"Last time I did my /5 I used hylomar on the base gaskets. They "weeped" eventually anyway. I decided, screw it and just cleaned the bases when I washed the bike. " dreibond/yamabond is the stuff to use, it should give you a completly dry joint, i used to use Hylomar, not any more.
Here's the small ding at the base of the cylinder I was referring to. I was a freakin idiot and let the piston rod drop. Any ideas on how to fix? I don't have the time to remove the whole engine block and emery paper/glass fix it at the moment. Should I just lightly coat the cylinder base gasket with sealant and pray it doesnt leak?
We can't see much in your foto. Is it just the shiny dot under the rod? That looks like it is only a little thing on the champhered edge of the bore. I believe the sealing surface of concern is the flat area the shim/gasket goes and the cylinder base mounts on the face of the block. If there is any RAISED area associated with this ding then use some sand paper or something to lower the raised edge. If you have a flat edge tool that can be placed against the block you can check it. It's easier to see sometimes in sheet metal like dings in fenders. A dent will have a raised edge. You can fill dents all day long and they will look like crap because you can see the raised edge. If the rod merely fell it probably didn't do any damage you can't fix. Look for a raised edge.
Thanks for the advice, Disston (is that the name you prefer to go by?). I'll try a touch of emery paper if there is any raised edge from the dent. It's pretty small, and if there's any raise, it's probably less than a 1/10 of a millimeter. The actual flat area where the gasket goes looks to be in good condition (e.g. no pitting) , so I'm not concerned about that surface. See my photos on the first page for that.
Call me disston or by my name Charlie. I have also been called Wildman, Chrome, Sir Charles and Uncle Charlie. Any very tiny amount of distortion is easily taken care of by the Yamabond or what ever is used for glue. This can be not good if a bike is stored with the rod resting on the block for some time because the rod will bounce up and down repeatedly. This issue is mentioned in all the manuals. The BMW shop manual even mentions it. I turned up the light on my computer and I can see now no damage.
Here's a closer look. It's the ding right below the piston rod. It's essentially messed up the bevel.
I got clumsy stripping mine down and mine are worse. Any raised metal in the bore will keep the cylinder from sliding into the Block. 320 or even 400 grit emery cloth should do. it's a heavy cloth backed sheet. Won't shed a lot of grit. Wet it with oil to help keep it from loading and to catch particles. Dress out the ding so there is no high metal, wipe clean with a solvent dampened rag and you are done. Your sealant will take care of the face of the area...so long as nothing is high. While you have the carbs off do your handlebar service. Take apart the throttle cam gear, clean and lube. inspect for the degree of wear on the gear teeth. These parts are getting costly, take good care of them The twist grip will slide off. Clean the inside and the bar and lube lightly. Remove the lever, clean and lube. Inspect the cable for broken strands right at the barrel. These are caused by lack of lubrication. The barrel must pivot freely in the lever...if it bends instead of pivoting the metal of the strands fatigues and then the strands break. it's a commoner problem on clutch side. So pull the clutch lever, inspect, clean and lube. If any broken strands found, order a cable. You is riding on borrowed time there. Novus plastic polish will get the oxidation off the switchgear (exterior) and make 'em look like new. looked for bad rubber boots and make a shopping list (the ones on the speedo cable at the transmission and the big one around swing arm/tranny are critical. They keep water out of the oil. bad boots here can get expensive). I'd say if you have the tube of sealant in your hand, use it. Save your bread for renewing bits of rubber, a set of conrod bolts so you can check those bearings, etc. Worst case you will get a poor seal and weepage at the bases. it's a cosmetic thing and cleans up easily. If you didn't have it I would heed some people suggestions for newer sealants that work well. get some Honda Moly 60 (honda MC shop) and do the tranny spline lube if it is due. Also lube the drive splines in the rear wheel. I've been using the Nickel based or an aluminum based anti-seize on those but am rethinking it. Will probably cook up my own anti-seize/moly blend. Then do your chassis lube. if you don't have a push greaser get one at a chainsaw shop, throw away the grease and load it with a good moly EP grease. I just use an injection tip on my regular grease gun. if you push the bike over using it you will be hating life. Owning a set of go/no-go feeler gauges will make you happy. Feeler gauges take some feel to use correctly. I've worked as a machinist and am quite good with them, used to buy gauge stock by the roll. I use the go/no-go almost exclusively in the garage. So much easier and if you haven't developed skill with feeler gauges they will get you perfect results anyhow. Pretty cheap too. use them for the ring gap measurements and later for setting valves. Get a small tube of silicone dielectric grease. Will last you forever. Use it when replacing rubber boots (a tiny smear around the inside) and most importantly on the spark plug boots, both ends. Also good on regular household light bulb threads. makes changing bulbs especially in can lights and sconces a breeze. An advantage of having the pistons hot tanked and the rods out is that you can then get nutso balancing them. Remember, BMW owners are totally anal/obsessive wherever possible. Time to start fitting in. I balance my pistons/rings/rods/bearings/bolt assemblies to less than a gram side to side. On my current build the (new) pistons were perfect but the rods were about 2.5 grams out. That is in spec but I took them to less than a gram because I can and I like smooth engines. Combine this with go/no-go gauges on the valves and very careful power balancing of the carbs and the motor will be as smooth as it ever can be. Any vibration left is coming from the wheels and tires for the most part. if you're still waiting for parts do the brake service. Tuning the /5 front drum is a black art as far as I'm