XS650 Hot Rod Racer


Been Around the Block
So Here is a picture of my new bike the day I bought it. 1980 xs650 SG model, 6600 miles.


The windshield came off immediately...because it is ugly! and it has a broken mounting hole so the thing vibrated like crazy about 2500 rpm.

It runs good, brakes work awesome and plan on riding the crap out of it! I did already buy a hydraulic clutch conversion kit from hugheshandbuilt and will install it as soon as I get it home. I had to buy it when I was out of state since my parents live in a more populated area with more/cheaper bikes. It will be home in about 2 weeks if all goes according to plan.

Here is my plan with this bike (I will probably leave some stuff out but you will get the idea):

priority 1 - Ride the crap out of it and really get to know it.

Priority2 - suspension and handling;
fork brace
minton mod the fork or upgrade to emulator
bronze bushings in swingarm maybe needle bearing kit
swingarm brace
rear shocks
maybe some frame bracing

the priority here is to get the thing to handle as good as I can get it! I am not interested in newer sport bike forks or swingarms. I prefer to modify the existing. I will do A LOT of research to figure out the best way to go about this task, and any help/info to aide my research is much appreciated!

priority 3 - Hot Rod Engine!
Head work, undecided what or where
rephase and perm magneto
bore, undecided how big (700, 750, +?)
probably a shell no 1 cam
carb upgrade, undecided what
Exhaust, again undecided

The idea, I want a Hot Rod Bike! I want to get as much of the Hot Rod sound and performance I can get! Again, A LOT of research will go into this as well. I doubt I will ever race the thing but I am looking to build this up as much as I can, within a little reason. I want to ride it! so reliability is still a factor. Again help with my research is much appreciated.

Priority sometime -
Clip ons
custom seat

I want to build a bike I can really get onto, I want to learn in the turns and push this thing to its max. I think this is the best setup for the job. I have a spare seat that I will build a custom seat onto the pan. This will all happen at one time, I want to build the seat to fit me when in the riding position the clip ons and rearsets will put me in, to offer the most support/comfort.

This will be a long term project. Priority 1 will be ongoing for ever! Priority 2 will be happening as I go and find out where the bike is lacking most and when I figure out exactly what I think will offer me the best performance in the handling/suspension arena.

I did buy some odds and ends to put the headlight together and such so I will post a pic when I get it here and put it all together.

Also it came with a spare set of carbs that match the bike and a pair from a '79, also spare jugs with pistons, and half of the head, without cam. I might be able to use the jugs and such to setup for the engine build, I am bummed because I only have the lower half of the head and no cam, or else I would send the head out to get a good head job!

Be patient with me! I appreciate your help in advance!
To me the XS 650 is one of the great all time bikes, no kidding. The head and cam box should be from the same bike they are a matched pair.
The frame braces are a good idea, I have done a lot to my frame. There is a 3/4" diameter tube (horizontally mounted) that goes on each side of the base of the main down tube out to the "ugly plates" They fit very close to the engine cases but can be made to fit and form a wide Vee. I have two ladder braces (1,18" diameter) between the front down tubes and one under the engine. I have two 3/4" dia. triangulating braces that run fore to aft under the tank. I would sincerely recommend making your own upper and forward engine mounts they will be stronger and much lighter by 10# lose the center stand 6# and cut all brackets off and make your own you can shed a ton of weight. Switch to 18" wheels front and rear. I could go on and on but I'm already being a bore but I really like these bikes. My avatar bike is a highly modded XS650.
Cheers, 50gary
can you send me some pics of your frame bracing, or a link your build with the pics? That would be very helpful. I am going to need to read through your build, it sounds like you have done a lot! Any recommendations on modifying my front fork. Like I said I want to keep it with the stock fork but I am trying to figure out what to do with spring, minton mods, or add a emulator? Rear shock recommendations would also be appreciated.

