Seca 550 mods

Got to keep up with the GPz 550's













I need to figure out what I'm going to do for a front end. I want to run the stock 19" rim. I may try an RZ350 front end swap, even though the RZ uses an 18". Calipers and fender look the same. Both have 35 mm fork tubes. Might be an easy swap.

I'll post up some of the bike tomorrow.

 

woah. Looking forward to seeing it!

I wish I had a 550.

 

Oh boy! This is how it should be done!

 

Man, If I ever get a cage Ill have to "upgrade" my seca...cant wait to see it done

 

Where'd you get the swingarm?

 

Thanks, gentlemen!

The swingarm is from Ueda in Japan. The carbs are from Bito R&D in Japan. I also have a cool Seca 550 fender eliminator from Japan that I'll take some pics of. I cant stand cutting a perfect fender. Sure, it was cool back in 83. It's not easy to find a nice rear fender these days.

Carbs

http://www.jb-power.co.jp/

Swingarm

http://uas.jp/

make sure to use your Google Translate. :wink:

The bike. It's already got a few cool parts on it. It's only issue is the tank got smashed by the handlebar end of my GPz550 as I was moving from NC to NM. :cry:

 

WOW! Keep it up and soon you'll have a bike with as much power as a modern 500 twin and handle like a 15 year old sport bike. I'm just teasing you. If my bike wasn't so close to stock, and I had the access to parts that you do, I'm sure I'd be upgrading mine too. I did add SS brake lines and that is the best thing I've ever done to the bike. Some days I'd like to have to have the stock exhaust back on my bike, but then I just wind it up and let the Yoshimura howl and I'm happy again. Those shocks look like they would be very happy on my bike.
Keep us updated on your progress and let us know what is an improvement and what isn't. I hope you had a stern talk to the GPZ for hitting the Seca in the tank like that.

 

Where did the rearsets and cams come from?

 

I think I'll have the power of a modern 650 twin. :wink:

Handling is all rider and setup. I can't count the modern sportbikes I've checked out on when I lived in the mountains of NC. That was when the bike was bone stock.

I've kept all the stock parts, but I doubt I'll ever use them. I'll keep them because you never know.

I think all the mods will be an improvement. I sure hope they do something! If not, she'll look cool.

The Raask rear sets were with a pair of 82 Seca 550's that I sold last year.

The Yosh cams I won on eBay a couple years ago.

 

If you can find a XJ/FJ600 head they are a straight bolt on and have bigger valves and ports and there is enough meat in the barrels to overbore to fit the 600 pistons

If you can find a 1mm oversize set of 600 pistons it makes it about 576cc I'm just in the process of doing it to mine

 

Interesting. I wonder if my Yosh XJ550 cams will work in the 600 head?

So you can't just swap a 600 head on a stock bore XJ550?

 

Geez, you musta got the last one. Found and (entertainingly) translated the website and Ueda is sold out of the XJ400D/E swingarms.

At ~$985.00 (plus who knows what to ship) it's a bit out of my range anyway. Nice work though, they have some marvelous stuff.

 

Yes they will, I have both on my bench and they will bolt straight in, only difference between the 550 and 600 cam is the 600 has slightly more lify

Thats been done here on a couple of XJ550 race bikes and seems to work quite well

 

I did get the last one.

Shipping is not as bad when you ship a big box with several things in it.

Ueda does make some sweet stuff.

Any cam specs on the 600? Also, are the carb boots different between the two? They look the same, but have different P/Ns. Are the carbs similar in size where they go into the carb holders? I want to be able to use the CR's. They're set up for the XJ550.

Thanks.

 

Measuring from the base circle to the nose of the cam show the 600 has about .7mm more lift (thats assuming base circle is ground the same)

600 carb holders are bigger ID by about 2-3mm

 

Thanks for the help.

One more question. Will the XJ550 carb holders fit the 600 head?

 

Haven't tried swapping them, but without removing them the verniers say yes

 

Thank you again!

I may see if I can find a 600 head on eBay. It looks like I'll be able to make the cams and carbs work.

 

This looks like fun! Can't wait to see some pictures.

 

Personally I wouldn't bother with the XJ550 manifolds as you'll need to do a bit of port matching to the head and the smaller manifold will be a bit more restrictive than the 600, I'd be getting new manifold stubs on the carb to match the 600 inlet manifolds or just try them and see what kind of fit they are