Malaguti Spidermax - Valve Job - Master 500cc Engine

it is quite easy to adjust the valves

Adjusting the valves from the 500cc Piaggio MASTER
engine is quite easy and takes less than 10 minutes...

,,,if they were easy to reach....
But getting there takes some time.
First put her on the center stand and remove the 2 screws what hold the seat.
Remove the seat
Remove the footrests
Remove the silver transmission plastic cap (and her 4 screws)
Remove the 2 screws in the gas flap

remove the gas cap - remove the gas spill guard - replace the gas cap

remove the battery and the screw what holds the battery holder then carefully pull the whole thing out

remove the 4 screws frrom the ECU

disconnect the ECU

look at the mess and move the cables etc. out of the way

remove the 3 screws - twist the connector to reach the left screw

remember to reconnect the grounding wire later (here with screw)

the valve lid is waiting for a 10mm socket and is just hand tight screwed

remove the service openings

you need to unscrew the hose holder and wonder about the placement of the support for it

loosen the 6 screws (some might held in place by the rubber seal) and carefully fiddle the lid out

you reached the valves

remove the screwed in plastic plug (don´t worry most thicker screwdrivers etc. will do)

rotate the engine slowly counter clock wise with the driving pulley nut until alignment

through the service opening you can also check the alignment for upper dead point

wiggle a bit on the metal cup between valve and screw to get it loose and here you want to put the feeler blade

you have 4 valves to service

use the 2 service openings for easy access to the lower valves

check how big the gap is (mine after 40000km was between 0,2 and 0,25 mm

choose the 0.15mm blade - open the nut so you can turn the screw - remember how strong the nut was tightened - insert the blade and tighten the screw as much so you can still slide the feeler blade but notice a good resistance - tighten the nut a bit and check for blade movement - mostly the screw gets a bit moved when you tighten the nut - recheck and tighten the nut - recheck - repeat with the other valves.
If a full screw rotation is 60 min, my valves needed between 10 to 15 min to get adjusted.

Now put it back together in reverse order and when you are tighten the valve lid do it a bit a time, hand tighten first and then in 2 steps final tighten the 6 screws.
Check if your bike is still running , if so - congratulations: you are now a junior mechanic first grade.


  1. Hello, Your article is very comprehensive. Congratulations. I recently removed my engine Maser for a checkup and while I opened it I found a spring about 7 cm long that I do not know where it came out. I think the valve spring pressure of the oil, but do not know where it exit off, you can help me posting the pictures? Thanks in advance.
    PS: Over the spring I found a clanking noise inside the engine, close to the motor-shaft, like a screw. Do you know what could be?

  2. Hi Alessandro, where did you find the spring exactly? The only one I can think of is the oil pressure spring in the flywheel cover. Look here: http://www.easyparts.nl/showdrawing/1232/26326/ac/0-968-1-m412-m1613-m1232-s1749-d26326/Flywheel_cover.html


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