660 to 700 top end conversion kit

[Eddie7]

Re: Raptor 660 conversion kit‏
From:  White Knuckle Racing (whiteknuckle.1@netzero.net) 
Sent: Tue 2/17/09 7:17 PM
To:  Eddie L Grant ()

We are currently working on putting together an entire kit to convert the 660 to the 700 top end. We will have a complete cost figured out next week. Feel free to give me a call next week for more info. Thanks, Eric
----- Original Message -----
From: Eddie L Grant
To: whiteknuckle.1@netzero.net
Sent: Tuesday, February 17, 2009 5:30 PM
Subject: Raptor 660 conversion kit


Do you make a kit to convert my 660 to the new style 700 cylinder head design? From what I was told the new design is much more efficient and make more power.

[disco]

That sounds very interesting and very expensive. Would it be FI did they say?  If I had the $$ I'd do it just to be different.  That 660 5-valve design always looked weird to me.  It obviously works but again, I'd like to change just to make people scratch their heads.

[Krandall]

I believe they are just using the head. Not converting to FI,

[Flynbyu]

You wouldn't gain anything by adding fuel injection other than extra weight.

The power delivery would be smooth, but the 660 doesn't have the clearance in the frame for fuel injection. Upgrade to the 686 kit, throw a new cam in, re-jet and you're hauling ass. That motor will rev harder than the 686 with fuel injection!

~Brian

[Krandall]

+1 FI is heavier. PLUS... there's be extra wiring you'd need to go to the TPS and to the injector itself... Only reason for the head swap is to go to the 4 valve design which is much better than the 5.

[Eddie7]

The 4 valve head is the reason to do this. I have yet to figure out why they would cram 5 valves into 1 head. 

[Flynbyu]

Who knows.

If we could only speak Japanese to ask why.



~Brian

[Peelz]

The 4 valve head is the reason to do this. I have yet to figure out why they would cram 5 valves into 1 head. 

more valves=more power. It is 3 intake valves, right? It was a way of getting a lot of power out of a relatively weak engine. From the utility family? Or so I read.
I know the 660 motor started it's sport tuned life out on a dirtbike in Europe.

[Eddie7]

True, but you cant get more in if it cant get it out. 

[Peelz]

True, but you cant get more in if it cant get it out. 

I guess the original design was kind of starved for intake. Thus the twin carbs for a single cylinder. And another valve. Everybody I know scratches their head at that one. I think the exhaust valves are bigger, though. Maybe This would explain why the ole' 660 had so much low-end, but felt like it went flat at higher revs. hmmmm.


ANd, I am very interested to see what gains you will see.

[Mad Dog]

Still not getting the point.

[4stroker]

down in alabama at the outlaw drags last october there was a 660/700 running the entire 700 top end including the fuel injection running low 4's. yamaha must like something about the 3 intake valves
they keep putting it in there 450.all the engine builders  i talked to would like to see the 4 valve head.

[Mad Dog]

The 700 motor has come a long way in terms of aftermarket development in the last year.  If you're serious about building a drag motor the 700's bottom end has plenty of advantages of the 660's, so the primary reason for a head swap would be to use parts you already have for the bottom end with the new top ends.  Sure there are some, but many of the country's racers will end up switching over to a 700 based build (many already have).

For the guy with a stock bottom end I'm having trouble justifying this, especially without the EFI.  Why not just buy a used 700?

[Eddie7]

From what I was told the bottom ends are the same. And if your making serious power you probably should upgrade the rod and crank in either. EFI is nice but it weights 10 lbs more and doesnt increase HP enough to justify it. I probably have 10k into my 660. So I cant justify selling it for 5k just to start over again with a new 700. Now if I was a turbo guy I would say 700 all the way.  :grin_nod:

[Mad Dog]

The bottom ends are not the same, though I too suspected they were when the 700 first came out.

As for the EFI, compared to what?  The Edelbrock doesnt flow enough for a 5 valve head, let alone a supposedly better flowing 4 valve.  Stock carbs need help too, even if you did adapt them.  So unless you're sitting on a pair of FCRs or lectrons with a very efficient and lightweight method for putting 2 carbs into 1 intake manifold port or a huge single carb (which is still going to cost money and weigh something) then I still think EFI is the best option as it will make significantly more power on a built top end than stock carbs and can flow or be modified to flow more than pretty much any of the off-the-shelf single carbs.