curvy valve mods

is it a rumor or anyone heard about this idea.

on a curvy engine im sure i heard somewhere swapping the exhaust and inlet valves round and replacing the inlet valves with one from a pointy or summit similar....

????????????????????????????????

[yorkie_chris]

Not valves, cams.

Originally Posted by yorkie_chris

Not valves, cams.

per.. propably. its either dislexia/hard of hearing or inset of old age.


do you know what it actually involves and how much of a difference it makes>?


cheers

[yorkie_chris]

Ask northwind, as I haven't done it.

It's roughly as involved as changing a shim. But none of the markings are right so you have to be careful.

Originally Posted by yorkie_chris

Ask northwind, as I haven't done it.

It's roughly as involved as changing a shim. But none of the markings are right so you have to be careful.

okies. OI..NORTHWIND! can we borrow you for this discussion??? p l e a s e ?

[northwind]

Nah, I'm busy having a futile conversation about religion

It's basically pretty simple- the pointy intake cams are a bit hotter than the curvy ones (based on the Yoshimura race cams I believe) so that's a straightforward swap, like for like. They cost about £130 new if memory serves.

Then, you have a spare pair of curvy intake cams. The exhaust cams on the SV- on a lot of bikes actually- are pretty restrictive because it helps to quieten the bike and cut down emissions. So, rather than just fitting pointy exhaust cams- which are a wee bit hotter than the curvy ones- you use your old intake as the exhaust cams. Cost, free

Obviously it's quite an invasive mod, it's not exactly difficult- though it does need a careful approach- but it's got the potential to cause a lot of damage if you get the timing wrong or drop a bolt down the camchain tunner or suchlike. So it's an approach with caution sort of a deal.

But, it's nice- there's no better performance mod for the SV, you get a few bhp all over, and a generally nicer power curve- the power lasts longer and doesn't fall as dramatically past the peak. Various people claim different power amounts, unfortunately my before and after dyno curves are useless because the "before" curve was completely screwed by the terrible renegade airkit I had fitted... But the usual claims are between 3 and 7bhp at peak.

Obviously, it doesn't make an awful lot of sense to tune a sub-70bhp bike at all, but it does give better overall rideability too, with a wider power range.

sweet... being added to my to do list i think.

How much engine tuning are you planning on doing?

Originally Posted by Dangerous Dave

How much engine tuning are you planning on doing?

a fair bit!..... without increasing the CC... if i get fedup a tl1000 will get shoehorned in the frame... and then tuned.


(obviously running gear would all be upgraded significently to deal with this)

[yorkie_chris]

You'd better be good at welding alloy then. More trouble than it's worth.