Wondered if anyone can offer some advice? I have a 1987 MC16 Engine. I was informed that putting on the MC18 barrels and heads on have a better porting system. However recently discovering that MC18 and 16 have a different carb set up as mc16 are 28mm and 18s are 32mm can I jet to suit? or should I change carbs? Also will the original cans for mc16 fit the 18 barrels. I am quite enjoying the work and getting the experience but am beginning to think I should just go back to the mc16 heads and keep the carbs as this is much easier.
It can all be made to work, but you need to invest a lot of time and effort (and potential cost) into the setup. The simplest solution is probably to retain the 28mm carbs and being prepared to spend a day at the dyno. I'd expect to see "high 40s" with MC18 barrels and heads on an MC16. Certainly more is possible, if you have the time and knowledge. The HRC TT-F3 spec is 65ps still on 28mm carbs, for example, but everything is different to stock.
A forum member (jeff350lc) did an MC18 conversion on one of his MC16s (88 barrels & heads/32mm carbs/MC16 HRC exhausts) which saw, if I remember correctly, about 53hp on the dyno. We never tested it though, so don't have any run data, but you're not going to just magic up the 60hp of the later models though without considerable effort, which includes opening up the bottom-end.
It's a tricky one, because in true Honda fashion, everything is very well optimised as stock for both the 1987 MC16 and 1988 MC18, so while a lot is physically interchangeable, it's not necessarily compatible.
Probably not what you want to hear, sorry. _________________ Andy.
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cheers Andy I appreciate your advice. If it wasn't for having young kids I would be heavily investing time and money in to the project but its just so difficult. I want to ride the bike and enjoy showing it off too.
I think the best thing I can do is send off original 16 barrels to get re-plated and keep the bike standard otherwise ill be fettling the rest of my life.
You could have a good 2-stroke tuner lightly port the barrels; preferably someone who knows Hondas (particularly NSRs and the NF5 RS250R as the motors are so similar) and their power characteristics. If you have/can get hold of an MC18 barrel to see the main differences, then they will have something to work with. The exhaust ports, so consequently the RC Valve flaps too, are considerably narrower than the MC18 items, so while you can widen the windows slightly, I wouldn't go too mad, as you'll soon be bypassing the benefits of the powervalve if exhaust gasses can pass right by them! The transfer ports need some tweaking, but the crankcases require the crux of the work, and without this an otherwise relatively stock motor just isn't likely to make impressive numbers.
You could try adapting a set of R2J expansion chambers, but remember they are optimised for the more extreme port timing of the MC18, slightly (marginally) higher compression, 32mm carbs, and a the new PGM ECU. If it were me, I'd be speaking very nicely to Martin77 to see if he'd be interested in making some hydro-formed pipes, but again you'd need to be prepared to pay for the privilege, and he'd need the bike for a while to build them en situ... if he was actually up for it! (He spends most of his time making Yamaha pipes, and is never short of work.)
There is 60hp in the motor, but it's going to be a pig to extract. A stock MC16 in tip top condition making its advertised 45hp is lovely to tootle about on though, and surprisingly nippy. A 50hp motor with a little effort would be great. Mid 50s would kick anything else's 1987 arse (RG/TZR etc., so long as your tuner doesn't go mad on porting and kill all the bottom-end/mid-range!) The HRC TT-F3 just made everything else in 1987 look silly! It was, after all, effectively a 1986 Grand Prix bike in a very poor disguise!
Sito Pons onboard the 1986 factory NSR250, upon which the NSR250R was based! _________________ Andy.
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Thanks andy. Always appreciate the advice. I have sent my original barrels (MC16s) to fire fox racing up north so they can re plate them. I think this is the best option for me at this current period in time.
Maybe in the future I can fettle to get some extra power but I don't race and its just local travel really. When the kids are older I can get stuck in. In the meantime i'll extract all knowledge from you guys on here and learn as much as I can.
When it's all back together, and everything's tip top (brakes/suspension etc.) I think you will be surprised at just how well a standard MC16 rides! _________________ Andy.
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Yeah the bike was imported so got running and Mot'd, insured and registered but never ran right that's why I decided to strip it down. but even the test runs it went surprisingly well. I couldn't believe what a pokey little bike it was. I think a lot of it is due to the lightness of the bike. After buying it off someone who raced it I was convinced he had some mods done but after stripping it realised there wasn't. which was a shame. Need to get it on the road this year. Will post some pics when i'm Finished.
Got the original barrels sent off, however I have misplaced the power valves now! typical. I'm hoping they haven't got lost when I moved recently otherwise project is getting pushed back.
Hi
Hope you found your power valves!
Just saw your post about you mc16, I fitted 18 barrels only to mine and played with the jets a bit it runs really well. Not sure what sizes I settled on but the carbs are in bits at the moment I can check if you still plan on using 18 barrels. Just seen a couple of 18 barrels on eBay.
m4rk79 wrote:Hi
Hope you found your power valves!
Just saw your post about you mc16, I fitted 18 barrels only to mine and played with the jets a bit it runs really well. Not sure what sizes I settled on but the carbs are in bits at the moment I can check if you still plan on using 18 barrels. Just seen a couple of 18 barrels on eBay.
Please feel free to discuss this conversion all day long, but please don't share jetting in the public forum... I don't need that hassle again if it all goes tits up! _________________ Andy.
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No worries, and thanks for understanding. Share the setup via PM if you wish, but please keep the rest of the discussion here so everyone can benefit/join in. _________________ Andy.
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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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