The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: ShutterPilot on May 08, 2014, 04:18:45 PM
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So, boys and girls, I'm taking off the heads to go get head work done on my '81 R65.
Surprisingly, the exhaust nuts came off with little resistance and no damage to the head threads (although, the left finned nut acted as soft as butter and "peeled" away at the fins - hmm, mebbe some aftermarket nut as it even looks a different color than the right side)
Anywhoo...
Clymers says"...pull header forward out of the head" or somesuch. Now, I'm pretty sure all bolts, clamps etc are loose/removed, but the header doesn't budge from out of the head. I've even done propane torch to the head threads, sucking liquid wrench into the teeny gap between the header and head port. Then a few hard blows with a 5 pound hammer onto a 2x4 wedged up against the rear crossover.
No joy. It appears the left side moves a little, so maybe only the right side holding on tight.
Any tips?
Poking around here and elsewhere turns up the usual "soak with ATF/acetone mix for several days and apply heat", which I've spent hours kinda replicating with liquid wrench and propane.
Any other ideas?
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You need to get the cross over pipes loose, before the pipes will come out of the head .
Had the same problem with my '81 R65 the first time I had to remove the pipes .
Ended up cutting the front cross over pipe, it wouldn't come loose from either header pipe .
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POR works well - my right header was so stuck it took a welding shop 20 minutes to dislodge it - be patient!
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I was able to remove my headers without loosening the crossovers. Biggest problem I had was that if one side started to budge out ahead of the other the headers would bind in place. I'd suggest tapping the pipes all the way into the head to start. It might help shock them loose (like tightening a stuck bolt) and will also help ensure the pipes are in-line with the heads and have no striction.
The weight of the pipes also makes them fall at the back end and bind in the head... but the pipe ends give you some good leverage. Gently wiggle them around to try and break the bond.
Also, try working alongside each side of the bike until both pipes can move, rather than doing it all at once from the start. Careful with the hammers. Even a plastic hammer can put a dent in the thin walled exhaust pipe (as I unfortunately know).
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Thanks for these tips. I need to keep everything original, so I'm trying to be extra careful and not have to cut anything.
I mixed up and applied with a squeeze bottle some atf/acetone mix to it last night. I'll soak it with that again after work, then try hitting it with the torch a bit to see of anything budges.
Both front and rear crossovers AND mufflers all still in place, as none of the joints look even close to being anything other than all-in-one welded at this point. Maybe this is creating a pinch problem? I've been trying to use the muffler end as a lever to wiggle the head end around a little, but so far it feels solid, just like everything is still bolted up.
And I'm really regretting not taking Montmil's advice awhile ago and procuring a china freight lift. I am SO tired of working on the floor...
I'll keep you posted as to my progress (if any!), and if anyone else has thoughts to offer, please keep 'em coming.
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The mufflers will give you a lot of pinch as they sag. However, if the slots in the muffler mounts leave you some room to slide everything forward, I'd probably put the muffler mounting bolts back in loosely to help support everything.
Also, the clamps that go under the rear motor mount nuts... I wouldnt count on the pipes sliding through them nicely. If you haven't already, pop them off the motor mount (you'll probably have to tap the mount from side to side a bit).
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The mufflers should come off with just a wee bit of wiggle work.
Loosen all clamps -plenty of slack.
I removed the headers and x-overs off my '81 as a "unit" due to rusted x-over connections. I used a dead blow mallet and a small piece of soft pine to alternately tap the ends of the header pipes. Try to align the pipe at the cylinder head exit prior to a few well placed taps.' After the system came free, it was a matter of tilting the bike to one side then the other to get the pipes away from the bike.
Use caution with the flame / acetone / atf combo. Fumes might be unhealthy. Or there's always the chance of setting your bike on fire. Quoting a famous movie doctor's creation, "Fire bad!"
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Finally!
Mixed up some ATF/Acetone and kept squirting in there over the course of 2 days.
Also, finally got the mufflers off. That really helped, as I believe they were indeed causing binding (as I couldn't be on both ends of the bike at the same time)
Once the mufflers were off, I lightly tapped the headers BACK into the heads with one of those rubber mallets filled with BBs. Once the right side moved, I knew it was free.
Light alternate tapping on the header ends where the mufflers go on, right then left then right etc, eventually freed the headers from the exhaust port.
The crossovers would not budge tho, and now I realize 2 of the welded crossover clamp bolts were missing (1 ea from front and rear), and I managed to knock off a 3rd from the rear when my 2x4 block slipped and clipped it back when I first began and was wailing on it a bit. :-[
So, while all this allowed me to get the heads off - nice and clean looking BTW - the header/Xover combo is still all one piece, and I can't get it to clear the centerstand. I've got the Xovers soaking in ATF mix, hoping they'll let loose so I can remove the pipes, as it looks like I need to replace the Xovers anyways due to the missing clamp bolts.
Meanwhile, Bombars has the heads and can start work on 'em anyways.
Another question - how best to clean the pistons?
Thanks for everyones help on this!
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I soaked my pistons in Hydroseal for a few days. That softened up the carbon deposits enough that they were pretty easy to scrub off.
