Hi There,

I'm working on restoration of an MC16. Hoping to do some minor tuning mods to get a few more HP. I note the comments on this site r.e being able to get up to 55 HP from one of these motors with "delimiting" but there is not much commentary r.e. what this de-limiting is on the MC16 vs the later models? I note comments on the tuning page r.e that performance of the mc16 is partly due to smaller carburettors though I was under the impression they are the same size as later models or am I mistaken? will fitting carbies from say a MC21 be a fairly inexpensive modification along with removing the airbox and re-jetting to suit?

Hoping to get some advice from anyone who has tuned the MC16 and has some tips. I'm not after massive HP but some good reliable power gains.

Thanks All.

Glyn Richards wrote:Hi There,

I'm working on restoration of an MC16. Hoping to do some minor tuning mods to get a few more HP. I note the comments on this site r.e being able to get up to 55 HP from one of these motors with "delimiting" but there is not much commentary r.e. what this de-limiting is on the MC16 vs the later models? I note comments on the tuning page r.e that performance of the mc16 is partly due to smaller carburettors though I was under the impression they are the same size as later models or am I mistaken? will fitting carbies from say a MC21 be a fairly inexpensive modification along with removing the airbox and re-jetting to suit?

Hoping to get some advice from anyone who has tuned the MC16 and has some tips. I'm not after massive HP but some good reliable power gains.

Thanks All.

Hello
Mc16 carbs 28mm the rest is 32mm, aftermarket expansion pipes,you can improve your compression,
rework your cilinder etc,etc.
I did on my mc16,32mm single carbs,with inlet rubbers from a mito125,thinner base gasket open air filters. I don,t know how much hp i have, but its runs ok, it revs in no time to 11.500 RPM.
Succes with your restoration project.Post Some pics

Thanks Jasper, good advice. was going to port match and look at aftermarket exhaust. the Mito mods sound interesting too. I'll look into it and post some pics along the way.

Cheers!

Lots, and I mean lots of small changes between 1987 (MC16) and 1988 (MC18 Mk1) took the power from 45hp to 60hp.

It's not quite as simple as just bolting the later parts on, but it can be done, although you'll need to spend a lot of time setting it up correctly.

First off; don't bother with high compression. NSRs really don't like it. Yes, there is a very small increase in compression year-on-year, but they are very small increases. In my experience it's a bad idea trying to run high compression.

As Jasper already pointed out, the MC16 runs 28mm carbs whereas all the other models run 32mm. The MC16 doesn't run a powerjet or any air correction. Simply bolting on MC18/21 carbs will take a lot of setup to get right. Just FYI, the MC16 TT-F3 is rated at 68PS with 28mm carbs... they're not actually as bad as you'd think. To really make the most of the MC18/21 carbs you also need the corresponding ignition & air correction. A lot of hassle!

MC16 expansion chambers are a bit crap, so you could consider some R2J pipes/silencers, and the crankcases can be improved greatly. You can see how if you get hold of some MC18/MC21 cases. The MC16 exhaust ports are very small, but be careful modifying them too much. MC18 cylinders can be used, but you need to be very careful setting the RC Valve up. Any gains from the MC18 porting are immediately negated (or worse!) by bad RC Valve operation.

The best thing, in my opinion, is to optimise the MC16 stuff; especially the crankcases.
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Andy

You said its not recomended to run a NSR on higher compression, can you tell me why.
Its my first nsr, i have several two strokes yamaha,mito and they all run with high compression.

Regards

Because they detonate.
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Andy.
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Ok its not explaining why especilly the nsr is afraid for high compression,every two stroke with high compression and rpm is sensible for detonation.

Andy wrote:Lots, and I mean lots of small changes between 1987 (MC16) and 1988 (MC18 Mk1) took the power from 45hp to 60hp.

It's not quite as simple as just bolting the later parts on, but it can be done, although you'll need to spend a lot of time setting it up correctly.

First off; don't bother with high compression. NSRs really don't like it. Yes, there is a very small increase in compression year-on-year, but they are very small increases. In my experience it's a bad idea trying to run high compression.

As Jasper already pointed out, the MC16 runs 28mm carbs whereas all the other models run 32mm. The MC16 doesn't run a powerjet or any air correction. Simply bolting on MC18/21 carbs will take a lot of setup to get right. Just FYI, the MC16 TT-F3 is rated at 68PS with 28mm carbs... they're not actually as bad as you'd think. To really make the most of the MC18/21 carbs you also need the corresponding ignition & air correction. A lot of hassle!

MC16 expansion chambers are a bit crap, so you could consider some R2J pipes/silencers, and the crankcases can be improved greatly. You can see how if you get hold of some MC18/MC21 cases. The MC16 exhaust ports are very small, but be careful modifying them too much. MC18 cylinders can be used, but you need to be very careful setting the RC Valve up. Any gains from the MC18 porting are immediately negated (or worse!) by bad RC Valve operation.

The best thing, in my opinion, is to optimise the MC16 stuff; especially the crankcases.

Don't get me wrong, Glyn, the later spec parts are definitely superior, but ideally need to be used as a complete package. I.e. all 1988 parts, all 1989 parts, or all 1990 parts (heads/barrels/carbs/wiring harness/ignition/servo etc.) used together.

If you're willing to put the time and development in, 1988/89 barrels and carbs will be of value to your tune, but you will definitely need different expansion chambers and a lot of fiddling to get the RC Valve operation correct. RC Valve timing is crucial for not only peak power, but also the NSRs characteristic wide spread of bottom-end/mid-range.

In my opinion, the greatest gains for the MC16 will be found in the crankcases and with a decent set of expansion chambers. I would probably start off with modifying a set of R2J pipes, as I already mentioned.
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Andy.
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Hi guys, I need to source a rebuilt crank for my mc16 or one in reasonable condition for a rebuild. Unfortunately mine is a bit far gone to be rebuilt. Any ideas how I can get hold of one?