Carb issues

[Session101]

*update*
finally figured out how to do a valve adjustment *applause*
so both side set to .006 intake and .008 exhaust, took a bit to get that
i did a flow test on the carbs, gas flows with floats and shuts off when level like it should.
re-tested the spark plugs resting against the head
i went ahead and reset and unscrewed the air/fuel mixture screw to a full turn out this time instead of 3/4.
started her up, seemed to be easier to start this time, but still the exhaust sound is way more prominent on the right side than the left, also the exhaust head is much greater on the right side than the left. the compression is greater on the right side by 10psi per a compression test. i can kind of hear misfire in the exhaust when rev'd up to higher RPM, also after being in the higher RPM the throttle is more responsive, still having trouble getting the bike to stay idle even with the choke on, the bike seems to shake more than a harley....

so what is going on?? what is next???

[Bob_Roller]

Have you performed a carburetor synchronization yet ?

[tvrla]

Sounds like a carburation issue to me.

I'll just bet the mixture screw o ring or idle jet o-ring is compromised. It's a very common problem.

The first step of the carb tune-up sequencee (after cleaning them up or rebuilding) is setting the mixture. Was this done?

[Mike V]

<snip>

Sounds like a carburation issue to me

+1.  I would start by checking to see if the mixture screw has a rolled or damaged o-ring.  To start with.

[Session101]

ill have to see if i can find a carb sync tool.

i can pull the air/fuel mixture screw on both the carbs to show that they are in good health, i didn't see anything when i tore the carbs down a second time. Setting the mixture is only what i read in the book to have the screw turned out 3/4 and adjust from there, but i can't get the bike to stay idling long enough to mess with it, the bike rocks worse than a harley at low idle

[Bob_Roller]

The adjustment you did, is a 'nominal' setting, to get you in the 'ballpark' area, you need to to accomplish a carb synch, all engines are different in the settings required to get a proper running engine .

[Session101]

well timing light is in the mail should get here wednesday or thursday. My plan is as follows...

1)properly time the bike with a timing light (i think this is a 2 man job, holding the RPM's at 3000 i think)
2) replace the spark plugs even though they are showing good spark
3) check the dwell on points with the meter that is also in the mail
4) sync the carbs also in the works of getting

still not running right?

next i will do 2 rounds of seafoam treatment and see it that helps the valves seat and seal better

and if that doesn't work then i think the bike is cursed...

[Barry]

Dwell is not something that needs to be absolutely spot on for our bikes. It's just not an issue as there is more than enough time for the coils to saturate.

One good advantage of a dwell meter is you can target a specific figure, set the timing once and at subsequent services  just reset to the same dwell figure to correct for points heel wear. That should automatically bring your timing back to spec.

[Session101]

ok update*

drained all the fuel out of the bike and ran a liter of alcohol to show a flow test and also to remove any water or bad fuel. filled up the tank with fresh fuel after 24 hours of evaporation.

New spark plugs

I timed the bike the way that it was running, its not running on one cylinder anymore, because when i pull the spark plug wire there is a change in RPM and sound

2nd i pulled the bike out to sync the carbs and the air/fuel screw has no effect on the left side *clue*

after that i started to cup my hand a certain way over the left carb and bam the bike sounds normal and great again

so, first what are some indicators on the carb? my first check is going to be the choke... and others?

[Session101]

Here's a video, this is after i turned the choke around which i still doing know if its right or not but blocking the choke hole in the carb doesn't seem to do anything. I wish there was a way to show passage ways in carb, i think this little guy goes to the atomizer right? and also why is it backfiring out the carb?

[media]http://www.youtube.com/embed/mktlKoLfZoM[/media]

[Barry]

There is some guidance on the correct choke orientation in the FAQ section.  In the diagrams fuel enters via the small holes at the bottom and mixes with air before leaving via the top left hand port.

http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1291933920

[Session101]

good news

i think the bike is running ok, however i think i need to re-time the bike because the idle is good @ 800-900 rpm but when you drive it the idle likes to hang at the 2000-2500 rpm range and take a long long time to come back down or just to pop the clutch a little and it goes down

should i sync the carbs then time the bike or get the carbs to idle fine then time then sync?

Basically i re-re-rebuilt the carb again but this time replacing the gaskets that are 300-400 miles old and the bike didn't want to start but then once i let her run and idle for a while it's easier to start but i still think there is a leak somewhere but i have replaced everything and still no luck, if the valves were leaking on the intake would that have an effect?

[Barry]

Ignition timing has to be a fair way out to influence idle speed. In principle excessive ignition advance will increase the idle speed.

If your idle is set at 800 -900 rpm on a fully warmed engine then the hang up symptoms are unusual.

-There are 3 scenarios that can cause the hang up symptoms:-

Idle speed set too high or set when the engine is not fully warmed up - probably the most common reason.

Sticking advance mechanism - probably a less common cause than it's made out to be.

Throttle stop screws set too far in and then idle revs reduced using the mixture screws. This is absolutely the wrong way to approach tuning the carbs as the excessive opening of the throttle disc at idle causes the transfer ports to come into effect and that will cause the revs to hang up - This is an unusual senario but I mention it because I recall your throttle stop screw initial setting being 1 full turn in which sounds way too much to me. 1/2 a turn in is too much on my carbs. If you need more than 1/2 a turn in to achieve a stable idle I'd say there is likely something else wrong.

[montmil]

[size=14]+[/size]1 with Barry's comment regarding high idle revs.

Before I built and began using my $4.00 Ghetto Manometer, I had the same high idle situation when the engine was at full operating temps. I would drag the clutch at stops to bring down the idle speed.

Doing a full carb tune protocol on a hot engine showed my mixture screws to be too far opened. The manual's mixture screw settings are only a starting point.

After backing off the throttle stops to a "no contact" position, I was able to close down the mixture screws while watching the fluid levels in the manometer. I set my idle at 900-1000 rpm.

From your carburetor performance description, I would bet Bengt Phorqs lunch money that your mixture screws are excessively open.