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Re: [Spridgets] SU rebuild time

To: Hal Faulkner <frog.aye@gmail.com>
Subject: Re: [Spridgets] SU rebuild time
From: John Farley via Spridgets <spridgets@autox.team.net>
Date: Tue, 14 Jun 2016 18:57:32 -0400
Cc: Spridgets <spridgets@autox.team.net>
Delivered-to: mharc@autox.team.net
Delivered-to: spridgets@autox.team.net
References: <39a3a2c5-d93a-f864-00d1-7ea07476c774@dinospider.com> <CAM6-Rjc+p04_M_m58M4i5mPxXq1P2AN+KjhtsgqYXFesxHTK=w@mail.gmail.com>
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Mike, I think you are referring to the "Piston Lifting Pin".  It allows you
to lift the main carb piston slightly to tune the rich / lean setting
without removing the air cleaner.  Half the SUs out there have a broken one
like you describe.  You just have to remove the air cleaner and lift the
piston slightly with your finger when setting the needle rich / lean nut.

The 1098 and 1275 needles are different for an HS-2.  They are easily
changed in the piston.  Most folks start with a "standard" needle, but
doesn't always work.  I ended up with a "rich" needle on my 1275.

Rebuilding these carbs are straight forward.  One key, check for wear on
the throttle shafts and where they go through the carb body.  Can't be
sloppy.   Worn throttle shafts are easily replaced.  The carb casting can
be bushed, but can be difficult.  If sloppy, I would try new shafts first.

Good Luck,
John F.

On Mon, Jun 13, 2016 at 9:40 PM, Hal Faulkner via Spridgets <
spridgets@autox.team.net> wrote:

> Mike, The re-build kit probably doesn't include the needle. Needles for a
> 1098 will probably not be correct for a 1275, and different cams/porting
> will also require different needles.  Check the "Yellow Bible" for more
> information.
> Be very careful about the glass beading.  The inner surface of the dashpot
> mates withe the piston to be part of the acceleration enrichment: if you
> mess with the mating surfaces you may change the action and this could
> throw your two carbs out of balance.
> Can't help you with getting the "piston" out.
> Good luck,
> Hal
>
> On Mon, Jun 13, 2016 at 8:26 AM, Mike Rambour via Spridgets <
> spridgets@autox.team.net> wrote:
>
>>  Ok, new son-in-law is trying to get his toy running and some of the
>> parts have been sitting for years out in the rain.
>>
>>  First up, the SU carbs.  I have NEVER played with a SU except minor
>> tuning or to replace with a Weber, this time we are sticking with SU's.
>> Yes, they sat in the rain 2 years at least of course barrels up and were
>> frozen solid, using wooden dowel and some brass punches we got them apart
>> after letting them soak in Kroil for a week.  I think everything is
>> re-buildable.
>>
>>  One of the issues we came up with is that the dashpot plunger was stuck
>> in the carb, we finally got most of it out but it left the piston (for lack
>> of a better name) in the hole, I guess we pulled too hard and snapped off
>> the little circlip and now what ? Its really stuck in there and its in
>> there deep.  Can't get to it from the other side so not sure what to do.  I
>> was thinking of trying to get a screw into it and pull it but that of
>> course implies I can get a new one, I suppose I could drill it out also but
>> that requires more accuracy than I might be able to do but I do have a
>> lathe/mill I could use for the task. (it seems my machining tends to be +/-
>> 0.25" accuracy not a typo :)  )
>>
>>  We got the full blown rebuild kit on its way, everything we should need
>> and tonight I will glass bead everything but that plunger in there is a
>> problem.  Also not knowing better what is in that housing that the dashpot
>> plunger goes into ? the other side has the long needle sticking out is
>> there supposed to be a opening from one side to the next besides the
>> obvious 2 holes on the side, there is hex screw looking thing near the 2
>> holes, should I remove that and what is it ?  I am hoping that in the super
>> duper $200 rebuild kit is a new needle because i damaged one getting it out
>> (after removing the screw on the side).   The carbs came off a 1098 and are
>> going on his 1275 as soon as we put it together :)
>>
>>  We have a issue with the head on the 1275 right now, the brass insert
>> between cylinders 2&3 is recessed causing a head gasket leak and allowing
>> water into the cylinders, even the insert leaks so I have to find a shop
>> that is trustworthy here in S. Calif. to get it out, thread a new insert
>> and machine it.  Getting down the last few details and maybe this motor
>> will be together in a month.
>>
>>  Mike
>>
>> --
>> A gun is like a parachute, if you need one but don't have it,
>> you'll probably never need one again.
>>
>> ------------------------
>>
>> spridgets@autox.team.net
>>
>> Donate: http://www.team.net/donate.html
>> Suggested annual donation: $12.75
>>
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>> http://autox.team.net/mailman/options/spridgets/frog.aye@gmail.com
>>
>
>
> ------------------------
>
> spridgets@autox.team.net
>
> Donate: http://www.team.net/donate.html
> Suggested annual donation: $12.75
>
> Archive: http://www.team.net/archive
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> Unsubscribe/Manage:
> http://autox.team.net/mailman/options/spridgets/jmfarley61@gmail.com
>
>

