RH Side Crankcase Build Cont’d
Message to self, reminder of torquing up Primary Drive Gear Bolt, a must in my case if it isn’t done straight away.
The Clutch Primary Gear was mounted on the Mainshaft together with its associated Spacers/Collars, Bearings & Oil Seal, please see http://www.nsr250.net/forums/viewtopic.php?t=15439&highlight= for more detail.




Thank goodness for Cardboard it has so many uses!




Slight application of Blue Hylomar to RH Crankcase Cover (love the stuff, been using it since the 60s!!! well it was ok for Rolls Royce so who am I to argue, ok it may have been used on Jet Engines LOL).
The water pump wasn’t removed as it was rebuilt very recently.




A new Sump Washer & Crankcase Cover Gasket was fitted, the Kick Starter & Crankcase Cover to Clutch Primary Gear Oil Seals were left as is, as they had been replaced very recently.
A slight manipulation of the Water Pump Impeller/Crankshaft was required to help mesh the Gears whilst trying to get the Crankcase Cover home before bolting everything up.

Checking Reed Valve
Although I was now ready to fit the Reed Valves, Stuffers, Gasket and Manifold/Insulator, I had previously inspected the Reed Valves and one had a slight gap in one of the Reed Petals which needed to be sourced & sorted first.
Note: A bit difficult to get a good camera shot of the gapping, holding it up against the sunlight hopefully you can just make it out. I would have tried a torch behind it, but I ran out of hands I’m afraid.




Dismantle offending Reed Valve Petals.




Re-fitting the new Petals sourced from WEBIKE, it’s ok to re-fit the screws using the existing spring washers apparently, however, I must own up to putting the very slightest of dabs of Loctite 243 on the threads to make sure.

Carb Manifold/Insulator Installation
Applied a little Blue Hylomar on the Reed Valve Gasket and placed it on the mating surface followed by the Reed Valves and Stuffers.




The Manifold/Insulator had previously been checked for any Cracks, Perishing, Splits and Warping (warping was checked with a straight edge across the mating surface held against the light), and although it looked good I’m afraid I succumbed & applied a little bit of HONDA Threebond to the mating surface for good measure.
Fitting the Manifold/Insulator I paid very careful attention to its tightening sequence, starting by hand and then gradually tighten up bolts to 5 lb/ft, 60 lb/in in several stages (didn't want to warp it).
Note: Made sure the longer 32mm Bolts went on the outer Edges of the Insulator, tightening sequence number Bolts 5-8.

Piston/Cylinder/Head Fitment
2 ‘Bs’ or not 2 ‘Bs’ that is the question LOL!.
The 2 Cylinders with Marks ‘B’ stamped on them had been sent away some time ago for some remedial work and Nikasil plating.
You can tell how NEW/NAIVE or JUST LUCKY I am to all of this, as the following came as a bit of a surprise. I assumed (yes assume stands for making an ass out of you and me LOL) quite wrongly, that the Cylinders when Nikasil plated would be automatically as per HONDA’s Cylinder & Piston Selection Table dimensions.
A ha! not necessarily the case, as I only found out the hard way by asking a few probing questions.

Although on the face of it, the Cylinder and Piston selection Table is a good place to start, there are some pitfalls that one should be mindful of when carrying out the selection process to which I was completely unaware of, hence the NEW/NAIVE or JUST LUCKY comment.

The following is my attempt to put some thoughts down on this process as follows, so hopefully it makes some sense (would be a first for me!!):

• It may not be all as it seems: The Cylinder Marking stamp of ‘A’, ‘B’ or ‘C’ on the side of the Cylinders only indicate the bore size when it originally came out of the factory, if they have been re-plated, then they may be a different Bore Diameter to that stamped on the side of the Cylinders (for example, thicker Nikasil plating applied to bring it back to STANDARD NSR125 Cylinders size of 54.00mm).

• Recommendation: Firstly provide the PISTONS to be used with the CYLINDERS to be Nikasil plated to the Service Supplier to make absolutely sure everything will be ok before re-plating process.

• Another guess: It’s only an educated guess, that there would be issues if you tried to use say PISTON ‘B’ (largest available Piston) in a re-plated Cylinder ‘B’ (smallest Bore Size), but you have to check that out with the Service Supplier.

End of confusion or my rant LOL!!

Fortunately for me, following a dialogue with the Service Supplier, I obtained HONDA Pistons Marked ‘D’ for a 54.0mm Bore without realising at the time what had taken place, as ‘B’ marked Cylinders should have ‘NO MARK’ Pistons, another lesson learned and chalked up to experience.




Applied a bit of heat to Piston to help slide Gudgeon Pin in makes life so much easier.




Ready to go Base Gasket on and of course with a bit of Hylomar.




Made sure Rings were positioned to abut the Piston locating Pins.




I decided to install the RC Valves before installing the Cylinder Barrels on the Crankcase, as I felt it would be a lot easier to do and especially as I had obtained T2’s special tool for Cylinder Nuts (can’t remember where from, although WEBIKE do supply them product code T2-Ti-SN-T) which makes the job so easy.
Installing the Cylinder is not an easy job particularly if you have Arthritic Hands & Fingers like me, I slid the Cylinder Barrel down over the Piston & Rings whilst holding Piston & using Finger Nails at the same time to depress the Rings and making sure they don’t move (‘like sticking your finger in your ear and singing ting-a-ling-a-loo’. Don’t try this at home LOL) and remain tucked in and abutting the Pistons locating Pins.
Et voila as they say in French! one Cylinder Barrel on and now to Torque it up.

philup_7@hotmail.com wrote:

Looks like you snuck a pair of HRC rectifiers (stuffers) in there on quiet!
_________________
Andy.
NSR-WORLD.COM

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