How much more power is gained by putting in larger intake valves? I have a 1996 rd king. That I'm looking at building. A minimum of port and polish on heads, 9.5:1 compression pistons, and. 030 cometic head gasket. I have an ev27 cam now but that will change after/during the build. I don't care about "street manners" I want a raped ape. But no more than 10.25:1 compression. I'm wondering how much more power is gained either hp or tq by putting in the 1.94 intake valves compared to stock valve size. I guess I'm looking to compare the cost to gains. Thanks for any advice and experience!

 

We use 1.900" intakes on our Stage I Evo Heads.
You will have a good running bike with the compression brought up, and a good set of heads, using that cam.
Scott

 

installing bigger valves,without doing any other (or improper) work can kill a head,if your looking for a raped ape.ide go with 1.900 headwork,10.5-1 & a woods 6H cam

 

Porting will be done. I don't want to run 10.5 compression ratio because of fuel. I live in NE and they love their ethanol, especially in western NE. How much more power is made from the bigger valve? Is it worth $300 or would I find more power spending that money on something else?

 

a 1.94 intake valve in a evolution heads is not a good idea for several reasons. first it is larger than the valve seat, a larger valve seat should be installed. Yes the larger 1.94 valve will flow more air but your motor doesn't need the extra air unless you increase the motor size. Stick with the 1.900 and you'll be fine. dsv

 

The larger valve seats would be put in. So the extra airflow isn't enough of help to justify the cost?

 

No not worth it, I am making 120hp in a 106 with a 1.9" intake valve, Don't get caught up in the bigger is better, matching your combo is key.

 

Thank you. That's kind of what I'm thinking. Thanks for the confirmation! Very helpful!

 

Im running a 1.98 intake valve in my 1250 sportster. It makes great power. If all the components are matched properly bigger valves work great. Like stated above....cams, compression, fuel ect all have to be on the same page.

 

We have corn fuel were i am from too. I run 91 octane with ethanol and it runs fine. 10.9 to 1 with a corrected compression 9.3 to 1