82 seca 550 front end swap to dual rotors?

what is needded to do the swap from a 650 with dual calipers to my seca 550 1982? What are the doable donar bikes and what do I need? Forks, tripples, wheel and calipers?

 

First what is the Seca 550 stock tube diameter and length? Measure this first. Unless I'm mistaken the Seca 550 uses 35 mm diam. tubes (1.375 inches).

Then I'd start looking at Yamaha XS '80-82 forks as most came with slotted dual discs standard. Plus these forks are more rigid = less flex. You could look at transplanting an entire xs850 G Standard front end e.g. using the stock XS triple tree, fork sliders, calipers, discs; the works. Most likely the XS850 forks will have to be either clamped higher in the triple clamps or get trimmed to match the Seca's fork tube length. Make sure you measure the fork tubes for both bikes first. That is, if you want "no surprises" handling.

As for using the Seca's oem front wheel with other Yamaha forks, I'm not sure. Again, measuring will help here. I have seen Virago spiral type rims used on XS frames.

Finally, you'll get much better braking response, "clamping power" by installing dual stainless steel hoses and a Cafe Master Cylinder designed for dual calipers (dual brake systems need the extra fluid volume). I used a pair of Goodrich hoses on my xs850 Kruiser project. Even riding two-up the bike stopped like it had been dropped into a sandbank.

I believe bigfitz has crossover tech / build data available on the Secas and possibly other Yamaha models.

The oem XS dual brake system is quite powerful and would be a cost effective and significant upgrade for the lighter 550.

 

what about using the front end from a xj750 as they are easy to find and the forks are 36mm so they would be larger than the 35 that I have now?

 

Since the xj bikes have similar handling profiles that might be a good idea. Go for the whole enchilada - a full front end transplant.

Depends on how fast you and your wallet wanna go. Don't forget, you'll be adding another 30 lbs or so to your bike.

 

hadden't thought about that....

 

who is bigfitz? I would love to see tha crossover data

 

The 550 Seca uses an "under the tube" front axle mounting point, whereas all the XJ750 models use a "leading/in front of" axle mounting point. This change in axle location affects steering, braking, etc. in ways that may or may not be to your liking, or safe!

The "rake" of the frame steering tube ("neck", or headpipe as Yamaha calls it) was designed with such an axle orientation in mind.

The XJ650RJ Seca and the XJ650LJ/LK Seca Turbo tubes have the same "under the tube" orientation as the 550 Seca does, so they would be the most likely possible donors. Other issues will also have to be taken into account, steering crown intechange (will your stock handlebars fit the other model steering crown, etc.).

The rest-of-the-world (non-North American) XJ550 models all used dual front disc brakes from the factory, and their fork systems should be a direct bolt-in replacement for your system. Unfortunately, you'll have to find a complete front end from such models in the UK or Australia/New Zealand (that's where the biggest sales of such models occurred) and then have them shipped over, which can get kinda pricey ($100+). BUT, it may be "the" way to go in the long run. Dual front disc brakes sure are nice to have..............

 

well I ordered a full setup off a 650 turbo minus the front wheel as it is ugly, I did get a wheel off a seca 650 non turbo, I imagine it should fit, hopefully anyway.

 

If you can find a FZ 600 front end you can use that also. Just use a larger dia front rim instead of the FZ's 16 incher. I think I used the front rim from either the FJ 600 or the vision 550 front rim. LOL now I have to go out and check..I will take pictures since it's been requested before but it's pretty dusty!!! Also if you wanted to use the stock 550 front rim you can. Just pop off the plastic cover that is covering the other holes on the opposite side of the rim and get a rotor and voilla, a stock looking dual disk setup for the seca 550.

Sean

 

oh that is good to know, I might just use my stock rim, even though I like the look of the rim I bought, they also had the rear, but I do not think it would work as it was shaft drove and mine is chain, am I wrong? Will a shaft drive wheel work?

 

Nope the shaft drive rear wheel will not work for the seca 550, it must be a chain drive setup. Completely different style of hubs. I did manage to upload some pics into my gallery but it might take a day for them to get approved. That poor bike hasnt moved since I bought my house almost 5 years ago.. Lots of dust on her now and I really should start getting her back to street legal form. Get rid of that silly fairing that is on there now and find the stock bodywork!!! Bet that motor will still lift the front wheel up tho ROFLMAO gotta put a back one on there first.. Cavi where do you live, I might have a spare rear rim if you need one.


Sean

 

I am in northern cal in Red Bluff about 2 hours north of sacramento,
thanks for the offer on the rim, but I did already buy one on ebay so I sould be set.

 

Me but I can't take credit for the "front fork crossover guide" that was another member. However, chacal is right, the absolute BESTEST way to do it would be to get Aus or Euro market parts as those came with dual discs. All you need is the left fork leg and caliper, the wheel is as Sean described the bolt holes are there. I was going to do the dual disc conversion but decided to upgrade the existing brake with an EBC floating drilled rotor and ss lines.

 

okay, but do you have a general file on what fits from one model to another other than just fork swaps?

 

No but I believe that info is on a thing called the "XJCD" and there's a link on ordering it on this forum. Personally, I'm working on figuring out how to do wire wheels "correctly" using Yamaha parts.

 

Sorry I just realized what Taildragger was referring to. You can use the Yamaha parts fiche to run a part number back through their system and see what bikes it's used on. It's limitation is its by PART NUMBER. There are some parts that are identical except for say, color, but since they carry different part numbers they don't cross. I use this fiche rather than the "official" Yamaha site because the diagrams are bigger: http://www.babbittsonline.com/pages/par ... fault.aspx Look up your part number in "Look up by model fit" and then copy/paste it into "quick lookup" and you'll get the aforementioned list.

