GS650 Front End Swap?

Hello everyone, been a lurker here for a little bit but finally picked up a XJ550 yesterday.

Seeing as my bike only has the single brake setup, I'd like to upgrade to a dual. Luckily, I found someone selling a front end off a 1982 GS650 for $45. Is this swap even possible? If so, how hard would it be? I guess my major concern would be if it would even fit? Will it be a cost effective swap? Any suggestions or advice are greatly appreciated. Thank you.

Here's a picture of said front end and of my bike:





I apologize if this was covered as I couldn't find any information.

Cheers,
Mike

 

No idea weather it would fit but if you what to go for the twin disk set up, then you would probably bettor of buying a European xj550 front end. The only problem would be weather or not you seca front wheel has mounts for a disk on the left had side?

Sorry I couldn’t help with the GS front end.

Al

 

I won't profess to know anything about front end swaps.

My thought...if you had $45, buy it and try to install it. If it doesn't fit, or not without custom made parts (etc.), sell it on.

The forks on both are 35mm, so you could just swap the fork tubes and use the stock yoke/triple-tree. If you do that, the only other size-consideration is the axle/fender, which may or may not be too wide for the 550's triple tree.

Source: Do The Ton - Fork Tube Size Reference

I say go for it, and see if it fits!

 

I picked this up because it was local and cheap. Couldn't pass up an entire front end for $45. I'm sure trying to source a euro xj550 front end would put me way in the red for my budget. I don't know if it does have mounts for the other side anyway. Thank you though.

 

Thank you so much! I was looking for some kind of reference chart to compare the forks. Since I couldn't find it, I just busted out the ol trusty tape measure. My only concern is the spacing between the two forks. I haven't had the time to disassemble the front end to get a straight measurement but they seem to be very close but we'll see later this weekend. Thanks again for that.

Cheers,
Mike

 

i would swap the whole front end. according to http://www.allballsracing.com/index.php/forkconvertion the steering bearings are the same on those bikes, top bearing being 25x47x15 and bottom 30x55x17.

the steering stem might not be correct lenght but then you just swap the stems.

do it mate and post pics!

 

You sir, are amazing. Thank you very much for checking that for me. I should have some time tomorrow, let's see what happens. I'll keep you guys posted. Thanks again.

Cheers,
Mike

 

That's gold, Jerry. GOLD!!!

 

Okay guys, I successfully removed the stock front end with some serious elbow grease but I ran into a bit of a wall..

As you guys pointed out, the fork diameters are the same (thank God) BUT the spacing between the two forks are not. The GS650's forks are closer by a few mm. While my main plan was to just pull the front end off and reuse the stock triples, this spacing issue has left me no choice but to go with the GS650's. I did a ROUGH measurement of the stems and they seem to be the same, give or take a mm or two.

Unfortunately, the GS650 front end did not come with a top triple so until I can source one, I am at a standstill at this point. I've seen some on eBay so hopefully one of them will do the trick.

If anyone has any concrete information regarding the stem lengths or compatibility issues in general, please feel free to chime in. Thanks again for the help guys.

Everyone loves pictures so here's a few. Sorry I didn't take more, my hands were full:



I found it funny that Suzuki and Yamaha basically used the same wheel design in the exact same year. That makes it easier for me so no complaints here.



Pre-Op



Post-Op

I would strongly discourage anyone from attempting to do this on their own. Especially if they are a broke college student like myself who lacks the proper equipment to carry out something like this safely. I used a motorcycle dolly with an air compressor to weigh the rear end down while I used a jack to lift the front end off. I had the left side stabilized with a tie down in case it wanted to tip over. I know this probably isn't such a good idea with a 848 and a GSXR 750 sitting right next to it.

I will be out of town for the weekend so I'll try to find a triple tree by tonight so I can finish this up hopefully by next week. In any case, I'll keep you guys updated when I make some progress.

Cheers,
Mike

 

Oh and one more thing, does anyone know anything the GS650's "Air assisted" front forks? On the lower triple tree there is a rubber air line that connects the two forks with a valve step on the side. I'm guessing it's part of the fork and will not come off. Does it require maintenance? I've never seen anything like this.

Cheers,
Mike

 

If you peek closely, there should be a thin circlip preventing the air thingy from moving up or down. It's springy, so pry it out with a screwdriver (or a fingernail) and remove it. This will allow you to remove the air thingamajig but there's a hole in the fork tube right about there so keep the tube upright.

 

As an owner of two 550 Secas I too considered the dual-disc idea until I did a little reading in regard to stopping distance, swept area, unsprung weight, etc., and decided to upgrade and keep the single disc brake. The bike is so light, it really doesn't NEED dual discs; what it does need is some improvement to the stock system.

