talked to trinity yesterday said they have a ds in the shop and working a big bore for it now. should be done in a month. what that means for the open market not sure.

 

they are a day late and a few dollars short for me, ( actually they originally posted that the big bore kit would be ready late summer) Do you know if it's gonna be a stroker? It'll be good to have more options if they actually offer it. Hopefully someone will have one for 4SW.
I was doing the numbers and a big bore , say a 690 would actually be pretty cheap for the DS. A 103mm bore renikasiled jug would run about $225-$250 a new 12:1 forged piston around $225, so with shipping you should be able to hog it out to a 690 for under 5Bills.
Any one interested?

 

What about cams, and all the other stuff needed??

 

head and base gasket about$50. Cams are optional- the stock cams aren't too bad - but a popular set of race cams from say Web or TVI would run about $265. There are quite a few folks that would argue that you'll get better cylinder filling with the stock cams and bigger valves than with just higer lifting longer duration cams.
I have a dyno sheet from samco and they made a full 10 more hp on top with their cams and their 720 kit- this was with the stock carb. I don't know if they had a pipe on it or not. The rest of the curve is just as impressive with 6-14hp gains thru out. At the price of their kit you'll get about 1hp for every $125 you spend. Pami's kits are about 1hp for every $200-300 you spend- the $703 being the better bang for the buck.
I believe that you would see about a 5hp top end gain and very similar gains thru the whole power band with a 690 kit( no cams). I believe that if some one developed the kit and market it for around 5-6 bills they would go like hotcakes. 5 bills is about the cost of the 45mm carb that woods sells and you don't get a 5hp top end gain with just a carb. You could pay 5 bills for a pipe and you won't get a 5hp gain top end. The rappys' have had 690 kits for over a year why hasn't some one jumped one the band wagon for a cheap kit for the DS.
My point is that I believe that it would be the best bang for the buck out there and a great place for guys looking to build their DS's to start. any takers? Marky? Trinity? Samco? Tvi? bueller... bueller??

 

I thought CT Racing had some sort of bigbore deal going on, and that someone in the forusm bought it and he couldn't get the head to seal properly. Or was that a larger diameter cylinder/bore? The 690 deal sounds like a good idea, if you can make it work I think you're right about it's popularity.

 

ct had a 105mm bore but it did have a problem sealing. samcoe already has the 690 kit and it is about 600 bucks. azsand tried the full 720 but it popped bad. but with a few changes it might be a great set up for the price. sam is also working on a 830 kit, said it wouldn't be much more than the 720.

 

I am pretty sure you can get a 680 from Pami.

Piston $345
Cylinder $320 - 102mm (exchange part)
Gaskets $80

(Prices are in Euro with a $1 = approx. .95-.97 Euro)

This is a 703 without the stroke.

703 Parts List

More than the $5 bills Major is talking about but, this price is more in-line with what the Yammy guys are paying for their 686 kits.

Anyone ever race a 680 Pami vs. a 686 Trinity? How does the 703 Pami do against the 686? How about the 727 Trinity, how does it do against the 703? The 760? I may have to wait to FSW's to find out.

 

when i ordered my 760 pami gottfried said that an 830 is already done but the guy who paid pami to develop it owns some kind of a hold on the new kit til springish? but remember when pami puts out there kits there more than just piston,cylinder. extra large cooling jackets, higher volume oil pumps with restriction jets to the top of motor,different bearing,crank improvements ect. just bolting on a huge jug and running 12.1 piston is like shooting nitrous thru a stock motor, you'r asking for trouble. spend you'r $$ smart, you need a solid platform from which to build horsepower from there are no goog short cuts!!:

 

samco told me that they did not have a piston with the correct wrist pin heigth to fit the stock rod so when I was looking at the 690 option with them It was a no go, otherwise I would have done it in a heart beat.

Obviously to keep the total price of a kit in line with my previous projections, you'd have to be willing to do the work yourself or you could easily double the cost by having a shop do it.

Jeffroe- maybe you could shed some light on the oil restriction purpose for the head, doesn't make a lot of sense to me. Why restrict flow? just for increased pressure? any time you restrict an oil passage that's gonna be the first place that a piece of debris will clog. Also the "new" bearing cup "with increased oil flow" is now a standard part upgrade from Bombardier. I replaced my bearing cup with the new and improved and Gary@ TVI says that's what the upgrade bearing from pami is?? ($25 part)
Bigger water passages in a bigger jug is always a good thing but now we're talking big bucks!

 

because of the increase in volume and pressure all that extra flow tends to cavitate the oil rather than flow thru (i'm no tech this is what i was told) it souds like there is already a oil jet of some type allready in there? i don't build motors, i like to let the guys who really know there sh*t tell me whats what and go from there. installing all the aftermarket goodies outside the machine is fine but i wont go inside the motor, robertson cycle is a real good place to have the things that are out of range for most to handle. and yes a new cylinder is big bucks but any big gains for a 4 stroke aint cheap!!