The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Lucky_Lou on January 24, 2009, 01:28:48 PM
-
Ok still cannot get the engine to run satifactoraly n/s pot will not run got spark tried a carb of my brothers bike (81 r65) so rulling ignition and mixture probs out im going to pull the head off even though my guage says ive got compression when i look through the spark plug hole i think i see oil and gunk not happy with it anyway.
As i dont know the history of the bike (previous owner riding in the sky) is there anyway of telling if the head has been converted to unleaded its a 1980 r65
Ta Lou
-
Unless you have the paperwork from the previous owner indicating so, it usually isn't possible to know without pulling the heads off to check - and even then it could be a bit of guesswork depending on how long ago it was done. One thing for certain, these bikes come originally with 7mm diameter valve stems. Sometimes when people have done a valve job and replaced the seats, they've also had the valve guides, valves, and keepers replaced with 8mm diameter valves - which is what the larger R80 and R100 bikes use. This requires a bit more machining work to accomodate the larger guides and valves.
If your valve stems are 8mm diameter, that would probably be a semi-reasonable indication that someone had replaced them, and if they did replace them they likely did the valve seats as well. Aside from this indicator, there aren't any other ways that I know of without pulling the heads and visually examining the seats and valve heads for wear, etc.
If you're still having issues with getting her to run right, maybe it is time to look at the valves anyway.
What does your gauge show for PSI? The best way to measure it is with the carbs removed from the rubber intake boot, and crank the engine 5 or 6 times around. If your not up around 130 PSI then something is leaking somewhere. Sometimes on higher mileage bikes, or bikes which have been run a long time with an incorrect mixture will get heavy carbon deposits on the top of the piston and around the valves, which can prevent the valves from fully seating/closing.
-
OFF with the head! Not really a titanic job on an AirHead. Look for a knife edge on the circumference of the valves, Worn slots on the stem where the keepers get a hold and a recessed seat in the head itself. If you find any of these you did the right thing! Might as well have a good look at the rocker needle bearings while your at it. Photos! We love photos.
rich
-
What does your gauge show for PSI? The best way to measure it is with the carbs removed from the rubber intake boot, and crank the engine 5 or 6 times around. If your not up around 130 PSI then something is leaking somewhere. Sometimes on higher mileage bikes, or bikes which have been run a long time with an incorrect mixture will get heavy carbon deposits on the top of the piston and around the valves, which can prevent the valves from fully seating/closing.
The bike has only got 30K miles on it. When i did the compression test it cranked at 140 then whent up to 180 after several turns.........?? is that too high could it be a blockage in the down pipe?? i put new silencers on it i will check it before i pull the head off will sort some photos out when i strip it next week
Ta Lou
-
Ok photos....still cannot load em up ????? no blockage on exaust....
first one shows the bore with the first ring in place it has a 28thou gap so no problem there
no wear on bore just tickled it with a honer before reassembley.
http://s278.photobucket.com/albums/kk113/luckyloudiamond/?action=view¤t=000_0006.jpg
second one shows the piston no wear just browning on top ?? is that normal..... so back to square one.
http://s278.photobucket.com/albums/kk113/luckyloudiamond/?action=view¤t=000_0005.jpg
I think ill strobe the ignition timeing but if it firers on one it should fire on both Valves seem ok so realy dont know what to try next
Lou
-
.028 ring end-gap sounds a bit excessive to me. I show the compression and scraper rings to be .0197 max, and .0158 for the oil ring. I just re-ringed the '82 LS and had about .025 gap on the oil ring and it smoked pretty bad when warmed up...
-
Curious about the left piston. Varnish of oil is what it looks like. Aren't there oil relief holes in the oil ring groove, under the oil ring? What did they look like? clogged, open?
rich
-
While reading through the thread I didn't see any reference to valve clearances. If this hasn't been checked yet that is where I would look if there is spark, fuel & compression. Valves clearances tend to be reduced with wear, sometimes to the point that the beast just won't run at all.
I would rather hear a little valve clatter than none at all.
