Stock Engine, Oversized Headers

[Live2Ride300]

I have a 2000 300EX, the engine is completly stock, im looking into buying an aftermarket exaust complete system or slip on. Ive heard that if your engine is stock then you really dont need the bigger head pipe that comes with the complete system. Is this true? Or do you get more power if you get the head pipe too, if you do get more power, is it alot? Or so little that its not worth it?Im looking into a WB E-Series, or Pro Circuit T-4 slip on. Thanks for all the info, its greatly appreciated,

charlie

[quadfamily]

If you were talking about a 400EX that would be true. But since you're talking about a 300EX it's a completely different situation. The 300EX's have a very restrictive head pipe. It's been said that you actually get more power on a (stock or modified)300EX by getting a larger diameter head pipe then by changing the silencer. I went with the Powroll large diameter head pipe with a stock silencer and I was very happy with it. I have since modified a stock 400EX silencer to fit onto my bike and I'm pleased with that as well. I don't have any internal engine mods yet just small stuff like filter and airbox mods. I also removed my choke and that really woke up the bike, it revs MUCH more freely now. Just remember with each, and I do mean "each", change you make which effects airflow either into the engine or out you MUST re-jet. Even changes you consider little. It makes a difference.

[Live2Ride300]

Thanks for your info quadfamily!
Where can you buy the Powroll Large Diameter Header? How much does it go for? Can you use this header with other silencers like WB, FMF, Pro Circuit etc? Is removing the choke hard? After I remove it can it be reinstalled? If I removed the choke, then I would have to install a larger pilot jet for easier starting right? Thanks for the help

charlie

[quadfamily]

Charlie,
You can go to Powroll's web site www.powroll.com and buy it there. They are a hundred bucks now but they were only 75 when I bought mine. You should be able to use any slip on silencer that fits a stock header since the header fits a stock silencer. Yes, remove the choke. It's really easy. there's a thread "all choked up" in this forum right now that explains how to do it. The procedure is the same for 300EX and 400EX. You should definately go with a 42 pilot jet when you do the choke. You will need to go up a "few" sizes in the main jet with the head pipe and also raise the needle jet one notch by lowering the clip one notch. I think I ended up with something like a 134 or 135 main jet, I also took off my airbox lid and replaced it with a outerwears cover and put in a K&N filter though.

[Live2Ride300]

Thanks for all your info Quadfamily, it really helped, more questions... Do you think its worth it to buy a complete jet kit, or just buy the jets i need indavuidually? Im thinking about putting those filtered vents on my air box lid, or gettin that outerwares cover you were talking about, (do you happen to have a picture of that? I think theres a review for it on here) and gettin a k+n filter with outerware, and either buying a jet kit or buying the jets individually , either that, or buying a complete K+N power kit. What do you think. Thanks again quadfamily:)

Charlie

[Live2Ride300]

Quadfamily- I looked at the exuast systems on powroll.com, the oversized header is 90 buks, and the complete system with a 3inch suppertrap silencer is 200 bucks. Im thinking about goin with the complete, but is it worth it, I could spend the extra hundred on filter, outerware, jets, etc. Does the complete system add alot more power, or is it not that noticable? I think I will just get the header, but im not sure yet, thanks again quadfamily

[ATVer14]

Live2Ride300- I have the complete Powroll system for my 300, and this winter I switched the Supertrapp silencer back to my stock one to see how it felt with the head pipe, and the Supertrapp does make a difference. With the Supertrapp, the engine revs much more freely and makes more mid-top range power. The only down side is that the Supertrapp is kinda loud, thats why I switched back to my stock silencer for the winter, since I would be riding close to neighbors that tend to get mad easily. When the racing season starts back up, I'm going back to the Supertrapp. To see a full review on this pipe/silencer combo, as well as pictures, go to my site at www.geocities.com/quadracr28. Hope this helps.
-Kenny

[quadfamily]

Charlie,
Looks like ATVer14 answered your exhaust question pretty well. The noise is why I didn't get the full system. I've heard them before and they are LOUD. Plus like I said before, Powroll told me that the head pipe makes more of a difference on the 300's because the stocker is so restrictive. As far as the jet kit goes, I wouldn't spend the money for a few jets, it's not worth it.
Genuine Keuhin jets are only around $4 a piece and you can buy a bunch of them for the price of a jet kit. I think hte stock jet is a 125. You should probably buy a 132, and a 135. One of those should be right. Skip the 128, it won't be big enough. Get the 42 pilot and you know that's the right one, no need to experiment with that one. You only need to experimant with the main jets. Raise the needle one notch and you're set. Jet kit is a waste of money for what you get.

[Live2Ride300]

Thank for all your info guys, it really helped!!:D

[Live2Ride300]

I have one more question, lol. I ride in alot of sand pits and i get there by taking the trails and alot of the trails have alot of mud and water, im wonderings if its safe to have air box mods, like taking the lid off and using the outerwares cover, or just putting some filtered vents in the lid. Is the outerware cover you have like the one in the review on this site? - http://www.exriders.com/reviews/aircover.shtml

I was wondering if i should leave the air box alone, or would it be protected enough with the cover? Thanks again guys

[quadfamily]

I have trhe same one as in the review and mounted it the same way. It should be protected enough that way

[Live2Ride300]

u run the air box cover and an outerware on ur k+n right?

[quadfamily]

No, I run a K&N with no outerwear. I cut out the whole middle of my airbox lid and used it to clamp down on my outerwears airbox lid cover.

[Live2Ride300]

i think im going to run an outerware on the filter for added protectoin, thanks for ur info