636 fork swap

RacinJason44 · Jan 26, 2008

I'm swapping an '03 636 fork onto my 650, and I figured there might be some people on here that hadn't seen that done or might want to know how to do it themselves. I'm going to be doing most of this tomorrow, more pictures will be coming. The '03-'04 636 triples are supposed to be a direct fit, you can use the tubes and brakes from any ZX6R from 03-08. The 650 and the '05-'08 ZX6R use a 300mm petal style rotor, while the '03-04 use a 280mm rotor. I am planning on using the 300mm rotors by using 10mm spacers to space the calipers out to clear. I am planning on keeping the 650 wheel. The 650 and '05-'06 have an idententical wheel, besides the bearing sizes. The 650 uses a 42mm od, 20mm id bearing and the 636 uses a 47mm od, 25mm id bearing. The 636 uses a 25mm axle. To use the 650 wheel on the 636 front end I am going to use a 42mm od, 25mm id bearing. Both stock bearings are 12mm wide, while all the available 42/25 bearings are only 9mm wide, due to the fact that they use a smaller ball. To compensate for this I made some 3mm spacers out of 1" schedule 40 aluminum pipe. It has an id close to 25mm and the spacers should hold the bearings tight in the wheel along with the stock 636 collars.

The 636 bearing is on the left, the 42/25 is on the right:

Here is the spacer I made, along with the stock bearing and the new bearing with the spacer:

Here is how the stock 636 axle and hardware fit together:

Here is how it fits together with the smaller bearings and the spacers:

I should have more pictures and info tomorrow, hopefully everything goes together as planned!

GreenBlur · Jan 26, 2008

Looks awesome, speaking of retrofitting types of things, on the ninja650.com forums, someplace in Germany installs Z1000/636 tails on 650s that looks awesome. Any plans to maybe try this with instructions on how to do this? 636 beaten up tails aren't hard to find. It might have been the Z750 tail, but think its the same as the Z1000 and well 750 parts are impossible to find.

RacinJason44 · Jan 27, 2008

Here is where I am at now:

My biggest issue is that I have no steering stops and my fork tubes hit the frame. I'll need to figure out what to do about that.

I have seen the Z1000 tail on a 650, it does look very nice, but spare Z1K parts are hard to come by. I am thinking about putting a Catalyst tail on my bike. I know its modeled after the 03-04 636, so maybe you could get one of those to fit as well, I don't know.

RacinJason44 · Feb 6, 2008

Enemy Zero · Mar 25, 2008

That's a great build and it came out looking good too. How's handling feel versus the old setup?

RacinJason44 · Mar 29, 2008

Once I got the suspension dialed in and set the sag it was a world of difference. It turns in better, overall a big improvement. The brakes are also a world of difference. The 650 has the same brakes as your Versys, they are ok, but not great. These radial mount calipers bite hard! I tore my bike apart this week and welded some steering stops to the lower triple to solve my issue:

I would definitely say it was worth it. There is more info on this swap here:

http://www.ninja650.com/phpbb/viewtopic.php?t=10167

6 maniac · Jan 4, 2014

RacinJason44 said:
Once I got the suspension dialed in and set the sag it was a world of difference. It turns in better, overall a big improvement. The brakes are also a world of difference. The 650 has the same brakes as your Versys, they are ok, but not great. These radial mount calipers bite hard! I tore my bike apart this week and welded some steering stops to the lower triple to solve my issue:

I would definitely say it was worth it. There is more info on this swap here:

Ninja650.com

loving the work dude, any chance of nipping over to thailand and welding some stops on my ZX10 yoke? im getting bored with thais telling me they cant do it when i know full well they could if i was a thai........

RacinJason44 · Jun 26, 2008

As an update, I have gone to using an 05-06 ZX6R wheel, my smaller bearings weren't holding up and I don't feel that was all that safe. Budget for a wheel if you plan to do the swap.

hoser · Jun 26, 2008

nice work jason

RacinJason44 · Jun 26, 2008

Thank you!

milimande · Mar 11, 2011

So by what i am reding an 03-04 636 complete front end should just bolt up to my 650r.

RacinJason44 · Mar 11, 2011

Yes it will. You need a set of triples from an 03-04, and any set of forks, wheel, axle, and brakes from 03-08. The only part that's not a bolt on are the steering stops, which I welded on.

milimande · Mar 11, 2011

sweet expect a write on mine once i get back in country nxt year

Arki Ninja 650R · Mar 11, 2011

yeah nice work! mods worth to look at!

pepitonet · Mar 11, 2011

here is my question, will doing this swap give you a better suspension than lets say getting the race tech cartridge emulator and springs?

I know that by doing the swap you get "better" brakes also but i am not interested on those the brakes of the 650 suit me fine as they are, so i just need a suspension comparison.

RacinJason44 · Mar 11, 2011

pepitonet said:
here is my question, will doing this swap give you a better suspension than lets say getting the race tech cartridge emulator and springs?

I know that by doing the swap you get "better" brakes also but i am not interested on those the brakes of the 650 suit me fine as they are, so i just need a suspension comparison.

