Cagiva Mito 125 Top End Removal ( Cylinder barrel - Piston )

Cagiva Mito 125: Step-by-Step Top-End Removal Guide

Performing a top-end rebuild is a standard part of owning a high-performance two-stroke like the Cagiva Mito 125. Whether you are replacing a worn piston or installing a new gasket set, removing the cylinder (barrel) and head requires a methodical approach to avoid damaging the delicate internal components.

This guide walks you through the teardown process for the Cagiva Mito Evo and SP525 engines.

Tools You Will Need:

• Metric Socket Set (8mm, 10mm, 12mm, 13mm)

• Allen Key Set

• Circlip Pliers (for piston pin removal)

• New Gasket Set (Base, Head, and O-rings)

• Coolant Catch Tray

Step 1: Drain the System & Strip Down

1. Drain the Coolant: Remove the lower radiator hose or the drain bolt on the water pump housing to empty the system.

2. Remove the Tank & Fairings: Gain clear access to the top of the engine.

3. Disconnect the Exhaust: Unbolt the expansion chamber from the cylinder exhaust port. Check the manifold gasket for wear.

Step 2: Cylinder Head Removal

1. Remove Spark Plug & HT Lead: Clear the area to avoid interference.

2. Disconnect Coolant Hoses: Remove the hoses leading to the cylinder head.

3. Unbolt the Head: Loosen the nuts in a diagonal "X" pattern to prevent warping. Lift the head off carefully. Inspect the combustion chamber for signs of detonation or pitting.

Step 3: Cylinder (Barrel) Removal

1. Power Valve (CTS) Disconnect: If your Mito is equipped with the CTS system, disconnect the cable and housing from the side of the cylinder.

2. Unbolt the Cylinder Base: There are four nuts at the base of the barrel. Use a 13mm spanner or socket.

3. The Lift: Carefully slide the cylinder up the studs. Ensure the connecting rod doesn't "clack" against the crankcase as the piston clears the bore.

Step 4: Piston Removal

1. Protect the Crankcase: Stuff a clean, lint-free rag into the crankcase opening immediately. This prevents a dropped circlip from ruining your bottom end.

2. Remove Circlips: Use your pliers to remove one circlip.

3. Push the Gudgeon Pin: Slide the pin out and lift the piston away. Take note of the "Arrow" on the piston crown (it must point toward the exhaust port during reassembly).

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Pro Rebuild Tip:

Always replace the little-end bearing (small-end bearing) whenever the piston is removed. It is a cheap part that, if it fails, will destroy your entire top-end.

Need the exact torque specs for reassembly? Download our Ultimate Cagiva Mito Workshop Manual Bundle for the official factory assembly data.

Buy Mitaka Barrels on Ebay UK here

Buy Oem barrels on Ebay UK here

or Better still have your old barrel Re nikosiled on Ebay UK here

Removing the top end and replacement it very easy to do and anyone with basic tools can do this is a day or 2 after you have done it a few times (which you will if you keep you mito for long in one afternoon)




remove the five bolts holding down the head


piston to the BDC , then undo the four bolts situated on each corner .

Now the cylinder itself is ready to be removed ,try to avoid small parts falling into the crank case if you do engine removal and swilling out with old diesel will be required
 , lift the cylinder off the crank case making sure its going up straight and not at an angle, lift it about 25mm and stuff a rag into the crank case tightly t avoid any debree falling into the crank case.

9. Once the cylinder is out of the way you can begin to remove the C clips which are are at the side of the piston (set in about 5mm) once these are gone remove the  piston pin / gudgeon pin this can be tight so be carful when tapping and removing it brace piston if tapping is required once pin is  removed, the piston will come off the con rod and you can remove the little end bearing.


Put a new little end bearing in the conrod (oil it before hand with 2 stroke oil, also oil the top of the con rod, now oil the new wrist/gudgeon/piston pin and place that inside the bearing. Next put the piston rings onto the piston, Every piston ring will have a stamp mark near the ring gap, This MUST be installed facing upwards. Also, locate the "locating pin" in the piston groove. The ring gap will go here, do this for both piston rings.


Now your piston is ready to go on the conrod, there will be an arrow on top of the piston, this faces the exhaust port (forwards facing on most bikes), place the piston over the con rod end and get the piston "holes" inline with the wrist pic which is already installed, once you have it inline place the C clips inside the "holes" so it locks the piston to the conrod and wrist pin, once there in fully make sure the gaps in the clips are not near the little groove or indentation in the wrist pin/piston holes else they may fall out.



Oil the piston with 2 stroke oil, especially around the rings. Now get your new cylinder or reconditioned one and lube the bore with 2 stroke. Now that your cylinder is ready place your base gasket onto the crank case cover (i would you the medium thickness one but this can be altered for squish readings when more advanced ) get your cylinder ready , hold the piston rings tight so they compress and slide the cylinder onto the piston, very slowly at first it will be difficult, once you get the rings into the bore it will slide straight on , once its on just work your way from step 6 to 1 in reverse order.


see very very easy

This is the coolant drain for Cagiva Mito 125 engine

let the coolant all drain out 

start undoing all of the hoses and remove them 

Now remove the CTS power valve unit 

The head will come of really easy just remove all bolts 

its easy to remove the piston just undo the 2 circlips holding it

in place and slide gudgeon pin free

Nice new Cagiva Mito top end with flare piston ready for fitting 

Cagiva mito engine 

                     

see more cagiva mito 125 posts here 



BUY our ultimate Cagiva Mito 125 workshop manual bundle HERE