YS 140 sport problem

Ed Miller edbon85 at charter.net
Sat Mar 26 16:38:57 AKST 2005


They work but weren't as durable in the Panhead and Shovelhead's. Too much 
heat variation and bad geometry, over time they would loosen in the head. 
Mostly drag racer's used them. The early Harleys didn't shed heat well and 
the lifter, pushrod, rocker to valve tip geometry made one think the 
engineers were doing a destruction test rather than building a "durable" air 
cooled V Twin. 30 to 50K was all you could reasonably expect out of a pre 
Evo top end. The Evo took that number to 60 or 80K. Now the current 
Twinkies, except for a few small initial issues, are nicely done. To bad the 
EPA will effectively legislate them into extinction in 5 years.
Ed M.
----- Original Message ----- 
From: "Bill Glaze" <billglaze at triad.rr.com>
To: <discussion at nsrca.org>
Sent: Saturday, March 26, 2005 10:27 AM
Subject: Re: YS 140 sport problem


> Ed:
> Just out of curiosity, did anyone ever try bronze valve guides?  The 
> worked well in the drag boat engines I built; can't begin to say how many 
> I built, and they lasted a long time, too.  Bill Glaze
>
> Ed Miller wrote:
>
>> The seat/guide assembly falling out of the head has plagued all YS 
>> 120/140 engines. Had a new SF do it myself. YS will replace the head. Now 
>> Harley's problem in '79 wasn't AMF in so much they got caught off guard 
>> with the advent of unleaded gas. I had a '79 80 inch Shovel FXS I bought 
>> new. The valve guides were tool steel and short. The #2 cylinder would 
>> get hot and stick the exhaust valve open. I fixed my bike myself the 
>> winter of '79/80 with sodium filled exhaust valves, hardened valve seats, 
>> longer cast iron valve guides I modified from another engine and I 
>> modified the lower spring retainers for valve seals. Harley came out with 
>> an exact kit fall of '80. AMF was the best thing that ever happened to 
>> Harley, without AMF Harley would have gone out of business in the early 
>> 70's. I bet there are a few AMF exec's wondering what if now 
>> though.......
>> Ed M.
>> ----- Original Message ----- From: "John Pavlick" <jpavlick at idseng.com>
>> To: <discussion at nsrca.org>
>> Sent: Saturday, March 26, 2005 1:04 AM
>> Subject: RE: YS 140 sport problem
>>
>>
>>> Holy sh*#... This YS stuff sounds like the old AMF days at Harley (valve
>>> seats falling out, valves bending and sticking because the guides were 
>>> too
>>> short ['79], etc.). Lately, a few people have asked me why I don't fly a
>>> 4-stroke in my pattern plane. My answer is: "Because O.S. doesn't make 
>>> one
>>> big enough". Uh-oh, I hope I didn't start something here. So much for 
>>> things
>>> being quiet on the list...
>>>
>>> John Pavlick
>>> http://www.idseng.com
>>>
>>>
>>>> -----Original Message-----
>>>> From: discussion-request at nsrca.org
>>>> [mailto:discussion-request at nsrca.org]On Behalf Of Joe Dunnaway
>>>> Sent: Friday, March 25, 2005 11:35 PM
>>>> To: discussion at nsrca.org
>>>> Subject: Re: YS 140 sport problem
>>>>
>>>>
>>>> I saw this happen on a 140 L at one of the contests last year...
>>>> Talked to
>>>> the guy at the next contest and he had put the seat back in and peened
>>>> around it.  He said it worked fine.
>>>>
>>>> Joe
>>>>
>>>> ----- Original Message -----
>>>> From: "Bob Kane" <getterflash at yahoo.com>
>>>> To: <discussion at nsrca.org>
>>>> Sent: Friday, March 25, 2005 10:28 PM
>>>> Subject: Re: YS 140 sport problem
>>>>
>>>>
>>>> > Wow, that is a new one on me. I would send it back to
>>>> > YS Performance for a new head. My guess is the seats
>>>> > are cast in place, there is little you could do to
>>>> > repair it.
>>>> >
>>>> > --- iflyrc24 <iflyrc24 at columbus.rr.com> wrote:
>>>> >> I was trying to start my YS 140 Sport and could not
>>>> >> get it to fire. While cranking with the starter the
>>>> >> compression went totally away. I took the valve
>>>> >> cover off and noticed the intake valve clearance was
>>>> >> about 1/8" or so. I pushed in the valve to see if it
>>>> >> was stuck and it fell into the cylinder. I removed
>>>> >> the head and the intake valve and seat assembly came
>>>> >> out of the head fully assembled with spring and
>>>> >> keepers in tact.
>>>> >>
>>>> >> Can the intake assembly be reinstalled in the head
>>>> >> and what holds it in place? Other than aligning the
>>>> >> intake ports is there any other alignments to watch
>>>> >> for?
>>>> >>
>>>> >
>>>> > Bob Kane
>>>> > getterflash at yahoo.com
>>>> >
>>>> >
>>>> >
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