I picked up this 21se some years ago now, come across it whilst buying a NC30 project and the seller mentioned he had a NSR in a similar state that was imported back in the 90's and had sat in his garage ever since being knocked off it not long after.


Wasn't the prettiest of bikes but for the money it was fair game, it had been sat in this garage for 11 years so i never bothered to try running the engine i knew if it did start it wouldn't last long so out came the engine, replaced all the frame/linkage and headstock bearings, rebuilt the forks with tyga tops and treated it to some BEET rearsets and a new ohlins shock. New C&S, tyga cans, hoses, pads, wheels refurbed with fresh rubber and sourced a half decent set of winners one panels.




The engine was still on the bench stripped awaiting for me to build up the courage and tackle it and find someone to do the crank so i dropped in a dry clutch MC18 motor i had that knew was a runner, then the cadwell classic came around so naturally the NSR got loaded into the van for its first proper ride.

At this point i knew i wanted this to be an all out track bike so a much as i loved the winners one scheme the panels were wasted on it and sold on.

It was around this time id made acquaintances with jonny mac who took on my original 21 motor in a box of bits and made this....

A far cry from what it originally looked like i cant thank him enough for doing this. So with the new motor fitted along came a set of JHA pipes, EBC discs, race loom with hardwired HRC box, some F3 carbs and carbon tray.



The track transformation was starting to take shape, i had a fairing set in the loft id bought some time ago which by coincidence had been cut to fit the fat JHS's so with a new screen brace and a few brackets here and there it pretty much went straight on





The F3 carbs had no provision for solenoids and no TPS fitted so i spent an evening at RSK's on the dyno trying to get to get it dialed in but i think the most we got from it was around 45bhp, not good

We concluded it must be down to the lack of TPS and possibly the air solenoids too so called it a night and went back to the drawing board. Trackday season was on us so i fitted some stock carbs and airbox with TPS and solenoids which made just under 60bhp with a good AF ratio on a quick return visit to RSK's.



Here we are at brands mid 2019 with Jonny mac and Paul g, Thoroughly enjoyed riding the 21 and later in the year also got to the cadwell classic where i really started to gel with the bike.

So this brings us up to winter where the bike is back on the bench having another make over and a few more upgrades which are nearly complete................


Last edited by drunkn munky on Tue Jan 14, 2020 2:16 pm; edited 1 time in total

Excellent! Great to see another NSR built up rather than broken for parts.

That bodywork sat in my spare room for years until LukeF finally decided he wasn't ever going to get back into NSRs! I was tempted to buy it many a time!

Two points of note:

1. Those air filters aren't doing you any favours!
   
   
2. You can use the HRC carbs and just plug a TPS into the harness and adjust it to a static setting. It's not ideal, but can get you close. You can also retro-fit the bracket, plastic coupler, and TPS, if you really want to. But in fairness, other than being able to say "HRC carbs", it's really not worth it over stock carbs with an HRC jet kit!
   

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Thanks Andy, the filters have been taken care of


Regarding the TPS i have got another TPS unit that ive plugged into the loom and set to fully open, i am in 2 minds of weather to retro fit it like you say as in my head this would be the better option, I could try both options on the dyno to see if it makes any difference

Good write up Tony, be interested to see what upgrades you have in store.

Were your dyno runs carried out before you "de-coked" the pipes at Brands That would have been holding it back a bit.

I think we chatted about this previously but I struggled to get my track bike running cleanly with the F3 carbs even after I had retro fitted the TPS. As soon as I tried the carbs from my road bike on it ran like a scolded cat! I ended up building a hybrid F3/stock set so I could run the solenoids and it runs great.

Hey Paul yes I remember our chats about the F3 carbs, I'm gonna give them one last try and if no joy I'll mod my stock set to run open with no airbox, it's probably the best option but I'm just a hrc magpie for things like this.

Yes both dyno sessions were before brands so therefore before I rebuilt those cans, it certainly made a difference it felt like a different bike cadwell.

Upgrade wise, lots of alloy and a dash of magnesium, oh and a bit of orange thrown into the mix too

I think we are all a sucker for an HRC part In reality there is no logical reason you cant get the F3 carbs running properly with some time spent jetting. Although I would say the TPS is a must have with the PGM 3 unit. I personally used up my patience and minimal jetting knowledge so just stuck with what worked.

Wide open isn't necessarily the optimum setting for the TPS.

HRC carb castings differ internally to the stock items, which is why the jetting can vary quite a lot from what you may use with standard carbs. 88, 89, and 90 HRC carbs all differ from one another too. As Paul says, you're much better off just using the stock carbs and air correction. It just works so well, even up to 70hp.
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Hmmmm sounds like im gonna have issues with these carbs then. The stock carbs i have are MC18 not 21, is the HRC kit compatible with the 18 carbs as i see the kit is only listed for the 21 on tyga's site.

Some more progress with the bike though, i bought some proper kit magteks a while back and these have been refurbished by TPCS, 3" front and 4.5" rear although i do have 3.5" front too to try at some point.



RS rear caliper conversion done with new disc, just needs a longer hose


I also wanted a alloy rear subframe and found that tyga's GPT one fits my seat unit perfectly which is RS250 of some kind.
Had to make a undertray for it which is a bit blue peter but serves its purpose.

Tony, you can fit a lightweight rs125 rear disc, muchos lighter than the stock one, had one on mine with the rs caliper, looks much racier as well.
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I think that is a rs125 disc les, stock nsr one was too big to fit

Looks the business Tony! All that weight saving really adds up, my track bike is noticeably lighter than my road bike.

I still have to get rid of the steel clock bracket and those stock tanks are quite weighty

The MC18 carbs have a different air solenoid set up to the 21/28 so that might be a whole different can of worms.

Cheers Paul, really looking forward to getting out on this, it already felt super light compared to my 400's.
The tanks are a issue, I bought a NXA tank in the hope I could get it to fit but it needed too much modding, I know someone in the process of having some alloy tanks made so I think I'll hold out for one of those.
I've got a F3 alloy clock bracket to go on it if I can get the hrc tacho to work I just need to make a foam surround to finish it off

paul g wrote:The MC18 carbs have a different air solenoid set up to the 21/28 so that might be a whole different can of worms.

It's just pipe routing though isn't it? I've been using the 18 carbs with 21 solenoids all last year and it's worked fine

drunkn munky wrote:

paul g wrote:The MC18 carbs have a different air solenoid set up to the 21/28 so that might be a whole different can of worms.

It's just pipe routing though isn't it? I've been using the 18 carbs with 21 solenoids all last year and it's worked fine

Maybe that's all it is, I remember the solenoids and plumbing being more complex then the 21/28 set up. But anyway if it works it works