What single engine mod adds the most power by its self? I am not talking about pipe or filter, I mean like cam, bore, high comp, or a ported head.

 

Thats kind of a hard one because the cam, piston, high comp,& porting kind of go hand in hand. But I as far as a stand alone I would go with the polished and ported head.

 

Ward660- my vote is the port and polish. My raptor can BREATHE and EXHALE now. I had forgotten the raptor has a rev limiter on it. I find it now, my 686 does not run out of steam on top like the stocker.

 

With just a port & polish its not nesessary to get a high comp piston and new cam?? What kind of HP gain could a person expect from just the port & polish? Mr. Mcdermott, would love to hear from you on this as well as others. [img]i/expressions/face-icon-small-smile.gif[/img] TIA

 

I've been wondering about this myself for a while also. I know a guy that could massage my head but could I expect gains and wait till I need a rebuild to upgrade piston/cam ? I think so. Anybody? Thanks.

 

Our 686 and 727 motor for the most part have been made to run on pump gas and are obviously low compression motors. So it's not the compression that is the reason for the larger bore sizes.
( believe it or not ) sure we gain some cc size from the bore but the real reason for the size is to free up the shrouding of the outside intake valves. These valves are blocked from breathing properly by the bore itself. ( wide 5 valve intake design ) So to answer your question, You would get an increase in hp by porting the head properly even on a stock bore, but there is so much more there that could be had if you go that little bit further ( if done correctly ). The cool thing about a raptor head is it is a very complicated design. This makes modifying it harder for the average hi performance shop to do.

 

harry, been thinking about you guys and the 727. i love my cam that i already have. could it be used again? and by reusing it would it save me any cash with you guys? i have heard there was some reliability concerns with your 727. is this true? also are there any steps that i can take to get a quicker return on my engine? thanks.

 

Thanks for your input Harry. One more question please. If a person was to get your porting only now for the stock bore. At some point in the future if they chose to come back and get the piston and cam would another porting be needed to accomadate the new piston and cam? Thanks.

P.S. Just one more please. [img]i/expressions/face-icon-small-smile.gif[/img] On your web site you have a Port & Valve job for 3 bills and some change. What is done to the valves under this? Thanks again.

 

RichieRoadRash
Some of the early 727 engines experienced head gasket problems, These were rectified with a new design and have not given us any problems since. As far as using your cam goes we would be more then happy to look over the cam specs and see if they will accommodate the 727. We now offer two different compression ratios for the 727, 10.5 and 12 to 1 these compression ratios are calculated with our chamber work and will not be the same if the cc size of the combustion chamber is different. That said we have developed a cam that works better on the 727 and it should be used. As far as turn around time, we have been getting most of the 727 motors out within around 4 weeks ( if we have no backorders on parts ) This turn around time will probably get better as we move into summer.

 

Guys- you just need to bite the bullet, and get the full meal deal. My trinity motor rips. If you think putting a pipe/jetting and open up the air box made a difference. Wait until you have the whole package. I hate to spend money just like everyone else, but the 686 was well worth it. You wont be sorry. This is a very rideable quad. I was concered that it would be tempermental, but it is not in the least. The price is great compared to modding a DS. They can't get there from here.