-
+1 with Justin - if the end gap is .028" I think that is definitely above spec, and that cylinder does look like there has been some oil getting by. Though if you were getting much oil past the rings I'd expect that cylinder to definitely do some smoking. What do the plugs look like on each side? Have you put new plugs in and run the bike for a few minutes, and then shut it down/pulled the plugs ? But, before we dive into the nuances of trying to read plugs, I think that engine could benefit from some new rings - make sure that you don't line up all the ring gaps together - best to put them 90-120 degrees apart. What were the valve clearances before you pulled the head off? Can you post pics of the head and valves?
Still, from what I see, I would think that the engine wouldn't have the difficulties in running that you indicate.
Hmm
[smiley=1drink.gif]
-
While reading through the thread I didn't see any reference to valve clearances. If this hasn't been checked yet that is where I would look if there is spark, fuel & compression. Valves clearances tend to be reduced with wear, sometimes to the point that the beast just won't run at all.
I would rather hear a little valve clatter than none at all.
forgot to check it brfore stripping will check the other side and report back on that one the vavle stems are 7mm so looks like it hasnt been converted ill pull the valves out in the next couple of days depending on work commitments and post a couple of photo links
There is an "oil varnish" on the skirt but no scoreing or scrape marks
ill check the oil ring drain holes before i rebuild it
I found 3 or 4 sets of used plugs in the fairing pocket so this could be an issue
thanks for everyones input on this
Lou
-
Managed to blag a Clymer manual ring end gap should be 18thou going to replace em anyway
couple of pictures first one shows exaust valve seat pretty crappy
http://s278.photobucket.com/albums/kk113/luckyloudiamond/?action=view¤t=000_0007.jpg
second one shows it cleaned up prior to regrinding the seat, cannot tell if its been converted?
http://s278.photobucket.com/albums/kk113/luckyloudiamond/?action=view¤t=000_0011.jpg
the valves themselves look ok have cleaned up nicely and reseated like new as have the pistons
just waiting fer the rings to rebuild it.
Lou
-
Best price I found for rings was Moto-Bins...
-
While reading through the thread I didn't see any reference to valve clearances. If this hasn't been checked yet that is where I would look if there is spark, fuel & compression. Valves clearances tend to be reduced with wear, sometimes to the point that the beast just won't run at all.
I would rather hear a little valve clatter than none at all.
forgot to check it brfore stripping will check the other side and report back on that one the vavle stems are 7mm so looks like it hasnt been converted ill pull the valves out in the next couple of days depending on work commitments and post a couple of photo links
There is an "oil varnish" on the skirt but no scoreing or scrape marks
ill check the oil ring drain holes before i rebuild it
I found 3 or 4 sets of used plugs in the fairing pocket so this could be an issue
thanks for everyones input on this
Lou
rebuilt one side and set valve clearance to 4 and 8 retested compression@ 130 other side(not touched it yet ) reads 160?? with 4thou on the exaust v/v and nowt on the inlet will strip this side at the weekend.
Lou
-
Looks like the were pretty heavily carboned-up ! With a bit of luck a good cleanup on the other side will net similar results, and you'll seen have her her purring like a kitten again... well, OK, "purr" isn't quite the right word when it comes to these engines, but you know what I mean!
:)
With tight valve lash like that it is no wonder that the compression readings are high - valves clearance have to be close to spec to be meaningful.
-
Ive stripped the other side down today(being snowed in isnt all bad news) her are a few pictures the whole thing is much better on that side
the piston looks pretty good compaired with the other side
http://s278.photobucket.com/albums/kk113/luckyloudiamond/?action=view¤t=000_0007-1.jpg
the head isnt as crappy as the other one
http://s278.photobucket.com/albums/kk113/luckyloudiamond/?action=view¤t=000_0008.jpg
the valve seats are better than the other side
http://s278.photobucket.com/albums/kk113/luckyloudiamond/?action=view¤t=000_0009.jpg
hopeing this will crack the problem should have it built up at the weekend
more snow please so i can tinker with my bike
http://s278.photobucket.com/albums/kk113/luckyloudiamond/?action=view¤t=000_0006-1.jpg
Lou