Author Topic: Tappet clearances  (Read 1403 times)

Online ellis

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Tappet clearances
« on: 21.04. 2016 21:08 »
Now to open a can of worms. Feb 1960 A10 s/a Eng. number  DA10.16377 Frame number GA7.5279. What gap would you set the tappets to ? *doubt*

Offline muskrat

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Re: Tappet clearances
« Reply #1 on: 21.04. 2016 21:21 »
G'day ellis.
The book says 10 and 16 for an iron head in 55-61. With an update to 8 and 10 in 60-62! Depends on the cam. Set at the larger gaps and hear if it's noisy when hot.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online trevinoz

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Re: Tappet clearances
« Reply #2 on: 21.04. 2016 23:23 »
That engine should have a 356 cam so the closer settings would apply.

Online bsa-bill

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Re: Tappet clearances
« Reply #3 on: 22.04. 2016 09:25 »
My 1961 Flash hand book gave two settings

8 and ten for quiet running or 10 and sixteen for maximum power, both  were specified in the handbook so the choice was that of the rider
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online ellis

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Re: Tappet clearances
« Reply #4 on: 22.04. 2016 18:02 »
Thanks again for all your feedback, 10&16 sounded quite noisy 8&10 sounded very quiet. Well I've gone for the happy medium and set them at 10&12 So I can just about hear them. Time will tell if I've got them right. *bright idea* 

Offline muskrat

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Re: Tappet clearances
« Reply #5 on: 22.04. 2016 21:45 »
G'day ellis.
It is a bit of a "suck and see" thing. The book spec for my cafe (A7 twin carb head on A10) is 8 and 12 but on a good hard run of 100mph+ they close up and prop the valves open. An extra 2 thou fixed that.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline wortluck

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Re: Tappet clearances
« Reply #6 on: 08.09. 2018 16:08 »
Ok folks, here we go (first time ever I've done this BTW).  Bike was running really well so thought all was ok.  Then I started getting a bit of a buzz from the top end so thought I'd check out the tappets (cold engine).  Went with a bit of a compromise on the book and thought I'd start with Musky's suggestion of 10 and 14 as I ride quite hard and long distance (book suggests 10 and 16).  Started on the inlet, hmm, 8 on l/h and 6 on r/h - fixed.  Then went to exhaust, OMG - tight 6 on l/h and 0 on r/h (r/h wouldn't even rock) *eek* :o *doh*.  As tolerances close up when hot, I'm guessing my r/h would have been a bit propped open and the l/h just about closing. :-\

Adjusted them up to 14, lashed it all back together and kicked it up - actually started second kick - I've  adjusted the tappets and not buggered anything up (I hope). *woo*

The bike sounds even better, ticks over more evenly, responds to throttle well, and the funny 'pop' I used to get from the r/h silencer has disappeared (a bit like a loose baffle type of noise).  Can't wait to get on the road tomorrow an see if the pinking has improved.  Maybe the oil I get at the end of the silencers will reduce too?? *dribble*

Obviously, when cold, it's a bit more tappetty, but nothing dramatic at all.  Used the method of one valve fully open, adjust the other side.

One last thing, would I have knackered anything by running with the valves as they were, doesn't seem to have affected anything thus far?
'62 Flash
'49 B31
'59 BMW R60
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Re: Tappet clearances
« Reply #7 on: 08.09. 2018 16:28 »
You can certainly burn an exhaust valve like that. Does compression feel ok on both cylinders, without hissing?

Service the bike at service intervals.  Don’t just keep running it until it goes funny.

Offline wortluck

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Re: Tappet clearances
« Reply #8 on: 08.09. 2018 21:04 »
Can hear a bit of hissing, but compression is very good.  In fact, the bike is a lot harder to kick over and runs really well - certainly better than before.  Slight puff of smoke from the 'bad' side (r/h) when giving it a bit of a rev, so probably some slight issue there, but it's not all the time and certainly not major.

Incidentally TT, what are the service intervals for tappets.