concerned. It's one evil MOFO and I had at least one crash because of the way it gets sticky when wet. Eventually replaced it with a /6 single disk which wasn't much any stronger but handled water better. BUT, the drum looks right on the bike, especially if the chrome hub cap is in good condition. Just watch your ass, especially if it's damp. On my /7 I'm collecting the parts to refit the stupid rear disk with a drum. Again, same braking power but in the rear you get better serviceability and with discs in the front water is less of an issue. The best way to make your front brake more powerful is called a dynabee. remove the battery box and inspect for bad paint and corrosion. it's a rust magnet. Inspect inside of frame near the battery as well. inspect the rear subframe just behind the flanges welded on the underside (at the rear) for cracks. Overloading a rear rack will cause damage here. popular mod was welding in some extensions to these flanges. Front fenders crack at the front mounting holes by the fork. I modified many front fenders with a strip of aluminum and ample epoxy fiberglass on the inside. (you must use epoxy, not a polyester resin). Renew cracked rubber washers. A lot cheaper from a hardware store. Polish the crap out of the turn signal housings and the rims. looks so right. On the shopping list add an H4 headlight conversion and a repro headlight guard. The gaurd looks right and saves those expensive headlight chrome rings if the bike falls over. Think about an alternator upgrade if it hasn't been done. With a shopping list and thinking about it a lot, the parts will come to you. (but buy the headlight guard now)
Took off the pistons and their rings last night (properly labeled, wrapped and packaged in ziplock baggy). I'm currently soaking the pistons in Marvel mystery oil, per recommendation from an airhead buddy. Hit the crowns lightly with 3M scotchbrite and it's pulling the carbon right off. I have a nylon brush as well to pull of some carbon. Going to check the ring gaps tonight. If all rings are in spec, they will just be cleaned up and put back in the piston grooves. BTW - I used this Ural guide for removing the piston pin, worked great! 3/8'' PVC is too small though, you really need 1/2'' or larger. Don't quote me on that, as I only had 3/8'' schedule 40 PVC and had to improvise with some other tools to get the pins out. http://myural.com/R&Ipistons&rings.htm
Wouldn't ya know it, this dummy lost track of which cylinder is left and right (sitting on the bike, looking down). Is there anyway to determine left or right cylinder from the numbers on the cylinders?
The value of a $1.00 sharpie marker can be amplified many times by the amount of grief such a marker can save when used to mark parts. A digital camera is a modern marvel when used to record disassembly and the images can be extremely useful for reassembly. For the ding, unless you want abrasive grit in your engine, don't use sandpaper. Use a small file to remove the raised section of metal around the ding. Hardware stores and Harbor Freight stores sell such files. Some duct or other tape will help keep any aluminum filings out of the crankcase - if you are careful. I wish you luck!
thanks. I have everything in baggies and properly labeled with a sharpie, specific to the side of the engine. I'm very good at documenting with a camera, too, this just slipped my mind
All rings are out of spec. Here is my 3rd/oil ring and a .40mm feeler. It looks like it's out of spec about .10mm more. The top and middle ring are out of spec by .5-.15mm as well. Any recs for good rings? This probably explains why I had tons of black carbon build up near the push rod seals and on the backs of the Bings. :/
Um...no. Check your breather setup. The rings are close enough, Install, drive, enjoy. I just put a caliper on a business card, it's .25mm thick. A hair plucked from an eyebrow is .05 mm. So you're off the thickness of two eyebrow hairs. Carbon builds up on the ends of rings. The error in question is completely trivial in light of this. You have so many bigger fish to fry.
The cylinders are always dirtier on the front. I wouldn't do like Duane Asherman and think you are measuring cylinder wear by the ring gap. The ring gap was often out of spec too big when the bike was brand new. The cylinders were often worn out brand new according to BMW. Some experience with these bikes will have you realizing that many of their specs are optimistically on the tight side. They never ran many of their specs as tight as they claim. Why measure the rod bearings. There is only one size available. Look at them. If they look OK, they are OK. The problem with that is you have to know how they look brand new but . . . . New rings? It's a toss up. I think I would keep those. The thing that wears is the top of the top ring groove in the piston. You can see it with a magnifying glass if it is worn. New pistons are the only fix for that. My R100 had one wearing but it had 101,000 miles on it. I would probably just wash the cylinders. I might dingle berry a high mileage setup but I try not to. Hones? I have never used anything but Sunnen. IMO they are so much better than other hones I don't even go there. Other brand hones aren't really even hones IMO. Same deal with Sunnen valve guide hones but then you have to get your guide ID undersized! The rocker arms on your bike are often toast with low mileage. The bushing ID wears. The bushing OD wears and the bushing start spinning in the rocker arms and wear the rocker arms out and at the same time wear the rocker arm shafts out. I have seen it numerous times. They are rarely in good shape when I look at them. The best way to fix those is to get later rocker arms. They have their issues but they are still are WAY better than the bushed setup.
Ha, not the direction, I'm not that dense. I'm talking about which cylinder goes on which side of the engine block.
Care to elaborate? The rings are out of spec per the manual. How do people determine when it's time to replace rings if we aren't going by a guide, such a Hayne's?
I go by leak down, compression test, and inspection. The piston tops look good. A lot of oil can get by the guides. How do they feel? Like I said earlier, lots of them came out of spec brand new.
What do you mean how do they feel? I've never done this before so I have no idea on what to go by other than advice here and the hayne's, ha