As per the title would this be a symtom of the Power valves not working?

I am just about to put all the std reed valves back in in an attempt to make my MC28 rev past 5500rpm.

All that is left of the tuning stuff i had fitted are my Tyga Pipes and Fontys Safe Main jet settings. It cant be that, as i have a spare set of std jetted carbs and it does it with those too.

Any idea's???

Cheers Rob
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Last edited by NSR250MC28SE on Sun Apr 19, 2009 5:48 pm; edited 1 time in total

Even with the power valve at their full closed position the engine will still pull through to almost 12,000rpm (it just wont much waft).

In most cases the power valve don't even start to open untill around 7,000 anyway so you are still below that point.

I'd be looking at your Battery, spark plugs and pickup/gen.
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If I have to take the carbs off once more...

Thanks for the reply Steve.

Bike has new correct plugs and a brand new fully charged battery.

Is it easy to test the pick ups?

Cheers Rob
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NSR250MC28SE wrote:
Is it easy to test the pick ups?

Probably... if you had a Workshop Manual!
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lol.

Test the gen' is easy. Just check the charging rate with a voltmeter.

Testing the pick ups is a little harder as you need an anolog meter rather than a digi multi meter to get worth while readings.

Simply disconect the pick ups and with the meter attched turn the motor over by hand. You should get a reading each time the trigger on the fly wheel passes the pick up.

If one reading is higher than the other then first clean the picks up and the fly wheel, if they still differ by a fair margin then you may need to replace them.
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If I have to take the carbs off once more...

Or get Charles's English Service Manual - it'll cover the whole electrical system!

Have you checked the output from the stator and reg/rec? When either of those break down the peak rpm rapidly drops.

Of course, the big question really is, did it all work fine before you fiddled with it? (I.e. pipes, jetting, reeds etc.) If it did, the first thing I would do is reset it, then fit one part at a time.
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Andy.
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Andy wrote:Or get Charles's English Service Manual - it'll cover the whole electrical system!

from Charles's Manual Post

Mine arrived this morning too, unbelievable quality, considerably better than anything i have for the Mitsubishi GTO's that we play with, and in it's in English too!!!

Top top work Charles, thank you hardly seems adequate as Fontyy wrote.

Fancy doing my GTO manuals.....lol

Mega thanks and a massively happy Rob

AAAAAA+++++

Andy wrote:
Of course, the big question really is, did it all work fine before you fiddled with it? (I.e. pipes, jetting, reeds etc.) If it did, the first thing I would do is reset it, then fit one part at a time.

Yes it did Andy!!!

You know the amount of times i tell my customers this is ridiculous and yet i did it myself..... its going back to completely stock and going forward from there. never never fit everything at once... Mental not to self.... You're an idiot

Cheers Guys i will now start from scratch and let you know how i get on.


Andy i didnt want to get a single mark on the manaul as it is just so nice to own and too good to get dirty......
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NSR250-MC28SE May be For Sale !!
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Of course we are talking MC28 here. There isn't much point working one of them harder than 5,500rpm anyway.
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If I have to take the carbs off once more...

I thought we were doing well....


Do the PV's move to closed when you power on if you open them by hand while the power is off?
Do they cycle at around 3000 pm?

The LCD display will report Err2 if it thinks the PV motor isn't working.
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Looks like Fontyyy's safe jetting is exactly that then... no revs over 5500rpm! You'll never wear that bugger out now!

The only safe MC28 jetting is Honda's and 40hp. It's a big claim to declare "full power" settings for a bike that's never officially been released in full-power form. Who's to say a full power MC28 would've come with the same pipes, same airbox, let alone airbox lid, or even PGM-IV? Those settings are specific, for a specific (i.e. Fontyyy's) bike(s). I can guarantee, as I'm sure Steve would, that another MC28 (yours for example) with exactly the same mods, will require a different setup.

We're not just talking +/-1hp difference either. We put barrels on my MC21 a few weeks ago that were exactly the same spec as the ones that came off, and on the same jetting it made -5hp.

Just look at Jap spec vs. UK spec RGV's to see an example of how different a full-power model can be to a Japanese model.

I think you missed the hearts and kisses on that message to Charles!
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I thought it was closer to 4hp Andy.

We need to have a little tweek with that at some stage.

Anyway Having just got off the phone about said '28 we have already discussed the error messages (or lack of them) so hes off ripping it to bits again now.

My own safe jetting tips 210m/j-F/R, 80 power jets, BA needles on clip 5, 45 pilots and 5mm float hight with stock air box and filter. Runs perfect on my bike

Whoops..shhh can't talk jetting
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If I have to take the carbs off once more...

See, that's why I don't allow jetting on the forum...

To be totally safe that needs a 0.5mm (0.01968503937") shim under the needles else it's just too lean at 1/4 (25%) throttle!
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What's 1/4 throttle in degrees?

If I have to take the carbs off once more...

I'm sending it to Stephen and i will play with my 3XV9-RS instead.........

Seriously... like you lot ever are.....

Cheers Stephen for taking the time to go through so much with me and letting throw loads of questions at you.

I will now beaver away and come up with what's wrong with it, apart from being an MC28 that is....

I will be up for a nice or not so nice test if you ever get it sorted too a sorta Yamaha Versus Honda with no Suzuki's

Cheers for you help again

Rob
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Well the std reed valves did nothing......

I have checked the wiring as good as is possible in no space and found nothing.

The headlight is well bright and the charging circuit seems to be 100%


The thing just bogs badly and wont rev any further than 4500RPM

Any further idea's

Cheers Rob
_________________
NSR250-MC28SE May be For Sale !!
TZR250-3MA5 For Sale
I have Loads of 3XV SUGO Parts For sale !!!!!

The collection has started to be sold.......lol