NSR250 Conrod Kits

I got a package in the mail today;  4 x NSR250 conrod kits.

Clearly, the crank pin is not needed, but I failed to specify that. D'oh.

These new conrods weigh 156 grams. The standard Honda conrod weighs 155 grams.
These new conrods are a bit thicker in the stem near the small end, so I suspect (I can't say for sure) they will be able to handle a bit more stress due to higher revs/heavier piston/more power etc.

The big end bearing weighs 25g
The small end bearing weighs 12g
The thrust washers weigh 6g each (total of 12 grams)
This gives a total of 205g

The big end pin weighs 176g but is not needed as it is an integral part of the crank web.

I am actually going to sell a pair of these to anyone who wants them. NZ$340 + freight each. (NZ$680 for the pair) Not cheap I know. That includes bearings, washers and bid end pin.


Now if only my man making the 2 central crankshaft webs wasn't quite so busy!
Patience.

In due course will be revealing the source for these NSR conrods ( <--click) on the new forum, just to give that site a bit more exposure.

www.NSR250Forum.com

<< www.NSR250forum.com >> <<== click to go to forum

Today I created a NSR forum at http://nsr250.freeforums.org/

The main purpose here is to have an open forum where people are free to talk about whatever they like in relation to the Honda NSR motorcycle, for free.

Other similar forums do exist, but are perhaps more commercial and not as open as a result.
However, I strongly urge people interested in NSR's to subscribe to other similar forums as they are pretty excellent. In particular NSR-World.com is an excellent resource with attached "message board" forum.

It was originally intended that this new forum be secondary to NSR-World.com.
However, if you find that what you have to say at NSR-World is not allowed, or just plain gets shut down somehow, then be re-assured in knowing that you can speak freely in this new forum.

Please feel free to register and add to the discussion on this brand new forum:  http://nsr250.freeforums.org/  or  www.NSR250forum.com
If you would like to be a moderator, or would like to see different topic categories, just let me know in the "General Chat" section.

The forum is totally free for anyone to use, and will remain that way, hopefully forever.
The freeforums.org people do place advertising in amongst the forum. This means that it costs us nothing but time to run the forum.

Enjoy.

Below are some links to possibly help google spider bots find the new forum and up its popularity in the searching stakes?
NSR Forum   NSR250 Forum
NSR125 Forum NSR125 Forum
NSR150 Forum NSR150 Forum
NSR250 Forum NSR250 Forum
NSR300 Forum NSR300 Forum
NSR500 Forum NSR500 Forum

Dave's MC18/MC21 engine

Nothing to do with my build, but, Dave ended up in a situation where he had an MC18 engine without a crankshaft. Then he got hold of a good MC21 crankshaft and MC21 cases.
So he put together an engine that was MC21 crankshaft and crankcases, but with a MC18 Barrels/heads and gearbox.
He bought an MC21 Selector drum and gear position sensor. Also bought an MC21 oil pump.
He has a (MC18) PGM II, so it is now just a matter of getting the neutral light to work off the MC21 GPS, with the MC18 PGM II (instead of the MC21 PGM III). This is very simple as there is a wire for the neutral light

MC21 drum has slot for Gear Position Sensor

Red circle is MC18 neutral switch trigger.
Purple circle is MC21 GPS slot.
MC21 drum has slot for Gear Position Sensor, and no taper in hole,
Otherwise it is the same as MC18.

MC18 and MC21 selector drums look the same from here

MC21 Gear position sensor with small roll pin for selector drum slot.

MC18 Neutral switch case. Offset from selector drum axis

MC21 Gear position sensor case. Coaxial with selector drum.

MC18 oil pump case

MC21 oil pump case with extra oil feed to RH main bearing.

Frame lug and race stands lugs

I took my frame and swing arm out to Adrian Rimmer (182 Omanawa Rd. Ph (07) 543 1121) who has a workshop set up at home.
I got him to remove an existing frame lug and replace it.  The existing one had been "fixed" in a way that looked bad.
I also got him to machine up some race stand lugs and weld them on the swing arm. And to machine up a couple of screw in pivot pins for the race stand to hook onto. All up $60. He did a really good job.
It is so nice to have a locally available aluminium welder that can do an excellent job at an excellent price.

