4K service

i cant cook either. well saying that i manage certain things and im not exactly suffering from malnutrition.

i enjoy baking but make such a mess.

but the days of women staying at home and cookin and looking after kids are disappearing. i would rather chew my arm off than stay at home all day. in partnerships these days its a case of doing jobs you enjoy and arguing about those you dont.

i would rather clean than cook my bf is the opposite so when we are together its ideal.

Originally Posted by stuartyboy

like the M.I.L,

The what now?

Mother In Law

Think yourselves lucky, £172.60 for my 4k service down sarf, they replaced oil filter, air filter etc.

Can't help on why women are rubbish cooks, but it's quite easy to follow a recipe.

Originally Posted by Law

Can't help on why women are rubbish cooks, but it's quite easy to follow a recipe.

Mine's read it in her horrorscope so who am I to argue

Back to the service...Had a very interesting chat with a guy from weir honda tonight. Says you should only tackle it if you really know what youre doing. Apparently the chassis' of modern bikes are so advanced that they need to have the bits put back together in the right sequence and at the right torque. If you tighten up things in the wrong sequence then you can affect the handling of the bike. Best left to the experts imho.

[northwind]

Tis ********, that. There's no secret code... Some parts call for opposite tightening or specific bolt install patterns- camshaft towers, casings, stuff like that- but other than that... You won't affect handling if you tighten the tank bolts in the wrong order

Still, I agree you need to know what you're doing to service a bike right- a lot of people think it's just following the guide in the manual, and miss out on the whole preventative medicine side of things.

Northy - I asked him "jokingly" if I could attempt a service. Was only passing on what he said and maybe i got it wrong.

I'll ask him what he meant but going by his bike mechanic hero god status at knockhill nobody thought he was talking ********.

edit: feckin site went tits up before i finished typing

Originally Posted by northwind

Tis ********, that....

Just had an email from him and he said its not ********. He says here's why...

Quote from his email

"Modern frames are designed to flex whereas older bikes had very stiff chassis'. Stiffer bikes gave less feel when leaned over. Flexi bikes are the opposite.

At lean when a bike hits a bump it has to move a lot further than when it does when upright so flex in the frame helps. On a twin spar frame there is most flex behind the engine where it needs to be. The more these areas flex the better the rear grip and steer. Make these areas stiffer and you have less grip and potential oversteer.

More flex = slower steering but more grip and tighter cornering. Less flex the opposite.

The amount the chassis bends is controlled by the engine mountings so there is a correct tightening sequence/torque which is vital to the bikes handling.

Take two rulers for example. Screw them both down to a bench at the 1 inch mark. Take one of the rulers and add a screw at the 2 inch mark. Take the other ruler and add a screw at the 30 inch mark. You now have two lengths flexing different ways. Now apply the same technique to a bikes chassis.

The frame spars flex more at the tail end than the front. So if you were to tighten one side from front to back and the other side from back to front then the flex in both sides would be different. This can make one side steer differently to the other"


Makes sense to me

[northwind]

The example dopesn't apply at all, since you'll be putting the bolts in the same places every time.

All the part about flex is correct as far as it goes, but the order of the bolts will make precisely no noticable difference to the flex of the frame, at least not on an SV. The reason being, the frame is stressed against hard points, so if you tension the main bolt first or last, makes no difference.

A better example would be a bow, or similiar. Say you have a bow that you're bolting in 5 places to a bench. One at each end, one in the middle, the rest in the gaps. If you do the bolts up in different orders it'll bend the bow into different shapes- if you do the middle one up first, none of the rest will line up. Things like that. It'll change the shape of the bow whenever you tighten a bolt, and it'll effect the tension in the other bolts.

But, if the bow was a bike frame, it'd have spacers between the bench and the bow- so the shape doesn't change significantly when you tighten it down. The engine's effectively one massive spacer here. Likewise the swingarm, the wheels... anything that bolts inside a chassis member.

What he's saying about frame flex is right, though- when leaned over, frame flex does make a difference, it's effectively leaf-spring suspension. Lean a bike to 45 degrees then push the wheel directly upwards 2cm. The forks actually have to travel 2.82cm along their travel- 2cm up and 2 cm sideways. That's with no flex. But, you set up the forks so that when they take an impact of X newtons vertically they compress 2cm. So, if you take that X Newton impact directly upwards when leaned over, it's not enough to push the forks 2.82cm along their travel- it'll push them 2cm as before, and then bump the bike up by... eh... a bit. This can cause you to run wide, as he says. Same for the rear, but that's more complex mathematically so I'm not touching it with a 10 foot pole

But, add in some flex, and the chassis will deflect upwards as well, acting as suspension.

So that's all true. But that only affects the main chassis bolts, and to be honest I doubt you'd even notice the difference if one was missing, never mind tightened in the wrong order The SV's got a pretty stiff frame.

Older bikes actually used to be incredibly bendy- famous for it. Then, along came things like Deltabox frames, which were very stiff. Newer bikes do have flex taken into consideration- but lets be honest here, the SV chassis was built to price not performance. It's a good frame, but it's not a superbike- you don't spend money R&Ding exact frame flex when you're going to fit suspension made out of door closers and biro springs

It's quite interesting how this develops... Harris, for instance, make different swingarms for roadracing and track racing. Bigger bumps on a TT so you want more flex. But they still sometimes make the frames themselves stiffer. Take away bad flex, add good flex. All about controlling where it flexes and when.

But this more flex = good, less = bad, is utter rubbish. It's a balance. "The more these areas flex the better the rear grip and steer"- up to a point only. After that point, the flex means you and the suspension are no longer in control of the bike.

The other thing is, in routine servicing you'll practically never adjust one of the relevant chassis bolts- and when you do, it'll just be to retighten. There's specific orders for reassembly- say you drop the engine- but that's very different.

Should put you two in the ring and

Emailed him and his reply was

"He's a very brave man if he wants to ride with a bolt one missing! Anyway, I'm not getting into it. I'm right, I know I am and that's what I'm paid for"

He did add a at the end so he took it in good fun.

I asked him to join the forum but he said he's enough on his plate without spending hours at a PC. I did try