Thursday, January 12, 2012

If i oversize the pistons do i need to oversize the valves too?

i have a virago1100 with vance%26amp;hines pipes,oversize jets,and a k%26amp;n filterIf i oversize the pistons do i need to oversize the valves too?
No. It's quite labor-intensive to install larger valves, and it's really unnecessary.



The larger piston will create a larger vacuum on intake, and push more air on exhaust. It'll feed itself just fine. As someone else said, a hotter cam, which has taller lobes that keep the valves open longer, will increase the amount of fuel draw, but it's not required.



By pulling more air into the motor, you will be leaning your fuel mixture. Plan on re-jetting again.



If you're going to all the effort and expense, you might consider upgrading your valves to a performance grade. Something in titanium would look nice, especially in a newly milled seat! Port and polish those heads, and you'll have a fire-breather!



Best of luck!
The simple answer is,, NO!

But and if you do, you have already upped the jet size so your mix will be fine, but I advise you ditch the V %26amp; H pipes, they look good, but are crap for performance, but it is a Virago, so comfy cruiser it is.

Ride it like it is, dont race it, but if you do rebore, remember to change your oil after a 500mile run in, gets rid of the micro particles off the new bores and rings.If i oversize the pistons do i need to oversize the valves too?
You dont HAVE to....but depending on what kind of performance you are looking for, it might be worth it. Personally, if I was going to mod my pistons...I wouldnt think about doing a cam job, without doing the valves and valve seats as well. Dont even waste the money unless youre going to do the whole thing, and do it RIGHT.
have never heard of a virago ...what part of the world are you ...what you need is a uk spec bike ..a lot are close to 200bhp and allmost 200mph fast ...standard road bike !!..come over here and be afraid ..very afraidIf i oversize the pistons do i need to oversize the valves too?
No. Hotter cams will do the trick if you NEED more power.
Yes,obviously

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