XJ650 Maxim basic newbie/mods questions

Hello everyone, been lurking around here for a bit, great site, great people.

Although some of these Q's may have been answered elsewhere, I'd like to get further clarity and all the answers in one spot so I can plan my project.

Okay, here goes:

1) Conversion to dual front disc brakes. What is the simplest, easiest swap to perform.....what models by year will swap? Is it best to just by an entire tree from another model and bolt it on? What model/years? What master cylinder to use, and what mods will I encounter in doing so?

2) Which other Yam wheels (front & rear) would be a bolt-on replacement? From what model/years? The turbo wheel is pretty cool looking. What about rear wheel width/tire size? Right now it's got 130-90/16 on the rear and it just about rubs on the LH side (drive shaft housing). Can that housing be moved out or the weld seam ground down just a bit (howt thick is that housing)?

3) Adding the turbo oil cooler.....I'll need a complete cooler with brackets and lines and the turbo oil filter housing (and filter).....what else? Pretty much a bolt-on after all those parts are acquired?

Thanks in advance for anyone's help!

 

Simplest swap to what? Could you please post the machine you wish to convert. Max or Seca? Year? Displacement? I'm getting old now so I'll stop but I'm certain you get my point. I have an 81 650 H Maxim and have the complete front end off of an 82 turbo 650 along with the rims. I also have purchased the oil cooler and it is a bolt on. How is that?

 

Simplest dual-disc system to swap into this bike, '82 XJ650 Maxim (not SECA, not a turbo, etc.....plain jane version). Just got the bike, no pix yet. Thanks for the info.

 

Hmmm, you probably have a 750 if you have the dual discs. I've never seen a 650 with the duals, except the turbo that is. AFAIK, all the 750's (Seca's and Maxim's) had the dual discs. The turbo and 900's had a wider bolt pattern rotor and larger disc, and the 900 had a rear disc as well.

 

I didn't think any of the 80-83 650's came with dual front discs? It was only the 750's and the turbo that had them.....

 

Whoops!!! Mis-read your post, I thought you were a different poster rather than the original person. Easiest IMO, would be to get the entire front fork setup from a 750 Maxim. It'll bolt right on, and go ahead and use the 750 master cylinder as well. You won't be able to do a dual disc swap using your current forks because there is no provision on the other side for mounting a caliper.

 

Hey guys, sorry for the confusion. Yes, this is currently a single-disc bike, it is a 650 Maxim. Want to (as easily as possible using stock Yamaha components) upgrade to a dual-disc system. So a entire front unit from a 750 Maxim would bolt-in. Any mods or tricky stuff that I should expect? Handlebars, etc?

Would the 650 Turbo front system work with the stock 650 Maxim wheel (single-disc style) or would I have to also use the turbo wheel, and if the answer is yes, does that present any problems (size/height etc.)? Is the turbo rear wheel a direct replacement for the 650 Maxim rear wheel?

Any opinion/experiences as to the pros/cons of the performance and/or installation of the 650 Turbo front system versus a 750 Maxim system?

Thanks!

 

Just changing the forks would likely be easier then doing the entire front end.

I recently change up the front end of my 750, I hated the bars on it. I put a couple pics in this thread, if you curious as to what the 750 front end looks like stock.

http://www.xjbikes.com/Forums/viewtopic/t=1624.html

 

Hessen, thanks for the input. I saw that thread the other day, nice work.

So I can JUST change the lower forks from a 750 onto the 650, that's all it takes?

If true, I assume the same thought applies to the turbo lower forks?

Thanks. I like the way your bike looks!

P.S. I thought I saw a picture on this forum a few days back...and like an idiot didn't print it out or save it.....that has a rear view of a dual exhaust system, and the "end caps" on the megaphones were ribbed or finned (rather than flat & smooth)----thus looking much like the valve covers or oil filter housing....looked pretty cool. Anyone know what I'm talking about, or know where I can get some?

 

To my understanding, yeah, just swap forks.

I'm not nearly as well versed in the XJ world as many other posters here, I'm sure someone else will be able to guide you better then I.

