This started because I decided to upgrade my MC18 R5K to ProArm and seems got carried away, after looking at the modifications required and still having an issue with shock matching I gave up on MC18 frame and now I have an MC21 frame coming so I was wondering what parts are interchangeable and what else I might have to get.

Form what I understand motor is a straight swap, forks, yokes, basically whole front end will fit. Using MC18 harness and PGM2

What I have to replace:
Subframe and fairings are different, I got the subframe with the frame and looking to get set of TYGA skinz
MC28 ProArm should fit right in?
Rear sets, looking to get set of TYGA's


Anything else I'm missing, like a radiator? oil tank etc?

Don't be shy, if you think i'm crazy just say it

MC21 frame arrived and first thing I tried to fit the MC28 ProArm, but no dice, pivot bolt size is different, also NC30 ProArm I have has yet another different size bolt, in between MC21 and 28

Steering yoke didn't fit either, stem too short, even the RC31 and CBR 600 ones I have didn't work because they are too short and steering stops are in wrong location.

Tank front mount does not work... looks like I will end up buying the entire bike piece by piece.

Interesting considering I had a bike in my shed for a while that was a 21 frame with a 28 arm in it. I have both a 21 and 28 triple that I can measure the stem on to see if they are different lengths.

The 18 yolks have a different offset and different stem length to the 21, the 28 and 21 yolks should be interchangeable although they are slightly different. The 28 has a hole in the stem for the steering look and the top yolk hasnt got the ignition key holder.

I seem to remember from looking at one of Watfordhorns nc30's the shock is offset to one side so I guess that would complicate things. I believe racer38 fitted a single sider to a mc18 many years ago so it must be possible, but why you would want to ruin a perfectly good bike by fitting one of those is beyond me

Look for Duncan's thread in Members Builds. He's recently fitted an NC Pro-Arm to an MC18.

http://nsr250.net/forums/profile.php?mode=viewprofile&u=1530

And, sorry Paul, but I have to say it... eggs come with yolks; bikes come with yokes!
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Andy.
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Andy wrote:Look for Duncan's thread in Members Builds. He's recently fitted an NC Pro-Arm to an MC18.

http://nsr250.net/forums/profile.php?mode=viewprofile&u=1530

And, sorry Paul, but I have to say it... eggs come with yolks; bikes come with yokes!

Doh!

Problem is I can't make up my mind and having all the extra bikes around further complicates things.

I like the looks of ProArm, always did, regardless of the extra weight, I't the reason I got the Hawk, 748 and still want to get couple VFR's in the future, both, the big 800 and NC30(35)

Always wanted NSR250, "Smart Card" bike has always been my dream but I can't afford one now or in foreseeable future (Thanks Wall Street!) So I got R5K (ended up with 2 of them) tried installing Hawk arm and it's too wide so I got MC28 arm, still a bit too wide but instead of shaving the arm I decided to upgrade the frame so I got MC21 frame with subframe and most of the fairings but it looks like I will need more parts to complete it.

At this point I have 2 complete MC18 PGM2 bikes, plus couple ProArms (MC28 and NC30) SP motor form Terra bike, MC21 frame, NC30 forks, RS250 Magnesium wheels and some other bits but I don't have any money left.

I was going to keep one bike all stock looking and go wild with the second bike but economy has taken a big chunk out of my income and now I must sell one of the NSR's and couple other bikes (Ducati mainly) just to stay afloat, instead of building the dream bike I am looking it bare bones build or just box everything till better times.

Pretty much all you have to do to put the MC28 Pro-Arm into the MC21 is have some bushes made to take the smaller Gull-Arm pivot shaft, or (a bit more awkward) get a machine shop to ream out the holes in the MC21 for the bigger MC28 shaft. Everything else is similar enough to swap.

As for the forks, you just need MC21 yokes, or get a new shaft machined, grind off the weld on the bottom of the MC18 yoke holding the stem in place, press the old stem out, and the new stem back in. No need to weld it in place really, as long as you have it made long enough!

Just measure the difference between the headstocks on the MC18 and MC21 frames to see how much longer the new stem needs to be! Take the MC18 bottom yoke to the machine shop, and say "I want one of these [pointing to the stem!], but xx longer!", and Robert's your mother's brother!

Alternatively, if you ask nicely in classifieds, you'll probably find someone has a set of MC21 triples (yokes) kicking about they will sell you! I think I have a set actually, but they are 6000 miles away right now!
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7000 miles in fact Andy, I sold them to a guy in the States for you
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If I have to take the carbs off once more...

In fact I have multiple sets kicking about

StephenRC45 wrote:
7000 miles in fact Andy, I sold them to a guy in the States for you

That was nice of you, Steve!

Do we have enough front-ends left for all the F-III's still?!
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Andy.
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Head stock is about 1" longer, that was second thing I measured after finishing with ProArm measurements, was trying to get the rolling chassis together so I can compare the MC18 to 21 with the Ohlins shock I was hoping to adopt, it fits but it seems too long still, had to compress it good 10 mm to get the ride height near stock MC18. I'm sure MC21 can take some height increase in the back, will get to it when I'm closer to finishing it, perhaps after a test ride.

I think the 21 yokes will be the easiest route, not that I'm afraid of making things, but I already found a lower yoke in US, just have to wait for the funds. I pressed Honda Fireblade stem in to Ducati 748 yoke to adopt a complete 748 front end to my Hawk, also had a sleeve made for the ProArm so now I have a complete rear eccentric, axle, brake, wheels and cush dive from 748 on my Honda

What is the length of the MC21 suspension link, the one from the frame to the triangle? Should I use MC21 or 28? I used a CBR one for now just to get the rear bolted on but it's 130 mm I believe, definitely longer then MC18

Yokes in the picture are CBR600, those parts are dime a dozen here, got a shock for $28 shipped, almost straight fit for MC18