Okay so I have a 05 450r, FMF Full Exhaust, HRC Cam, K&N, Jetted 185 / 50.... No air Box.... Anyways I want to go faster, I am not looking so much for top speed just more HP and from what I hear increasing the compression is not such a good idea, I know stock is 10:1 is increasing to 12:1 really worth it, what kind of gains can I expect, are there any alternatives that dont cost a fortune, I can get a piston and install it myself... What does porting and polishing cost, and what type of gains can i expect there too... Any recommendations on what to do next????

 

Honda did a nice job with the stock flow. You might gain a little with porting, but there isn't alot of room for improvement. I would say looking into an Athena bigbore 480, bolt on. Those are 10.8:1 compression and have bigger water jackets. In some ways it will add reliability to a great engine.

 

porting makes a little bit of a diff when you add a bigger carb and stuff like that but not that much with out it.....

 

we have an 04 with mild porting and a 11.5 ta 1 high comp. je piston the je piston is the only way to go it starts better than stock with the kicker and pulls 3 quad lenths in 25 yards on my 05 with pipe jetting and honda hrc cams, the stock carb will do a lot more than you need! cam air porting pipe will get there quick and in a hurry ,porting will take a bit away from the bottom end but really kicks in at mid and top it flys!!it will run with the camed and piped 06 trx450r easy and they are fast!!!

 

I belive the '04 and '05 stock compression is 9.5:1.
I put an Athena 480 big bore kit with a 10.7:1 piston on mine with ported head, stage II Hotcam, FMF Q2 slip on, 185/50 jetting, cut open (HRC style) airbox lid and a Uni filter.
I really like the power gains and I did all this for around $1,000.00

 

we are lucky our local honda dealer has race specials, they do a great port and polish for $150 the hrc kit installed for $280 the piston was $154 ya cant beat that for hp to cost any where!!! and the exspert class in dist 3 is as fast as any they took many trophys at the dila nats the last two years and this thing will run with em! binghamton honda rules!!!the je piston will go the whole season with no problems!!!

 

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