I check everything else oils, tyre pressures, spark plug/points gaps, nuts and bolts, chain tension inc primary, etc.  Is there anything else that needs looking at periodically.  Engine oil is changed ca. 1-1.5k.
'62 Flash
'49 B31
'59 BMW R60
FS1-E, YB100, RS100, RD200DX,250DX,350B, XS750



"I may disagree with what you have to say, but I shall defend to the death your right to say it."
Evelyn Beatrice Hall

Offline muskrat

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Re: Tappet clearances
« Reply #9 on: 08.09. 2018 21:47 »
G'day wortluck.
Good to hear mate. I'd check'em every 2nd oil change or any time you have the tank off.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline wortluck

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Re: Tappet clearances
« Reply #10 on: 08.09. 2018 21:55 »
Cheers Musky, sounds like a plan to me.  Must admit, I was surprised I hadn't buggered the whole thing up when I checked the clearances.  Couldn't believe the r/h clearance was practically nothing.  As I said, when the l/h exhaust was completely depressed, the r/h wouldn't move.  Tried .002" feeler and still couldn't get it in.

Given that it might have been that way for a while, and that I don't hang about, it shows these bikes can put up with a bit of stick.  However, I will be checking them way more often now.

Going out for a long test ride tomorrow!

Thanks again mate.
'62 Flash
'49 B31
'59 BMW R60
FS1-E, YB100, RS100, RD200DX,250DX,350B, XS750



"I may disagree with what you have to say, but I shall defend to the death your right to say it."
Evelyn Beatrice Hall

Online Triton Thrasher

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Re: Tappet clearances
« Reply #11 on: 08.09. 2018 22:12 »
Incidentally TT, what are the service intervals for tappets.


On your bike?  I’d be the last to know.

Offline wortluck

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Re: Tappet clearances
« Reply #12 on: 08.09. 2018 22:38 »
Incidentally TT, what are the service intervals for tappets.


On your bike?  I’d be the last to know.

Heh *doubt*
'62 Flash
'49 B31
'59 BMW R60
FS1-E, YB100, RS100, RD200DX,250DX,350B, XS750



"I may disagree with what you have to say, but I shall defend to the death your right to say it."
Evelyn Beatrice Hall

Offline wortluck

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Re: Tappet clearances
« Reply #13 on: 09.09. 2018 22:45 »
After setting the tappet clearances to what they should be (or near enough), I went for a 200m spin around the North Yorks Moors.  Bike went like a dream.  No pinking at all despite a pretty fierce headwind and plenty of hills.  Pulled like a train and responded without complaint to throttle - I also didn't lose anything/break anything this time!!  When I got back, plugs (B6HS) were a dark tan.  Still a little oil right at the back of the silencers.

So, the upshot is, I want the bike to run like this all the time.

Question, engine sounds very tappety now that the there is actual clearance on the tappets!  Do I recheck to see if they've slipped?  I'm happy to look or leave for a bit now I'm confident in doing them.  One more thing, I have the adjusters with the square top.  I can't get much of a spanner on the square bit when trying to tighten the locknut.  Aside from getting the Allan key adjusters, do I just persevere?
'62 Flash
'49 B31
'59 BMW R60
FS1-E, YB100, RS100, RD200DX,250DX,350B, XS750



"I may disagree with what you have to say, but I shall defend to the death your right to say it."
Evelyn Beatrice Hall

Online berger

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Re: Tappet clearances
« Reply #14 on: 09.09. 2018 23:22 »
wortluck alloy head? mine sounded that loud one day I thought the oil feed to rockers had gone awol, everything was ok though. you might find sat above the tank it magnifies the noise , I've found that when they seem to be extra noisy if I lean out a bit to hear what's going on they shut the f--k up . anyway there no where near as noisy as the trident I once owned.  ---everybody should have one once..- that is a sentence out of a nineties classic bike mag.... back to the point , you may or may not find the valve stem tops have got slightly hammered *bash* even though they are hard and the adjusters hammered as well *bash*. taking into account the valves tend to turn they may be finding the slightly hammered bits that might be giving them a touch more clearance maybe? -pub tomow deffo Monday club *beer* thankyou for listening- over