BadTwin said:
Hi all. Planning a build for my 91 fxrs and i'm wondering if I have to stay with 1340 jugs? I want the black and chrome finish but i'm having a hard time finding these in the 1340's. (as take-off's)
TC88's wont fit, right?
Any popular build combo's for evo's? (I havent searched yet)
Well... here's what I've been running, and I love it!
I kept displacement at 80 inches. Shaved the heads to increase compression ratio to about 10:1, stock pistons, stock heads ported and flowed by a shop in Michigan. Stock diameter Black Diamond valves w/ 5-angle cut, Comp Cam valve springs, EV-27 cam, Dyna 2000i ignition, S&S Super E carb w/ Yost Power Tube (eliminated all hesitation/spitting), V&H Pro-Pipe HS exhaust. I'm getting HP and torque numbers in the 90s with this setup (enough to walk away from my friend's Stage 2 Twinkie)

. This winter, I'll be putting a higher lift cam to take better advantage of the flowed heads... most likely the Woods W6H. Gonna need roller rockers with that cam's .590 lift. That will probably be the only changes I'll make. That should bump my torque over 100... don't care about the HP, torque is far more important for a street bike. The EV-27 cam is one of the best "bolt-in" cams for an EVO street bike. It has short duration which means more torque in the low to mid rpm range. That's why I'm going with a higher lift, rather than a longer duration cam. I want to keep the most torque in the rpm range that I ride in most.
You will notice a major improvement in perfomance by just using a good carb, cam, and exhaust. A 2-1 exhaust is the best for torque. There are only two 2-2 systems that perform well on a street EVO. They are the Python III and the Bartels systems. Nothing else compares.... Also, EVOs do not like drag pipes!! They will kill a huge amount of your torque!!
You made a good choice for a cam. A word of warning, though.... this cam makes a LOT of noise! I have seen many people waste a lot of time and money trying to get rid of the ticking. I can tell you that only about 20% of the EVOs I've seen are reasonably quite with this cam, even using the stock cam gear. This is due to the cams fast ramps, and the extreme angle that the front cyl. exhaust pushrod is at in relation to the tappet and rocker arms. This is made worse if you shave the heads. Mine makes a heck of a racket, but I don't care because it runs GREAT! It's still a lot quieter than my old XLCH. LOL!
Concerning the displacement... it doesn't really matter what's "popular". 80 inches is all you need to get plenty of torque for the street. With the right combination of parts and proper tuning on a dyno, you can easily get numbers in the high 80s to mid-90s. Even 100s are possible with more time, money, and effort. Don't just upgrade the engine size for bragging purposes. Personally, I wouldn't change the jugs/pistons unless the old ones are damaged. On the other hand, boring it .040 will give you a slight increase in power, all other things being equal.
Good luck and have fun!
