Modifications - Performance Discuss aftermarket and DIY performance modifications

RC51 swingarm Mod.

Old 10-07-2009, 12:20 PM
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RC51 swingarm Mod.

OK, new thread to cover my questions, didn't want to continue tresspassing on Trinc's, nice mod that one too, just have a chance to scoop this up cheap.

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Old 10-07-2009, 12:32 PM
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So the other question that pops into mind, is the axle the same diameter? I also plan on going with the F4i shock mod, did you (Tweety) run into any issues when you install the Jamie modded unit, and I'd like to stick as close to the stock height as possible.
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Old 10-07-2009, 12:41 PM
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SlowHAWK is right on the money...

Bearings are easy, sleeve the needle one and replace the others... I have the allballs numbers somewhere... The bar... Just cut it... It really does nothing useful...

As for the linkage... I did it the hard way with welding on the swingarm... BUUUT... I have since done it do a friends VTR and we figured out a way that only involved the tools in my shop... Easy(ish) to do...

Do Tell? Easyish??

Don't worry... It's kind of on topic... It's atleast better than our standard thread drift around here... Then we'd be talking about dog's or politics...
Thanks, I appreciate that, but, I'm not all that much up on dog politic's...

On my swap I did use the stock RC dogbone that was cut and welded to the swingarm... I left the mounts on the arm, made the bit fit snug with the bolt in place and had it spot welded at the ends, then cut of the mounts and finished the weld... http://cgi.ebay.com/HX-Honda-RC51-SP...item20ad3f5416

But, as both me and Hawkter996 have said... Do this at your own peril... I'm alive, but that's no certainity for someone else...

Understood, waiver signed, it's in the mail.

If you give me a few days to go dig through my stuff I'm 99.99% sure I still have the paper templates for the plates (about 10 different verisons!) I can scan them and mail them...

Sound great, it's a winter project so when ya get the chance.. I'll be here.
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Old 10-07-2009, 12:54 PM
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Originally Posted by stebbdt
So the other question that pops into mind, is the axle the same diameter? I also plan on going with the F4i shock mod, did you (Tweety) run into any issues when you install the Jamie modded unit, and I'd like to stick as close to the stock height as possible.
Nope... axle is 25mm... you'll need an RC/954/929 rear wheel/cush drive/caliper bracket.... basically everything although you can re-use the VTR rear caliper, but the bleed screw is in the wrong spot when mounted to the rc caliper bracket, so you'd need to bleed it, then bolt it on.

J.
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Old 10-07-2009, 12:57 PM
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for the rear , the RC51 uses a 25mm axle (SH and most other hondas 20mm). Easy if you swap wheels to use the lighter and wider RC wheel, otherwise just replacing bearings seems simplest. Finally you could have small spacers made with 25mmOD and 20mmID to fit into the axle holders.

What is the difference in the mounting points on the swingarm for the suspension linkages? Why not just cut and remount in the correct location to duplicate the SH linkage mounting point? I'm sure its easy to say when viewing them but I don't have an RC arm in front of me.
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Old 10-07-2009, 01:10 PM
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Originally Posted by cliby
for the rear , the RC51 uses a 25mm axle (SH and most other hondas 20mm). Easy if you swap wheels to use the lighter and wider RC wheel, otherwise just replacing bearings seems simplest. Finally you could have small spacers made with 25mmOD and 20mmID to fit into the axle holders.
The easiest swap would be either the CBR1000RR rear wheel, looks the same as the VTR front but is 6" wide so it needs a 190 tire... Or the CBR600RR... Same looks but 5.5" width like stock... I chose the 600RR (But have a 1000RR laying around... Haven't decided if it's going on at the next tire swap...)

Originally Posted by cliby
What is the difference in the mounting points on the swingarm for the suspension linkages? Why not just cut and remount in the correct location to duplicate the SH linkage mounting point? I'm sure its easy to say when viewing them but I don't have an RC arm in front of me.
Nope... Won't work as the mount would then be hanging in the air... The length difference in the RC arm is mostly forward of the "H" part in the swingarm... But making two new plates and using the placement from the RC arm works just fine once you have worked out the linkage ratios... I did the math and some trial'n'error... But I'll gladly pass it along...
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Old 10-07-2009, 01:18 PM
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OH BTW I'm not gonna try to be an expert in any way... But since I did my swap, as said I did a swap on another VTR for a friend... That was an SP1 arm... Like stebbdt is doing... So I'm guessing I'm the only one having done both... (Make that dumb enought to try...)

