After fitting a new crank I have a problem aligning it with the clutch. There is no white dot on the old clutch. During strip down I only marked the clutch together with the prime gear and not the crank shaft, so I cant use the old parts as a reference.

The pics in the workshop area are not much good since they have been resized and cut in the edges.


The shaft that the clutch is fitted on is not totally symmetrical since there is a little "cut" in the edge, and the clutch itself is not either symmetrical since there are 6 symmetrical "holes" and one extra, in between two of the other holes.

I have marked the "symmetrical divergences" with a red line. How should these red lines be in comparison to each other to align the clutch with the crank.

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MC21, GP-Replica (Daijiro Kato, Telefonica Movistar Team 2001)

I wouldnt worry, I did a Dry clutch conversion and had the same problem, im not sure what that's all about, Just slip the clutch on, Mine had no problems at all and no marks!, and when i asked the same question i dont think there was a concrete answer...

if someone wants to correct me then please go ahead!! but i think youll be fine!

Ok, if you say so. Then I know who to blame

Also realised that the shaft going to the gear box have nothing to do with the alignment since there are bearings between the shaft and the clutch (of course, otherwise there would be no need of a clutch).
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MC21, GP-Replica (Daijiro Kato, Telefonica Movistar Team 2001)

I don't understand the whole white dot thing. I don't see how it can be important.
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james
Its not how fast you go...Its how you go fast.
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Is I see it there is no need for alignment like in 4-strokes, regarding to timing of the cam, but needed when it comes to "balance". The clutch will spin pretty fast, and if it is not "balanced" together with the crank I guess there could be some nasty vibrations. Maybe the "unbalance" of the clutch is supose to take away the "unbalance" of the crank. Most single cylinder engines has a balancer shaft, maybe the clutch on the NSR corresponds to such a thing...(seems strange though since the clutch wont spin with the same frequency as the crank).

If everything was balanced directly from the factory then there would be no need to align, so the white spots must mean that the clutch is not perfectly balanced. At least thats how I think.
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MC21, GP-Replica (Daijiro Kato, Telefonica Movistar Team 2001)

Yeah thats what i was thinking.........However, pull the clutch in and its ballance has now changed........ the iner stops/slows as the outer maintains its speed from the crank... release and its now diffrent as the gearbox shaft is in a diffrent location!!!

Slap it in..... If its wrong Blame Andy!!! LOL

When i took the wet clutch out i had NO marks at all....

I've rebuilt one....no maybe two NSR250 engines and I don't think that I've ever paid any attention to any white dots.

Let's have a look at it logically.

The engine doesn't have a balance shaft, so there's nothing to align there. The primary drive gear fits on splines to the crank. there's no missing spline to locate it so it can be fitted in any position. It has no lightening holes, or offset weights so chances are the COG is pretty much in the centre. If exact rotational location was necessary then Honda would have made it fool proof and punched or scribed a permanent mark of some sort.

The primary drive gear drives the primary driven gear on the clutch at a ratio of 2.36:1 (MC21) or 2.5:1 (MC28), so if you align anything statically then after 1 revolution of the crank you're gonna be miles out, so obviously nothing needs aligning there. You can see that the 28 would requires 5 revs of the crank to line up the dots again. The MC21 would align every 59 revolutions.

Other gears attached to the primary are the same story.

The answer is, throw it together and don't worry. If it vibrates then something else is wrong. It's not due to misalignment of the gears .

There are a lot of little things on the main site that need updating, it was essentially written 10 years ago after all, and contrary to popular belief I wasn't actually as perfect back then as I am now!

I'm pretty confident that there is nothing dangerous on the site though, old erratum's included.
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Andy.
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Andy not perfect???????

Oh, I guess not. If you were perfect then there would be two of me running around

I wasn't back then...



I'm pleased to report that I haven't grown up any more over the last 10 years though!
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Andy.
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Andy wrote:I'm pretty confident that there is nothing dangerous on the site though.

not if you work in a replating plant anyway;

the tuning section wrote:run the bike flat out in top (6th) gear, near the "red-line", i.e., 12000rpm, for at least 10 seconds, preferably slightly uphill

Well, that will establish if you're in the least bit lean, try it in the cool of dawn for a best reading.
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

To be fair, both myself and Andy hold ours flat out for well over a mile each time we ride them. And I mean proper flat out!
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If I have to take the carbs off once more...

Yeah but can't you 2 only move your right wrists through 15 degrees...
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NSR300R - Why did i ever have a 250...

It's just a little over that with a quick action throttle Maxim!

The "chop straight" is great isn't it Steve... we laugh about it every time we get to the end of it! About 2/3 of the way down you can hear the motors just won't rev any more, and the 30 limit signs/pit lane turning are still some way away yet!
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Andy.
NSR-WORLD.COM

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lol, yeah Ive often thought, damn... its still a long way to go and I'm already flat out.

1 and 2 and 3 and 4..... lol its still a long way to go.... 5 and 6...7...

My fingers start to tingle at the tought of full bore for more than 30 seconda at a time.
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If I have to take the carbs off once more...