I've had my first blast on my mc28 and first impressions are very good. The engine pulls well and handling is sublime. However just checking if the symptoms of running out of steam around 10,000 rpm is normal in a standard restricted bike. It's almost as if the power is cut off dead, the bike doesn't want to pull to the redline and you end up changing up a gear. Query also is that it appears ro behave slightly differently depending what gear I'm in.
The other guys in my group have 400's, of which I also have a zxr250 and 400 and having ridden 4 strokes they don't seem to suffer this clipping of the top end.
So I'm wondering . One is this normal and I should expect this restriction, and two if I were to go for a set of Tyga pipes, jetting and fly wheel etc would this overcome the top end symptoms.
Cheers
Graham
In my first outing with my MC28, it felt like mine was running out of steam around 10,000. Upon running the rpm's up a couple of times in the pits, noticed it wouldn't rev past 10,000.
My RC Valve servo may have been on it's way out or the cables too stretched, but it turns out the RC valves were way out of adjustment. (I had a spare servo and cables assembly I picked up from auction the week before for loose change and dropped it in...).
That might be the cheapest fix if it is actually out of adjustment. You should see on the tuning page how to adjust the RC valves in you're not familiar.
Dana
*edit* I'm just getting my feet wet with NSR's so maybe somebody has more experience...although us MC28 owners must be the red-headed step children around here.
If the bike is new to you it would probably be worth taking the fairings off and giving a once over. Clean the carbs, check air filter, check rc valve adjustment, while you are at it and seen as you are riding with mates on 400 i would carry out the wire splice then you have full power all the way up (easiest job of all) and just have a look over all the bike and check all fastners are tight and everything is ticketyboo. All the info on wire splice and rc valve setting is in the tuning section as mentioned by Dana.
andyo wrote:
...i would carry out the wire splice then you have full power all the way up (easiest job of all)...
There is no "wire splice" for the MC28. Well, technically, that's not correct, but the MC28 splice simply allows you to run an HRC card (which must be coded to the PGM-IV) on a road/street harness.
Fitting aftermarket chambers, opening up the airbox, and fiddling with the flywheel (timing) will give a power increase, but you'll still be wasted by any delimited 400 or MC18/MC21 in a straight line. In my experience (that's the key word, experience, not hearsay!), you'll be lucky to get much over low 50's hp without also running an HRC card and jet kit, it should at least then rev however. This will allow you to run slightly taller gearing, giving a little more top speed, but remember you need horsepower to drag you and the bike along at any substantial speed. The OEM gearing (15/44) is good for 154kmh @ 10,000rpm (approx 115mph @ 12,000rpm). You should be able to run 15/40, which will theoretically see you with a top speed of around 125mph... IF the motor can pull it! 50hp and 15/40 will still feel pretty weak, but 15/40 and 40hp and some rpm is gutless!
Simple truth is the MC28 needs all the help it can get, but it can be made good... it's just not going to be cheap. You can grind the washers out of the headers in the OEM pipes, but the pipes are crap, so don't expect anything but RPM. Again, simple truth is OEM MC18 and MC21 pipes work, MC28 do not! 88~93 pipes are all capable of allowing the motor to make almost 70hp, and anything from 89 onwards will also need the silencers replacing, as the OEM ones are progressively choked, model on model, with the MC28's again being the most heavily restricted.
As Dana and Andy have already mentioned though, make sure the RC Valves are set bang on, as it can have a huge effect on power and RPM. Not good when you only have 40hp to play with!
At the end of the day, if you want any kind of true performance out of an MC28, you have to get your hands deep in your pockets. There's no cheap shortcut. Yes, they may be lovely to ride in standard form... alone, but ride in any group where the other bikes are all making at least 50% more power than your stocker, and it will soon wear you down! The niggling thing is the MC28 motor has at least 60hp in it, without even touching it, but you need the extra (now very costly) bits to release it. That's the price you pay for "progress"!
Cheapest way around all your problems? PGM-II and harness! Easiest way? Re-coded PGM-IV card to 010 or 030 spec, aftermarket pipes, HRC jet kit, and preferably open carbs. The easy option will cost ten times as much as the cheap option today.
And please don't PM me for technical info. If I answered every one of my PM's I don't know when I'd ever breath fresh air again! _________________ 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.
sorry duff info on my part, the wire splice is no good for the 28 you need the hrc card instead. Seen as it is spring and biking weather is here now what i would do is just enjoy riding for now and start picking bits up you need/want to improve things and embark on a tune up over next winter. Depending on your budget you can pick things up new or keep your eye out on classifieds here and yahoo japan has worked for me, there are some mc28 needles and x & Y pieces in the classifieds right now but im not sure if there the ones required.
Personally I wouldnt just be adjusting the powervalves I would be pulling them out and cleaning them. If they are carboned up and seizing you will soon be needing a new power valve servo and PGM when they burn out!
Cheers for the advice guys.. I realise it will be costly if I look at derestricting the bike. Re the power valves I'll check these again but I'm not sure they'll be wrong. As Tom had these set up by Fontty I think he said. The bike pulls really well, strongly and cleanly through the gears between say 7-10,000 rpm. But it seems to tail off at this point and changing up gives another strong 3,000 powerband and so on. Reading an old performance bikes mag in which there was an mc28 it also mentioned that the bike fell flat at the top of rev range.
So if there is anyone out there with a stock 40hp model i'm wondering if this symptom is normal or if by playing with the rc valves etc that I may see some improvement.
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