Raptor720 who do u think is the best engine builder? I want to build my engine so that it is reliable yet awakend...I was thinking 686 or I think sparks has a 690, what is your oppinion????what compression, cam, springs, air box mods, and exhaust do u recomend?? I have the FMF header and powercore iv spark arrestor with the arrestor screen ripped out. I havnt done any airbox mods yet because I dont know what to do or what jets I will have to go to...currently I have 150/155 jets everything else in the carb it how it came. Any suggestions or help would be greatly appreciated....

 

I have spoken to the owner of "CT racing" in CA, who offers a 720cc 11:1 kit (they used to offer it in 12:1, but they coudln't get the engine to turn over easy). If you have the money, and the time it is a great kit. but you have to split and machine the cases to fit the new sleave and the quad is going to run hotter. It is greatly suggested that you match the high compression w/ a nice cam. I recently just went through the same thing, I was going to go w/ the 720 kit but the $ aspect and all the extra work scared me off. So i went with .020 over in a 12:1 with a white brothers cam, and matching white brothers valve springs and titanium retainers, and new valves (cause i melted the old ones, whoops). who else out there makes a big bore kit for the raptor? CT was the first kit that i had found.
jay

 

Best bang for the buck is the 680 kit. I have had the Trinity 680 kit now for around 6 months or so and am extremely happy with it. I have yet to find a raptor around my area that come close to me.

There is one problem with just boring and installing a larger cam and is you need to have the HEAD PORTED to get the most out of the piston and cam. The +2mm center intake valve is another modification that Trinity does and that helps you get the most power out of the other modifications.

Outside of Trinity, there is only one other company I found knowledgeable enough to consider having this type of work done. Bikeworx. There is a reason these companies have been in business as long as they have.

For the cost minded individual the 680 kit from a professional builder (trinity ot bikeworx) is the way to go! The increase in power from top to bottom is amazing compared to stock.


Good luck!

RE: the Sparks 690 kit, I haven't heard any feedback from anyone using this kit.

 

I think that the best thing we could do as customers is to not use CT for anything. This would be a good response to show CT that we don't appreciate his slanted Dirt Wheels Raptor Pipe Shootout article. Perhaps he will then realize that he must change his ways.

 

I am on the Curtis Sparks schedule for early march to have his 690 kit installed on my '01 raptor. Trinity and CT make a great kit...so does Powroll... I choose Curtis Sparks for his reputation with motor building...His record shows that he knows exactly what needs to be done when building a motor....Although from a cost standpoint his kit is not cheap...other factors that made me choose his kit over everyone else is this.....his kit comes complete with 102mm JE 10.75:1 piston, cam(mx), port/polishing, 3angle value job, clutch kit, Sparks X-6 full pipe, super charger airbox, (2) 35mm FCR carbs.... i choose his kit because it comes as a complete package and he is prolly the best builder around...i am not against trinity or ct or powroll...but his kit is a complete package....for $3000 you too could have the work done...but his is so busy now, you wouldnt have it done until after march sometime...this is just my opinion, so take it for what it is worth...i will be racing my raptor in new england this coming summer, so if your in new england and race in the NEATV-MX series, come by me and i will let you check out my setup....My racing number is #352...good luck with your decision...
herbdon out.......

 

A $3000 Sparks 690 kit?? How did they do the math to turn a 102mm piston and 84mm stroke into a 690 (or did CT do the math)?? Last time I did the math, it was a 686. On those 35mm FCR's on a 686 -- your stock carbs will work better than the FCR's for your application. The FCR's don't fit worth a damn. Also, that the 102mm piston that you mention has fairly low compression. One final thought, your 3 angle valve job is not high performance by any standard. In fact, a basic 3 angle valve job will hurt air flow.

Here are the popluar prices ---- piston $200; cam $200; Sparks pipe $500; air box $200; 3 angle valve job $100; bore cylinder $75; clutch kit (plates, fibers, springs $125; unnecessary FCR carbs $800; porting $250. That is $2450 without assembly.

I suggest that you trash the carb idea, modify the stock carbs, get a better valve job, add valve springs, and increase compression. Since I have yet to see Sparks port work, I can't comment on what that may need.

 

ct,sparks,prowell,fst,trinity,bikworx,ect.,they all seem to use either a ross or je piston,all use a web cam,some recomend valve springs some dont,basicly most charge a inflated amount to bore a cylinder,what it all boils down to is head work,who can port the head the best. wouldnt it be nice to see flowbench data from all the differnt shops,but have a independant source take heads from them and test them all the same day on the same bench,at the same lift,ect.i too agree dirt wheels sould have found someone like dyno jet to run the quads for the pipe shoot out,i also think they should have run them all with a airbox lid then without,using the dynojet jet kit both ways.

 

If you can get DW do do the test on the flow bench, say at a high perf street engine builder's shop on a SuperFlow600, I would participate in the test.

 

All these shops, and I have visited both Powroll and Trinity's machine shops, know what they are doing, Pete at Powroll was playing with a 750 big bore stroker Raptor and was in the planning stages for some major Raptor Head surgury after flow benching both a Raptor head along side a race YZ426F unit, they have flowed all sorts of combinations to death......

however it would seem that Trinity have figured the current HOT combination...... having meet Harry MacDermot and seen there protoype machine shop I'm not surprised......

Cams, don't for a minute think that a web cam is the same as a Powroll, Powroll ownes and has agreements with commercial cam grinders that Powrolls grind specification belong to and are trademarked to Powroll and I know that Webcam will not sell you a Powroll profile even though they often manufacture Powrolls cams. You can bet that Trinites profiles are similarly unobtainable outside Harry MacDermots machine shop...

Just my thoughts on the matter....... at the moment i'd go for Trinity if i had the bucks to do a full engine build ..... but I know that just maybe, something really wild could be coming from Powroll <grin>

Kiwi

 

Just to set the record straight I mostly have WISECO build my piston's when I do 50 or more [such as my 12:1 686cc piston's].As far as cam's go I do the same thing we did when I worked at POWROLL and that is we take grind's that are all ready out there and make them better for the type of riding that atv will be use for[It's call R&D].You will pay more for a cam from POWROLL,SPARK'S or my self but you get your money's worth.Doing a good 3 angle valve is part of port and flow work and if you did a DYNO shoot out on all the top engine builder's head you would see very little difference.There are so many way's to build each engine that when you choose a engine builder make sure you tell them what you want but then listen to what they say all so.