a barn fresh r50/5 - Page 3

bmwblake · 04-30-2012, 05:49 PM

Quote:

Originally Posted by disston

Boring to next oversize for the cylinders will be the minimum I believe. It may need taking to the second size. Those pits look pretty deep. What is the line we see in the bottom of the cylinder? The circlip was completely missing? Those pits were caused by water I think. If saving the cylinders by boring is possible they will have to have new, or another, set of pistons. You might do better with another pair of cylinders all together.

the line in the bottom of the cylinder was caused by the wrist pin moving outward from where it should be. a circlip on one side of the pin was missing and i didn't find it in the pan. i'm guessing it was left out on assembly by the last guy working. there was a bit of rust in the cylinders but nothing that made me want to toss them other than the giant scrape from the wrist pin.

Quote:

Originally Posted by disston

About your comment, "i'm not sure if it's related but there's also a good bit of slip in the connecting rod on that side." Do you mean the rod big end seems loose? After this much investigation and all the damage you have already found you should take the rods out. They can be checked for size at a machine shop and when reinstalled use new bolts and new big end bearings. When they are out you will be able to see the condition of the crank at the rod journals at least.

You need the special rod bolt tool to remove them.

Everything is related. Was water in that cylinder? What does the other side look like? If water got in the lower end of the engine there may be damage to the crank. you need to check this.

there is front to back play in the rod big end on the right. i plan to remove it and get new bearings. no evidence of water in the bottom end.

i was hoping to keep this an r50, but looking around for parts there are way more r75 and r60 parts. that makes sense when you look at how few r50 bikes were produced.
if anybody has an r50 top end laying around give me a shout.

disston · 05-01-2012, 05:14 AM

I have an R90 so I think there are more R50 parts and 900 cylinders are rare. I guess it's a matter of one's view point.

bmwblake · 05-01-2012, 06:18 AM

it's a 79 bultaco sherpa. it's waiting in line for some attention. i've been ignoring it for months.

Quote:

Originally Posted by Sniper X

Cool resto! Is the blue framer in the background a Montessa Cota 247 Trials bike per chance?

bmwblake · 05-14-2012, 07:31 AM

this weekend i pulled the front forks apart and was met with the nastiest smelling oil i've ever encountered. i replaced the fork seals and the rubber bits in the bottom of the forks. here's what they had become

i need to drop the springs back in and add some oil and the new fork boots and the forks will be done.

lucky23 · 05-14-2012, 09:33 AM

Quote:

on a side note, while cleaning up the bottom of the center stand with a grinder to fill in some holes, i managed to hit my left index finger with the flap wheel. it now looks eerily similar to the gouge in the right cylinder.

safety third. i'm renewed my policy on wearing gloves while grinding.

Uuuggghhh, those flap wheel burns HURT like hell...I've done the same thing.

disston · 05-14-2012, 09:40 AM

It's good to get fresh oil in the forks. If they seem to not always go up and down easily then you may have to check more but the fresh oil and some parts is a good start. I just wanted to say that the old oil always looks like that. It was in there too long but nobody changes it often enough.

bmwblake · 05-22-2012, 07:01 AM

i have a used set of barrels, pistons, heads coming my way.

i also ran into an old friend this weekend that happens to have a media blaster i can use. that answers the question of how to best clean the frame and all the other painted parts that have corrosion.

datchew · 05-22-2012, 03:52 PM

Quote:

Originally Posted by bmwblake

it seems that someone forgot to put in a wrist pin circlip on one side of the right piston. any thoughts on repair methods would be appreciated.

You didn't happen to buy this bike from Stagehand did you?

datchew · 05-22-2012, 03:53 PM

Quote:

Originally Posted by bmwblake

i have a used set of barrels, pistons, heads coming my way.

i also ran into an old friend this weekend that happens to have a media blaster i can use. that answers the question of how to best clean the frame and all the other painted parts that have corrosion.

find a local sandblasting joint. buy 2 bags of play sand from the local lowes/home depot. pay the guy $20 + 12 pack of bud. Blast down to bare metal.

check for cracks.

strive to prime and paint before further corrosion sets in.

disston · 05-23-2012, 05:05 PM

That cylinder with a single scratch in it also looks like it is quit pitted. Just from the photo I'd say it was not usable as is.

bmwblake · 05-23-2012, 06:02 PM

agreed. while i didn't get the bike from stagehand it appears to have suffered at the hands of an owner who also has wristpin clips remaining on the bench.
looks like my new pistons and such will be here on 5/29.

matt, that's the route i'm headed with blasting though i doubt i'll even have to buy the bud.

