Performance Upgrades

As some of you may know I am in the process of removing the motor from my 82 XJ750R Seca. It appears that the carbs are in quite good shape internally and compression is 120 cold on all but one cylinder(it is 100). I am planning to change the cam chain and dampers while it is out as well as do a ring set and check all valve shim specs.
While I have the motor out of the frame what else should I consider changing or checking? Also, what are some performance mods that can be done without major work. I am experienced with auto engines and am curious if polishing intaking and exhaust ports is feasible on an XJ. I am already planning to add a supertrapp muffler to my older MAC header and pipe as well as K&N pods when the motor goes back in. Dyna DC1-1 coils and some MSD wires are also on the list. What other options do I have (excluding cams)?

P.S. I know people have had mixed results with pods but have considered building a "cover" over them (open to rear or down) so as to "settle" the air a bit before intake. I also think that being able to restrict or open the exhaust almost infinitely will help me in tuning out the possible lean condition that I may experience even after a jet kit. Does this make sense?

 

If you are taking the Head off ... do the Valves and seals. The combustion chambers are nearly flawless on the XJ-Heads and there isn't much to gain Porting.

If you are taking your time with it ... I'd polish the Ports and the Combustion Chamber. You'll gain a little performance ... but, there isnt much to gain because they did such a nice job making the Head.

You might find a Casting imperfection that's causing some carbon build-up ... Easily taken care of with a sanding disc on the end of a Dremel Wand.

Do as much as you can reach. There's no water jacket and you can only make the Head run cooler.

 

Rick-o-matic, thank you for the quick response. I have read many of your posts and have learned more about motorcycles through this site than I could have ever done on my own.

What is your opinion on Supertrapp mufflers? Will it give me the adjustability that I think it will?

This question is for anybody who has input on the subject. I am not trying to exclude anyone by "talking-up" Rick-o-matic. I just feel that people who provide so much information to so many (at no cost) deserve a little bit of thanks once in a while.

Thanks again to all who participate in this site. Sorry for going off topic!

Regards, XJ750GUY

 

I'm taking care of the stock system. I'm a stock guy! But, I will say that eventually we all will be the aftermarket exhaust market, soon enough.

When that time comes, ... I'm pretty sure I'm going to make my decision based on the requirement that I won't have to Re-Jet to make it work.

As far as I know, SuperTrap is as close to straight-out as you can get. That means you'll be playing the Re-Jetting Game.

I have my big "Water-cooler Jug" accumulating the savings-up I'm doing for a MOTAD Stainless System.
MOTAD claims it goes right-on, fits, don't block the Filter, leave the Center Stand on and there's NO Re-Jetting.

MOTAD does a Huge business in Europe.

When the time comes ... I'm striking up a relationship with somebody from the UK who needs stuff from USA.

There's an Underworld of Members that Chop, Mod, Rad-Mod and Pod, in here, those are the guys you need to tell you about Performance Mods.

Me?

I felt guilty ditching the Stock Headlamp for a SilverStar Bulb!

 

the biggest gain i got out of my xj was knife edging the crank. it usually costs 300-400 bucks but was worth every penny. there are aftermarket tdi ignitions on ebay that are pretty cheap and help play with the timing curve for better top end. after i port and polished the heads and knifed the crank i got another 20 mph out of my bike.

 

How much material do you remove when you take the blunt surfaces off the Crank?

My impression of the Oiling of the Engine is the the crank isn't splashing through oil. The Mains and Bigs have their separate feed. Although the drawing is a bit confusing.

Do you do it for Drag ... or, Weight?

If you haven't been to their Site and called-in to speak with one of the Isky Team Cam Professionals ... Iskendarian Racing Cams of Gardenia California can reface the Cams with a slightly hotter Duration.

I think the Stock Cams are precariously close to all the Lift you can get on them.