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Go back and re-read my last post. You can get the header pipes and x-overs clear of the bike while all in one unit.
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Hi Montmil,
Dude, I tried, but unless I'm not "wrestling" enough, I can't seem to get the pipes anywhere close to going over the centerstand. They interfere on both sides at once, and I tried CS up and down.
Of course, I can always just remove the CS - and since its pronated way beyond center (see my avatar photo), I should anyways so I can get the tangs welded up a bit.
Good news is that at least the front left Xover connection is loose from my wrangling.
I've put a goodly dent in the rear Xover, right at the right side junction. I'm hoping a machine shop can put the header connector back round again.
But I'm excited to be getting new seats, valves, springs, guides etc for the head, and along with new rings I'm hoping leakdown gets into the single digits and we'll get some decent power of the mill.
Provided I can get it all back together again!
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" I can't seem to get the pipes anywhere close to going over the centerstand." Well, no doubt there. :-D
Whew... Bike on centerstand. Pipes laying on the floor. You may need someone to tip the bike up on one leg of the centerstand while you slide n' rotate the system under it. Tip bike the other way and repeat. Done.
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Or take the bike off the center stand and fenagel the pipes out from underneath the bike.
Can't tell you how I did it specifically, but I did take the pipes out from under the bike on my lonesome without leaning it to and fro.
You could also consider leaning the bike over on one of the valve covers. Be gentle and put a towel under the aluminium... and maybe take off the carb bowls to avoid accidental flooding.
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Thanks guys...I know I sound stupid.
What I mean to say is that the header pipes won't clear the mount bolts at the top of the center stand - ie: the centerstand mount is wider than the header span. Its trapped in the air between the top of the center stand and the bottom of the cylinder, if that makes sense. If I could drop it to the floor there'd be no problem.
I've not been able to get back to it for a couple days. When I return, I may just remove the centerstand and it should drop to the floor.
Now - anyone ever made a dented crossover connector on the downpipe back round again?
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Now - anyone ever made a dented crossover connector on the downpipe back round again?
I think it's a pain to get the pipes, crossed over, off around the center stand, but I've done it. Now I have nice stainless pipes with anti-seize and it's pretty easy to take them apart and put them back together.
Maybe you could find one of those exhaust pipe expanders small enough to fit into the cross-over opening and expand it back round.
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Exhaust pipe expanders should be available at your local auto chain. Pay a deposit to rent the tool, get all your money back when you return it.
If the dent is in the middle of the pipe you could try finding a socket with an OD equal to or slightly smaller than the crossover's ID. Put a long extension on it and bang it through with a hammer. (start with plastic or rubber)
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Never thought of using an expander - Duh!
Thanks guys.
I'm going to revisit the header removal this weekend, with more patience and less emotion to see if a cooler head will prevail, rather than all the ratsin and fratsin going on last week..
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... If the dent is in the middle of the pipe you could try finding a socket with an OD equal to or slightly smaller than the crossover's ID. Put a long extension on it and bang it through with a hammer. (start with plastic or rubber)
Dunno, but I'd be mighty hesitant to attempt this. What would be the odds that the socket would become tightly lodged in the pipe due to carbon build up, a small dimple in the pipe, dead mouse, whatever. Yank on that extension and all you may get out is... the extension. Pound it the other way?
You know many Airhead riders buy a chrome vacuum cleaner wand, trim it and slap in on. What's that Homer Simpson says...
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi196.photobucket.com%2Falbums%2Faa1%2Fmontmil%2FFunny%2520Pics%2FHomerDOH_zps2d63ca37.jpg&hash=fcaf54d838abec60c11a1b6ac86d51ebad5122c4) (http://s196.photobucket.com/user/montmil/media/Funny%20Pics/HomerDOH_zps2d63ca37.jpg.html)
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A bit o grease might help, as would shooting some solvent and paper towel through the pipe to clean things up. I shoulda said a deep socket, as it should be long enough that it won't twist much and further ruin the pipe.
And yeah, if it gets stuck, tap it out with a drift or extension from the other side. Free and easy to try.
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I used a cleaning product (Simple Green) to clean my pistons after I had removed them from the rods. Put just enough in a pan to wet the tops of the inverted pistons and let them soak over night. It did a good job of loosening the carbon and I finished off with a piece of hard wood as a scraper. I was careful to rinse thoroughly and spray with WD40. I also did the heads.
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Thanks, Gus on the piston cleaning. Clymers says to take care NOT to remove the carbon ring at the piston crown, nor on the top of the cylinder, or excessive oil usage may occur afterwards.
What?! I'm assuming that with all new rings and scrubbers, that shouldn't matter, so that's how I'm proceeding, unless someone has some tales of woe otherwise.
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Hello !
The pistons have, above the upper most ring, a set of small rings one can easily remove by scrubbing.
This is why it is recommended to leave the deposit alone in this area.
I confirm that too clean piston, without "the" little rings, increase oil consumption...
I've in my garage a living example with new rings....
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Thanks Georges, I'll take a close look a those before cleaning when I get the pistons off.