curvy valve mods
 

is it a rumor or anyone heard about this idea.:smt083

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....

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

Re: curvy valve mods
 

Not valves, cams.

Re: curvy valve mods
 

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

Re: curvy valve mods
 

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.

Re: curvy valve mods
 

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

Re: curvy valve mods
 

Nah, I'm busy having a futile conversation about religion :smt019

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.

Re: curvy valve mods
 

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

Re: curvy valve mods
 

How much engine tuning are you planning on doing?

Re: curvy valve mods
 

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)

Re: curvy valve mods
 

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

Re: curvy valve mods
 

hmm...monster TL engine in SV chassis on wobbly sv suspension



widowmaker II

Re: curvy valve mods
 

It's been done and it's really hard. Got to weld frame and all sorts... including swapping all the rse end over to other side. (TL rear header is offset the other way) Then you'll get the problem of the mudguard and the radiator making friends as the TLS engine is longer.

Re: curvy valve mods
 

If you plan to heavily tune the engine then I would recommend JHS cams, there a couple of stages available to suit many states of tune. They also work well with bored engines if the future goes that way.

+ 1, a lot of hassle and it would be far cheaper to buy a TL1000S and sort the suspension which isn't as bad as many think. A lot of people tell you how bad it is, many haven't ridden one though.

Re: curvy valve mods
 

I rode a TLS with its widow maker suspension and with Ohlins all round. The bike was still scary with both. Nothing to do with the suspension, more to do with the mental power delivery!! Excellent bike and a pity they dont make anthing like that anymore.

Re: curvy valve mods
 

If I had a bit of dosh to spend building a "moderate" engine at roughly stock displacement:

hone barrels
'busa pistons
balance crank to match
mild porting job (just a cleanup of casting flash really)
JHS cams
M4 pipe
BMC race RS + rejet to match

That should give a reliable and useable 85-90bhp.
Then again since you'd have motor apart you might as well fit some CP pistons and take it out to 700cc...

Re: curvy valve mods
 

Aye