 

okay, looking at pictures of the 82 maximum 550 front end it looks identical to the seca, the wheel mounts at the bottom of the fork, not behind the fork like larger models. Are the forks the same length, as I am going to try and find a euro set of forks and I might find a maximum set before a seca set.

 

I might be able to get a set of forks from england, can anyone tell me that they are the same diameter and length as the usa version for the 550 seca 1982, I ask as there will be a decent outlay of money on a set of forks that are in shi# shape, I will really only use the outter tubes

 

Should be. The "rest-of-the-world" models (with the dual discs) use the same chrome upper (inner) tubes as the North American single-disc bike. I would bet (but don't have a parts books to confirm for sure) that ALL the fork parts for the Euro models are identical, save for that single left-side lower (outer) fork tube, which has provisions for the left-side caliper mounting.

 

thanks, I will keep posted if I manage to get them

 

also, is the 84 and beyond 550 a different diameter fork?

 

I thought that too--"ooh, all I gotta do is get some Maxim parts and..." WRONG. Maxims had different DIAMETER front fork tubes.

There were no US market 550s after 1983. '84 and beyond in the states was an FJ600 and I don't know if the forks were a different diameter or not.

I want to go to dual discs when I switch to wire wheels, and will probably scrounge up a left outer leg and caliper from the UK or Australia where the 550s were popular.

One last thought, and I haven't done it yet, is to play the "parts catalog" game with the SR500, which had the mounting ears cast in on BOTH legs even though it came with only one disc. Not sure on fork diameter though, it's only a thought.

 

Dude, do yourself a favor and get a Euro, Austrailian, Japanese xj400d/e left fork leg. Thats all you need. Then a Maxim 550 calipar and you're set. You can order the lines from HEL USA. You can use two Seca disks, or get some new ones from Len.

I'm going to try some RZ350 forks with air assist.

 

well it looks like I will end up with the lowers from a EU 550. The uppers are very pitted so I am only having the guy ship me the lowers to save on postage, or does anyone think I need any of the other parts?

 

Save even more by having him ship only the left fork leg.

 

Bingo. Everything else can be "parts room engineered" from USA market bikes. Start looking for a 550 Max caliper, or if the guy has the left caliper have him send that and you're good.

Now get a pair of these from chacal and you will be able to pick the back wheel up. (I'm going with one for now.)

 

P.S. the 550's (maxim and Seca) use the same (appropriate side) calipers as the 750 Seca models..........which are completely different and will not/do not/don't even try to interchange with the 750 MAXIM calipers.....

 

what about the calipers from a 650, I have both right and left since i was going to use the 650 front end?

 

650 Turbo calipers are the same as 750 Maxim calipers.....I don't think they will work properly..........you can try and see how things line-up.

 

Also, RZ350 rotors will work. You can usually find a decent pair on eBay.

 

I know but I think the EBC floating disc rotors are sexy, especially once I paint the inner section black...

 

Once you have your dual disk setup, it'll be time to step up to Brembo's.

Talk about some frame bending, fork flexing stopping power!

http://page18.auctions.yahoo.co.jp/jp/auction/w25554595

Here's the master cylinder.

http://page3.auctions.yahoo.co.jp/jp/auction/c201253299

That's a trick brake upgrade for an old Seca, if your frame and forks are up to it. :lol:

 

I was ALL OVER Brembo's site, trying to figure out which part number would work. Personally I don't think the 550 is heavy enough to NEED two discs I want to upgrade my existing ONE. (That being said, once I get the wire wheel thing figured out I'll probably do the dual discs too just for looks.)

I was just trying to figure out how to fit a dual-piston caliper of ANY make as an improvement over the stock single-piston unit.

Now if I could only read Japanese...

Cavi you need these!

 

Notice the aluminum adapters on the calipers? :wink:

They make it a direct swap on the Seca 550 fork legs.

 

Disregard previous post. I did the currency converter you'd be looking at over $462.00 before shipping how do you say OUCH in Japanese?

 

how are working that site as it is all in japanese, even at that price I might think about it, it just depends on what I decide to do with this bike. If I end up tearing it completly apart and doing a full frame up then it would be worth doing it, but I do not know if I want to do that yet. Fitz you mentioned that some 600 engines are a direct drop in, any idea which ones and if someone has done this before?

 

the british fork tubes are on the way, I am having them send only the lower tubes, as shipping will be much less and the sliders were real rusted and pitted

 

You should have told hiim to keep the right tube.

Also, RZ350 brakes will bolt up.

Don't ask how I know this.

 

Yeah, I saw that. And these should be available SOMEWHERE else in the world, maybe we just need to be looking for the Brembo kit for one side of an RZ350?

 

Would any of you guys buy an adapter if I got a pair and then have my machinist buddy make a few?

 

First what calipers would this work with? As long as it works with my forks I would probably buy them, and I had both sides of the forks just because I want to use both sides if possible so they match

 

YES. If it would bolt to the Seca 550 front fork and allow fitment of a Brembo dual-piston caliper pn (xxxx) I would certainly want one. (A right one, I'm just upgrading the original brake.)

 

well, small progress today, I ordered a set of silver forks off e-bay, the stock ones for single caliper, I did this before I found the euro fork, anyway, I put them on today as my stock black ones were leaking badly. I was shocked at how much firmer the bike was, I do not know if it was all due to oil, or maybe these forks have firmer springs, anyway, major improvement. I also finished the blinker swap, and replaced the pod that has the ignition button, as mine was broken and the previous owner had just jury rigged a dirt bike kill switch to the handlebars as a starter button, looked real sharp.......not. I also started my process of eliminating the horns, I need to get a smaller black one, for now I am only running one, right under the headlight