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3 Plug Head???

8K views 56 replies 14 participants last post by  maxtrax 
#1 ·
I wouldn't consider myself a novice to raptors anymore, but I've been hearing about a 3 plug head. I know what it is. I just wanted to know based on the mods in my signature which includes just about everything except internal work, what would I need to do further to be ready for a 3 plug head? Or, can I do it now? And, how much does it cost to either get mine done or buy one? Thanks,
 
#2 ·
You need a Dyna FS programmable ignition pack ($200-300). You also would benefit from FCR carbs ($500) and a good port job ($500 and probably best to have this done by whoever does the 3 plug mod). The three plug mod itself is going to most likely cost you $500+. That is mostly external stuff without going into the motor.

Three plugging (IMHO) is almost a last step in the modding process. When you have everything else, unless you are doing it all at once, then do the three plugger.

Here is what I would recommend for inside the motor:
Get a heavy duty HR crank or have a heavy duty rod installed on your stock crank. Go with a good high compression piston, good cam for your riding style, heavy duty valves and springs. The FCR's are going to make your life alot better and you will notice a good performance gain.
 
#3 ·
Most of my riding is done in the dunes. So what cam would you recommend? Also the FCR carbs...What brand and size are those compared to stock? Basically what do I type into ebays search bar or the search bar for the classifieds on here to find them?
 
#4 ·
The FCR's are FCR brand. They come in 35mm and 39mm. The benefits are a flat slide carb with direct throttle control (not vacuum controlled). The FCR's also have an accelerator pump that offers crisper throttle response.

For dune riding (if mostly open area) you would probably want a megacycle x4 cam, which offers a little better top end than a hotcams stage 3. To make the most use of it you will need a good port job though. To feed that style top end for WOT riding you would want the 39mm carbs.

The 39mm carbs offer better WOT performance for a high volume setup.
The 35mm will keep air velocity through the carbs at a lower throttle position, making them better for on/off throttle applications

Here is a set of 39mm FCR's on ebay (I just typed 660 FCR). If you wait/shop here and ebay you can usually find them for around $500-600 used.
http://cgi.ebay.com/ebaymotors/Yamaha-Raptor-660-FCR-Carburetors-39mm-Carb-Kit-_W0QQcmdZViewItemQQhashZitem335c246490QQitemZ220589221008QQptZMotorsQ5fATVQ5fPartsQ5fAccessories
 
#5 ·
The FCR's are FCR brand. They come in 35mm and 39mm. The benefits are a flat slide carb with direct throttle control (not vacuum controlled). The FCR's also have an accelerator pump that offers crisper throttle response.

For dune riding (if mostly open area) you would probably want a megacycle x4 cam, which offers a little better top end than a hotcams stage 3. To make the most use of it you will need a good port job though. To feed that style top end for WOT riding you would want the 39mm carbs.

The 39mm carbs offer better WOT performance for a high volume setup.
The 35mm will keep air velocity through the carbs at a lower throttle position, making them better for on/off throttle applications
most of my riding is on off with occastional wide open throttle for hill climbing or dragging. Would I benefit from FCR's as my setup currently is with no porting or anything internal only the mods that are currently on my bike in my signature? If so I'll grab some now and continue using them after I do the cam and porting and all the other stuff.
 
#6 ·
You can use them with a stock setup but they require a different intake flange for your head. Sometimes you can find those on ebay or trinity racing, I think kenzcycletech and some others carry them. If you ride the woods and tighter stuff then you will probably want the 35mm.

The FCR's will simplify jetting alot and also increase the crispness of your throttle. My setup required me to unbolt my airbox and slide it back a 1/2-3/4 of an inch.
 
#7 ·
If I'm not in the dunes then I just ride around my neighborhood on the road. No woods or trails for me. Wide open dunes or pavement.
 
#8 ·
The 39mm FCR's might suit you. It really depends on how much air you plan on pumping through the engine. If you don't have a big cam and high displacement then you won't need the volume and the 39mm's will just cause poor performance. Really, building the engine requires lots of reading and research through threads and threads.

I have spent countless hours reading on here and finding out what works and what doesn't. Look at the big builder's signatures and seeing what they are running. I thought that I knew what I wanted but turns out 6 months later I had it back apart and was undoing some stuff that I overlooked in my research.
 
#9 ·
I hear you on the research. I don't really plan on doing a cam or anything internal just yet, but I'm thinking the 35's will work for me as of now and probably after I do that other stuff as well. Have you heard anything good about that Edelbrock single carb? I've heard good and bad. I don't plan on doing that, but I'm curious as to if its any good.
 
#13 ·
FCR's will make a diffrence in the 3 plug build, but is not a must have at first. I am feeding my 3 pluger with stock carbs for now & they work good. I plan on getting a set of FCR's soon.....Ya no what..I think the carbs are the only stock part on my motor, or damn close to it LOL
Im kinda suprised the OP didnt ask what to expect from the 3 plug head....:)
 
#14 · (Edited)
Just don't forget that anything that you do on the build internally - cam, porting, compression, etc - all works together. You can't just throw in a high lift cam, high compression piston, and bore the intake out. I calculated my build all out and I can run pump gas on mine still.

Also don't forget that the stock raptor connecting rods are known to be weak so don't get to excited with the power until you fix the heart of the engine.

