Power Loss

[clouseau]

So, I'm the guy with the useless choke/enricher & random dies at idle problem.  I promised I would get back after a FULL carb rebuild. I went a step further and replaced choke and throttle cables, leaky crankcase vent valve gasket & hose, carb sleeves (both ends) and everything in between to the air box.  I meticulously rebuilt the carbs down to new needle jets, jet needles and float needles.  Yeah, I got a little crazy...

Good news: First start after rebuild with choke lever full on, it starts and stays running albeit a bit rough.  But I'd say that's pretty darn good considering I hadn't made any adjustments yet. It certainly wouldn't do that before.

However I've got a power loss issue. In my best estimation it's somewhere around 20% after 3000rpm under load and sometimes will kick back up after 6000.  I can also sometimes feel the power surge and lower in mild waves.  My best guess guess is fuel delivery.  My fuel filter with only 400miles on it looks like this and since I had the tank off for a few weeks and put it back on I'm thinking there's a flow restriction from particles being shifted. I just find it hard to believe it would be the carbs or air delivery since I replaced practically everything.

[Ed Miller]

Uh, did that red stuff come with the filter?  If not, your tank needs cleaning.  Here's an article covering some of that stuff, mostly section six:

http://bmwmotorcycletech.info/fuelmiscl.htm

Sorry I can't remember what you did before, but are your valve clearances good?  And your ignition timing?  After all that, measure your fuel flow past your NEW filter; I think Snowbum's articles say what it should be.  It does sound like a fuel problem to me, but I've learned that I can't tell that way and have to check the motor basics before I start messing with all those nice convenient screws and stuff on the carbs.

By the way, what you mentioned for a carb rebuild doesn't sound crazy, it sounds to me like you you rebuild carbs.  

[nhmaf]

Yes, those red flecks in the filter (either rust, or the original red tank-liner peeling off) isn't a good sign and indicates that something needs to be done with the tank - otherwise particles will continue to clog up the filer in the petcock, your in-line filter, and possibly even your pristine carbs.

[clouseau]

I should add that the power loss is AFTER I tuned and synced, which I believe I have become pretty good at.  

I've adjusted the valves a couple hundred miles or so ago.

The tank is the next order of business.  I was looking at this product:
http://www.4secondsflat.com/Fuel_Tank_Sealer.html
I don't think a simple drain will suffice.  Anyone ever heard of the BB method?  You add some diesel fuel and some BBs and shake the tank around to break stuff loose.

Thanks for the input and I'll report back after some tank reconditioning...

[clouseau]

I ordered this:
http://www.hirschauto.com/prodinfo.asp?number=CRK-01

[Ed Miller]

I've never seen that; it looks generic. Let us know if the cleaner gets the old liner out, as I understand that's desirable.

[Justin B.]

Ed, this looks suspiciously like the Eastwood kit I had so much grief with.

Clouseau, when you get this stuff let us know if in the instructions it informs you that you need to scrounge acetone and muriatic acid to properly clean and "pickle" the tank.  If so, it is probably exactly the same stuff...

[clouseau]

Will do!
Here's a link to more info.
http://hirschauto.com/crksheet.pdf
I won't be using the sealer unless I can get the remains of this red liner out.  I just may have to acetone it on my own if the cleaner and etcher don't do the trick.

[Justin B.]

I bought a kit that included these same components (with Eastwood's labeling)  and when I started to line my tank the directions then pointed out I needed to get the acid and acetone!  The acid did produce a completely rust-free tank interior after about 10-22 hours. Tthe actual liner was/is white and so far hasn't started flaking off.  The POR15 stuff is metallic silver and doesn't require near as much prep and takes several days to fully dry/cure.

[Ed Miller]

Those instructions slam the POR 15 kit pretty hard.  I have that (POR 15)in my Triumph tank (so far, so good) and will be using Caswall in my other Triumph tank, so I'll have the two to compare.  My BMW lining still seems OK; at least I'm not plugging up my fuel filter.

Caswall doesn't come with the cleaner and stripper, so it's much less convenient, but the tank I'm using it in has been hot tanked, so it doesn't matter.