Author Topic: Adjusting tappets  (Read 11923 times)

Offline Bradders

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Adjusting tappets
« on: June 22, 2024, 07:31:31 PM »
Adjusted the tappets on my 400/4 today for the first time. What a fiddly pain in the neck job! Any tips for making it easier? 

Offline Alexrayz

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Re: Adjusting tappets
« Reply #1 on: June 22, 2024, 07:41:39 PM »
Hey there!

Yeah it sucks. I tried with tools provided with the honda kit and other regular square wrenches and what not but it still sucked.

Personally I went with a gizmo that does both the hex socket for the counter nut and the square socket for the screw. They fit together so you can really keep one hand free and really do fine adjustments without turning the damn counter nut.

You can find something like I got on Amazon with the keywords « tappet adjustment tool Â» The one I got costs 8.98£ from bjebndd. I’d share a link but not sure that’s allowed.

If others have tips I’m listening too!


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If it aint broken don't fix it

Offline Bradders

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Re: Adjusting tappets
« Reply #2 on: June 22, 2024, 08:01:18 PM »
Thanks for your reply Alexrayz. I gave up on the two rear ones near the carbs, I just couldn’t undo the nut with my spanner’s. How often do you guys do them, it says every 1,500 miles in the manual?

Offline Alexrayz

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Re: Adjusting tappets
« Reply #3 on: June 22, 2024, 08:02:36 PM »
Well I hope your back is okay!

I just listen to what the manual says yeah


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Offline McCabe-Thiele (Ted)

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Re: Adjusting tappets
« Reply #4 on: June 22, 2024, 09:00:15 PM »
Adjusted the tappets on my 400/4 today for the first time. What a fiddly pain in the neck job! Any tips for making it easier?

Always fiddly first time - that's why I like hydraulic car tappets.
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Mikep328

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Re: Adjusting tappets
« Reply #5 on: June 22, 2024, 09:42:42 PM »
"How often do you guys do them, it says every 1,500 miles in the manual?"

Is that in the owners manual?  The CB400F service manual maintenance schedule on page 104  says to check them every 3000 miles, adjust if necessary.
Mine:
1976 CB400F
1973 Norton 850 Commando
2015 BMW R9T
2017 BMW R1200RS
2021 Moto Guzzi V7 Special
Wife's:
2015 Ducati Diavel
2019 Honda Africa Twin
2019 Honda NCT750

Offline Bradders

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Re: Adjusting tappets
« Reply #6 on: June 22, 2024, 10:44:05 PM »
Sorry Mikep328 you’re right , it says in my manual every 3,000 miles. Think it was the YouTube video I was watching saying every 1,500 miles.

Offline Bryanj

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Re: Adjusting tappets
« Reply #7 on: June 22, 2024, 10:58:00 PM »
Oil every 1500, but i do filter as well, service 3,000, majour sevice 6,000

Offline Mikep328

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Re: Adjusting tappets
« Reply #8 on: June 23, 2024, 10:03:36 AM »
The only thing I would do at 1500 miles is to MAYBE observe that the bike had gone 1500 miles!  :)  But I'm pretty lazy!
Mine:
1976 CB400F
1973 Norton 850 Commando
2015 BMW R9T
2017 BMW R1200RS
2021 Moto Guzzi V7 Special
Wife's:
2015 Ducati Diavel
2019 Honda Africa Twin
2019 Honda NCT750

Offline McCabe-Thiele (Ted)

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Re: Adjusting tappets
« Reply #9 on: June 23, 2024, 03:37:29 PM »
1500 miles would equate to 5 years use for me.
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Bryanj

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Re: Adjusting tappets
« Reply #10 on: June 23, 2024, 05:55:37 PM »
You really need to change the oil at 1500 as the gearbox destroys the quality, Ted i would change yours every other year to get rid of water contamination

Offline SeanFD

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Re: Adjusting tappets
« Reply #11 on: July 12, 2024, 07:02:11 PM »
While trying to retrieve that bit of camshaft I have posted elsewhere about, I removed the sump and, naturally, before doing so, drained the oil.

It has been in there for about 18 months, just sitting and doing nothing. The engine has been kicked over now and again and run for about 3 minutes.

I was amazed at how dirty it looked! The inside of the sump was coated with what looked like dust mixed with the oil.

So I go with Brian; I would change it at least every year or so, or before you start to use it again after a break.
CB750 K2 - See: Belfast2BelfastByBike.com
CB750 K1 - The less, said the better!
CB450 K1 - A work in progress. (Still!)
CB400F Supersport - Rusty - not any more!

Offline Athame57

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Re: Adjusting tappets
« Reply #12 on: July 12, 2024, 07:37:15 PM »
How often do you guys do them, it says every 1,500 miles in the manual?
Quite honestly I do them when sounds are telling me something, or by opportunity when it is in the workshop. I can never remember how far I've gone since they were last done. Never did me any harm. When I first got this bike six years back ( I paid too much!) the tappet covers were stuck fast , the hexagons on them mostly rounded off, I needed the mechanics to get them off and do the tappets, gawd knows how overdue they were, it may have a lot to do with how hard the bike is ridden of course. My Elen has been leading a gentle life really, something to do with MY age.  ;) my dispatch days are history.  ;D
I brake for animals!
1978 CB400F2 named Elen.

Offline McCabe-Thiele (Ted)

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Re: Adjusting tappets
« Reply #13 on: July 12, 2024, 07:53:30 PM »
You really need to change the oil at 1500 as the gearbox destroys the quality, Ted i would change yours every other year to get rid of water contamination

I changed my oil at 18 months 250 odd miles Bryan.
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Bryanj

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Re: Adjusting tappets
« Reply #14 on: July 12, 2024, 08:46:15 PM »
You could have stretched that to 24 months on that mileage Ted