Hey Guys,

I currently have a '98 Sport with an RcR Stage 1 kit (mid-range pipe), and a 42mm TMX carb. I was happy with the results from these two mods, but I would really like to get a little bit more top end out of her. I had thought of putting on a new sprocket, but I don't really want to do something that will sacrifice my low end. How much of a gain will I see from Boyesen Reeds? For best results I'm guessing I should buy them with the Rad Valve right (well I guess if you buy the Valve they come with it anyway)?

I'd rather stay away from porting, because I'm not really experienced with that stuff, and it looks like it is pretty risky business.

Like I said, I want to get some more top end out of it, but still keep the nice low end power that it's got now. Thanks for any suggestions.

-Josh

 

Piranha,

If you want gobs of low end, there is nothing like a "big bore kit". Because of the angles of the ports, with a big bore kit they will be lower thus resulting in tons of low end power.

Oddly enough from everyone I've heard the Boyessen Rad Valve gives better low end than the Delta V-Force reeds, which are geared toward more top end performance.

Don't be afraid of a port job, if you lose a little low end, it isn't that much of a big thing on these Polaris machines. You just push the throttle a little more and you're there.

A word about sprockets, you have the smallest rear and ther biggest front sprocket they make. If you want more speed, you'll have to get more RPMs ourt of the motor. If you decide to go with a port job, do your self a favor and get a Wiseco piston put in. the stock piston doesn't respond well to mods.

Hope this helped!

 

Thanks Mike,

Man, Porting is so tempting, but I really don't know much about these things and I'd hate to screw something up. It's probably the best bang for the buck mod out there after the pipes right?

If I lived anywhere Rick or HPD my porting job would probably have been doen a long time ago, because I could just give them the whole darn quad and say "Have at it". I don't trust myself, or many of the mechanics around here to actually do a good job even after HPD does the porting (I mean with the Jetting and stuff). I haven't had good experiences with them before.

Do you think that I'll see a fair performance gain with the V-force reeds? Are they good for a couple of mph's up top?

I reall want to get some more top end power. I'm happy with the low end, but plan to work a little bit with my clutch just for the heck of it.

Thanks for your suggestions. Glad there are guys like you around. Oh, so it looks like I'm SOL when it comes to my sprocket Idea huh [img]i/expressions/face-icon-small-happy.gif[/img]

Thanks again Mike!

-Josh

 

Piranha, like hypersport said don't be afraid of the porting, it will wake your engine up.
You can easily take the jug off yourself, it's only 4 bolts and send it to RCR or somewhere else that's reliable for the port work. I just took mine to the local pack & ship store and they packaged & shipped it for a few bucks. You can put in a new Wiseco yourself when the cylinder comes back and you're set. Trust me you'll love the power gain. It's only a couple of hours work and it's a nice performance gain.

 

I am having too many problems getting mine right these days so I will not say anything...but...Portingis the way to go. Power all the way through. The 12:1 head gives you more low end also.

If mine doesn't run this week...I am selling it for sure. (If you are still interested...hehe...)

 

Josh,

No problem, that's why I'm here!

The neat thing about porting is that the guys (Rick and Darryl) will give you the proper jets for the carb. Mainly it's just the pilot and main jet that need changing. Remember when jetting always go with the biggest jet they give you and work leaner till you get a nice crisp throttle response. When I had mine ported, I went from a 370 main to a 410. That'll give you an idea on how much more mixture is flowing into the cylinder from a 38mm TMX. I went to the 39mm PWK when I realized that the 38 wasn't flowing up to the potential of the engine.

The sprocket idea isn't a bad one. I thought about it myself, but for different reasons. I wanted the front end to stay planted and steering under acceleration. I ended going to a longer swingarm to get much of the same effect.

The Delta V-force reeds will give you slightly more top end and about 2 more ponies in the engine. The odd thing with the reeds is that you must jet LEANER with them. This is in direct contrast with porting, where you have to jet richer.

Hope this helps.