The outside of a motorbike engine seen up close near the exhaust

Home Repair And Restoration

70,000 Mile Tappet Check

Blog Date - 29 December 2017

The correct service interval for the CBF 125 is 2,500 miles. Each and every service should include a tappet check. This is ESSENTIAL for the first 10 to 15 thousand miles but after the motor has settled in it is, frankly, excessive. As such I now check the tappets every 10,000 miles. And as the engine has just achieved 70k it's tappet time.

Inside the rocker cover on the old CBF 125
We meet once more my aging engine internals.

I'll not bore you with how to do it - if you want to know then look at CBF 125 Tappets - Brief Guide  (just look at how clean and fresh the engine is in the pictures!)

The inlet is supposed to be 0.08mm. The 0.08mm feeler gauge goes in the gap just fine and the 0.10mm is very tight. It's probably about 0.09mm, I ain't touching it, that's just fine with me.

The inlet tappet as well as the camchain and cam gear
What a good little inlet valve you've been. Well done.

The exhaust, last checked 10,000 miles ago, is a tiny, teeny weeny bit tight. It's supposed to be 0.12mm. The 0.10mm goes in tight so this too is about 0.09mm. I don't mind the tappets being a smidgeon slack but I don't like them at all tight.

I'm getting good at this now (I've had enough practice). It takes longer to find my self made tool than it does to make the adjustment. I'd say it's now at 0.14mm.

The exhaust tappet of the cbf125
I've sorted you out too now behave!

A cursory look at the rollers and camshaft offers no signs or scoring or damage which is good. What I do notice is the amount of varnish (the brown and black staining from the hot oil) is noticeable these days. Having worked on cars and bikes for years I've seen this a lot and it is to be expected. The old motor is getting old I guess.

The camshaft followers with roller bearings and rocker arms
Not too bad for an old lump.

I do have a oh-so-slight concern that this staining could be building up in the oilways which would eventually be disastrous. I've had a look online and the general consensus is that it's nothing to worry about. I wonder if any readers have any thoughts on the matter? 


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Reader's Comments

Pocketpete said :-
Everyone's intervals suffer from ageing.

Look at me my internals can now only manage 6 pints of bitter in session instead of 10.
31/12/2017 5:48:58 PM UTC
Bob said :-
Looks clean enough given the miles - don't worry about it.
1/1/2018 6:49:38 PM UTC
Ren - The Ed said :-
Oh Pocketpete that's such a terrible shame. Just think of your liver, if you're not drinking 10 pints it might have a chance to recover and that would never do.

Bob - yeah if I stripped the motor I'd just make things worse not better. I'll leave the varnish as it is.
2/1/2018 10:25:53 AM UTC

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