How To Install a Clutch Kit on a 1978 Yamaha IT250 Dirt Bike

How To Install a Clutch Kit on a 1978 Yamaha IT250

Why replace the clutch on a 1978 Yamaha IT250

The 1978 Yamaha IT250 is a two-stroke enduro/trail bike with a wet, multiplate, cableoperated clutch. Over time the clutch can show classic symptoms slipping under load, dragging when released, inconsistent lever feel, hard or noisy shifting, or a lever that suddenly needs more or less travel. These symptoms come from worn friction plates, hardened or warped steel plates, weak springs, or notched clutch basket fingers. Replacing the clutch restores direct power transfer, crisper throttle response, and predictable shift quality so the little 250cc twostroke behaves on trails or in woods the way it should.

What you'll need

• Complete clutch kit compatible with 1978 Yamaha IT250 (friction plates, steels, springs as applicable)
• Basic hand tools: socket set, box wrenches, screwdrivers, pliers
• Clutch alignment tools or soft drift for pressure plate if needed
• Clean pan for oil, fresh engine oil recommended for reassembly
• Clean rags, brake cleaner or solvent, small parts tray
• Clutch cable inspection tools (lubricant, replacement cable if worn)

Prepping the bike

Park the IT250 on level ground, secure the bike with a stand, and allow the engine to cool. Because this is a wet clutch you should drain the engine oil into a pan if the clutch cover is integrated into the crankcase or if you'll be removing oil-contacting parts. Clean around the clutch cover so dirt won't fall into the assembly when you open it. Note cable routing and lever free play before you disconnect anything.

Removing the clutch cover & access

• Loosen and remove the clutch cover bolts in a crisscross pattern to avoid warping. Pull the cover free you may need a gentle pry, but avoid damaging the gasket surface.
• With the cover off you'll see the pressure plate, springs, and outer plates. Keep parts organized as you remove them so reassembly order stays clear.

Disassembling the clutch pack

• Loosen the clutch spring bolts evenly a little at a time to relieve pressure on the pressure plate. Remove all springs and the pressure plate.
• Pull out the friction and steel plates. On the IT250 they alternate remove them in the order they come out so you replicate that stack on reassembly.
• Inspect the thrust washer, pushrod, and any retaining clip. Note any excessive play or scored surfaces.

Inspection what to look for

• Friction plates: check for glazing, uneven wear, burned or hardened surfaces. If the fiber surface is smooth and shiny, it's glazed and needs replacements.
• Steel plates: look for blueing, discoloration, or bellmouthing/warping by laying them on a flat surface. Replace any that show heat damage or warping.
• Clutch basket & hub: inspect basket fingers for notching where plates engage. Light grooves are normal; deep notches that cause plates to hang up mean the basket should be replaced or filed by a qualified shop.
• Inner hub splines: check for rounded splines or excessive wear where the plates slidesigns of slipping torque loads over time.
• Springs: compare free length of old springs to new ones in the kit. Weak springs contribute to slipping and should be replaced in matched sets.
• Thrust washer & pushrod: ensure flatness and smooth contact surfaces; replace if peened or scored.
• Oil condition: dark, burnt smelling oil can accelerate clutch wearplan a fresh oil change.

Preparing new plates

Soak new friction plates in fresh engine oil for at least 15-30 minutes before installation. Properly saturated plates seat faster and reduce initial slippage. Keep steel plates dry until ready; wipe any factory preservative off.

Reassembling the clutch pack

• Install plates in the same alternating order you removed them friction then steel then friction, etc. Ensure each plate seats fully into the basket fingers and hub splines.
• Check that the inner hub splines allow the plates to slide smoothly; if they bind slightly, clean and lightly lube with engine oil.
• Fit the pressure plate and install new springs. Tighten spring bolts evenly in stages so the pressure plate remains square.
• Recheck pushrod and thrust washer engagement as the assembly compresses.

Clutch cover & oil refill

• Clean the clutch cover surface and install a new gasket or gasket maker as preferred. Reinstall the cover and tighten bolts progressively to seat the gasket.
• Refill engine oil to the correct level for the IT250. Use an oil suitable for twostroke engines if required by your bike's setup and the kit instructions.

Clutch cable check & adjustment

Since the 1978 IT250 uses a cable clutch, inspect the entire cable for fraying, kinks, or binding. Lubricate the cable with a dedicated cable lube or light oil if it's in good shape. Set free play at the lever so there's a small amount of movement before the clutch begins to engage this avoids dragging but retains positive engagement. If the cable showed stretch or sticking, replace it; improper cable tension can mimic a bad clutch by preventing full disengagement or engagement.

Initial startup & breakin

Start the engine and let it warm briefly while the bike is on the stand. Test clutch engagement off the stand by slipping the clutch gently from low RPMs new plates often require a short breakin period to fully mate to steels. Avoid heavy launches for the first few rides. Recheck lever free play and oil level after the initial run.

Riding context & wear prevention

The IT250's 250cc twostroke nature and enduro/trail use mean clutches experience lots of modulation for tight woods, hill starts, and aggressive sand or mud work. Frequent slipping at the line, repeated burnouts, or running the bike in very hot conditions speeds wear. Regular oil changes with the correct oil type, gentle cable maintenance, and replacing springs with the clutch kit prolong life and preserve crisp throttle response and shift quality.

Final checks

• Confirm smooth lever travel & consistent engagement.
• Listen for unusual noises from the clutch area and recheck for oil leaks at the cover.
• After a few rides, reinspect cable routing and lever free play to ensure nothing settled loose.

Related Shopping Categories

Shop Clutch Kits for a 1978 Yamaha IT250 Dirt Bike.

Shop Clutch Baskets for a 1978 Yamaha IT250 Dirt Bike.

Shop Clutch Springs for a 1978 Yamaha IT250 Dirt Bike.

Shop Inner Hubs and Pressure Plates for a 1978 Yamaha IT250 Dirt Bike.

Shop Clutch Covers for a 1978 Yamaha IT250 Dirt Bike.

Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.