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MC 28 tuning.


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Juls

 
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MC 28 tuning.

Fri Jul 21, 2006 5:12 pm » Post: #1 » Download Post

Hi, finally got my MC28 tuned. After fitting carbon reeds, HRC card, 145MJ, Mod air-box, and some unknown pipes but better than stock, I got 58hp on a dyno run.
Just wondering if that is what I should get?
Do you guys think if I fit a set of tyga pipes I can get around 63hp maybe?
Is 145 MJ a normal one to use with these sort of modifications? (On some post I read someone using 160MJ that seems to be way richer than what I'm using, I can feel my jetting already little rich speically when engine not warm up or at low rev, but thats safer from seizing.)
Whats the next logical modification?
thanks
[/img]
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fontyyy

 
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1991 Honda NSR250 MC21
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Fri Jul 21, 2006 11:39 pm » Post: #2 » Download Post

It doesn't sound too far off power wise. Dyno to dyno readings can vary by several hp so anywhere near 60 is OK.

145 seems quiite small, it's just two sizes up on std and you've gained nearly 50% more bhp!
Be very careful here, you could well be lean, it's not rich for sure, it would be totally rideable with the std card, pipes and airbox lid back on, most HRC carded '28's end up so rich they are unusable on the std card.
I'd definately get hold of some mains (at least) a couple of sizes bigger and see if it's better or worse on them.

I run the HRC jet kit (so no powerjets) but if my maths is up to scratch to get a similar fueling with the powerjets back in I'd be running around 170's. Maybe a bit leaner as you really shouldn't just add jet area sizes togeather like I have done but that's where I'd start.

Next logical mod is to at least try and borrow some known pipes to find out how good yours are (or are not) and get either a decent selection of main jets or go for the whole the HRC jet kit setup and see what works best. To get 60+bhp requires some fine tuning.
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j911brick

 
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Sat Jul 22, 2006 4:15 am » Post: #3 » Download Post

Better to be too rich than too lean. I would probably start at 160 and work my way down. Do plug chops, check and adjust. Don't expect both cylinders to be the same MJ size.
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Juls

 
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Sat Jul 22, 2006 1:00 pm » Post: #4 » Download Post

I see thanks.
Well do you think the hi-flo reed valve from tyga will help gain couple HP ?
Could it be my air-box not as open than ones with 155MJ, so I'm still fairly rich for my set up? Or could it be the pipes that I'm using that cause me not need to use the bigger main jets?
I'm seriously thinking about getting the tyga pipes just wondering how much gain compare to the one im using now and compare with the JHA pipes which is much more expansive, how good are the tyga pipes?
I wanna upload a picture of my pipes so hopefully someone can identify them, but just donno how to upload on this forum.
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pbekkerh

 
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Sat Jul 22, 2006 5:53 pm » Post: #5 » Download Post

Tyga has performance curves for their chambers on the site.

Pictures should be uploaded to another site, there are several free sites, and the url posted here as [img]picture[/img], mind the size !
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