Easy'ish way to make a linkage work...

I made a large chunk of alu the width needed to bolt into the stock tabs on the RC swing, drilled the hole and pressed in the bearings from the stock RC dogbone, then ground out the thickness of the two side plates and bolted them to the alu block... The plates have the same dimensions as mine, just cut off after the bolts holding them to the block...

The F4i shock from Jamie works fine for me... But you do need it too be height adjustable... Either shell out for the adjustable version Jamie have (but isn't selling yet?) or DIY like me...

Last edited by Tweety; 10-07-2009 at 01:20 PM.
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Old 10-07-2009, 01:22 PM
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BTW have a look here... http://images.tweety.se/

It's my gallery for the bike mods... My text is in Swedish so it won't be of much use, but the gallery works in any language...
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Old 10-07-2009, 02:00 PM
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Originally Posted by Tweety
BTW have a look here... http://images.tweety.se/

It's my gallery for the bike mods... My text is in Swedish so it won't be of much use, but the gallery works in any language...

practice makes perfect and necessity is the mother of invention. Nice job. I can't tell which links show the part you fabricated but I understand from your description. Sounds like a good solution.

I have to say, Stebbdt, if I were going to all the trouble to do this, I personally would wait for an SP2 arm that looks so much nicer. But that is pure cosmetic I'm sure. just my opinion but having put lots of work into things only to later wish I had done it another way, that is what I'm left with. Good luck either way.
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Old 10-07-2009, 02:23 PM
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Originally Posted by cliby
practice makes perfect and necessity is the mother of invention. Nice job. I can't tell which links show the part you fabricated but I understand from your description. Sounds like a good solution.

I have to say, Stebbdt, if I were going to all the trouble to do this, I personally would wait for an SP2 arm that looks so much nicer. But that is pure cosmetic I'm sure. just my opinion but having put lots of work into things only to later wish I had done it another way, that is what I'm left with. Good luck either way.
Unfortunately there are no pics there of that particular solution... I'm looking for them... I'm sure I have them somewhere, but on which SD card I can't figure out right now...

There are other reasons for going with a SP2 swing... It's a bit lighter, looks nicer and it's 16 mm shorter than the SP1 one meaning less change to the wheelbase... Also no need to mess with sleeves for the bearings... Other than that it's the same...

But I understand it's a budget decision too... If he leaves the arm unchanged, ie no welding, he can easily just swap for an SP2 arm later... The linkage if done as described above, and the wheel and all that will just swap over... Also selling the arm is easy if no welding is done too it...

Last edited by Tweety; 10-07-2009 at 02:25 PM.
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Old 10-07-2009, 02:37 PM
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Ok, wow, guys thanks for all the responses', So.. 25mm, I figured that may be the case.

Slowhawk: Nope... axle is 25mm... you'll need an RC/954/929 rear wheel/cush drive/caliper bracket.... basically everything although you can re-use the VTR rear caliper, but the bleed screw is in the wrong spot when mounted to the rc caliper bracket, so you'd need to bleed it, then bolt it on.
Cliby: for the rear , the RC51 uses a 25mm axle (SH and most other hondas 20mm). Easy if you swap wheels to use the lighter and wider RC wheel, otherwise just replacing bearings seems simplest. Finally you could have small spacers made with 25mmOD and 20mmID to fit into the axle holders.
Stebbdt: The spacers for the swingarm slots would be a cake walk and I would really like to keep the stock wheel if at all feasible.
Cliby: I have to say, Stebbdt, if I were going to all the trouble to do this, I personally would wait for an SP2 arm that looks so much nicer. But that is pure cosmetic I'm sure. just my opinion but having put lots of work into things only to later wish I had done it another way, that is what I'm left with. Good luck either way.

Stebbdt: Thanks, I assume that’s what tweety has on his, and I agree that it does look way better, but I have this one now and if I find an Sp2 down the line, I’ll already have a handle on how to mod it, and, have a modded Sp1 version to pass along.

Tweety: The easiest swap would be either the CBR1000RR rear wheel, looks the same as the VTR front but is 6" wide so it needs a 190 tire... Or the CBR600RR... Same looks but 5.5" width like stock... I chose the 600RR (But have a 1000RR laying around... Haven't decided if it's going on at the next tire swap...)
Stebbdt: I may have to go one of those routes if my spacer feasibility study doesn’t work out.
Tweety: Easy'ish way to make a linkage work...

