to all the frankenviffers, this one's mine, VFR750RR

[flyguyeddy]

Have you checked your wheel alignment yet?

I just checked the alignment of my 4th gen with the 900RR swingarm and the rear wheel was offset about 6mm to the right(throttle side).

The stock 900RR left side swingarm pivot spacer is approximately 41mm(measured 40.91 with my vernier calipers), and I just happened to have a 36mm swingarm pivot spacer left over from when I had the 600RR swingarm mounted. Swapped that spacer for the 900RR one and sure enough, I'm only out of alignment by 1mm. Unfortunately a 36mm spacer on the left side of the swingarm means it's almost flush with the left side pivot seal. Ideally the inner face of the frame where the spacer meets should be milled 1mm, but it has to be precise unlike the right side that doesn't touch anything once the pivot bolt is tightened up.

Another bonus to getting the wheels in better alignment is that the shock linkage is also aligned much better, the dogbone had zero side clearance before, now it can slide side to side about 1mm. Unfortunately it looks like the chain run is going to be off a bit now, but that should be easy enough to remedy.

DAMMIT! JUST when I think I've got the 929 rear wheel situation sorted:(

[Guest]

Have you checked your wheel alignment yet?

I just checked the alignment of my 4th gen with the 900RR swingarm and the rear wheel was offset about 6mm to the right(throttle side).

The stock 900RR left side swingarm pivot spacer is approximately 41mm(measured 40.91 with my vernier calipers), and I just happened to have a 36mm swingarm pivot spacer left over from when I had the 600RR swingarm mounted. Swapped that spacer for the 900RR one and sure enough, I'm only out of alignment by 1mm. Unfortunately a 36mm spacer on the left side of the swingarm means it's almost flush with the left side pivot seal. Ideally the inner face of the frame where the spacer meets should be milled 1mm, but it has to be precise unlike the right side that doesn't touch anything once the pivot bolt is tightened up.

Another bonus to getting the wheels in better alignment is that the shock linkage is also aligned much better, the dogbone had zero side clearance before, now it can slide side to side about 1mm. Unfortunately it looks like the chain run is going to be off a bit now, but that should be easy enough to remedy.

what wheel are you using? i'm using a '96 900rr wheel and swingarm, the shock and linkages lines up perfectly as well as the chain alignment is perfect.

[kostritzer]

I'm using the complete rear end from a 98 900rr, wheel, swingarm, linkage etc. I would verify that your wheels are in-fact aligned before going much further. The way I did it was with tires off both rims, bike on a flat surface, take a long piece of string and wrap it around the back side of the rear wheel so that you have two lengths of string long enough to reach past the front wheel. Now take a 2X4 and lay it flat against the front of the front wheel and measure the exact width of the rear wheel and mark it on your 2X4. Take your two pieces of string pulled tight(you may have to tape them at the rear wheel side to keep them from sliding up the rear wheel) and tape them to their respective marks on the 2X4. Now center the 2X4 to the front wheel by making sure the string from the rear wheel just touches the front edge of the rear wheel. Now measure the distance between your marks on the 2X4 and the edge on the front wheel on both sides, subtract the difference and divide by 2 and that's how much your wheels are misaligned.

Maybe the difference between the early and late 900RR's means that yours is perfectly aligned as is, but wouldn't you like to know for sure?

Here's a pic that would probably explain my method a little better, this is not a 900RR arm obviously.

[flyguyeddy]

Is that the 600 arm?

[flyguyeddy]

My linkage is bound up as well:(

And by bound up I mean its all forced to one side.

[kostritzer]

My linkage is bound up as well:(

Yeah, that's the 600 arm. Fit beautifully except for the linkage. I think the magic number for the left side spacer is 35mm. This will make it flush, or near flush to the left pivot seal, but should get the wheels almost perfectly in line. I have a spare 96/97 swingarm with an extra left side spacer(which is also 41mm) that I'm going to get machined down to 35mm when I get a chance. This also means that you wouldn't have to remove as much material from the right side of frame either, too late for that now! Probably have to revert to the VFR threaded spacer as well.

[kostritzer]

My linkage is bound up as well:(

And by bound up I mean its all forced to one side.

I think the fix for that is to have the sides of the dogbone milled 1-2mm, shouldn't affect strength much if at all. In fact the dogbone in my Daytona is about 66% as wide as the one on the Honda, all other dimensions are similar except length. I also have a couple of spare triangle plates from a street triple that have slightly different dimensions to the CBR900RR plates mounted on the bike currently. They've done two things, raised the rear of the bike slightly, and brought the shock further away from the swingarm pivot where there was hardly any clearance. Overall linkage ratio is about 2.5:1.

