i think my cagiva mito has siezed :(

beasty6

beasty6

beasty6

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Kettering
Hey guys,

My front exhaust pipe broke yesterday so I got a arrow race exhaust to replace it, so I fitted it at work today and ride home after, only 3miles, now it seems like it's restricted, I've lost so much power, now just as I got onto the drive, it started bogging down and cut out and will no longer fire up.

The bike moves still so there's still moment in the cylinder, what could I have don't to my mito! :(
 
It might of run too lean. If the exhaust is breathing better, you usually need to up jet it.

Have you still got good compression? Might just be rings/piston if not.
 
Presuming you haven't run it low on oil etc....

If you had the standard restricted front pipe then it will definitely have been running lean with a tuned pipe on it. If so you can probably say goodbye to the piston and rings at least. Take the pipe off and have a look up the port with a torch and see if you can see any evidence of lean running such as lines scored into the piston skirt from a partial seize, or melted top ring land.

Does it now feel easier to turn over on the kick start than it used to?
 
It's a 2000 model so it has no kick start just a electric starter, it's also a full power model from the factory.

I always check oil before I use the bike and always use castrol power1 fully synthetic oil
 
they have a servo exhaust valve under the riders seat,check its still opening/closing

if its shut its probably shutting off the gases and choking the engine?

I did say they were fragile,they can also suffer from a cold seizure so a mechanic told me,idk how true it is
 
I shall have a look at that tomorrow, so dose my bike need re-jetting now? If so any idea what jets I need?
 
it should run fine imo

when you turn the ignition on you hear the servo swing open then shut,with the arrow race system on I don't know if its still working or not,if I remember right its up by the exhaust port into the cylinder,a metal slide that slides open/closed

but it moves depending on engine revs

EDIT: im only guessing its that mind,but if all you've changed is exhaust id look into the exhaust valve
 
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I only have the arrow expansion chamber, I'm still using the oem cagiva silencer, I'm going to get a new spark plug tomorrow, what would cause the servo to stop working? I know the part you are talking about, I did not touch it at all, just swapped the exhaust over and kept everything just as it was.

Why would it not start up again though, I'm going to have a look at it again tomorrow, when I changed the exhaust, the bike would no longer idle, i dont really want to have to do a top end rebuild, trying to save for a big four stroke, plus the mito is going to be turned into a Sunday blast with a big bore kit and 34mm carb when I'm finished with it
 
idk,thats why you need to check it

I don't think its seized,it would just lockup solid

just check everything over,clean the sparkplug up leave it dangle with cap attached and thumb the starter to makesure its sparking

you can buy a grade hotter plug if need be
 
Yeh I'll get a new one anyway, haven't replaced it since I got it, and it was sat for 7 years before I got it lol

Also, I want to change the gearbox oil, I've searched and can't get a definite answer, so.. what gearbox oil do I need?
 
Put your hand over the exhaust and kit it over with the ignition off.

If you've replaced the exhaust and not rejetted then you could have a holed piston, lack of back pressure through the exhaust will indicate if this is the case.

Two stroke tuning is a fine art, you can't just stick a an expansion chamber or big bore kit on and expect everything to run just fine.
 
an aftermarket exhaust is fine if its designed for the bike

usually you don't have to rejet, big bore kit is a different matter

I never had any trouble sticking a big one/fresco exhaust on my kmx
 
atpbx said:
Put your hand over the exhaust and kit it over with the ignition off.

If you've replaced the exhaust and not rejetted then you could have a holed piston, lack of back pressure through the exhaust will indicate if this is the case.

Two stroke tuning is a fine art, you can't just stick a an expansion chamber or big bore kit on and expect everything to run just fine.
Click to expand...

sorry what do you mean by kit it over?
i hope this is not the case, i got the road approved pipe aswell so i did not have to tinker with it

this is what i got
http://www.pjme.co.uk/acatalog/Cagiva_Mito_125__Performance_Exhuasts_.html

Cagiva Mito 125 Arrow Front Exhaust Pipe 1994-2006 Road Aproved
 
Little update guys, I checked the servo valve and that's working fine, cleaned the spark plug up and it's sparking, i can feel abit of pressure from the exhaust when I try to start it, the only thing I can think of is a fuel issue, but i checked the fuel line from the rank to the carb and it's clear.

Anything else I can try?
 
beasty6 said:
sorry what do you mean by kit it over?
i hope this is not the case, i got the road approved pipe aswell so i did not have to tinker with it

this is what i got
http://www.pjme.co.uk/acatalog/Cagiva_Mito_125__Performance_Exhuasts_.html

Cagiva Mito 125 Arrow Front Exhaust Pipe 1994-2006 Road Aproved
Click to expand...

It was supposed to say "kick" :)

Road approved just means for noise regs, that's all.

It will still reed rejetting most likely so it doesn't run lean and burn a hole in the piston.
 
beasty6 said:
Little update guys, I checked the servo valve and that's working fine, cleaned the spark plug up and it's sparking, i can feel abit of pressure from the exhaust when I try to start it, the only thing I can think of is a fuel issue, but i checked the fuel line from the rank to the carb and it's clear.

Anything else I can try?
Click to expand...

Take spark plug out, put your thumb over the spark plug hole and crank the engine. The engine should develop enough compression that you can't hold your thumb over the hole. If it's low on compression, that would tie in with the engine dying as you slowed down.
 
Compression is fine, got the bike fired up again but it's now idleing at 3500rpm instead of 1000rpm.

I stripped the carb and cleaned it out, it has 65 65 120 jets, any idea what I should change them to?
 
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