Sounds like a fun project in the works. I especially appreciate your attention to Priority #1 - just ride. The XS650 are stellar bikes, I hope to make one of those my next build. Good luck and keep us updated!
Ryanglade, here's a link to my notes on the build. I built this bike in 2003-05 as my very first custom build. It was a throw-away frame and a spare motor someone had so I had complete freedom to screw up or succeed. It's bike #1401 on 650 motorcycles. Check out the rear brake lever, nothing is stock on the bike. It's fun to ride and loud open exhaust 1.75" tubes no port gasket, ceramic coated inside and out. I have a friend that has made race car headers for 30 years and he lets me pick his scrap for pieces, the slash cut dump is from a sprint car set up. Fun.
I would go with Race Tech emulators and their springs too. I would not use a progressive rate spring ever (maybe on a touring bike for variable loads) I can send you some pictures of the bare frame if you wish?
Cheers, 50gary

http://www.650motorcycles.com/50Gary.html **** NEW ****
That is a SWEET build! I like alot of things that you did. I like the modern components like the front end, mono shock and such. For this build I want it to still look like an xs650 by upgrading the components on the bike. If you wouldn't mind, I would love to see pics of teh bare frame so I can see your frame supports that you did.

I think Front suspension, brace is going to be my first part to tackle. I know the race tech emulator and springs are good. I have read of someone using, I think, traxxion, I will have to doublecheck. They carry both good srings and a good emulator. I am looking at one of 2 fork braces also. We will see what happens when I get it back and put the miles on!
Thanks, I had a lot of fun building that bike. I would like to do another XS650 and make it a 'sleeper" as we used to call hot cars that looked super normal. You can bolt up a set of FRZ 600 forks they are 41mm but look normal and R1 or R6 calipers bolt up to the FZR lowers for super brake power. I use Galfer Stainless steel brake lines but get them in black so at a glance they look nearly stock. Most of the guys here don't use side covers but I like them too for the stock look. I'm doing an dt250 right now and will use 18" spoke front and rear skinny wheels and tires rock. Light weight and quick turn in. The XS650 is set at 27 degrees rake but lowering the clamps on the fork tubes you can get steeper than that, also longer and ride height adjustable rear shocks can help in that department too. If you can score a set of Kawasaki ZRX shocks at a price they can be made to work well. I have a set on my cafe CX500 Honda. You can re-valve them like an aftermarket shock and they are longer than stock and not too expensive.
Cheers, 50gary
I am thinking about the whole sleeper thing. I was flipping through an old mag and saw an article on Darwin's GT3 FXR, it looks clean and not all low like a cafe racer or sport bike.

Also on the ZRX shocks, I found 2 different styles. which one are you referring too?



The second one appears to be worth a hundred more but I would be willing to go either for extra height and rebuildable/adjustable options.

Man, I need to get this bike home! All these nice days and the stuff I am learning, is driving me nuts with no bike!
The second link are the OEM ZRX shocks with the piggyback reservoir made by KYB. Bear in mind the ZRX is a very heavy bike and your XS will be quite a bit lighter therefore you'll have to change the springs to match. I look at the ZRX shock as a cheaper alternative to the very costly Ohlins, Penske, or Race tech.
If you want I can email the frame photos, PM your email if you like.
Cheers, 50gary
Thanks for the frame pics!

So if I go this route with the zrx shocks, where would you recommend going to get springs set up for them?
Call Bruce Blake at Michigan Engineering @616-554-8071 tell him Gary in Saginaw recommended him. Bruce is a sponsor of AHRMA vintage racing and knows a lot about setting up suspensions of vintage bikes. He's an OEM manufacturer of much of what goes inside modern shocks. He did my ZRX shocks for my Cafe CX500 and they're great. He also did my brother's race forks, Suzuki GT750 but set up for his Suzuki T-500 for AHRMA racing. I would call before buying anything he'll have some ideas for sure. I hope this is not against any forum rules??
Cheers, 50gary
I will do that. Thanks for the info!

Right now I a getting all my stuff to get ready for its 6+ hour ride to bring it home, oil, plugs and lights and such. I need to get it back, the weather is too nice not to ride!
So, the bike is home!

I put about 700 miles on her last week, including an almost 400 mile trip home. My hands are still feeling the vibrations!

I have some stuff to do but have a couple questions.

1) It takes a good 10 mins to really warm it up so that it doesn't stall out. Is there anything I can do to reduce the warm up time? I wouldn't mind as much but I am going to use it as a daily driver and would like to be able to minimize my time warming it up. The big issue is warming it up to go to the gym and then an hour later after it cools down to go from gym to work.