Like I said, I have two 550 Secas; they each got a front brake upgrade but executed slightly differently:

My '81 got a complete system rebuild (which you've already done, RIGHT???) plus stainless lines, new Yamaha pads, and I had the stock rotor surface-ground and drilled:




My '83 got a complete system rebuild plus stainless lines, an EBC Full-Floating rotor and EBC pads:




Both gave me a greatly improved brake over stock; the EBC is better yet. That being said, the single biggest improvement on both bikes was upgrading to stainless steel lines.

I hope before deciding to upgrade the front brakes, you've at least gone through the system and replaced the hoses and rebuilt the master cylinder prior to beginning the upgrade project. Also plan to rebuild the Suzuki calipers if this succeeds, as their rubber bits are equally as old.

Also, remember that in switching to dual discs, you also need a larger-capacity MASTER CYLINDER in order to pump enough fluid to activate two brake calipers instead of only one.

 

Ah thank you that's going to help a lot.

Cheers!

 

I appreciate the time you took to reply. While I agree with what you say, the big reasons I went with this direction was merely cost, availability and time. I found this working, front end for $45. It came with everything I need minus the top triple tree. That is including the master cylinder you mentioned (thank you). Luckily the guy kept the brake lever and m/c intact so It will be a matter of swapping parts. I just bought a top triple so once that comes in it should be done.

This bike will be a gift for my father. It runs great, I just preferred to have a dual brake setup for safety reasons.

Cheers,
Mike

 

I got the triple trees from the mail today. But as usual, I've stumbled upon another problem. Apparently I got the wrong style of triples for this front end. These triples fit the stock XJ forks ironically. So, back to eBay for another set. I bought another from the same year with what appears the right style this time. And once again, this problem is postponed till next week. I'll let you guys know when I get it in.

Here's a side by side comparo:


This is a bad angle but the front end I have has more of a triangular style triple opposed to the ones I just bought which are more of a flat style.

 

So much for that idea. Also, I'm concerned that your "working" Suzuki front end, being the same age as the Yamaha's, will STILL require the calipers to be rebuilt and the (most likely original) lines to be replaced. Going from an un-rebuilt 30-year old single disc system to an un-rebuilt 30-year old dual disc system is NOT any sort of a "safety" improvement.

You really need to go throught the Suzuki brakes and do the same things you would need to do to the Yamaha-- rebuild the caliper (now two) and the master cylinder, and replace the original, old rubber lines. Suzuki's caliper and M/C seals and lines weren't any better than Yamaha's were at the time; and a lot of parts were probably from the same vendors.

If you really want the bike to STOP and BE SAFE then you're going to need to completely rebuild whatever brakes you install, be they Suzuki or Yamaha.

NO SHORTCUTS on brakes.

 

I hear what you're saying and I totally agree. Brakes are probably one of the most important systems on a bike. I have no intention of going the cheap and easy way.

Having said that, I never stated that I wasn't going to rebuild the brakes on the Suzuki. My gripe is with the single caliper setup. For the size and power I realize it's adequate but not for me. Given the opportunity, I would prefer to upgrade to a dual caliper setup. Luckily, I found that opportunity on craigslist for $45.

And just so we're on the same page, when I said I went with this setup due to time, money and availability, I was trying to say that for the money, it would yield better cost/benefit opposed to simply rebuilding the stock brakes. I understand that switching to a dual caliper setup is going to cost more to maintain. But seeing as I scored the entire, working front end for such a low price, it offsets the cost of rebuilding it, thus further increasing it's cost/benefit ratio.

Just to clear some assumptions, this is by no means, a DD bike. I already have a 04 GSXR 750 and a 74 CB450 so please don't think I'm gunning this 30yr old bike around the twisties like a madman. This is a project bike that will ultimately be a gift to my father once completed. Although I am pressed for time, I am not going to compromise my father' safety simply in order to get him riding ASAP. I will be rebuilding the brake system, thoroughly.

Now that we have that cleared up, I do want to say I appreciate your concern. You seem to be well versed in these bikes, I'll definitely be needing your advice in the near future.

Cheers,
Mike

 

Well! After finding out that the first triple tree I purchased was the wrong style, I finally received the second one I bought off eBay. I should be studying for my final (that's in two hours) but I couldn't help myself so I went to the garage for a quick test fit. And YES! We have a winner.

Pass or fail, I'll be swapping in the front end today. Tomorrow is my father's birthday and what better way to celebrate his birthday than to surprise him with a newly swapped front end? In the next few weeks, I hope to rebuild the 30 year old brake system and do some maintenance on a few things. One step at a time, right?

Anyway, just thought I'd give a little update for those who are interested. I'll do my best to document the process tomorrow. Thanks for looking.

Cheers,
Mike

 

@Ludacity .. how did it turn out?

 

He was last seen here in August 2012......