Texas500 said:

Just today I was wondering how to adjust the valves. Mine have a little too much clatter. Thanks for the instructions!

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I wonder what "too much clatter" is. I know these engines are a bit noisy but never know when it's time to adjust the clearances. Recently installed a new 650cc. Not sure if I should adjust the tappets or just leave them be.

For some unknown reason, the 126 engines are nowhere near is prone to tappet-closure as the 500 engines are. It might be a wise move to check your clearances, make sure that they are 'spot-on', then listen to them. That way you will know what they SHOULD sound like. It is always wise to go through an engine after it has 'settled-in'.

Is it only the 2 nuts that have to be undone to take the rocker cover off? I’ve undone these but the cover seems to be stuck fast on. No movement at all... or is there something else I need to undo first?!

Bubins said:

Is it only the 2 nuts that have to be undone to take the rocker cover off? I’ve undone these but the cover seems to be stuck fast on. No movement at all... or is there something else I need to undo first?!

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Hi, only two nuts on the top nothing else - give it a gentle tap on the side as the gasket may be holding it on - mop up the oil !!!!!
Ian.

Bleeding Knuckles said:

Hi, only two nuts on the top nothing else - give it a gentle tap on the side as the gasket may be holding it on - mop up the oil !!!!!
Ian.

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Thanks. I gave it a bit more of a pull than I was prepared to the first time and it has come off

Sorry, probably a lot of basic questions coming now.

When one rocker arm goes down is it normal that it will then stay down for a while while I turn the fan belt wheel? I’m turning it very slowly and the arm stays down for a little while before moving back up. Not sure if I’m doing it right but if I am then the valves are way too tight. Rocker arm 4 just went down and a 0.015 inch feeler gauge doesn’t even come close to fitting in the gap for valve 1

Sunlight isn’t making photos easy here but attached is a photo of what I think is the 4th rocker arm in a down position.. seems pretty similar to the others but it won’t go down further.

When you come to adjust the tappets the easiest system is "1 more than there are rockers" Therefore, with the 500/126 engines which have 4 rockers, the number you are looking for is---5. When rocker 1 (nearest the BACK of the car) is fully down you adjust number 4 (1+4=5)---when number 2 is fully down you adjust number 3 (3+2=5) etc, etc. The valves WILL stay down for a short period of time. It will be made a lot easier if you remove the spark-plugs when adjusting the tappets. The feeler gauge should be firm "pull-through" when the clearance is adjusted correctly. If you set them to 8thou. for the inlets (rockers 2+3) and 10thou for the exhaust (rockers 1+4) you will be just about right.

Well surprisingly I didn’t break the car. The valves were so tight so I corrected them and took it for a test drive and it ran very well. The hesitancy issues weren’t present all the time, they’d come and go, so a few more test drives needed to make sure I’ve sorted the problem.