Quote:

Originally Posted by disston

That cylinder with a single scratch in it also looks like it is quit pitted. Just from the photo I'd say it was not usable as is.

Strongwater · 05-23-2012, 06:43 PM

Great news on the new pistons and jugs!

bmwblake · 06-20-2012, 11:09 AM

i need some assistance with an issue i found with the right connecting rod. it had what i thought was an unacceptable amount of play front to back. i pulled the rod and measured the bearing shell at 2.04 mm and the end to end measure of 48mm. they don't show any concerning wear.

i put some plastigauge in and reassembled. the plastigauge showed a .051 measurement. this is in spec according the manual.

am i just being paranoid about the play in the rod? is there something else i should be checking?

datchew · 06-20-2012, 07:08 PM

Quote:

Originally Posted by bmwblake

though i doubt i'll even have to buy the bud.

Not buying bud will help to maintain your reputation.

coastranger · 06-22-2012, 06:46 AM

Quote:

Originally Posted by bmwblake

i need some assistance with an issue i found with the right connecting rod. it had what i thought was an unacceptable amount of play front to back. i pulled the rod and measured the bearing shell at 2.04 mm and the end to end measure of 48mm. they don't show any concerning wear.

i put some plastigauge in and reassembled. the plastigauge showed a .051 measurement. this is in spec according the manual.

am i just being paranoid about the play in the rod? is there something else i should be checking?

front to back is ok, its the in and out play thats no good

05-01-2012, 05:14 AM	#32
disston ShadeTreeExpert Joined: Mar 2011 Location: Silver Spring, Md Oddometer: 5,222	I have an R90 so I think there are more R50 parts and 900 cylinders are rare. I guess it's a matter of one's view point. __________________ Never memorize something you can look up. ---Albert Einstein

05-14-2012, 09:40 AM	#36
disston ShadeTreeExpert Joined: Mar 2011 Location: Silver Spring, Md Oddometer: 5,222	It's good to get fresh oil in the forks. If they seem to not always go up and down easily then you may have to check more but the fresh oil and some parts is a good start. I just wanted to say that the old oil always looks like that. It was in there too long but nobody changes it often enough. __________________ Never memorize something you can look up. ---Albert Einstein

05-23-2012, 05:05 PM	#40
disston ShadeTreeExpert Joined: Mar 2011 Location: Silver Spring, Md Oddometer: 5,222	That cylinder with a single scratch in it also looks like it is quit pitted. Just from the photo I'd say it was not usable as is. __________________ Never memorize something you can look up. ---Albert Einstein

05-23-2012, 06:43 PM	#42
Strongwater Adventurer Joined: Mar 2012 Location: Wash DC metro Oddometer: 23	Great news on the new pistons and jugs! __________________ "It's life Jim. But not as we know it." "Hey, easy man, I've got a beverage here." 1988 FLHTP - Caddilac pearl white road sofa. 1975 R75/6 - in boxes.

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05-14-2012, 07:31 AM	#34
bmwblake ^OP upside down parker Joined: Mar 2004 Location: nashville, tn Oddometer: 3,238	this weekend i pulled the front forks apart and was met with the nastiest smelling oil i've ever encountered. i replaced the fork seals and the rubber bits in the bottom of the forks. here's what they had become i need to drop the springs back in and add some oil and the new fork boots and the forks will be done.

05-22-2012, 07:01 AM	#37
bmwblake ^OP upside down parker Joined: Mar 2004 Location: nashville, tn Oddometer: 3,238	i have a used set of barrels, pistons, heads coming my way. i also ran into an old friend this weekend that happens to have a media blaster i can use. that answers the question of how to best clean the frame and all the other painted parts that have corrosion.

06-20-2012, 11:09 AM	#43
bmwblake ^OP upside down parker Joined: Mar 2004 Location: nashville, tn Oddometer: 3,238	i need some assistance with an issue i found with the right connecting rod. it had what i thought was an unacceptable amount of play front to back. i pulled the rod and measured the bearing shell at 2.04 mm and the end to end measure of 48mm. they don't show any concerning wear. i put some plastigauge in and reassembled. the plastigauge showed a .051 measurement. this is in spec according the manual. am i just being paranoid about the play in the rod? is there something else i should be checking?