Pointy spark plugs and PAIR valve?

Hello All,

I did a clean up on my sv650 and discovered that i only have 2 spark plugs for 4 cylinder. how does that work ?

Also the PAIR system, does that impact performance at all ? I did clean the reed valve and they were deposited with carbon which I cleaned but according to haynes if it has carbon on it the pair system is faulty. but I did test the pair system by simply giving the pair valve 12 v and it did shut the valve thus not letting any air go through which is the way haynes suggest to test ( when power is going through it , it should not let any air though). so why did I get carbon deposit on those valves?

My bike has done 26k and don't think it was ever cleaned. I bought it when it had 25k on the clock .


Thanks

First, what age of SV?
You do realise the SV is a twin cylinder bike right?

[Sid Squid]

An SV650 has two cylinders, not four. Later models have four plugs - two in each cylinder - as part of an emissions reducing measure.

If the PAIR system tests out as you have found, it's fine.

thanks it is a sv650 2005 model.

I was under impression v twin means it is arranged in v shaped as with some cars which have a V shaped engine as opposed to inline.

and never did a google as I thought this is the same v which means they are arranged in a v shape but upon further research it looks like they are only 2 cylinder hence why v twin. so now 2 plugs makes sense but why 4, 2 per each in the latter model. each cylinder only needs one to fire.

also how often do you change your sv plug ?

thanks

this may also explains why r6 and inline 4 have more hp . I was thinking if they al have 4 cylinder and 600 then why one produces 70hp(mine) as opposed to r6 with smaller engine (130hp or so). does this mean v twin has bigger bore compared to inline ? almost double ?

if r6 is getting 130 or so hp from 600cc is that only due to engine or other factors? why does my 650 only gives me half that if cc is all that matters

V twins dont rev as highly as four cylinder bikes. Power is torque x rpm. Obviously the higher revving bike will make more power.

That does not mean an SV is less rideable though, far from. Less weight, better traction. It's not all about power you know.

[aesmith]

It isn't all that matters. There's a load of factors such as how fast the engine turns, and how much internal pressure is generated. I'll bet your R6 revs a lot higher than the SV to get that power, and you may even find that the R6 is no more powerful at low revs.

By the way just to show that cc isn't the only thing, our boat's engine is 744cc but only 13HP.

[Bibio]

[jambo]

V-Twin - V engine layout, twin cylinders.
V4 (As for Honda VFR series, RC30, RC45, Aprilia RSV4 etc) V layout, 4 cylinders.

Twin Spark - marginally cleaner burn, important when emissions regs for unburned particulates are so tight, hence the additional spark plug per cylinder from 2007 onwards.

Power vs displacement, it's really not that simple. Money spent on unobtanium parts helps engines rev higher without self-destructing. Trading off low end power for a high amount of top end power helps too if big numbers are your goal. Ultimately more cylinder to valve area ratio and higher rev ceilings will give you a bigger number on the dyno.

Plugs are usually removed using the tool in the kit, the front can be tricky to access and is easiest with the radiator removed, but that's not strictly essential.

Jambo

Is this thread a wind up?