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Showing posts from January, 2012

Crankcase headaches...

I'm missing the days when I knew shit about two strokes... things were pretty much easier and less time consuming. I didn't had the knowledge to go any further though, so I reckon that's a good thing in my book.
I will do a write up on CCSpecialty porting tools real soon.
Big cheers to Vaggelis(GR) aka 1/2 Racing that lend me some of his tools. A young guy that knows more about porting work than old-aged tuners here in Greece.
Nsr250 crankcases in the background...

Dzus Fasteners

Quarter turn fasteners are essential for track/ racing bikes and save a lot of time and effort. Dzus bolts are the most commonly used fasteners and come in a variety of types (spring, slip-on, riveted etc) to cover any application needed.
Position of the Dzus spring plates should be right behind the back panel or just slid over it if your stud doesn't have the sufficient length needed.











Mark the position and drill 3mm holes for the rivets and about an 11mm hole for the flared spring plate. On the front fering panel, use a nylon washer after you've inserted the stud as this will keep the stud in place when the panel is removed from the bike.

NX5 Ohlins rear shock on a Nsr250

Spyros aka Bismarck came for a coffee today, bringing along a couple aluminum spacers for the mc28 project. We fitted the Ohlins Rs250 rear shock and it seems like I finally have a rolling chassis. 










Both ends of the Ohlins rear shock should be modified to suit the mc28 frame-proarm. Upper fitting needs to be machined as length is too large to fit the nsr frame and mounting hole should be enlarged. For the lower fitting, we used an eyelet type, kindly donated byKRT aka Kalogiros Racing Teamand a couple spacers to suit the nsr shock linkage. 
Even then, there are a few minor issues as the upper part of the Ohlins rear shock has contact with the aluminum spacer of the subframe bolt and the LH rearset will not clear the proarm due to the added length of the Ohlins shock. Also, rear brake hose needs to be relocated. Most of the issues already corrected... a rolling chassis at last! 

Ethos Tornado

I came across a set of Nsr250 mc28 expansion chambers made by Ethos, so I couldn't resist taking some measurements.
*Stingers have an ID of 21.5mm and are 400mm long. 
Below photo of the pipes mounted on a Nsr250 plus a couple more, can be found at Jamie's Nsr site. Browse the links while you are there as it has tons of interesting info.

Nsr250 swingarms: Proarm Vs Gullarm

Ok, I might getting a little bit anal here but I had both swingarms side by side while trying to stay open-minded and consider both of them for my nsr250. So, I couldn't resist comparing them...   First of, the eternal debate about the weight of both swingarms.  A complete Nsr250 mc28 Proarm measures about 9.800Kgr and an almost complete mc21 swingarm measures about 8.500Kgr. 
So, mc21 swingarm is 1.300Kgr lighter but to make things clear, these measurements are really rough.  As you can see from the photo, the mc28 proarm is complete while my mc21 swingarm has quite a few parts missing. Also, I haven't measured mc21 wheel bearings and all 4 metal spacers as these are part of the wheel while on the proarm these are integral parts of the hub-axle assy (hence included on the above measurement).  Overall, I believe that both swingarms weight really close with the mc21 maybe ending up being just a bit lighter. 
I really like the robust looks of the gullarm design and tyga-perform…