Roadracing an XJ

I just wondered if anybody else is racing an XJ? I seem to be the only one out here. It is kind of lonely. Most of the people modding on here are more into the bobber style rather than the performance and handling side of things. I am much more into improving handling and brakes. I really like the 80's superbike look.

Ken

 

So, are you racing the Seca 550 or do you have something else?

 

The Seca and FZ600. The Seca in WERA and AHRMA and The FZ in WERA and CCS.

Ken

 

What have you done to the 550 for Race Preps?

 

Mostly Chassis and suspension work. I am running a stock motor and carbs with a 4-1 pipe and the rubber velocity stacks from the stock airbox. I rejetted up one or two sizes on the main and shimmed the needles.

I have Progressive Suspension rear shocks on it with an 84 VF750 forks and CBR600 Hurricane wheels. I am running a110-17 and 150-17 Metzler Racetec tires.

I need more power, but the chassis is getting there.
2 weeks ago at Vintage Motorcycle Days at Mid-Ohio





Ken

 

Get a set of Stock Cams from Ebay or a blown motor.
Find the "Technical Data" for the Stocker's Timing Curve, showing the complete cycle: Open, Closed, Lift and Duration.

Send the Cams to Isky after you call and tell a Race Tech you'd like a Checkered Flag running Iskenderian Cams.

Ed Iskendarian Racing Cams
16020 S. Broadway
Gardena Ca 90248

Phone: 323.770.0930
Fax: 310.515.5730

Be sure to tell them there isn't a lot of room for more Lift.
But, they ought to be able to grind you a set of Cams that will goose that 550 in the Midrange and and up.

If you get a 1/4 Race 0r 1/2 Race Grind the Idle won't suffer so badly as to telegraph to everybody you're running Hotter Cams.

 

Rick,
Thanks for the input. I have a spare Seca motor, so I have plenty of parts. I also have FZ600 parts, and the cams interchange, so that would give plenty of extra lft. In fact, I am looking at putting the whole FZ head on the 550 bottom end , although I may stick the FZ crank and cylinders on the XJ cases. It is all legal for the classes I run as long as I use the XJ cases. It will be the winter project using the spare XJ and FZ motors that I have. The main problem with higher lift cams is finding HD valve springs. Megacycle used to make a set but they are no longer available. I also have a set of 34mm FZR600 carbs that I am going to fit on there. They will kill the bottom end and not help the midrange but should give me some more on top, especially with it as a 600.

Ken

 

VERY cool Ken. I chatted with some old timer recently that talked a bit about endurance racing XJ motors. He mentioned silver soldering in the shims after they spat a few running it up to 13k+ rpms. (Until that moment the reason for shim UNDER bucket never occurred to me) Said with adequate springs and that patch/hack they never had any other problems redlining the ever living F#*& out of these motors. If you source some stouter springs that you think you like the buckets should have enough meat on them to bore out a few mm and lighten in other ways (I'm thinking a hole pattern sunk in around the boss that the shims ride in) Should take a machinist about an hour for the first one and ten minutes for each there after.
I've considered it on my spare motor but money is ludicrously tight these days and there's no point doing that while mine's only quasi road worthy and I'm pinching pennies to save for my next set of tires and brake pads.

 

I have seen a motor that spit a shim and it wasn't pretty. It fired the shim forward right through the head casting. All in all kind of amazing. I am not worried about spitting shims, since I don't rev it that high. My rev limiter kicks in at a little over 11K and I don' have the need to go any higher at the moment. I would worry a little about lightening the shim buckets. If they were to fatigue and break, that would cause all kinds of issues.

Ken

 

true, you always sacrifice some longevity when hot rodding, you just have to choose how much is acceptable for your own goals and accurately achieve that decided upon balance through engineering. As buckets are effectively part of the overall valve mass moved by the springs lighter ones can close faster avoiding valve float. As neither this nor spitting shims is an issue with the rev limiter in place then certainly there's no point. I just have this spare motor is all and would feel much more comfortable bouncing it up into the red if my own hands and carbide had carved on the internals. Nobody on the street NEEDS to do 50mph in first gear but I'd take some personal satisfaction believing I could.
Just throwing some thoughts out there for ya.

 

Hey Ken, are you the guy that goes by the same name on caferacer.net? Sounds familiar as I'm on that site sometimes.
I go by the nick name BANDIT in there.

 

Yup,
That's me. I pretty much am either on there or the WERA BBS. My focus is more on racing than street riding at this point. But I kind of like this board, too. It is more street stuff and bobbers, but I am thinking I might like to do a bobber the way I think it should be done, with more emphasis on handling and suspension. No cafe, but with the same philosophy.

Ken