I made a large chunk of alu the width needed to bolt into the stock tabs on the RC swing, drilled the hole and pressed in the bearings from the stock RC dogbone, then ground out the thickness of the two side plates and bolted them to the alu block... The plates have the same dimensions as mine, just cut off after the bolts holding them to the block...


Stebbdt: Ok I have to admit I’m not quite following ya here, I had planned to fab up a block just like you’re describing, with the hole for inserting the bearings, bolting it in just like you did with your sectioned dogbone and welding it up as shown then remove stock tabs.
Does this sound like what you mean?

Thanks again all mucho appreciated
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Old 10-07-2009, 02:39 PM
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Originally Posted by Tweety
Unfortunately there are no pics there of that particular solution... I'm looking for them... I'm sure I have them somewhere, but on which SD card I can't figure out right now...

There are other reasons for going with a SP2 swing... It's a bit lighter, looks nicer and it's 16 mm shorter than the SP1 one meaning less change to the wheelbase... Also no need to mess with sleeves for the bearings... Other than that it's the same...

But I understand it's a budget decision too... If he leaves the arm unchanged, ie no welding, he can easily just swap for an SP2 arm later... The linkage if done as described above, and the wheel and all that will just swap over... Also selling the arm is easy if no welding is done too it...
Ok, so I definatly missed something about the easyish method, no welding??
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Old 10-07-2009, 02:42 PM
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Originally Posted by Tweety
Unfortunately there are no pics there of that particular solution... I'm looking for them... I'm sure I have them somewhere, but on which SD card I can't figure out right now...

Yeah I know what ya mean, I have 5 jump drives and 4 laptop usb drives that I store stuff on, make it as hard as finding that lil dealie I stashed in the garage cause I knew I'd need it someday, lol
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Old 10-07-2009, 02:48 PM
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Originally Posted by stebbdt
Thanks, I assume that’s what tweety has on his, and I agree that it does look way better, but I have this one now and if I find an Sp2 down the line, I’ll already have a handle on how to mod it, and, have a modded Sp1 version to pass along.

Ok I have to admit I’m not quite following ya here, I had planned to fab up a block just like you’re describing, with the hole for inserting the bearings, bolting it in just like you did with your sectioned dogbone and welding it up as shown then remove stock tabs.
Does this sound like what you mean?
The swingarm I'm using is indeed a SP2 one...

You can easily do this swap with the SP1 without any welding, then the swingarm is unchanged and can be re-sold as stock...

On the RC swingarm (SP1 & SP2 both) you have two tabs... The stock RC dogbone goes between these...

On the VTR you have two plates going over two ends, the shock and the link to the engine... And in stock form, a mount on the swingarm that is completely incompatible with anything else...

What I'm talking about is a combination of these... The tabs on the swingarm is retained, no cutting or welding on the arm...

You make a pair of plates for the two holes, bolted to a very small block with the bearings for the bolt to the tabs...

Does this make sense?
Attached Thumbnails RC51 swingarm Mod.-block.png  

Last edited by Tweety; 10-07-2009 at 03:05 PM.
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Old 10-07-2009, 03:02 PM
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Ok. So..the stock tabs stay, do I need the stock RC dogbone?
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Old 10-07-2009, 03:03 PM
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Well, that would be the easiest source for the bearings...
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Old 10-07-2009, 03:14 PM
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So, in the drawing I'd make the block, are the plates something from either the RC51 or VTR swingarm? Also are the bearings the same as the ones for the shocks, I have some of those laying around.
Ohhhh, I think I understand now, gotta make the whole thing, right?

Last edited by stebbdt; 10-07-2009 at 03:25 PM.
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Old 10-07-2009, 03:26 PM
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Crap, be right back, gotta go home now.
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Old 10-07-2009, 03:54 PM
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Yep you make the whole thing... Two plates, two bolts, one alu block...

But the bearings should be possible to source from the end of a shock instead, yes...

And like I said, it's more than possible to make this with basic tools... A drillpress and handtools should work... But if you have access to better tools it's easier...

The most complex is the hole for the bearings and thickness of the block so that the plates match up to the ends of the shock and link...

Last edited by Tweety; 10-07-2009 at 03:58 PM.
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Old 10-07-2009, 04:01 PM
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This is from my thread on the build...

