You can use the standard NSR plugs, they are much cheaper than the HRC shorty units and will provide no power increase. You will just need to trim the plastic if you are running stock plastic with the head conversion.

Wiseco pistons work, but the only ones I know that work are for an '85-'99 RM125 and the pin-to-piston crown distance is short by about 1mm. You will have to have your cylinder bases machined down to get them to work. Heck, while you are at it, you might as well get the 2mm oversized pistons, bore, and replate for a full 268cc NSR. The 2mm over pistons are part number 641M05600. Contact Eric Gorr www.eric-gorr.com , he does the overbore and porting required for this.

The crank has little potential. I have seen the race shops weld the crank pins, but this really does nothing in the NSR where the crank pin is not really a removable pin, but is actually part of one half of the crank itself. I have seen NO upgrades to larger bearings or stronger rods available.

I believe all the MC28 SE's and SP's use the same close ratio gears. Going with the HRC units would be an upgrade, from what Harc Pro told me, but that is mainly due to the "weak" stock 2nd gear. Most people will never have a problem with it unless they are running the piss out of a bike that pushes over 60hp on a constant basis. You can also back-cut the stock units to help the durability.

I have heard RS250 coils will help, but how much? Anyone have some data on this? I always thought the stock NSR units were the best for cost/weight/performance.

The shift drum spring is a good choice. The HRC unit is a tad stronger and helps with the 2nd gear problem.

The shift drum upgrade is actually a lighter weight MC21 piece taken straight out of the MC21 parts manual. Honda has quit production on these and superceded the part number with the MC28 unit, so if you can find the MC21 unit, snag it quickly.

The TSR carbon clutches are the thing to get. Wish I had one. But I have no problems with my stock clutch plates on the street, though I really needed the JHA stronger springs I added. My bike is nearly 70hp.

TSR chambers are actually made by Harc Pro. They are a great design, but have not been updated since about 1996. They have always been the best, but I believe the new JHA's, Ethos, and especially the Tyga's have matched if not surpassed their performance. The Tyga's are definately the best bang for the buck, and one of the best designs on the market.

Get the HRC reed stuffers. Cheap and very effective. Harc Pro sells them for around 500 yen each.

I would advise the Tyga carbon reeds, though. I tried the HRC units and was dissappointed. They helped overrev, but hurt the midrange. The Tyga units gave more overrev and hurt nothing, and you cant beat their price.

The Daytona filter will give virtually no effect on power by itself. The unit I bought was a dual-layer unit, with a restrictive layer of plastic between the foam layers. I had to peel the foam layers apart, remove the plastic layer, and sew the edges to hold them back together. That helped a tad. The best airbox upgrades, though, were to open the inlet, cut a section of the airbox divider out, and install larger diameter rubbers between the airbox and the carbs (hillbilly mod, but it works like open carbs, except that I dont have a dirt ingestion problem).

I had no luck at all with the carb setting kit. This kit is designed for race use, oil injection removed. The ONLY benefit for me was the adjustable needles. The Mains and Pilot jets were all too large for me (mains range from 180-210, pilots from 40-45). I could not get the bike to run lean enough in low RPM and get rich enough in high RPM. Seized her twice at WOT, and got rid of the jet kit. I gained alot of midrange back going back to the stock setup, lessened tailpipe spooge, and my reliabilty and fuel mileage went up. You can order the needles only from Harc Pro if you want. I have the part numbers lying around here somewhere if you need them.

Of course, this is just my personal opinion. I spent alot of time and money trying all kinds of things on this bike while I was in Japan. This bike was my daily driver and weekend warrior for 3 years while I was over there, so I racked a ton of miles trying all kinds of stuff. I you want a reliable streetbike with a great compromise of durablity and power, just follow Tyga's simple upgrades. You cant go wrong. And put a .6mm base gasket on the lower cylinder if you do the head swap.

Hope this helps!
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
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