TAPPET ADJUSTMENT - HOW THE HECK DO YOU GET A FEELER GUAGE IN???

[johncam]

I’m looking to adjust the tappets on my 750 four and my Clymer manual says remove the caps in the rocker cover and go from there. Only problem is the depth the tappets sit at don’t allow a normal feeler gauge in easily. Are there special bent end feeler gauges for this job? Obviously with the rocker cover off the job would be easier but I’m not sure it will come off in the frame?
All advice gratefully received and for those that replied on my carb balance item thanks again! Particular thanks to those that offered to lend me one – nice community!

[Nurse Julie]

Just bend over the last 3/4 inch of the feeler gauges, they go in then. (leave them bent and buy yourself another set of straight ones) And no, the rocker cover does not come off with the engine in the frame, that is a complete engine out job.

[Simon46]

Damn good idea! Mine are rusted together it's that long since I used them.

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[oapcb400]

on a 400/4, Rick Parkington's rebuild in classic Bike, he states the thread pitch of the adjuster is 0.05mm, so a single full turn of the adjuster moves it by half a millimetre or 20 thou. with the crank set to the tappet setting position,wind the adjuster down until it touches the valve and then reverse by one full turn.  two full turns equate  to  1mm or 40 thou.    not sure of other bikes thread pitch.  I' m new to honda's, i'm just posting what i read, ready to be corrected!

[Nurse Julie]

Damn good idea! Mine are rusted together it's that long since I used them.

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Don't forget to remove the rust first !!! 

[Rob62]

on a 400/4, Rick Parkington's rebuild in classic Bike, he states the thread pitch of the adjuster is 0.05mm, so a single full turn of the adjuster moves it by half a millimetre or 20 thou. with the crank set to the tappet setting position,wind the adjuster down until it touches the valve and then reverse by one full turn.  two full turns equate  to  1mm or 40 thou.    not sure of other bikes thread pitch.  I' m new to honda's, i'm just posting what i read, ready to be corrected!

Assuming that the pitch is indeed 0.5mm, it probably is. Then you need to wind it in and then back out by one tenth of a turn to achieve 0.002” (0.05mm).... thats not going to be easy to judge. I would prefer to use feeler gauges i think although its useful to know.

[oapcb400]

Hi Rob. i'm still locked into £sd and Feet and inches, but i read the article to mean backing off the adjuster one full turn gives you exactly the 0.05mm gap, as i said i'm of a certain age and easily confused!!!

[ka-ja]

Solely using the thread pitch as a measure is dodgy, the clearance needs to be checked when the lock nut is tight, the tappet always moves slightly when the lock nut is tightened

[Bryanj]

Giving away a 40 year old trade secret, if you move the rocker end up and down and can feel movement but not hear a "click" that is damn near 2 thou--if you undo a fraction more till you hear a very slight "click" that is 4 thou-----WARNING----- THIS METHOD TOOK YEARS TO PERFECT SERVICING HONDA'S DAILY

[sprinta]

You could get one of these:

https://www.ebay.co.uk/itm/Motion-Pro-Valve-Clearance-Feeler-Gauge-002-003-Inches-05-08-mm-Motorcycle/401487923010?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Yes a bit pricey, around £10 inc p & p from the US, but if it does the job and makes it easier it's worth the money?

[Simon46]

I'm going to start buying feeler gauges and kink them. This time next week I'll be a millionare

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[Nurse Julie]

I'm going to start buying feeler gauges and kink them. This time next week I'll be a millionare

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Someone got there before you Simon.....

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Even these aren't really bent enough though, maybe you could adapt a little and then you would be a millionaire 😊

[Simon46]

Damn dell and Rodney beat me too it

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[Rob62]

Hi Rob. i'm still locked into £sd and Feet and inches, but i read the article to mean backing off the adjuster one full turn gives you exactly the 0.05mm gap, as i said i'm of a certain age and easily confused!!!

0.05mm is roughly 2 thou, so if one full turn is 0.05mm that would be a thread pitch of 500 tpi imperial which it definitely is not. Its more likely to be 50 tpi (threads per inch) or 0.5mm pitch which is still incredibly fine...  as has already been said, feeler gauges is the only way to go and even then its not easy to get right as tightening the locknut alters the gap..you’ve got to make sure the feeler gauge is dragging nicely but the bend in the feeler can make it difficult to judge... Its a nice simple mechanism compared to having to change shims but does require a certain knack...

[johncam]

Thanks all - think I will bend the end of the appropriate size one on the set . Feel like I should have thought of that first off!!