ADVrider

Go Back   ADVrider > Bikes > Old's Cool > Airheads
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 09-09-2012, 02:46 PM   #46
disston
ShadeTreeExpert
 
disston's Avatar
 
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 8,247
The Alcohol in the Gasoline, now to be called Gasohol, is more corrosive to the Styrofoam float material. Eventually the floats have to be replaced.

Several riders have talked about sealing the floats with some kind of spray shellac or something but I never heard of any successful experiments. Maybe somebody tried it but I never heard it actually worked. I guess you have to start with new floats before spraying and if the material doesn't work it might make them not work from the beginning. I guess this could get expensive.

My idea is to use the metal bracket for the Styrofoam floats and construct small brass float chambers by hand from thin brass. I've never done anything like this before but I think it can be done. I just don't have enough time to play with it. I'm too busy trying to survive and writing diatribes all day long on the Web.
__________________
.
Never memorize something you can look up.
---Albert Einstein

Pay your debt, piratejohn.http://www.advrider.com/forums/showthread.php?t=949341
disston is online now   Reply With Quote
Old 09-09-2012, 03:15 PM   #47
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,202
We already have a lot of years experience with alcohol in most all the gas here in Ca. I have seen no change in how long the floats last. I see floats lasting decades in bikes all the time. Some people say they replace them every year? I see some of these bikes. My advise is that there are plenty of things that really need replacing.
supershaft is offline   Reply With Quote
Old 09-09-2012, 06:22 PM   #48
senatorperkins OP
Adventurer
 
Joined: Jun 2012
Oddometer: 34
Chobro, wouldn't heavier floats be less buoyant thus requiring a larger displaced volume, resulting in a higher float level? My level is 17mm as well when they're parallel. I wonder if there were different float replacements sold with different geometry or buoyancy. Or could the floats be getting lighter/more buoyant with age?

Okay, I think I was lean for this trip as well, seeing as my floats were set parallel, and the stutter only showed up on certain days (come to think of it, the weather was on average 15-20 degrees colder during those two weeks than the rest of the time I've had the bike this summer, so this makes sense because colder air causes leaner running. Also, when it rained it stuttered less, which checks out as well.)

What bugs me is that my plugs look like they do on page one (specifically the photos after I took it for a ride, not after idling) - half of the insulator looks white, which would indicate lean to me, but the other half is black. Could my exhaust valve guides be worn and leaking oil which is burning only on that side of the plug, which happens to be facing the exhaust port? I'll mention again that my consumption is high at 1500miles/liter.

Glad I'm fixing the timing too, but maybe that wasn't the cause of my issue.
senatorperkins is offline   Reply With Quote
Old 09-10-2012, 03:45 AM   #49
ME 109
Beastly Adventurer
 
ME 109's Avatar
 
Joined: Jun 2009
Location: Albury Australia
Oddometer: 1,902
Thumbs up for Aussie premium and 31 year old carby floats.
Miss that super tho'
__________________
Lord of the Bings
ME 109 is online now   Reply With Quote
Old 09-10-2012, 06:40 PM   #50
MickeyDee
n00b
 
Joined: Apr 2011
Oddometer: 1
I experienced some of the problems you are having. It took two years to figure it out,and talking to everybody I could to now avail. I stumbled across a photo of the Bing carb and thought something looked different. I checked it out and discovered the linkage for the enrichment (choke) was upside down. I didn't notice when I rebuilt the carbs, it still had spring tension which leads you to think that all is right with the install. The bike ran fairly good at first but after a couple of hundred miles it started exhibiting some of the same problems as yours. It ends up fouling your heads allowing your valves to stay open with subsequent loss of power and the sputtering. My linkage had a bend to it, that bend should look down. If yours are the straight variety you might have the enricheners on the wrong sides. They are right and left sided. Good luck with your project. Have thought about joining the Airheads? There is a lot of good info on all the old warheads.
MickeyDee is offline   Reply With Quote
Old 09-11-2012, 10:21 AM   #51
Chobro
spinning the wheel
 
Chobro's Avatar
 
Joined: Jan 2004
Location: Albuquerque, NM
Oddometer: 740
Quote:
Originally Posted by senatorperkins View Post
Chobro, wouldn't heavier floats be less buoyant thus requiring a larger displaced volume, resulting in a higher float level? My level is 17mm as well when they're parallel. I wonder if there were different float replacements sold with different geometry or buoyancy. Or could the floats be getting lighter/more buoyant with age?
I reckon that's right, mind boggling. . . That two tone spark plug is really interesting. Would a leak down test confirm valve/valve guide condition?
__________________
-Chobro
Chobro is offline   Reply With Quote
Old 09-11-2012, 10:51 AM   #52
disston
ShadeTreeExpert
 
disston's Avatar
 
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 8,247
A lot of good ideas. But. Gasohol soaked floats will cause too high a fuel level. Problems would more likely be at idle. I set the float levels one time to cause the gas level to run really, really low. At 80 mph I would run the carbs completely out of gas, the bike would stall but because I was moving at 80 mph it just slowed down. I backed off the throttle, the carb bowls filled and I cranked them open till it did it again, till I used all the fuel. It was not a stuttering situation. The carbs were either on or off. That's my point. Not something I would call stuttering.

