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How lean is too lean? #738974
06/17/18 11:00 am
06/17/18 11:00 am
Joined: Jun 2010
Posts: 525
Maine
M
MikeinBiddeford Offline OP
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Maine
I put on a new AMAL carburetor and ran my 1952 ES2 about 10 miles to a bike show and on the way back home she started to clatter and then just died. I wasn't even going the speed limit.
I pulled the barrel off on Thursday and I'm now looking for a +30 or +40 piston.
I was going to check the plug when I got home to see if I was running too rich or lean, but it wasn't soon enough. Actually the plug looks fine.
Moral to the story is, when the guy sells you a carb and says he is going to set it up for your bike, don't believe him.
https://www.dropbox.com/s/dzpm9uxoc4bf0qi/IMG_2564.JPG?dl=0[/img][img]https://www.dropbox.com/s/c3f3ophyhbpm5jl/IMG_2563.JPG?dl=0[/img]

Last edited by MikeinBiddeford; 06/23/18 10:53 am.

Please do not believe anything I write. I am a hack but I like to guess the right answers.
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Re: How lean is too lean? [Re: MikeinBiddeford] #739017
06/17/18 10:18 pm
06/17/18 10:18 pm
Joined: Aug 2001
Posts: 2,205
Oztralia
R
Rohan Offline
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Rohan  Offline
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Oztralia
How is it set up ?

Was this bike previously a reliable runner ?
A lot of rebores are done to modern watercooled specs, and its too tight for an aircooled.

You have to sign in to google to view those pics ?

__________________________
48 ES2 (project), amongst others.

Re: How lean is too lean? [Re: MikeinBiddeford] #739028
06/18/18 12:46 am
06/18/18 12:46 am
Joined: Jun 2010
Posts: 525
Maine
M
MikeinBiddeford Offline OP
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Maine
I thought I could get away with Google being the host for my photos. When you click on the link, does it ask you to join or log in? I sorry if it does. My photobucket account was closed and I haven't figured out what to do next. I"ll think of something.
The bike was rarely used by the previous owner. I would take it for shot rides around the pond. Never on the highway/county road.
I can still see the hash marks in the cylinder walls. Is that any indication of how many miles it has on it?


Please do not believe anything I write. I am a hack but I like to guess the right answers.
Re: How lean is too lean? [Re: MikeinBiddeford] #739569
06/23/18 10:54 am
06/23/18 10:54 am
Joined: Jun 2010
Posts: 525
Maine
M
MikeinBiddeford Offline OP
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Maine
OK. Can someone out there tell me if the photos above can be seen from my Dropbox account?
Thank you


Please do not believe anything I write. I am a hack but I like to guess the right answers.
Re: How lean is too lean? [Re: MikeinBiddeford] #739571
06/23/18 11:05 am
06/23/18 11:05 am
Joined: Mar 2006
Posts: 3,771
Norfolk, UK
L.A.B. Online content
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L.A.B.  Online Content
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Posts: 3,771
Norfolk, UK
Originally Posted by MikeinBiddeford
OK. Can someone out there tell me if the photos above can be seen from my Dropbox account?
Thank you


Yes (as links).

Re: How lean is too lean? [Re: MikeinBiddeford] #739572
06/23/18 11:46 am
06/23/18 11:46 am
Joined: Aug 2001
Posts: 7,548
scotland
triton thrasher Offline
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triton thrasher  Offline
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Posts: 7,548
scotland
“The moral” is start rich.

Nobody can set up a carb for a 66-year old bike without road or dynamometer tests.

As said above, if it hasn’t done many miles since rebore and now has seized, it may have been set too tight, by some goon with a boring bar.


Amateur Loctite enthusiast.
Re: How lean is too lean? [Re: MikeinBiddeford] #739583
06/23/18 3:40 pm
06/23/18 3:40 pm
Joined: Dec 2013
Posts: 4,283
ohio, usa
kevin roberts Offline
fefsa
kevin roberts  Offline
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Joined: Dec 2013
Posts: 4,283
ohio, usa
[Linked Image]
[Linked Image]

imgur


"Are bikes so nice as all that?" asked the mole, shyly...

"Nice? They're the only thing," said the Water Rat Solemnly, as he leaned forward on the handlebars. "Believe me, my young friend, there is nothing -- absolutely nothing -- half so much worth doing as simply messing about with bikes."
Re: How lean is too lean? [Re: MikeinBiddeford] #739584
06/23/18 3:53 pm
06/23/18 3:53 pm
Joined: Aug 2001
Posts: 7,548
scotland
triton thrasher Offline
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scotland
Was there not loud detonation?


Amateur Loctite enthusiast.
Re: How lean is too lean? [Re: MikeinBiddeford] #739613
06/23/18 10:00 pm
06/23/18 10:00 pm
Joined: Aug 2001
Posts: 2,205
Oztralia
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Rohan Offline
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Oztralia
Yes, have/had you checked the spark timing, and it was fully advanced at the time ?
(Was it a hot day ?)

