Carb leaking, R27

[DIS295]

BTW, I'm diagnosing a problem on a friend's r69s. We thought it might be carb, so I took one off my r69s and put it on his. No change. Eliminated that for consideration. Anyone local have an r27?

[schrader7032]

It might not stop the engine from vibrating, but they act as dampers so hopefully forces are much reduced.

[Flx48]

Hi Patrick-
Thinking of your rattling shock; three things come to mind, if your rattle is external of hydraulics.
Are the mounting bolts secured; easy enough to check.
Are the silent blocks intact; see that the black rubber is not cracked or missing, see that inner bushing is still being held centered within outer bushing by the rubber.
And has the shock rod unscrewed itself from the upper mount; check by taking hold of the shock midway between the two ends and push and pull it sideways.
If rod has unscrewed itself from the upper mount, the shock assembly will feel hinged in the middle.

By your description I’m as baffled as others re: carb leaking fuel out the tickler.
My thought also is the float/needle are not doing their job, and the float chamber is filling completely with fuel.
Baffling is that while flooding up and out the tickler, it is not running out the idle air adjustment screw, (the normal drain route for an overflowing float chamber) and also baffling is that it’s not causing an over rich running condition for the engine when it overflows.

DIS is spot on re engine vibe isolation from chassis.
Best-
George

[pmtremblay]

I'm starting over with cleaning the carb to rule it out - maybe it's just a bit of stubborn gunk in the wrong passageway. I took it apart again, sprayed and soaked it in some nasty carb cleaner, now it's soaking for a few hours in Berryman's chem dip. If that doesn't work I'll find an ultrasonic cleaner and try that. If that doesn't work, I'll do my best to find a loaner carb.

The only annoying part is I'm on a mileage tear and wanted to get another couple of thousand miles in before the end of March for the annual BMWMOA mileage contest. I have a respectable amount in already, but want to show what these little old bikes can do. This has set me back weeks.

The front suspension issue might be a whole other can of worms I'm afraid, I'll start a thread on that later today. The carb is a deadline item, so that's priority.

[pmtremblay]

Rotten day here for the R27! After a very, very thorough carb cleaning I went for a test ride. The first 15 miles were great, the bike was running well and the carb was dry. I love this bike so much! Then it all hit the fan.

First the front suspension started feeling off, then I looked down to see the same gas leak from the top of the carb float bowl. I was feeling defeated. Then the front suspension just altogether stopped working. This was all within about a half mile. I was able to limp home at 20 mph.

Gas leak: I have a compression tester coming tomorrow, it’s the only thing I haven’t checked. Everything seems good and normal, the bike runs and sounds great, except for the stream of fuel from the float bowl. I’m also looking for a loaner carb or a reasonably priced used one.

Suspension: The right shock and/or spring is toast, video below. Are these things I can replace myself? There’s a /2 shock video that makes it look deceptively simple. I have zero experience and just basic tools. https://www.youtube.com/watch?v=uSPNfjzaOAk

Ugh.

My toasted front shock on YouTube: https://youtu.be/gf554J1reUk, or download it from this site.

video.mp4

(1.91 MiB) Downloaded 121 times

My poor front end.

[weh8127]

Patrick, you can buy a complete assembly ready to go vintagebeemerparts.com/bmw-r26-r27-front-shock-complete-all-new-parts/ or you can disassemble the one you have and only replace the parts necessary. They're not that difficult to work on. If you don't already have one, before you do anything else, buy the Barrington R 27 manual!

[jgreen]

Buy the Cycleworks shock tool. You'll need it. Anything else is a major pain in the rear.

If you are lucky, the shock has unscrewed itself from the top mount of the shock absorber assembly. You can screw it back in, but you'll need to compress the spring and the black shock cover while you do it, and that's a task without the tool.

If you have to replace the shock itself, you'll need to unscrew it from the bottom part of the shock absorber assembly, and that is going to be a task, becuase it's probably not been apart in 65 years, so penetrating oil and heat will be needed.

The shock removal tool from Cycleworks includes two metal plates that clamp around the shock itself, and you claim the assembly in a vice, and then you can twist off the bottom part. Any other way really run the risk of permanently damaging the shock absorber, but if it's already toast, it may not be a concern.

[pmtremblay]

I just ordered the Cycle Works shock tool, thanks for the suggestion. I have the Barrington book and a couple of other reference manuals to read up on it while I wait. There’s a great thread on here viewtopic.php?t=18246 from 2023 that’s helpful, complete with some photos from my friend George. Hi George! It sounds like unscrewing itself is not uncommon, but replacement shocks are under $200 a set, so still affordable if it's something worse.

It’s supposed to snow tomorrow, so at least I’m not missing much riding.

[Flx48]

Hi Patrick-
My shock tool is available, should you want to use it.
Best-
George

[pmtremblay]

I pulled my front shocks off, and everything came apart too easily. The right shock had unscrewed itself fully from the bottom, causing the failure. The left shock was intact, but very close to being unscrewed at the top. Everything looks serviceable, so I'll put it back together when my tool arrives. New pre-ride check will be the gap between the top and bottom shroud, as I realize the unscrewing made it noticeably wider.

Thanks for the tool offer George! I already ordered one from Cycle Works. There are rights-of-passage to new vintage BMW owners, like a phone call with Vech, ordering something from an all-German website, and buying your first special tool.

I’m still stumped by the carb. The last thing I can test is the air mixture screw. The Barrington book says there's an overflow passage at the top of the float bowl that goes through the air screw hole. I’ll pull the carb off again, confirm that passage is clear and that the air screw isn’t blocking something.

If that doesn’t work I’ll be looking for a loaner or replacement carb.