This is the order I think most people would agree upon when it comes to an engine:
Connecting rod - anywhere you feel like too much power will result in catastrophe :(
Intake and exhaust
Cam, valves, springs, and porting
Carbs
Bore and (stroke or 3 plug... not both)
:DAlky/NOS/Turbo -:D:D

Obviously if you have an end result that you are trying to reach, for example my build:
Megacycle x4 cam
HV porting with Ferrea SS valves
102mm 12.5:1 piston
39mm FCR
Hotrods HD crank that has been statically balanced
Dynatech Programmable Ignition with WK custom tunes

You may want to consider the end build when purchasing parts. I would not have been able to get the 12.5:1 piston without first getting the x4 cam (would have required high octane with a stage 2 hotcam) This is why I did the cam, head and piston all at once.
 
#15 ·
I have run the three plugger for almost 4.5 years now, this mod along with running a stage 3 cam or an X 4 or 14, along with HV porting and FCR 39mm carbs have propelled my Raptors into the winners circle practically every time, whether it was atv pulling or oval track racing, I have used several different styles of porting, along with the 3 plug mod, but the three plugger mod is the most important in my books, it puts the engine into a new class, one of its own....................
 
#19 ·
I agree with Willy 100%. I dont have the FCR's yet, but I have had a chanse to race both a big 3 mod 700 & a 660 based 720 stroker W/ all the trimings.I devistated both of em from start to finish:). The 660 stroker guy got mad & wanted to run again, so we did with the same outcome:). The 700 guy is a regular riding buddy & he just went with it.. Also keep in mind I was basicaly just breaking the motor in & was not going all out with her.
Long story short, the 3 pluger puts the 660 in a class of its own.
 
#16 ·
willykiller, I have an 01 rappy with some mods already HR HD crank new with 10.75:1 686
and was considering to do 3 plugger with next stage of build,my question is how does it compare power wise to a 700 with big 3 ,the reason i ask is is it worth staying with a 660 and building it or selling it and starting a 700 it seems a lot easier to get more HP from 700.
I would like to stay around 65HP
 
#17 ·
Let say that is a good starting point for a three plugger.........and as far as comparing a stock cc 660 with mods plus a three plugger to a equally modded 700 without, no comparison, 660 clubbers the 700..........:D
 
#20 ·
Sorry to interject a question...This is for both Willy and Banshee. If I keep this junk yard dog I may consider the 3 plugger. I'm not looking for killer horse power on the top end like 10,000 RPM and up but mostly something that will make the motor rev up faster. I like the stage 2 cam for lots of reasons since I'm in tight woods mostly and I only run the 11:1 JE piston. Banshee, you seem to be confident the 3 plugger was the source of your noticeable gains but what else did you do at the same time you increased the number of plugs? what did you start with? was it a stock head then you switched to a 3 plugger with porting and bigger valves at the same time? or did you already have porting and larger valves then step up to 3 plugs. I'm just looking for some data to make a reasonable case for the investment. I also have two heads to consider as to which one I'd mod with 3 plugs. #1. has some decent port work and stock valves and #2. has considerable port work, +1 valves and throats cut to 87%. I don't run the 2nd head because I lost to much bottom end in the woods.
 
#21 ·
I started with a stock motor with a full Yosh pipe , K&N opend air box & jetted carbs. After my motor went bad I desided to pull the triger & build it up. Other than the Hot rod, stage 3 HC , & Ferrea valves the rest is in the head.. The 3 plug mod is amazing... Dont worry about loosing bottom end with the set up because I gained more low end grunt than ever before & top end is endlessss.. It revves so wickedly quick that you must hear it to understand how explosive it is..Now I am still running mu stock carbs, so I no Im being held back a bit so FCR's are in order when I get a chanse, Also a FULL suspension upgrade is a must have on my list. The front end is alwase up in the woods .
 
#29 ·
So in simple words, you guys are drilling and tapping two extra holes screwing in two spark plugs, adding two more coils and im gussing wiring them right to the stock coil wires and you guys are getting a extreme noticable amount of power?
 
#30 ·
as far as i can read they use the dyna for a special timing sequence of the 3 plugs, so they will not fire at the exact same time.
 
#33 ·
By chance do you happen to have pics of this creation? My curiosity is very heightened here.
 
#35 ·
Thanks for the link. I think im going to give it a whirl, i got a head laying around...
 
#40 ·
I have never Dynoed anything but the guy I bought my HV 3 plug head had it dynoed at 84hp with a 6mil, 106mm bore, FCR's and Barker drag pipes. I have not seen to many 660 build myself with this high of a number but I didn't start riding a raptor until last year and the 700's seem to make a lot more HP for the drag guys.
 
#43 ·
My DS has 2 plugs also but the Plug layout is Way different on the 660s and think that has alot to do with it. One int the center and one on each side of the piston in between the valves. I had doubts if the 2 extra plugs made a difference but it seems to on mine. I think it has more to do with being able to change the timing then anything.
 
#51 ·
You will need a full P&P plus a programmable ignition, while you’re there you mise as well open up the bore to a 686 to freshen it up a bit…

Also you will need a set of FCR Carbs to let her breathe a little better…. I have a set on order and ill post back with the results..
 
#52 ·
bent_links did you get the 35's or the 39's?
 
#55 ·
I wish you would have talked me into the 106mm piston the other day lol If you would have said that I would have bought one just didnt feel like splitting the cases again. I guess I have a new project for the winter. but I gotta get some use out of the 102mm I just got from kenz.
 
#57 ·
Yes the revving is much quicker. Like tbarker said, yes it would be the most noticeable on a bigger bore but thats not to say that you can't notice it on a 102mm.
 
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