There is still enough good piston skirt left that you should be able to measure what the bore clearance actually was ?
Measure across the piston skirt at the base, at right angles to the pin. And across the bore at the base.
Anything less that 5 thou is just not enough, and some pistons need more,

Also, Is the washer(s) on the oil pump still in place and in good condition ?
If you were losing oil flow to the big end, things up top may not have been getting enough oil.
Just hunting for likely causes here....

Re: How lean is too lean? [Re: MikeinBiddeford] #739660
06/24/18 10:24 am
06/24/18 10:24 am
Joined: Jun 2010
Posts: 525
Maine
M
MikeinBiddeford Offline OP
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Maine
Thank you Kevin Roberts for reposting the pictures.
I have the barrel and old piston boxed up. I'll be getting a new +30 piston on Monday and I'll send it up to a guy in mid coast Maine that does such thing for a living.
I'll report back
Thank all
Mike in Biddeford

Last edited by MikeinBiddeford; 06/25/18 11:06 pm.

Please do not believe anything I write. I am a hack but I like to guess the right answers.
Re: How lean is too lean? [Re: MikeinBiddeford] #739809
06/25/18 10:17 am
06/25/18 10:17 am
Joined: Jun 2010
Posts: 525
Maine
M
MikeinBiddeford Offline OP
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Maine
And how do you fix this?

[Linked Image]

[Linked Image]

Last edited by MikeinBiddeford; 06/25/18 10:25 am.

Please do not believe anything I write. I am a hack but I like to guess the right answers.
Re: How lean is too lean? [Re: MikeinBiddeford] #739812
06/25/18 11:18 am
06/25/18 11:18 am
Joined: Aug 2001
Posts: 4,068
argyll. scotland, uk
gavin eisler Online content
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gavin eisler  Online Content
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Posts: 4,068
argyll. scotland, uk
machine out the cracks from above with an end mill, braze in mild steel round bar same size, machine back to level correct height, drill and tap.
Pre heat the head before brazing. If you can get an end mill/ round bar the same radius as the broken bosses it should be an invisible repair.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
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The poster formerly known as Pod
Re: How lean is too lean? [Re: MikeinBiddeford] #739886
06/25/18 11:34 pm
06/25/18 11:34 pm
Joined: Jun 2010
Posts: 525
Maine
M
MikeinBiddeford Offline OP
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Maine
The new piston came today. It has a flat top. The old one has a dome. I think the old one may have been a high compression piston. The manual says that high compression pistons should be used with alcohol only. I was running regular gas. We'll see what my mechanic thinks.


Please do not believe anything I write. I am a hack but I like to guess the right answers.
Re: How lean is too lean? [Re: gavin eisler] #739927
06/26/18 10:48 am
06/26/18 10:48 am
Joined: Jun 2010
Posts: 525
Maine
M
MikeinBiddeford Offline OP
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Maine
If I send it to you, what would you charge? LOL


Please do not believe anything I write. I am a hack but I like to guess the right answers.
Re: How lean is too lean? [Re: MikeinBiddeford] #739934
06/26/18 1:10 pm
06/26/18 1:10 pm
Joined: Sep 2007
Posts: 1,120
Ottawa, Canada
gREgg-K Offline

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gREgg-K  Offline

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Posts: 1,120
Ottawa, Canada
Originally Posted by MikeinBiddeford
And how do you fix this?

[Linked Image]


Looks like this head was previously cracked just above, and to the left of the boss being pointed to. To me, the area above the boss was repaired by a process called "pinning".

Prior to doing any more repairs, it may be worth having the entire head inspected for other defects.
... Gregg


Spyder Integrated Technologies
Lucas, BTH, & Miller Magneto & Dynamo Restoration
SMITHS Chronometric Restoration
magneto@spyder-it.com
Re: How lean is too lean? [Re: MikeinBiddeford] #739937
06/26/18 1:36 pm
06/26/18 1:36 pm
Joined: Mar 2005
Posts: 10,197
Boston, Massachusetts
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John Healy Offline
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Posts: 10,197
Boston, Massachusetts
From the pictures this was not a clearance issue. If it was there would be evidence of seizure just below the oil ring on the thrust face. There is some signs of a four corner seizure more evidence that the problem was caused by excess heat generated by abnormal combustion (detonation).

This bike suffered from severe detonation. If we are to believe you were below the speed limit I doubt it was caused by the person setting up the carburetor. To be able to isolate the problem to the carburetor someone would have had to put in a .105" needle jet.

You say the plug looks good. It shouldn't. I would expect to see some oil on the plug, that is if it isn't a grade or two to hot.

May I guess: Warm day, fresh motor, a lot of high gear work using the throttle instead of the gear shift lever on undulating terrain and what grade is that Autolite plug



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