Rear Shock Link Plate Options. Part 1

I have been thinking about getting the HRC F3 rear shock link plate cut out of some 5mm thick 6061-T6 Aluminium. Probably using an abrasive water jet cutter.

So while I am thinking about it I might as well do a few drawings I guess.
For the standard link plate I just measured my own one.
I got the HRC F3 link plate geometry info from NSR-World.com.

For those who want to be difficult and use a link plate that is a compromise between to two plates shown above: Well OK, ...  here you go. Note that I have curved the sides slightly to make it distinctive and easily recognisable.

If anyone else wants to do the same, here are the .dxf files needed by the cutting machines:
Standard MC18 Link Plate
HRC F3 MC18 Link Plate  (linked to correct file 09-Nov-2012)
Compromise MC18 Link Plate

I have taken all care, but will accept NO responsibility. OK. Do at own risk, blah, blah, etc.

[Edit -19/05/2013: I have been using the Compromise link plates on my bike and am quite happy with them. The HRC plates are really only suited to the track. As the shock compresses it gets very stiff very quickly due to the increased rising rate caused by the HRC link plate geometry]

Attempt at polishing fork legs

I have previously bead blasted my fork legs and was wanting to take them to a metal polisher to get them looking a bit better. There is only one good metal polisher around Tauranga, where I live. I have rung him and left a message, and visited his shop only to find it not open. So I went to my local hardware store and bought a polishing wheel and compound.(NZ$34.00)

One leg bead blasted and buffed up, the other  just bead blasted.

I did this just on dusk and it looked pretty good. However, in the light of day there was a sight mottling or unevenness to the polished surface. The finish was not a high polish, and actually was about right compared to factory as the fork legs do not come standard with a high polish.
Paul sent me a photo (below) of a fork leg that was vapour blasted and then "grained" using a Scotch Brite on a drill as a flapper wheel. Some dude in the UK on PhotoBucket called "pgperformance67" is all the detail I can get.

 This looks not too bad so I might give that a go. It is tricky to get the legs looking nice but not too polished, like they are when new.

Re-assemble swing arm into frame with new bearings and seals

I bought 3 new bearings and 2 new seals for the swing arm main pivot. Cost NZ$62.77
I fitted them to the swing arm and assembled the swing arm back into the frame this evening.
One thing I didn't cotton on to during dis-assembly of the swing arm is that the main bolt/axle that goes through the main swing arm pivot can effectively be used as a 16mm Allen head key for doing up the threaded spacer.
When I was about to tighten the spacer up between the swing arm and the frame, I made sure to first do up the upper rear frame bolt as shown circled in red below. This just stops the frame from getting pushed apart as the threaded swingarm spacer is tightened up. Probably a bit of a small point as the frame probably wouldn't spread too easy anyway.

I bought a swing arm chain slider off Adrenalyne Motorcycle wreckers in Mt. Maunganui for $25. The rubber was developing a few cracks especially in the stressed part of the loop that hooks over a lug on the top of the swing arm. I just squished a bit of 5 minute Araldite into the cracks and left it for 24 hours. It seems to have done a pretty good job.
The threaded rivet thing on the side of the swing arm (that the bolt with a slotted and stepped washer goes into to hold the chain slider rubber onto the side of the swing arm) would spin when I tried to undo the bolt so that I could fit the chain slider. By squeezing in behind the stepped slotted washer with a pair of side cutters I was able to get the screw out. This will be a problem if I ever go to take the chain slider off again, but hopefully that is not something that I will be doing.

Also, I pulled apart the little double swivel spacer item that goes on the LH side of the swing arm and has the main swing arm pivot bolt go through it. I was little surprised to find 2 O-rings in this little sub-assembly. But I just gave it all a good clean and greased it up before re-assembly. The bushes are noticeably worn, but hopefully it will be OK for another 30,000 kms.

Note that on the body of this part is an arrow with an "F" stamped next to it. Obviously, this is so you don't forget how to orient the part upon re-assembly.

At the moment, I have to confess that I don't actually know what this swivel spacer part is for. But I will know soon enough.
Next up is the rear shock. The polishing of the front forks is not quite right, so I am taking a bit longer to get the front end sorted than I had hoped.