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<div dir=3D"ltr">Mike, I think you are referring to the &quot;Piston Liftin=
g Pin&quot;.=C2=A0 It allows you to lift the main carb piston slightly to t=
une the rich / lean setting without removing the air cleaner.=C2=A0 Half th=
e SUs out there have a broken one like you describe.=C2=A0 You just have to=
 remove the air cleaner and lift the piston slightly with your finger when =
setting the needle rich / lean nut.<div><br></div><div>The 1098 and 1275 ne=
edles are different for an HS-2.=C2=A0 They are easily changed in the pisto=
n.=C2=A0 Most folks start with a &quot;standard&quot; needle, but doesn&#39=
;t always work.=C2=A0 I ended up with a &quot;rich&quot; needle on my 1275.=
</div><div><br></div><div>Rebuilding these carbs are straight forward.=C2=
=A0 One key, check for wear on the throttle shafts and where they go throug=
h the carb body.=C2=A0 Can&#39;t be sloppy. =C2=A0 Worn throttle shafts are=
 easily replaced.=C2=A0 The carb casting can be bushed, but can be difficul=
t.=C2=A0 If sloppy, I would try new shafts first.</div><div><br></div><div>=
Good Luck,</div><div>John F.=C2=A0</div></div><div class=3D"gmail_extra"><b=
r><div class=3D"gmail_quote">On Mon, Jun 13, 2016 at 9:40 PM, Hal Faulkner =
via Spridgets <span dir=3D"ltr">&lt;<a href=3D"mailto:spridgets@autox.team.=
net" target=3D"_blank">spridgets@autox.team.net</a>&gt;</span> wrote:<br><b=
lockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px =
#ccc solid;padding-left:1ex"><div dir=3D"ltr"><div><div><div>Mike, The re-b=
uild kit probably doesn&#39;t include the needle. Needles for a 1098 will p=
robably not be correct for a 1275, and different cams/porting will also req=
uire different needles.=C2=A0 Check the &quot;Yellow Bible&quot; for more i=
nformation.<br>Be very careful about the glass beading.=C2=A0 The inner sur=
face of the dashpot mates withe the piston to be part of the acceleration e=
nrichment: if you mess with the mating surfaces you may change the action a=
nd this could throw your two carbs out of balance.=C2=A0 <br></div>Can&#39;=
t help you with getting the &quot;piston&quot; out.=C2=A0 <br></div>Good lu=
ck,<br></div>Hal<br></div><div class=3D"gmail_extra"><br><div class=3D"gmai=
l_quote">On Mon, Jun 13, 2016 at 8:26 AM, Mike Rambour via Spridgets <span =
dir=3D"ltr">&lt;<a href=3D"mailto:spridgets@autox.team.net"; target=3D"_blan=
k">spridgets@autox.team.net</a>&gt;</span> wrote:<br><blockquote class=3D"g=
mail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-l=
eft:1ex">=C2=A0Ok, new son-in-law is trying to get his toy running and some=
 of the parts have been sitting for years out in the rain.<br>
<br>
=C2=A0First up, the SU carbs.=C2=A0 I have NEVER played with a SU except mi=
nor tuning or to replace with a Weber, this time we are sticking with SU&#3=
9;s.=C2=A0 Yes, they sat in the rain 2 years at least of course barrels up =
and were frozen solid, using wooden dowel and some brass punches we got the=
m apart after letting them soak in Kroil for a week.=C2=A0 I think everythi=
ng is re-buildable.<br>
<br>
=C2=A0One of the issues we came up with is that the dashpot plunger was stu=
ck in the carb, we finally got most of it out but it left the piston (for l=
ack of a better name) in the hole, I guess we pulled too hard and snapped o=
ff the little circlip and now what ? Its really stuck in there and its in t=
here deep.=C2=A0 Can&#39;t get to it from the other side so not sure what t=
o do.=C2=A0 I was thinking of trying to get a screw into it and pull it but=
 that of course implies I can get a new one, I suppose I could drill it out=
 also but that requires more accuracy than I might be able to do but I do h=
ave a lathe/mill I could use for the task. (it seems my machining tends to =
be +/- 0.25&quot; accuracy not a typo :)=C2=A0 )<br>
<br>
=C2=A0We got the full blown rebuild kit on its way, everything we should ne=
ed and tonight I will glass bead everything but that plunger in there is a =
problem.=C2=A0 Also not knowing better what is in that housing that the das=
hpot plunger goes into ? the other side has the long needle sticking out is=
 there supposed to be a opening from one side to the next besides the obvio=
us 2 holes on the side, there is hex screw looking thing near the 2 holes, =
should I remove that and what is it ?=C2=A0 I am hoping that in the super d=
uper $200 rebuild kit is a new needle because i damaged one getting it out =
(after removing the screw on the side).=C2=A0 =C2=A0The carbs came off a 10=
98 and are going on his 1275 as soon as we put it together :)<br>
<br>
=C2=A0We have a issue with the head on the 1275 right now, the brass insert=
 between cylinders 2&amp;3 is recessed causing a head gasket leak and allow=
ing water into the cylinders, even the insert leaks so I have to find a sho=
p that is trustworthy here in S. Calif. to get it out, thread a new insert =
and machine it.=C2=A0 Getting down the last few details and maybe this moto=
r will be together in a month.<br>
<br>
=C2=A0Mike<br>
<br>
-- <br>
A gun is like a parachute, if you need one but don&#39;t have it,<br>
you&#39;ll probably never need one again.<br>
<br>
------------------------<br>
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</blockquote></div><br></div>
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