road and since then I have been worried about it happening again and possibly being too cautious and stiff concerning cornering..Makes a bit of sense to me really...I trust him when it comes to experience on bikes and so will try to be a bit more relaxed and not so tense when riding and see how it goes....Thanks to everyone for their input on the subject and I will keep you updated if there are any further issues..

 

If you had been a heavyweight, I would have offered a suggestion. You aren't. I am stumped.

 

Whether or not your problem is 'solved", your tires are from 2008. Ain't no way I'm riding around on 5-6 year old tires on my bike. Regardless of what they might look like, you have no idea what the composition of the tire is based on how it was used/stored previously. Get new ones.

 

I read the wrong numbers on the tyre wall....date is 06/10 so no worries there..

 

Is your chain too tight--it must be loose enough to still have sufficient slack not to bind the suspension when fully loaded in a corner at the full compression stroke.

At 175 kg you are considered a heavy rider and will probably need a stiffer spring.

By lowering 35 mm at the rear you have reduced the swingarm down-angle by extending the swingarm up toward the fully-horizontal position (zero angle). In a corner you may be compressing to an over-horizontal condition (swingarm goes to an up-angle) which is an unstable condition and will cause the rear wheel to step out especially if the chain is too tight for the maximum extension position of the swingarm.

Get your buddy to take a picture of the swingarm with and without you sitting on the bike--you are looking at the angle from the front sprocket thru the pivot to the rear sprocket. If those 3 points are in the same line there should still be 1/4" slack in the chain, but you really don't want the suspension to ever get to that position when riding--you don't have any stability margin at that point.

You may need to get a stiffer spring and raise the rear such that you never go past the fully extended position at your maximum loaded condition. It only takes a 45 degree lean angle to generate a 1 g turn on a motorsickle, if you like to ride hard then the cornering load must be included when setting up the suspension.

 

For sure the lowering links are not helping matters, but I would say that your problems are centered around the shock itself. You have been given a lot of advice about linkage bearings and tires - both of which are items that need to be in good working order - but I don't think they are contributing to the problems you describe. It is most probable that your stock shock needs rebuilt at minimum. I think you will find with a good working shock your problems will be solved. This will be especially the case if you choose to make an upgrade while you are at it.

Good luck!

 

Dude....175 kilos is about 280 lbs.....not a heavyweight???

 

Hold on folks - its easy to make a typo - and my guess is that he actually meant 75kg (which is indeed close on 12 stone). If Don1163 really meant he weighs in at 175 kg that would be almost 30 stone - hence I pretty much ruled it out as a typo.

So before we head in the wrong direction with our advice - it would help us all Don 1163 if you can confirm your weight?

Even so, I think given the updated tyre(tire) info, I am inclined to think Jamie is spot on with his diagnosis.

Thanks



SkiMad

 

The stock spring on a 1997 VFR750 is ideal for a 120lb rider. I think it is safe to assume ALL riders need a new spring.

 

Was a typo....I meant 75kg, thanks to everyone for their input it has been very helpful..