If I wasn't at work I'd check on the fork lengths but if memory serves me, they should work.

 

So no 650 max has dual disks?? I guess that means the front end of my new 81 650max is not the origional, correct??

 

Not on the 81 650. I'm unaware of any 650 Maxes being treated to the dual front disk. It has been only the Secas that I've seen with it.

 

You won't be able to use the turbo brakes with your wheel, they have a larger bolt pattern where the rotor bolts to the wheel. You should be able to use your original wheel with the dual discs however, the holes are already there for the other disc, they're just plugged off with a plastic cap on the single disc bikes.

 

Hey Joel, thanks for the answer, can you help me out a bit more? My wheel does have the drilled right side rotor mounting holes (plugged by plastic caps, as you say). So I can use my original wheel with WHAT dual discs.......off of what machine(s)? You say that the brakes from a 650 Turbo model won't fit....what WILL fit?

I wouldn't mind swapping an entire wheel/rotor/brake assembly onto this bike from another model, or just cannibalizing another model for parts that will directly bolt-on and fit. I've read a couple of other threads on here (and elsewhere) and it's sorta hard to decipher the exactly what people are trying to say (mainly because I'm new to all this). I come from the classic car world, where things are a bit more developed on the parts interchange/upgrade side, so....for example....a 1970 Camaro with front drum brakes can be upgraded to front disc brakes as long as you pull the entire assembly off of a '70-78 Camaro with disc brakes....."entire" meaning everything from the ball joints outward, the front brake lines, the master cylinder, the master cylinder push rod (to the brake pedal), and you'll have to change the distribution block, etc. In other words, a complete set of instructions of what parts you'll need from what type of donor vehicle.

The last thing I want to do is to buy something that won't work, or will only halfway work, and I'll have to do all sorts of unplanned (and perhaps undesired) modifications after I start tearing things apart!

So from your previous post, I can take any year 750 Maxim front forks, rotors, calipers, brake line/distribution block, and master cylinder and associated brackets, screws, etc. and it will just bolt right up to my stock wheel, frame, and handlebar......right? Or is there a certain range of years that I should be looking out for, and is there any significant differences in the components by year that I should also consider?

Sorry to be so anal about this, I just want to measure twice, cut once, that sort of thing. Thanks for the help!

 

Any year XJ750 Maxim complete front end should be an easy swap. Meaning the entire fork assembly from the front end. But, most of the time you'll find just forks and calipers sold by themselves. If that's the case, you can use your wheel/hub assembly, and bolt the 750 rotors onto your current wheel. Basically what I'm trying to say is that all you REALLY need from the 750 is the fork tubes, calipers, rotors, and master cylinder. Everything else you can use off of your current bike.

Also, an XS750/850 brake setup will work, however there are some differences in the forks, so I'd stick with the XJ750 stuff to keep it simple. I will be doing an XS brake swap on mine in the future, since I have a parts bike here for the taking.

 

Joel07, you da' man. Thanks for the info. My search begins.........I'll keep everyone posted.

 

Any year 750 maxim, or 650 turbo seca as well as a lot if not all regular 650 secas will have a dual disc front. It is a bolt on application but you cannot, I REPEAT, CANNOT! re-use your existing master cylinder with success. It has a much smaller bore than is required for the dual calipers and therefore doesn't move as much fluid as is needed to properly actuate the calipers. I would either use a complete front end, including handlebars. Or cough up the $65 to buy an aftermarket dual disc master cylinder. And yes you can still use your existing wheel. I'm not sure about the turbo secas having never worked on one myself. But the front wheels should all be compatible. The rears aren't as the maxims rear wheel is 2? inches smaller in diameter than those on the secas.

 

Thanks artistic gore, that's a help. Never realized the turbo wheels are SMALLER in diamter. But I can rob the forks, rotors, calipers, lines/distributioon blockl/brackets/master cylinder etc. off a 650 turbo and it'll bolt up to my 650 Maxim stuff no problemo? Is the brake lever assembly interchangable....can I continue to use the one I have or do I have to change that along with the master cylinder?

