Intro / front end swap

[midnightforever]

Hello everyone!

I've been lurking around here on the forums for a while and I decided to get an xs after a good deal of research. A few weeks ago I got my first bike from a friend of a friend, a 1983 xs650 heritage special. It was running at the time, but as I soon found out, it needs some work... But that's ok! if I didn't want a bike I'd be working on I wouldn't have gotten a classic

After my MSF course and some riding around in the hills I ended up getting into a low speed tank slapper and I crashed coming out of a turn, I walked out of it alright and was able to ride the bike the rest of the way home.

Turns out the stock bearings were screwed, so I got some tapered bearings to replace them and a new front end with rim (bent), tire, caliper and rotor from a kawasaki zx6r 636 from craigslist (great deal!). Later find out it's not exactly a bolt-on, center stem doesn't fit yoke. From some other threads I've read that people have ended up cutting the center stem from the XS out and welding it onto the trees from the donor front and it worked out well enough for them... but now after more looking I'm concerned about how it'll affect my trail, might be too unstable. Alternatively I'd replace the entire triple and try to find a place that would help me fabricate new ones, or just sell the new front and try and find another that would be bolt on. (using allballsracing.com this time to make sure it should be).

Thanks for your help guys, I've really been enjoying the forum, there's been some great stuff and some great bikes! I can post pictures if anyone is interested.

 

[nj1639]

Welcome aboard! Always post pictures.

 

[jd750ace]

Have you even heard of anyone usuing the 636 front end?

 

[GreasyC]

Most modern sporty triple trees would result in MORE trail than stock, which shifts you towards too stable (slower steering) not the other way. Modern trees have less offset because the bikes they came off have less rake.

 

[CDNTX650]

but the forks are shorter than the ole xs forks...so it's less stable i think?. There is a thread on it.

 

[GreasyC]

Shorter forks drop the front end lower which will decrease the rake and quicken it back up again. If you dropped it so much it came down below 25 degrees or so you'd be at the same rake and trail as the bike they came off, and that's a much twitchier bike than an xs.

 

[midnightforever]

Thanks for the quick replies guys!

The only other person I've seen do something like this is guy: http://www.clubchopper.com/forums/metric-builds/53656-my-xs650-project.html

however he used a 79 xs650 and a 2004 zx6r. I got the idea for a stem transplant from Lunatic (about midway down the thread, where the pics are) : http://www.xs650.com/forum/showthread.php?t=1773

the problem with the trees from the zx6r 636 is that they have less offset (as shown in included photo), and the angle I'd be able to actually turn the wheel drops, in the 5th pic the INNER wire represents how far I could turn the stock top tree vs the 636 one's OUTER. which would probably screw me over on those twisties in the hills depending on how much I can actually countersteer.

GreasyC, what do you mean by twitchier bike? more responsive? less stable?

In any case I'm going to check out some local machine shops tomorrow and see what they can do. Also need to replace the rim on the 636 tire, PO lowsided it so it's bent or off-center.

 

[jd750ace]

I don't think your stop to stop would be quite that tight partner. You're going to want to keep those big clamps for those inverted tubes. I think a few folks have done late model GSX-R headsets, and nobody has mentioned the steering getting THAT tight. The original setup has almost 90 degrees of travel, which is pretty much uneard of now on a street bike. Have you done a runout check on the wheel, because it looks like the tubes are twisted in the lower tree to me. Check it all out before you go buying another wheel. Twitchy, more responsive, and less stable are things I would not worry with. Your bike out of the box is at 28 degrees of rake. Bikes don't get all crazy until you get under 25 degrees, then things start to need a really good balance. Work on getting a stem to fit, and do a runout check on that wheel. A low side should not bend a supersport grade wheel unless it ate an inanimate object or flipped. My SV has been high sided once and low-sided twice, and my wheels are straight.

 

[midnightforever]

I've done a runout test by eye, http://petercomley.com/Spoking_a_wheel.pdf < link I found for how if anyone needs... My wheel is DEFINITELY not true. Tubes looking twisted could just be because of the angle of the photo and the wheel, I thought the same until I saw it in person but a wiser eye is always welcome. I'll attach more pics of the front for a better view, I'm really hoping the PO had it diagnosed correctly as I think a rim replacement would be way easier than fixing twisted tubes... Hopefully I find a shop that can transplant the stems and I'll ask them about straightening forks or rims as well.

 

[jd750ace]

Those fork tubes are pretty darn stiff. Get a manual to take those apart and check the tubes.

 

[midnightforever]

will do. I don't have the tools to check it out myself yet though so I'll just bring the whole front to the shop when I get the stem welded...

 

[Signal]

Midnight, there are a lot of easier and reliable ways to make you bike handle better than a front end swap.

New tyres, swing arm bushes, decent rear shocks, install the tapered steering bearings you have, recondition the XS forks with better springs (maybe race tech emulators) and fit a fork brace.

All of this is pretty much bolt on and will be easier than fitting that Kawasaki front end to your bike.
I have had numerous problems to address when fitting a 2000 SV 650 front end to my XS street tracker. In short I doubt it will be worth the effort but I am determined to see it through.
Perhaps you could try the easy stuff first and if you still don’t like it then get the 636 front end out from under the bench….

 

[jd750ace]

I plan on making the best of the stock setup myself.

 

[Micha7el]

what front swap is the best ? Other than stock.....1980 .....want a rocket front

 

[Ratranger]

I have 2012 ninja forks on mine. Made a steering stem to use standard tapered bearings, made an upper clamp to get a little height back, and modified a cb550 hub to fit. It'll get real spendy real fast if you can't make parts yourself.

 

[fredintoon]

Hello everyone!

I've been lurking around here on the forums for a while and I decided to get an xs after a good deal of research. A few weeks ago I got my first bike from a friend of a friend, a 1983 xs650 heritage special. It was running at the time, but as I soon found out, it needs some work... But that's ok! if I didn't want a bike I'd be working on I wouldn't have gotten a classic
After my MSF course and some riding around in the hills I ended up getting into a low speed tank slapper and I crashed coming out of a turn, I walked out of it alright and was able to ride the bike the rest of the way home.
Turns out the stock bearings were screwed, so I got some tapered bearings to replace them and a new front end with rim (bent), tire, caliper and rotor from a kawasaki zx6r 636 from craigslist (great deal!). Later find out it's not exactly a bolt-on, center stem doesn't fit yoke. From some other threads I've read that people have ended up cutting the center stem from the XS out and welding it onto the trees from the donor front and it worked out well enough for them... but now after more looking I'm concerned about how it'll affect my trail, might be too unstable. Alternatively I'd replace the entire triple and try to find a place that would help me fabricate new ones, or just sell the new front and try and find another that would be bolt on. (using allballsracing.com this time to make sure it should be).
Thanks for your help guys, I've really been enjoying the forum, there's been some great stuff and some great bikes! I can post pictures if anyone is interested.

Hi midnightforever and welcome,
while it's certainly possible to swap in different front forks, from what I see in these posts it will be easier and less costly to fix up your bike's stock forks instead.
And if you re-sell those Kawi forks you'll likely have money left after buying any XS650 parts the fix may need.
Put grease nipples into the frame headrace tube and give them an annual shot. That alone will stop the replacement headraces from dieing of neglect.
And if you must ride an XS650 off-road, installing a WER or similar hydraulic steering damper is a good idea.