Yamaha TRX850 Enthusiasts Forum

So, is there any that actually has a bigger diameter than 40 so one can port the exhaust as well??
Or is it just go custom?? What is akra for example?

well akra has an adaptor that goes into the head, then the header pipe goes into the adaptor. The inlet to the header is probably the same size as the exhaust port, not much more.

youngy wrote:well akra has an adaptor that goes into the head, then the header pipe goes into the adaptor. The inlet to the header is probably the same size as the exhaust port, not much more.

Yeah, but akra has those water flowed pipes dont they....kinda velocity porting but in the headers!

you mean conical headers? yes.

youngy wrote:you mean conical headers? yes.

Think they send HIGH pressure water thru pipes when glowing red?! ...not a bad idea....wich we could have a 2-1-2 Akra!

I'll take a measurement of my Over system so you can compare as well. Just have to wait for the sun to come up.

Kevtrx849 wrote:I'll take a measurement of my Over system so you can compare as well. Just have to wait for the sun to come up.

GREAT STUFF!! Just what i wanted that is!

Over system is 43mm at the head. Glad to help.

Kevtrx849 wrote:Over system is 43mm at the head. Glad to help.

Top!
....could you check inner diameter of the can as well....or outer on the end of pipework....

No worries, i'll do that tomorrow when i get home.

OK, 43mm at the head. 50mm after it divides under the bike and 60mm at the can connection.

Kevtrx849 wrote:OK, 43mm at the head. 50mm after it divides under the bike and 60mm at the can connection.

That really beats everything i know of....exept one offs...

Much appreciated!!



....oh crap, measurements where in the shop!

http://www.overracing.com/shop/YAMAHA-T ... 433SC.html

how does it run at low rpm with headers so large is there a step in power at higher revs

cheesie wrote:how does it run at low rpm with headers so large is there a step in power at higher revs

I have the MAB system so you have to ask the Over pipe guy´s on that one...

I reckon that the overs make the bike more rideable at low speed. Less twitchy on small throttle openings if that makes sense Power comes on good at mid range to wide open. This was true also before i fitted the FCR's.