[flyguyeddy]

I'm using a 3rd gen vfr adjuster inmine anyway.

[flyguyeddy]

I REALLY want that 600 arm on my bike lol. Too bad for the linkage issues...

[SEBSPEED]

I think it was the late model 900RR's that had the shock offset, or was it the earlier models?

I know for sure that the arms are different, maybe that's why you guys are seeing differences in end result.

[flyguyeddy]

I'm a little bummed about this scenario. I might have to switch back to the damn 900rr wheel:(

[kostritzer]

You should definitely measure your setup before you change anything. Like Seb said, there could be some variables between the different arms. One thing that's surprising to me is that the 96-97 arm looks nicer than the 98-99 arm, at least at the axle end. The 98/99 doesn't use the "blocks" to locate the axle, just the stamped steel adjusters.

[flyguyeddy]

I have a 93 arm on the bike and a 98 arm at the shop at work. As far as I could tell, the pivots are all in the same place. Personally, I preder the stamped adjusters over the blocks anyway:) but thay arm is far too dented and scratched to use on something I plan to make minty fresh.

[kostritzer]

Yeah, the stamped steel adjusters are much easier to use, and a lighter setup overall. They just look kinda dated compared to the block setup I guess.

[flyguyeddy]

Where do u get that spacer from? I've looked and can't find it

[kostritzer]

It's the one that rides in the left side pivot bearing.

[kostritzer]

I'll try to post some pics of my project tomorrow and take some pics of the "little details"

[Guest]

guys, my wheels as well as sprockets are spot-on, checked exactly the same way described above.

[kostritzer]

Thats bizarre, did you do your meaurements with the tires removed?

Here are some pics of how my swingarm is lined up currently. First pic is with the 36mm spacer(still needs to be turned down to 35mm), second is showing the material removed from the frame and a 900RR threaded spacer, which is too short now(got an ebay 4th gen spacer on the way). Third pic is the stock 900RR 41mm spacer.

[kostritzer]

Alright Brandon, time for you to take some measurements so we can compare!

[zRoYz]

Can I ask, what is the reason for wanting to swap out rear swing arm to conventional swing arm when most want the single sided swing arm on other bikes, is it purely for weight saving which when you take into account the weight of the rest of bike is allot of work for little gain.

[kostritzer]

Yes weight mainly, and I'm pretty sure the 900RR swing arm is quite a bit less flexy than the VFR single sider, but I think that's mostly a bench racing point in reality.

Onespeedpaul found almost a 20 lb difference between the 900RR rear end vs. the VFR stuff. That's quite a bit of weight off an already rear-heavy bike! Since its so difficult to make power with these engines without spending lots of money, losing as much weight as possible is the only viable alternative to increase performance substantially. Now if I could only get this goddamn alignment figured out.

[kostritzer]

Just spent an hour out in the garage playing with swingarm offset and triple measuring everything, I think I've come to the conclusion that I don't have the front end perfectly centered, so I can't trust the measurement I'm getting for the rear. I need to figure out a way to center the triples in the frame, but there really isn't any reliable reference points to use. Looks like my front wheel has a small amount of runout as well. Used parts can be the biggest variable when it comes to this stuff.

[SEBSPEED]

Just spent an hour out in the garage playing with swingarm offset and triple measuring everything, I think I've come to the conclusion that I don't have the front end perfectly centered, so I can't trust the measurement I'm getting for the rear. I need to figure out a way to center the triples in the frame, but there really isn't any reliable reference points to use. Looks like my front wheel has a small amount of runout as well. Used parts can be the biggest variable when it comes to this stuff.

Time to load up your parts and schlep them over to GMD Computrak...

[kostritzer]

I may do that just to double check everything when I'm done, but I think I've figured out a "close enough" way to align the wheels, assuming everything is relatively straight. I know that my rear wheel is pointing straight ahead, at least in reference to the swingarm pivot since the distance from the axle to the pivot is exactly the same on both sides(hopefully my swingarm is straight, but there's not a whole lot I can do about that at the moment).

So I used my string alignment method using the rear wheel as my "straight ahead" reference, the only extra step I needed to do was measure the distance of the edge of the front wheel on both the front and back sides and make sure they are equal distance to the string, any difference front to rear means the wheel is turned. Looks like my front wheel was turned slightly to the left, throwing off my measurements(likely due to my not perfectly flat particle board table).

Using this method I've determined that my 36mm spacer is pretty much spot on as far as aligning my bike. I'll have to verify it once its all put together on a professional alignment machine, but I don't think there will be any major changes required at that point.