Hi all, I'm new to the forum but not new to bikes, engines or performance by any means. I have a trailblazer 250 I'm preparing to mod a bit because it's a natural born dog (gasps with surprise). Before I get any "blah blah blah junior" stories, I have owned several bikes including a WR400F and a YZ490 modded (ported, piped, carb, bored etc) So I know what a decently fast bike is. I also ride super bikes and that's why I have my trailblazer (knee injury, can't start the YZ anymore).
My intro aside, what I am considering doing very soon is going with a cyclone 250 cylinder bored 20 over, run a wiseco piston and a moderately shaved cylinder head, probobly run a hpd trail pipe by suggestion from Rick Ritter (whom will be supplying most if not all my parts). I will be running a HPD MTQuiet silencer and bump my carb up to a 34mm scrambler unit with the throat bored probobly 1mm (so 35mm). It's a roundslide carb, but it should fit with the original airbox to my understanding. I'll also be using a foam uni-filter. I plan on running stock gearing with 20" holeshots on the rear and 21" holeshots on the front and +5" width front and rear. And of course clutch it with primary and secondary springs and weights, but I'll probobly forego the helix.
So do some of you with experience on these machines think this will be a descent set up? I crave power, but like to stay on the realistic side, often times 1-2hp on the top comes at a hefty price of torque and ultimately makes a slower trail machine. Do you have any recomendations? Would I be better with a 35mm TMX Mikuni? Or will it not be worth the extra cost? Should I go for the top end pipe over the trail pipe? The cyclone cylinder ports should have me running around 7k rpm... well thanks for the help

 

The stock carb for a Cyclone was a 38mm, so you will be going backwards with the 34. Also the boots are different. Good luck Doc

 

IF you dont already have a Cyclone cylinder the stock ones port out real good.
Porting,mill the head .020,HPD pipe,matching clutch kit(red/yellow primary spring,S58 weights,gold or violet secondary),TMX35 carb,Allumium wheels.And these little 250s will rock.

 

Thank you for the information on the carb Doc. I'll probobly go 38mm in that case, I had assumed that would have been to large, but good to know! Also I plan on buying the intake and intake boot for the cyclone cylinder, because if I'm not mistaken the cyclone has a larger intake.

ftwflh- I already have a cyclone cylinder procured and bored, this will prevent me from having to have any down time....i'll be going from 19whp to 30+? whp in one shot LOL. Thanks for the clutch spring specs!

Thank you so much for the recomendations, I'll definately talk those suggestions over today when I talk to rick about what I'm going to order.

 

ftwflh are those springs and weights from polaris? I know that the spring rates can vary per manufacturer and color coding. Just wanted to verify. Thanks

 

Those are HPD springs and the kit is matched to the HPD pipe(the best performer for the 250)

 

Well, I placed my order today: Cyclone cylinder 20 over, wiseco piston, rings, wrist pin and bearings, gaskets, intake, modified cylinder head, 38mm TMX carb, Clip on unifilter, HPD pipe, MTQuiet silencer, and clutch kit tuned to 7k rpm max. I may be missing something, but I think that was it. I'm pretty pumped about it. I just need to try my best to guess jetting on the 38mm carb....any clues?

 

I just joined this site because of my interest in souping up my girlfriends 1993 polaris trail blazer. I'm the type of person that loves watching old beat the new. I raced vintage snowmobile ice ovals and fell in love with the old polaris's. The past two years on laborday weekend I've raced her trail blazer in the WATVA's offroad challange. I raced in the 400cc and under 2 wheel drive class and placed second both years. I ran against 300 ex's,400 ex's, 350 raptors and smoked the majority of them. I am going to build it all out this winter for next year and want to take first. Third times a charm. I learned that taking the baffle out of the stock exhaust will gain about 3hp. Alot cheaper than buying a pipe and silencer. I have a seperate pipe for this along with jug and head. I have a little porting experience and would love to know if a person can port and campher the jug of a 250 trail boss to a cyclone profile. along with the max mm that the head can be shaved. I have more questions but I'll wait for feedback first.

 

Taking the baffle may gain 3hp, but a pipe is where the gains can be had. Pipe and silencer is worth 7-8hp on these quads. But check out some of the dynos on aaen's site and HPD performances site. Also rick ritter from ritter cycle racing has some great deals and is super to work with. He can get parts from Aaen and HPD and put together a comprehensive kit for you and offers great prices. I got all my parts from him. They should be here in the next week so I'll keep you posted, but I should be looking at between 32 and 38hp which will be screaming compared to stock. As far as milling the head goes depends on what type of gas you're runnin. If you run race gas you can go with a tight squeeze, also modifying the squish band region of your head is worth while once you start bumping up the compression. You can port your cylinder out actually larger than the cyclone, but then you have problems with running good CONSISTENTLY. It will tend to heat soak I am told. The cyclone cylinder is about equivalent to a trail port job to my understanding. If you have any questions don't be afraid to ask and I'll try to help you as I know others will. Also Aaen, HPD and Ritter have all been helpful in answering my questions over the phone. Best of luck!

 

I've built a couple of polaris snowmobile moters which this if basically the same but it is my first polaris atv buildup. I greatly appreciate everyone's help and i'm sure I'll be asking more questions. thanks