The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: D Mann on April 08, 2014, 12:06:43 PM
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Just finished replacing the timing chain and went to adjust the valves. Left side no problem, right side no clearance even with adjusters backed all of the way off. Yes I rotated the engine 360 deg and watched the valves close. I need some recommendations for a shop that can do a good job on the heads without breaking the bank. I am in northern Illinois.
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I need some recommendations for a shop that can do a good job on the heads without breaking the bank.
Common suggestion, although I'm not familiar with your neck of the woods: air cooled VW mechanics.
When I had my head worked for a broken exhaust valve, worn guide resulting from same, etc, I went through my "un-affiliated" air head mechanic. He's a bit of a unique guy, but has the knowledge and connections to get the job done. There may be a similar individual around, especially in the Chicago area.
If you want to investigate shipping to the ATX area, check out http://www.ororcycle.com
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Two of the very best Airhead head repair and overhaul:
West coast: Ted Porter's Beemer Shop http://www.beemershop.com/
East coast: Tom Cutter's Rubber Chicken Racing Garage http://www.rubberchickenracinggarage.com/
Neither are "economy" shops and both gents are usually booked 5-7 months ahead for head work; particularly now that Spring has done Sprung. Prices hover near $600-700/pair for total refreshing and all new parts.
An alternative is to check eBay. Sometime years back, I purchased a pair of prefect late model R65 heads off a bike that had massive front end damage and was being parted out. Even the exhaust stub threads are virgin-like. $130.00 the pair.
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In this case it would seem to be valve seat recession, there is no cheap fix as the head needs to be welded up and then cut so a new seat can be pressed in, then the guides need to be done, new valves (probably get away with exhausts only) cut (minimum 3 angle) and grind.
If you are bucks down, a serviceable set of 2nd hand heads is an option but measure the guide clearance (a set of k-lines can be fitted cheaply and will last almost as long as new guides) and then monitor them closely. Any heads manufacturer pre-1985 may suffer from seat recession when used with unleaded or low lead fuels - there seems to be no rhyme or reason, some will recede and some will not. I dose my fuel with a lead replacement - costs me about $2.20 per tank of fuel, I regard it as insurance and as a hedge putting off the evil date I have to fit hardened seats to the exhaust valves.
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Thanks for the tips I will do some checking.
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Well I called a few places and Brunos in Canada looked like the quickest turn around at about 7 weeks. I pulled the exhaust and rotated the engine to see the valve through the exhaust port and suddenly there was a lot of valve clearance. I made a newbie mistake!!!! I had been watching the cam sprocket to rotate 360 deg instead of the crank sprocket. I never had my left cylinder at TDC on compression. Well I re torqued everything and there is plenty of adjustment. Sure glad I caught my mistake before I spent big money.
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2:1 ratio on crank and cam rotation. Swell. Now he tells me! ;D
Good you caught this now. Otherwise, you'd be buying new big n' little o-rings, a pricey head gasket and a pair of pushrod tube seals. Plus, if you don't have one, a torque wrench... which you should buy anyway.
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You do know there are marks on the flywheel for this? There's a black rubber plug behind the left carburetor covering a 'window' to view the flywheel. There's a tab on the flywheel with OT marked on it - translation = Top Dead Center.
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Yea I know, I just got caught up in cranking it around and watching the easy to see mark on the cam chain, lets face it, I had a brain fart but recovered before any damage was done.
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I just had a set of 1979 R-65 heads re-done (and updated). Contact Leo Goff at Memphis Motor Werks. Not cheap but I had the exhaust stubs re-done and the heads rebuilt and they came back in about 6 weeks looking like some kind of Mechanical Pornography. The bike is finished and it runs like a champ. Excellent Value for Money. Highly Recommend. :) Very Professional.
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Dang, I always put my thumb in the sparkplug hole and when I feel compression I poke a drinking straw through and use it as a TDC indicator as I "bump" it...
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Hurray! I'm not the only one to use the thumb over the sparkplug hole - feel for compression - check for TDC with a straw approach. I even have a dedicated straw.
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Hurray! I'm not the only one to use the thumb over the sparkplug hole - feel for compression - check for TDC with a straw approach. I even have a dedicated straw.
I still have one of these ancient things (micro-time) dating from the time when setting timing was a black art.
books.google.com.au/books?id=SNgDAAAAMBAJ
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Tony, I too have a vintage Micro-Time tool. Still have the booklet that came with it -giving what mark on the plunger should be 'locked in' for timing a Yamaha DT-1, etc. Been in my tool chest for over 40 years.
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Tony, I too have a vintage Micro-Time tool. Still have the booklet that came with it -giving what mark on the plunger should be 'locked in' for timing a Yamaha DT-1, etc. Been in my tool chest for over 40 years.
Mine was purchased to use on a Bultaco Sherpa-T, 1975 seems a long, long way away now.....
but i think you are a few years older than me.
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Some years ago we had a discussion about accurately determining TDC and the Micro tool was mentioned. I punched the numbers into a piston position calculator ad determined it would be a challenge to make it work very accurately as at TDC a 1 deg rotation of the crankshaft produces only 0.00024" of piston movement which is less than bearing clearances.
If anyone wants to use the tool for it's intended purpose the static timing mark at 6 Deg is 0.00848" below TDC. It would be more accurate at this piston position as 1 deg error now produces approx. 3 thou of piston movement.
When I crunch these numbers it always surprises me how very close to TDC the piston is when the fire is lit by the spark. Even at full advance the piston is only 0.232" below TDC
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Tony, I too have a vintage Micro-Time tool. Still have the booklet that came with it -giving what mark on the plunger should be 'locked in' for timing a Yamaha DT-1, etc. Been in my tool chest for over 40 years.
Mine was purchased to use on a Bultaco Sherpa-T, 1975 seems a long, long way away now.....
but i think you are a few years older than me.
That was uncalled for. Be nice to your elders ;)