Also, do I use the entire fork/tube assembly or can I just use the "outer tubes" (is that the right term.....the tube that the calipers/fender/axle shaft attaches to)? There's no difference in the diamter of the fork shafts between standard Maxim's and turbos or SECA's?

Thanks everyone for all your help, I'm learning!

 

No, there is no difference in diameter of the fork down tubes. So in theory you could just swap the sliders and be done with it. Another option would be to leave your triple trees in place and change the down tubes and sliders and then at least you wouldn't have to mess with your steering head bearings. Assuming you haven't changed out your head bearings allready those little balls get everywhere. I may have mis-typed in my previous post. I'm a little too tired to re-read it right now but the rear wheel on the Maxim is smaller than the rear wheel on the Seca. It is a common mod to swap out the 17" rear wheel from the seca for a 15" rear wheel off of a maxim to increase torque. For some reason this has me thinking that the swingarm & driveshaft on the seca could be longer, but I digress. Your brake lever should (should) swap over without a problem even in an after-market application they are damn near the same. Hope this helps at least a little.

 

Artistic, I sent you a PM......

 

Maybe someone else could help out with this. Chacal says that the guy holding the auction believes the seca has 35mm fork tubes and the maxim has 36mm. Personally I have never heard anything like that nor could I understand putting out two bikes where the only differences are the body style and foot peg position. It just doesn't make sense to me logistically to have a major component differ between two bikes that are so similar. If anyone can help with this, I am going to see what I can find out but I won't be able to do so until much later today.

 

I think the angles of the mirror and lever mounts are different between a maxim and a seca. just something to be aware of.

 

Allright, I asked a couple folks more knowledgable about XJs than myself and here is what I came up with...

The two different turbo years had two different fork tube diameters --
neither of which was 35mm. The original 1982 LJ had 36mm forks, same as the 650 Maxim and the 650 Seca. The 83 had 37mm forks.

Another issue might be the axle position. The Turbo axle is aligned with the
forks, designed to suit the 27.75° rake. The Maxim has a leading axle design
for it's 29° rake. Putting Turbo forks on the Maxim will increase the trail
which will affect handling, making it heavier at low speeds.

 

Robby you make a good point. The angles are different between maxims and secas due to the sweeping handlebar style on the maxim. When I swapped out my bars I decided to go completely aftermarket to combat the difference, i.e. new mastercylinder (vice rebuilding the old one) and a new clutch control mount.

 

One more thing I haven't seen mentioned:

My 82 Maxim 750 has air-adjustable forks. There is a "tire valve" that connects to the forks, and you run them with about 10psi of air.

The forks have a c-clip groove that holds the inflator assembly near the triple clamp. They also have a hole in them where the air enters.

I don't know what bikes have "inflatable" forks, but if you don't have the whole setup, they won't be good. I guess you could plug the air hole and ignore the c-clip groove. Might need stiffer springs than stock.

Just my 2-cents.

 

Since your working on an XJ why not keep it XJ
If you look on e-bay do a buy search with key words XJ700 you should find some front end assys. If not today maybe tomorrow.
Some of the wrecking yards listed in the listings like pinwal have all the info you are looking for and when the right one comes along youll be ready.
By the way XJ700 has dual disc brakes on the front

 

Just to let you know that XJ650 comes with dual break discs at the front. Please see photo of my bike it's a first reg. 1984 but I think it is a 1983 model 650 4Ko

 

And another photo

 

Holymoly! This is the oldest thread I've ever seen resurrected! How long since Chacal had noob questions? That's frikking crazy!

 

hehe. yeah. I know. but I thought this might help someone.

 

I think that the 550's euro models came with dual front disc breaks as well. They just didn't make them for the US models.

 

Matti,

.... And if ya look really hard, you could find some of my earliest posts----

And in another 10 yrs, we're gonna open the time capsule on YOUR first posts---- lol

 

But here's the thing... I already know everything. I was born that way.
Oh wait, no. In ten years, I'll still be a knucklehead, so the contrast won't be so shocking.

 

hehe

 

This post makes me happy....its good to see the now experts were once new as well