I forget which bike this is? Does it have ignition points? Too little Dwell, which is too wide a gap, will cause a stutter at higher rpm.

I've seen the two tone plugs a lot. I think it's a result of Gasohol. It may be that a proper plug reading on Gasohol will be more white than anything else. We are not seeing brown very much, I think. We did a thread on this subject several months ago. Sorry I couldn't find it.
__________________
.
Never memorize something you can look up.
---Albert Einstein

Pay your debt, piratejohn.http://www.advrider.com/forums/showthread.php?t=949341
disston is online now   Reply With Quote
Old 09-11-2012, 07:29 PM   #53
senatorperkins OP
Adventurer
 
Joined: Jun 2012
Oddometer: 34
Oh, I'm glad these 2-tone plugs aren't totally alien, I've never seen them before and they were freaking me out.

Yes, points, I always set at 0.016 with slight drag on the feeler gauge. We'll see how the Sachse ignition does when it comes. Planning a trip at some point in the fall, I'll report back.

Chobro, a leakdown test won't tell anything about the valve guides.. the valve guides are only exposed to the combustion chamber when the valves are open.
senatorperkins is offline   Reply With Quote
Old 10-12-2012, 09:13 AM   #54
senatorperkins OP
Adventurer
 
Joined: Jun 2012
Oddometer: 34
Okay, so here's a coda to this thread as I don't like to leave things hanging.

While waiting for my Sachse ignition to arrive from Germany I did a whole laundry list of maintenance items including some that were suggested to me on this thread. I flushed the tank, cleaned the petcocks, inspected and cleaned the crankcase breather, changed all the fluids, oil filter, new oil pan gasket, cleaned and rebuilt the carbs with new gaskets and o-rings, installed with new plastic elbows and fuel hose, new cables, did the pushrod seals, sealed the cylinder base, new head gaskets, set the float height to 24mm, set the valve clearances, installed the ignition, timed it, and synced the carbs. Obviously not everything here could be related to the issue, but they were things I was planning on doing anyway once I had the time.

Here's a photo of the Sachse. On my model I had to relieve a section of the front cover with a dremel to make room for unit. The wiring was easy, I mounted the control box behind the battery, and I just need to switch a wire terminal at the right coil to swap back to points. No modifications to the harness necessary.


A word of caution to anyone thinking of installing a Sachse - see the wire heading down from the Y terminal on the alternator in this photo? It looks like it's insulated, but the insulation did nothing, and it shorted through the aluminum base of the sensor (you can actually see it touching in this photo), which shorted out my whole charging system. Luckily it came back to life when I bent the wire out of the way and added some shrink wrap.

I went for a 70 mile ride yesterday and there was not a single issue. I didn't have the time to isolate the problem by doing an item then testing, then proceeding, but I believe it was either fuel starvation from a low float height or misfiring from my screwed up points.

So thank everyone for your help, I'll see you on the road and around the forums!
senatorperkins is offline   Reply With Quote
Old 10-12-2012, 10:28 AM   #55
ozmoses
Ride On
 
ozmoses's Avatar
 
Joined: Jul 2009
Location: USA
Oddometer: 2,460
How do your plugs look now?
__________________
Opinions are like internet connections- everybody has one.
ozmoses is offline   Reply With Quote
Old 10-12-2012, 01:47 PM   #56
senatorperkins OP
Adventurer
 
Joined: Jun 2012
Oddometer: 34
They look pretty good - perhaps a little lean, but then I realized I left the vacuum port plugs out for the whole ride after my carb sync . I'll do a plug chop at the end of my next ride.
senatorperkins is offline   Reply With Quote
Old 10-15-2012, 01:21 AM   #57
chasbmw
Beastly Adventurer
 
Joined: Feb 2006
Location: Bath Uk
Oddometer: 1,745
The Sachse set up is really nice, the timing on mine was absolutely spot on for a dual plugged engine. Setting the timing initially was also very easy. Much easier than the Silent Hektick ignition on my other bike.

I feel that the misfire was most likely caused by the float height being too low. It seems that it is too easy to change it when doing a carb refurb?
__________________
Charles
http://i46.photobucket.com/albums/f1...ps6e61ae2e.jpg
R90s 1070 replica, R90/6
1971 Commando Fastback
chasbmw is offline   Reply With Quote
Old 10-16-2012, 04:19 AM   #58
Beemerboff
Beastly Adventurer
 
Joined: May 2005
Oddometer: 2,214
http://www.gremlinracetech.com/product/BBMP

These systems fit your bike, and include coils, leads and plug caps , so the price of around $200- is more than reasonable , and if you can convince them not to charge the 18 ? % UK sales tax it is a positive bargain.

I have had the basic system on my 75/7 for 15 years / 150,000 trouble free km, fit and forget, so it has probably been cheaper than replacing points , etc over the same distance, and the the Micropower system on my twin plug 1000cc G/S has been the the same over 100,000 km, and it has a curve which suits my bike very well.
__________________
Adelaide Hills, Australia. 93 R100 GS, 77 R75/7 ,70 BSA B44VS, , 86 R80 G/S PD, 95 BMW Funduro F650 ST

Beemerboff screwed with this post 10-16-2012 at 05:22 AM
Beemerboff is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 07:43 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014