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So I'm in the progress of rebuilding my motor. I just got the head on today and i will be installing the cams and chain etc. tomorrow and setting the timing to the right marks.

I also did a port and polish on the head while it was apart and port matched the intake, and exhaust gaskets (risers on the intake)

With that said, what kind of gains do you think i will see out of the port and polish, have any of you done this mod? EVERYONE i have talked to has said it is probably the best thing you can do for power (other than new pistons camming etc), what kind of gains do you think i will see?
 

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As low as 2-3 or as high as 5-7 with the port and polish, depending on how much you ported it. With the headers and exhaust, Im guessing 10-15 total depending on, once again, how much on the port you did. So congratulations your 600 has just became a 750:thumbup:
But who knows maybe I am totally guessing:shifty:headscrat
 

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Probably 7-10 would be my guess seeing that it's an older carburated bike. You should be right around a stock 600 HP range on these new bikes because your bike when new was under 100hp
 

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Probably 7-10 would be my guess seeing that it's an older carburated bike. You should be right around a stock 600 HP range on these new bikes because your bike when new was under 100hp
Oh snap, I did not take that into account on the age of the bike. So I would go with what the man said.
You can always do a dyno, which some would argue that dyno's are not accurate. But all in all it would give a good idea on where you stand.
 

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There are some healthy gains in porting and polishing. FOr the valves going bigger is going to put your power gains higher in the rpms. Same with going with bigger carbs and exhaust tubes. It's normallly best to leave the carb size around where it started because going bigger has the engine only putting out at higher rpms and lagging in the lower rpms. You will have some good gains but not sure how much. The fact that you touched up the valves is good for increasing the power too. If your model year wasn't already a good in the intake and exhaust department I'd figure probably at least 20 hp.
 

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So I'm in the progress of rebuilding my motor. I just got the head on today and i will be installing the cams and chain etc. tomorrow and setting the timing to the right marks.

I also did a port and polish on the head while it was apart and port matched the intake, and exhaust gaskets (risers on the intake)

With that said, what kind of gains do you think i will see out of the port and polish, have any of you done this mod? EVERYONE i have talked to has said it is probably the best thing you can do for power (other than new pistons camming etc), what kind of gains do you think i will see?
hard to say.. a lot of things will depend.. 1st... did you have the head ported by someone who knows how to do it and a flow bench or did you just match up the port size yourself and not flow it? if its not done properly you will most likely loose power due to the air flow speed changes ( if you just open it up with out the right size shape of the ports you will lose too much velocity and will end up with crap low/ mid range power and minimal if any gains at peak) also did you do any other changes? are they still stock pistons, comp , cams etc. if its still all stock you wont see to much gains from the head( if the head is even done correctly) due to not adding any more air flow (increased cam size, comp, displacement etc..) how are you going to reinstal the cams? are you installing adjustable cam sprockets and degree them in or just line up the stock marks on the stock gears? also.. what is the rest of your set up? do you already have a good full exhaust and carbs jetted? do you have more jets to re jet the carbs after the head job?
there are a lot of factors than can change the outcome here. but from exp i would say if you already have a exhaust, carbs jetted, aftermarket air filter and you just did a port match to the head you may see a 1-3 hp gain if its not over done.. if so you will def loose some power. so best case you may be @100 hp+-. also and very importantly...did you do a base dyno run before any of this so you will even have a base to compair it to? if not you will never know if it helped or hurt you and where..
 
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