I can beat any stock 450 in a drag up Sand mountain (Utah dunes). With piped yfz's its hit and miss, but any other mods they smoke me. Whats my next upgrade???

 

Head work(Including Valves and springs, Cam), Big Bore Kit (690 or 730) and a Rod. Thats all and you be surprised !!

 

Thats all? You just named about 2000 dollars worth of upgrades...

A higher compression stock bore piston, a new camshaft and springs, and good tires go a long way and should put you awfully close to most bolt on yfz's.

But if you're getting a yfz, why upgrade the rap? If the engine is still unopened you dont want to take it apart then sell it, better resale when its mostly stock.

 

with my mods, piped/jetted yfz's are no problem and I aint got $2000 worth of mods. Do what I did...buy the parts and install them yourself. Any competent human being is able to work on these engines. Competence and some help get you through the install.

 

Has anyone ever explained the reason the already huge raptor engine has such low power output for its size? From its specs they should easily have DS power . Is the exhaust that restrictive or just a wierd bore /stroke combo. Ive always wondered why they have to be modded to beat much smaller engines.

 

It's a mild engine in stock form. Low compression, restrictive exhaust, and poor flowing intake ports are the major contributors. But in modded form, they're almost untouchable. YFZ's, DS's, and TRX's don't have near as much potential.

 

It generally takes a higher compression piston, a hotter cam, and some porting to beat a bolt-on YFZ consistently. We have several YFZ's and Rappy's in our camp. And that's been the general consensus. The YFZ's light weight, quick revving engine, and close gear spacing make it tough to beat in a hill shoot or drag.

 

Why does everyone think the DS in stock form is faster than a Raptor? I have been wondering this ever since I purchased my First Raptor and dont understand??? I have raced several stock DS's in the beginning and have never been beat by one since. What gives??? Did they upgrade the DS engine ever since they first came out???

 

I agree.I think a stock DS is slow,but with a pipe,k&n,and some internal engine work these bikes really wake up.Seen some really fast ones.

 

Hey pitdawg,have you removed the air lid and jetted accordingly?