Name:  PICT1788.jpg
Views: 370
Size:  77.5 KB

The plates are laid over the now three ends... One being the welded one... Just imagine the one to the rear of the swing being the block...
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Old 10-07-2009, 04:57 PM
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Ok, yes I see now, the block with bearings will attach to the stock rc tabs with one bolt, two bolts just connect the block to the plates, that then attach to the the shock and also the link/arm yes?
So is the spacing of the bolt pattern as shown in the pic above equal? Do you have the measurements C to C, And are they in a 90 degree configuration.
And the shock & link/arm are the stock VTR units correct?

Last edited by stebbdt; 10-07-2009 at 05:30 PM.
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Old 10-07-2009, 05:25 PM
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Like This?
Attached Thumbnails RC51 swingarm Mod.-pict1788-1.jpg  
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Old 10-07-2009, 05:25 PM
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Shock and link/arm is stock VTR yes... Or F4i shock...

The bolt pattern in the picture was one of my fist tries, not what I ended up with... So that's not something to copy... I'll get the templates when I'm in the garage next time...

Now I'm gonna go have a nap... It's in the middle of the night here...
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Old 10-07-2009, 05:53 PM
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Ha, I was kinda wondering about that (the time diff).
Really man, thank you very much. Check back when ya can, I'll start on some drawings for the block and see about getting that part made.
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Old 10-07-2009, 06:28 PM
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Originally Posted by Tweety
Unfortunately there are no pics there of that particular solution... I'm looking for them... I'm sure I have them somewhere, but on which SD card I can't figure out right now...

There are other reasons for going with a SP2 swing... It's a bit lighter, looks nicer and it's 16 mm shorter than the SP1 one meaning less change to the wheelbase... Also no need to mess with sleeves for the bearings... Other than that it's the same...

But I understand it's a budget decision too... If he leaves the arm unchanged, ie no welding, he can easily just swap for an SP2 arm later... The linkage if done as described above, and the wheel and all that will just swap over... Also selling the arm is easy if no welding is done too it...
Hey Tweety... I think you have the measurements wrong on the SP1/SP2... the SP1 is the shorter of the two swingers... it was actually an "upgrade" made to the SP2 arm that they added the 16mm - 1/2" to it. That's the only reason I was messing with the SP1 arm (to keep a short wheelbase), as the SP2 arm is a quite a bit stronger and you don't have the bearing issue.

J.
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Old 10-08-2009, 02:03 AM
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Actually you're right... I should know better than to post half awake...
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Old 10-08-2009, 04:09 AM
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Originally Posted by SlowHAWK
Hey Tweety... I think you have the measurements wrong on the SP1/SP2... the SP1 is the shorter of the two swingers... it was actually an "upgrade" made to the SP2 arm that they added the 16mm - 1/2" to it. That's the only reason I was messing with the SP1 arm (to keep a short wheelbase), as the SP2 arm is a quite a bit stronger and you don't have the bearing issue.

J.
If I'm picking up on this correctly, that 16mm was added forward of the crossmember in front of the wheel, hence different plates would be needed to address the geometry.
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Old 10-08-2009, 05:00 AM
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No, that part is the same... It's the rear part that changed... But the front part is a bit longer than stock vtr, hence the need for a larger triangle plate than the vtr... The swingarms are interchangeable apart from the rear caliper arm and pivot axle... The sp2 one is a popular upgrade on sp1's...
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Old 10-08-2009, 06:12 AM
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Thanks for the clarification.
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Old 10-08-2009, 06:31 AM
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One thing I'd HIGHLY recommend on this swap is when you are working on the linkage plate make a few out of wood with different hole locations. (Obviously don't put weight on them though, make sure the bike is suspended securely). Reason being, you will find the ratio (swingarm travel to shock stroke) is greatly effected by this geometry. In a perfect world, you'd want the travel at both the arm and shock to work just like stock aviod your suspension being too soft/hard or bottoming out.

I don't know if I am correct in my thinking, (so please let me knwo what you all think) but when I was working on mine, I was measuring the wheel travel at the axle and trying to get that close to the VTR spec (I think it's close to 125mm / 5")... and at the limits, I wanted the shock fully compressed/unloaded.... I actually cut the spring of an old stock shock to use so I could move the arm by hand and measure, cut another plate, measure again... just a thought.

J.
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