I guess that is about it right now. I have to chase down the source of some extra vibes and tackle some wiring, rebuild the carbs and some stuff.

Thanks and I will put up some pics after I get a couple things, it wont look quite as ugly as it did when I bought it.
So to elaborate more on the trip home and the bike.

It is rougher than I remember from when I looked at it. I must have had some "must have xs650" blinders on. It is not too bad really but a little rougher than remembered.

It vibrates like a mother! I have found some of the cosmetic culprits but suspect some more "non-cosmetic" as well. Still investigating. I have lost a handful of bolts from various places and at different times throughout my first week of riding it. I am in the process of going over everything and putting locktite on every bolt. My back rest for the rear seat vibrated sideways. I lost a mirror, almost too on my voyage home.

My chain is going out, need to get replaced. How do I tell if the sprockets are good? I can tell if it is obvious, but the more subtle hints I could use some help on.

I ordered a bunch of gaskets and swingarm bushings ans steering neck bearings, a good start to the upgrades. Soon I am going to go through a major tune up and check valves and everything and get a better understanding of the engine condition.

Any pointers on things to look for would be greatly appreciated! While I am already digging into the bike to make it run properly I would like to tackle other things you guys might know of to look out for on these bikes.
Have your carburetors professionally synchronized with vacuum gauges, it will help smooth out the engine a lot.
I would buy all new chain and sprockets in 520. The 520 is much lighter and more than strong enough. If your chain is worn and the bike is older the sprocket aren't likely to be in great shape either? For highway use a popular mod is to add one tooth to lower the RPM while at cruising speeds or take one or two off the rear wheel sprocket. This will help give a less 'buzzing ' feeling in the hands. Stock gearing is 17/34 I dropped 2 teeth off the rear, but my 650 is stripped to be fairly light weight, as mentioned I used 520 O-ring and Sprocket Specialists for the hardware.
Cheers, 50gary
Thanks for the response.

So the debate is longevity (530) vs. Lighter (520). I will ponder on it, but honesty I am leaning toward 530 right now.

So I went to my local shop and we were looking up chains and sprockets. The topic came up about having enough clearance for an o-ring chain. It has been recommended so I am sure it will be fine but I want to ask the question anyway.

Has anyone had any issues with an o-ring chain rubbing either the case in the front or tire/wheel in the rear?

We compared measurements and the o-ring chain is a little more than 5mm wider than the standard chain. That makes it 2-3mm wider on each side, it is such a small number but he has had customers with clearance issues.

Thanks for the help.
So, I was rebuilding my carbs, installing my Hydraulic clutch and switching handlebars and such. Had a bunch of issues.

My hydraulic clutch has some issues so I will have to take it all off and install my cable clutch again. :(

So I started taking off my rear wheel, My new chain should be here monday or tuesday and I got my new bushings for my swingarm. I took my swingarm off, which was easy! Huray for a non stuck swingarm bolt!!! I was looking at the bushings and they appear to be metal. I was under the impression that they were rubber, but these look to be some sort of metal, not bronze, they are black like the frame but they are not rubber. Unless of course they hardened up to the point of no give at all. They dont want to come out easy either.

Any ideas of what the bushings could be or how to get them out?
So I successfully got my bushings out using a toggle bolt trick I found online! and pressed my new bushings in using all thread and some washers and bolts as a press!

It was a good night! Now I need to get some good grease and a grease gun to get it all back together, also added a grease hole in the tube.

I got my sprockets also, just waiting on my chain and then I will get it buttoned up and put on a mew rear tire. The chain ate up the side of my tire pretty bad, and it has a gash in it so it needs changing anyway.
NEw sprockets and chain and rear tire on!

I will have to post a new pick of the bike, it is different now.

So I am now finding that my petcock is leaking. I can remedy it by turning it off, but when it is on it leaks. It does not have a vacuum hose running to the manifold so I am thinking someone wither modified this one or put a not vacuum one on. Does anyone know an easy way to tell? I guess if I take it apart I will be able to. I would like to figure it out before hand if possible to help in ordering the right parts, either a rebuild kit or new petcock altogether. I am thinking about just ordering a manual petcock replacement from 650central to start from scratch and know exactly what I have on there. The current petcock is pretty ugly anyway, signs of previous leaks and rust too.

Any thoughts?
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