Hello guys i have some questions for you:

1.Is there any difference in the look of a wet clutch mc18 engine with a wet clutch mc21 engine??I think that the kickstarter of the mc18 is a little bigger.

2.Where is located the engine number??Cause i may buy a nsr engine and i want to know if it's a mc18 or a mc21...

3.The mc18 crank fits in the mc21/28 cases?Are they identical or do they have differences??

that's it

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Sorry for my english

MC18 and MC21 are different the mc18 has hexaganal heads mc21 round heads .The mc 21 has the gear sensor mc18 dosn`t . cranks are different .

nsr250agr wrote:
2.Where is located the engine number??Cause i may buy a nsr engine and i want to know if it's a mc18 or a mc21...

The number on all normal road bike NSR engines starts MC16 so is no help whatso ever.

I'm not sure if you can tell the mc18 from the mc21 cases without taking them apart and as '21 barrels bolt onto '18 cases that's no guarantee either.
Steve or Andy may know better.
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Easiest way to tell them apart is the gear sensing position pickup located below and behind the gearshift rod on the LHS is present on the 21/28 cases. It is absent from the 18 cases and instead there is a single brass 'sender unit' which is for determining if in neutral. The brass sender looks in appearance similar to the water temperature thermocouple that sticks out of the cooling system thermostat.

how do i know this..... 2 surplus 18 cases and a hunt for 21 cases!

cheers,

Easiest way is to check the engine numbers. Says so in the Honda parts manual. Sorry Fontyyy.

Guys yesterday i realised that my engine has the low cylinder mc21 and the upper cylinder mc18!! The rest of engine is mc21(checked engine number).Has the mc18 cylinder different port timing compared to mc21 cylinder??I hope not...

Yes it does, and it's generally a better port design too.

The SP head / barrels are also different to the standard (R+SE) barrel / head.
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So,am i gonna expect problems with the configuration i have now?I mean the cylinders are working differently,may this cause problems to the crank or something else?

If both are working and jetted properly it shouldn't cause problems, although if one is producing a lot more power than the other you would suffer vibration. Almost impossible to detect though, unless you want to two a dyno run for each cylinder with the cap of the other removed!
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Dave Ett wrote:
Yes it does, and it's generally a better port design too.

There's virtually nothing in it, and you won't notice the difference with one of each type of barrel, especially if they are standard.

Dave Ett wrote:
The SP head / barrels are also different to the standard (R+SE) barrel / head.

That's incorrect Dave; the SE & SP are the same, and differ from the R.
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Andy.
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Dexter wrote:Easiest way is to check the engine numbers. Says so in the Honda parts manual. Sorry Fontyyy.

Go one then

whats this from - MC16E 1210695 ?
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Thank you guys for the replies.Actually the bike runs great without vibrations etc...So,unless i find a good offer of cylinder+head here in Greece,i won't change anything.

fontyyy wrote:

Dexter wrote:Easiest way is to check the engine numbers. Says so in the Honda parts manual. Sorry Fontyyy.

Go one then

whats this from - MC16E 1210695 ?

MC21 R7L or R8L

Andy wrote:

There's virtually nothing in it, and you won't notice the difference with one of each type of barrel, especially if they are standard.

Ah ok, just going on what Stephen has said in the past. Maybe he's biased!

Andy wrote:That's incorrect Dave; the SE & SP are the same, and differ from the R.

Ok, knew there was something different! Ta.
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

There are differences in the porting, but it's negligible. The MC18 porting does appear to have been finished better and more consistently than the MC21/28 barrels, but it's the overall package (top-end, bottom-end, and possibly exhausts) that (often) makes the MC18 produce better power in a standard form.

The later barrels are unquestionably stronger than the early hexagonal type though, with better thermal properties.
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Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

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