Hi guys,

My mc28 seems to be slow compared to my mates rgv vj22 and cbr250rr. my bike is standard except for a short throttle cable. Is this normal? I seem to lose to the cbr in a striaght line drag from 0-100km/h i only manage to creep up when in 3rd. My mate with the rgv (stock) even says the bike is slow compared to the rgv but the power delivery is smooth doesnt feel like there is powerband. My bike has done 22000k no rebuild. Is this normal?
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Stock and really slow MC28SE Repsol Rep... =(

PhiLLaY wrote:Hi guys,

My mc28 seems to be slow compared to my mates rgv vj22 and cbr250rr. my bike is standard except for a short throttle cable. Is this normal?

yep its a 28

fontyyy steve or andy will be here in a bit they will tell you how to get more from a mc28 mate

If the bike is 100% stock then you will struggle to keep up with cyclists. The MC28 is quite heavly restricted. Most of the information you need can be found in the Tuning section of the site.

A quick run down of what you need to do though is.

Wire splice
Derestrict the stock pipes or fit race pipes

Or

HRC card
Wire splice
Race pipes
HRC jet kit

This will see you from around 40hp (stock) to 55hp (option 1) to 60hp (option 2).

I admit I'm not that in the know when it comes to '28 as they are.. lol a bit weak.

I'm sure Fontyyy will put me right if I've gone wrong anywhere (in the post fontyyy not in life thanks).
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If I have to take the carbs off once more...

There is no wiresplice to do on the '28 unless you've got an HRC card, it's not restricted as such, it's just rubbish.

Basically the '28 ingition is far is too retarded as std, I've not seen a decent one with the normal card, Matt has made some vaguely impressive (ish, high 50's) figures, I'll bet he still fell asleep road testing it.
Leigh's is particularly poor, even with a '21 flywheel you're right - there is no powerband

You need an HRC card, a modded airbox and either derestricted stock pipes or fit race pipes, alternatively get used to RGV's whipping your ass.
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

Watch it !!!

Mine has a HRC card !

Thats nice Leigh, maybe you should try fitting it at some stage?
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If I have to take the carbs off once more...

Thanks for all the info guys, I know the 28 was restricted but i wasn't expecting to get whooped not by a cbr250rr

ok so I have to hunt down a HRC card, some pipes and drill holes in the airbox to fight off the RGVs and lift the front wheel up.
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Stock and really slow MC28SE Repsol Rep... =(

Himmm, the CBR250 coming past could be rider error.......
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

rider error?ah... no m8, nice try

um i have a mc28

it goes very fast compared with my cbr250r (mc22 RR engine conversion)

i think a full carb clean should restore lost power,
other than that i dont really know, but yeh cleaning carbs has always restored alot of lost power on my bikes, new plugs, air filter/ fuel filter works nicely also,
mainly carbs,,


i duno but mine pulls up in first gear and u can definatly feel alot of power hit in at 7000-8000 rpm

hope u get it sorted,,

Put a set of Tyga pipes on there and tune the jetting right, you will be pleasantly impressed!

For a very long time, I ran my '28 with just a set of older JHA's, opened airbox, and Daytona filter. That configuration held me neck-and neck with any CBR or VFR 400.

My guess is that your stock pipes are plugged with soot.

Most would say your mileage is high, but I have seen these engines pull over 50,000km without rebuild. I wouldnt recommend that, though, as those engines ran their entire life in stock, restricted form.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

before you do anything anyone says that requires high amounts of money,

just get the carbs cleaned,
it may fix the powerloss,

alright I will take apart the bike on the weekend, would it be beneficial to take the exhaust apart and clean it if thats even possible? what is required for a carb clean?
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Stock and really slow MC28SE Repsol Rep... =(

Take a look at the carbs and see how clean they are, but usually there is no problem unless the bike has been sitting for a long time or if junk from the tank made it past the fuel filter. If the bowls look real clean, I suspect the carbs are just fine.

Take a look at your exhaust valves and see if they move with the bike running. Maybe there is a problem. I would suggest removing the valves from the heads and cleaning the carbon from the valvles and the exhaust ports.

As for cleaning the pipes, I have heard of people hot-tanking them at an engine shop. Baking also works awesome, but makes a smoky mess, so you need good ventilation. If you baked the carbon out of the pipes and cut the restrictors at the inlets, it would most likely make a DRAMATIC difference on your bike with 20,000km.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

when i purchased by bike from its previous owner, it has been parked in the garage for 6 months but still serviced every 6 months. It had only done 500km in the last 2 years until i got it 4 months ago i have covered 2000km. On some days the bike is fast but usually its smooth I don't think the engine is dying but it should be putting out more power. Is there some spray that I should use?
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Stock and really slow MC28SE Repsol Rep... =(