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Old 03-23-2015, 02:12 PM   #1
GrahamM OP
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87 R100RS - Valve spec

Hey top end gurus...

Just when I thought I had my rs ready to go I found the exhaust valve leaking badly. The bike has 103k km on it and the valve/guides are quite slack and the seat face is extremely wide. So I am going for new valves and guides for the bike.

My bike is listed as a '87 serial WB1045508H0160582, shown to be produced in '86

my dilemma is that Motobins crosses over kits R100 in 86/87.... anyone know how I can tell if I should buy the 1977-1986 (Valve7A) or the bottom kit for 1987 and on (Valve8A)....

Anyone install this Swiss made kit? I am going to go for the high temp guide update for the extra 9GBP

https://www.motobins.co.uk/bmw-parts...&bikeref=R90-6

or is there a better option, shopping in the US for us Canadians right now is way to expense right now so looking towards Germany or UK. BTW for you US guys I noticed that some parts I checked at Max are the same price in USD as a Canadian BMW in Canadian dollars... that's a 20% discount right now for you guys!

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GrahamM screwed with this post 03-23-2015 at 02:25 PM
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Old 03-23-2015, 02:25 PM   #2
BigAldo
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I got my heads done a few months ago by Scrimingers in the UK. Steve Scriminger thought the Intervalves were pretty good, but said avoid the pattern valves at all costs.

Apparently a customer complained that the valve clearance kept opening up, and when Steve checked the newly redone heads, the valve tops were mushrooming to the point where the pattern valves wouldn't slide out the valve guides. Less than 2000 miles from what I recall!
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Old 03-23-2015, 02:28 PM   #3
GrahamM OP
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I think I just answered my own question, I put my serial number in the Max fiche and it brings up the 30deg cut valves. So it looks like I need the bottom option.
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'10 Husaberg FE450
'81 R80G/S: WP4860 KTM front end, Wilber's 633 rear ready to roll
'86 R100RS - in progress for 2015 ride season
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Old 03-23-2015, 02:37 PM   #4
GrahamM OP
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Hey I think I found another option... ??????

the std valves have a 8mm stem, I see that both the inlet and exhaust are offered with 8.3mm from BMW... at a decent price at motobins

is this so the guide can be reamed out and all I have to do is buy the valves and springs?

If this is the case does anyone know where I can get a 8.3mm reamer?
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'10 Husaberg FE450
'81 R80G/S: WP4860 KTM front end, Wilber's 633 rear ready to roll
'86 R100RS - in progress for 2015 ride season
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Old 03-23-2015, 02:45 PM   #5
disston
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We no longer have our Sunnen reamer expert. Somebody else will have to step up.

The problem is that the cheap reamers, cost about $70 each will not produce a truly square hole or a hole with parallel sides. The Sunnen reamer costs about $500 each for the tool and each reamer for that is another $100.

So what you really want is a machine shop that has done Airheads before and will do the job without charging you an arm and a leg.

Maybe there are other opinions on this? I'm struggling with the idea of doing my own valve guides myself and it doesn't look good for this Shade Tree mechanic.
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Old 03-23-2015, 02:56 PM   #6
gordongraham
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what is 'normal' lateral movement for valves in guides? my exhaust valves won't slip out of the guides, sounds like the mushrooming you describe aldo, though they only catch once they are about 50% out. there looks to be a touch under 1mm side to side movement when valve head just off the seat.

where did you source your valves aldo?
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Old 03-23-2015, 03:52 PM   #7
CafeDude
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Tricky job. I'd send my heads out to a guru: either Randy Long, or Tom Cutter here in the States, unless you have a guru on your side of the pond.
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Old 03-23-2015, 05:38 PM   #8
Clay Spinner
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There's Richie Moore, Jim Cray, Steve Scrimminger, and probably a few more that I can't remember the names of. Postage is dirt cheap in the UK so shipping things around the little island can be done with relatively no burden on total cost. For example, I could ship an airhead gearbox to Scotland from Devon... almost the whole length of the country for 8-11 GBP depending on Courier and how quick I wanted it there.
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Old 03-23-2015, 06:06 PM   #9
GrahamM OP
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I'm in Peterborough, Ont, Canada...
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'10 Husaberg FE450
'81 R80G/S: WP4860 KTM front end, Wilber's 633 rear ready to roll
'86 R100RS - in progress for 2015 ride season
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Old 03-24-2015, 12:03 AM   #10
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Quote:
Originally Posted by gordongraham View Post
what is 'normal' lateral movement for valves in guides? my exhaust valves won't slip out of the guides, sounds like the mushrooming you describe aldo, though they only catch once they are about 50% out. there looks to be a touch under 1mm side to side movement when valve head just off the seat.

where did you source your valves aldo?
I got my valves from Motobins. Interestingly, when talking to Steve Scriminger I asked about acceptable play in the valve guides. He says that the action of the rocker on the valve pushes the valve sideways slightly in the guide. As the guide wears, the sideways movement becomes more pronounced and the rate of wear increases. I had detectable movement, but very little in measurement terms, maybe half a mm.

He was also of the opinion that the 30 degree valve seats allowed the guides to wear a little quicker than the older 45 degree seats, because the sharper angle of the old seats did a better job of guiding the valve back on to its seat as it closed.

Steve charged 20 per guide to fit, ream and re-cut the seat. (plus parts +VAT)

That guy knows his stuff!
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Old 03-24-2015, 12:25 AM   #11
ME 109
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Another vote for sending heads to a known specialist. It might be a pain in the butt, but so is doing the job again.
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Old 03-24-2015, 01:49 AM   #12
chasbmw
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The cost of fitting 4 new guides from Steve Scrimeger was around 150. Used parts returned. Quick turn around.
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Old 03-24-2015, 08:28 AM   #13
Clay Spinner
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Quote:
Originally Posted by GrahamM View Post
I'm in Peterborough, Ont, Canada...
I was confusing you with gordongraham or the chap up in scotland!

Move along people... nothing to see here!
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Old 03-24-2015, 08:54 AM   #14
gordongraham
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yep dana, im still up in scotland ;) and we do seem to fare quite well with courier costs. lots of competition seems to keep it decent.

aldo, ill look at motobins. im unlikely to get the heads and valves done this season but def on the books. working well before teardown but would be nice to know that they are fresh.

Quote:
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I was confusing you with gordongraham or the chap up in scotland!

Move along people... nothing to see here!
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Old 03-24-2015, 12:39 PM   #15
moosehead
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Graham, have you spoken with Bruno in Iron Bridge, ON re any head work. He's reasonable and knows his stuff. Worth checking him out.

www.brunos.us

No affiliation just satisfied customer over the years.
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