Yes, way better. The cartridge emulators are trying to emulate the style of suspension that the OEM ZX6R forks have already. You also gain a huge amount of adjustability over the non-adjustable 650 forks.

chuckbear · Mar 11, 2011

You're also dropping some unsprung weight, I'd guess.

RacinJason44 · Mar 11, 2011

Some, yes. The USD forks have less unsprung weight than the big aluminum lowers on the stock RSU forks. The tubular 636 axle is also lighter than the solid 650 axle.

In addition the lower triple on the 650 is a big brick of cast steel, and the alloy lower triple from the 636 is much lighter.

slev · Mar 11, 2011

This thread has been rediscovered like the Titanic, but nice job nonetheless, Jason

RacinJason44 · Mar 11, 2011

Thank you good sir!

It is a blast from the past, but still good info.

LarryJ · Mar 12, 2011

I did the swap on my ZZR and I agree with Jason, it doesn't feel like the same machine. Handling, braking, everything feels different. The radial calipers are way better than the garbage that comes stock on the ZZR and 650 for sure, so no, "swap pads and you're good to go" is not going to cut it. Makes you realize there must be a reason inverted forks are the way to go for sport bikes.

Arki Ninja 650R · Mar 14, 2011

oh ok i get it... that's why Im convinced that switching to zx6r fork will be very different.. as if you're riding a sports bike... if i can get the parts i'll surely do it...
but here, its difficult... can you send me the parts required for this via PM's thanx...

nice work by the way!

andysongtn · Apr 11, 2011

so the triples from 05/06 is not going to work?

I took the ex650 out to a track day yesterday (Putnum) and the bike was great, brakes felt woody tho, I like to do you mod but was wondering if the 05/06 636 triples will work? Or will only the 03/04 triples pop in without major trouble?

Thanks for the great info Jason.

RacinJason44 · Apr 12, 2011

andysongtn said:
I took the ex650 out to a track day yesterday (Putnum) and the bike was great, brakes felt woody tho, I like to do you mod but was wondering if the 05/06 636 triples will work? Or will only the 03/04 triples pop in without major trouble?

Thanks for the great info Jason.

I have never messed with an 05-06 lower triple personally, but if I remember correctly I remember someone saying that the 05-06 steering stem is longer than the 03-04 or the 650 stem. I think it can be machined to fit, but like I said, I have not done it myself.

The 05-06 upper triple will work with either lower, I believe.

ickle pob · Apr 28, 2011

Jason, if you use the 03/04 triples, do you keep the origional headstock bearings or do these have to be replaced.

I am building an 08 650 in the UK to race, and have just come across a cheap set of 06 ZX10 forks and calipers so am using those, but am on the hunt for triples now. A good friend says the 08/09 triples are a direct fit including the bearings, but the ZX10 triples are hard to find, and over priced when you can. He has put a complete 09 ZX10 front in his to compete at the Manx GP later in the year.

Any help you could give on the bearings would be great

Paul

RacinJason44 · Apr 30, 2011

To be honest, I am not 100% certain which ones I used now. The triples I bought came with bearings, not sure if I used the 636 bearings or the original 650 ones. I will look through some of my old pictures to see if I can find out more.

RacinJason44 · Apr 30, 2011

Well, I looked up some part numbers, and the 07 650 and the 03 6R use the same headstock bearings, exact same part number, 93045-1384.

ickle pob · May 2, 2011

Jason - you're a star, thanks very much. I'm struggling to find anything over in the UK for reasonable money. I've found a set in the States for $325 delivered so it might be the only option, as UK breakers want nearly double that

I'll start a race bike build thread when I have anything people may want to see

Paul

Arki Ninja 650R · May 2, 2011

yeah do that!

ickle pob · May 3, 2011

Parts should be coming in now - forks should land tomorrow, so will get on the thread writing

Paul

Burgy · Jun 4, 2011

I'm currently trying to do this to my 09 er-6n, I have an 04 636 bottom triple and forks, however it seams like the stem is too short, its 7.5 inches from bottom bearing to top of threads (spanner nut threads) on the stock stem, and only 7 inches on the 636 stem, this makes it so the spanner nut won't even grab a thread. Did they change the neck size on the newer 650r's?

RacinJason44 · Jun 4, 2011

I just measured the frame on my 07, and the neck looks to be roughly 7.5 inches long. :dunno:

RacinJason44 · Jun 7, 2011

Not sure now which bearings I used, but I think the bearings are interchangeable, the 636 and 650 bearings have the same p/n.

burfster · Jun 9, 2011

Just picked up entire 636 front end for $300 so I'm finally pulling the trigger on this. I've found plenty of how-to's for the swap, but does anyone have any tips for removing the ignition module? I haven't tried it yet but I recall readin that it is a major PITA. Appreciate all the help.

RacinJason44 · Jun 9, 2011

Yeah, it's a bitch, to be honest. You will have to drill or grind out the tamper proof bolts that hold it in the triples. The heads of the bolt shears off upon installation, so no tool is available to remove them. From there you will need a tamper resistant torx bit, but that's relatively easy to get at most auto parts or hardware store.

636 fork swap

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