A Newbies Adventures in Maintenanceland!

Patton wrote:

Might have already been suggested, but would also check integrity of vacuum hose to petcock (if so fitted) and end connections where the hose attaches to the carb and to the petcock.

Any air leak from a crack or poor connection could result in the racing idle, same as any other leak allowing outside air intrusion into the intake tract.

If not already done, would also check integrity of vacuum caps (plugs).

Good Fortune!

interesting, does the vacuum hose have any clamps on it, or is it just press fit onto the barbed fittings? I had no clamps anywhere...

9am53 wrote:

i have not verified it working properly, but will. It wasn't being weird before, and it was in good shape and I cleaned and greased it up, so I don't know if that's it, but I will check it out. The plan was to ride it for a little while, break in the rings and whatnot and then worry about all this stuff. That's cool.

I do have a dumb noob question though regarding the carbs, lets say the idle mixture screws are set too lean and I am running lean beacause of the tailpipe, wouldn't that just make it hard to start and run on choke only? How would running lean make it race uncontrollably?

A recently cleaned and lubed advancer unit in good condition is likely functioning all right without sticking or hanging in advanced position, and therefore not a likely suspect as cause for the racing idle. But would visually inspect its operation under timing light to confirm it's working correctly. Might be some damage that went unnoticed or was caused during the cleaning and lubing exercise.

How would running lean make it race uncontrollably? --- Analogous to air leak causing ultra-lean mixture, and racing idle.

Good Fortune!

9am53 wrote:

...does the vacuum hose have any clamps on it, or is it just press fit onto the barbed fittings? I had no clamps anywhere...

A snug press fit at both ends should be just fine.

Good Fortune!

kuul, thanks. Today is colder than a witches tit outside, so I am finishing my little diy humidor today, and will work on the bike after I get back from beating on some little youg-uns in the pit at the immortal show on saturday \m/

Thanks for your help folks...

Givin the throttle a twist before starting is ok, but not during. It defeats the choke system entirely giving it throttle. It should start easily with just a press of the button on full choke, nothing else.

ALL good info, Patton...

Don't bother smearing the stuff all over the rubber @ the head, those products must be installed between two pressurized surfaces to have any real effect. Unless you want to use glue!
You can back the bolts out of the carb holders and pull the whole rack of carbs back with the boots and just slant it down underneath the head. Then smear your tiny 2mm beads of gasket maker on the head. Then pull back on the carbs, line em' up, and let them seat back forward onto the new gaskets you just made. Screw em back in.

The screws being way too lean can cause the idle you describe, and they richen up pretty quickly with minimal adjustment. Once the engines hot and you pull the choke out, it should stumble pretty bad, not race.

Oh yeah, the adjuster screws are the ones that are recessed in the top/front towers on the carbs (closest to engine). Unscrew them all the way and make sure the little rubber o-ring on them is in good condition as well, and dont loose the springs if they happen to stick and come out with the screws!

You dont need clamps on the vacuum lines unless they are loose. They should have a nice snug fit everywhere, and no slits or cracks.

cool, thanks. Where are these mixture screws Jay?

maybe I am dumb, but I still don't understand how a lean a/f mix will cause the motor to race. If I try to start the bike with no choke (too lean at that moment) the bike will stumble and stall...how does it being lean by a leak cause it to run faster rather than stall it? I am not trying to argue, just don't get it. Thanks for your patience

9am53 wrote:

...adjusted knob on the back of the BS34s to lower the idle, it did nothing...have not done a bench sync....

Proper bench sync is a necessary prerequisite to final sync on running engine.

Bench sync does two things:

(1) equates slide heights (the "beginning" position);

(2) allows positioning of idle thumb screw at about mid-thread position to permit its fullest range of motion in later simultaneous lowering or raising of the slides.

Where bench sync is omitted or improperly performed, it may later be impossible to sufficiently reduce the idle rpm by turning the thumb screw (because it simply runs out of thread).

Good Fortune!

9am53 wrote:

cool, thanks. Where are these mixture screws Jay?

the adjuster screws are the ones that are recessed in the top/front square towers on the carbs (closest to engine). Unscrew them all the way first and make sure the little rubber o-ring on them is in good condition as well, and dont loose the springs if they happen to stick and come out with the screws!

looking down from above, you'll see the little brass screws in the square front part on top of the carb.

9am53 wrote:

maybe I am dumb, but I still don't understand how a lean a/f mix will cause the motor to race. If I try to start the bike with no choke (too lean at that moment) the bike will stumble and stall...how does it being lean by a leak cause it to run faster rather than stall it? I am not trying to argue, just don't get it. Thanks for your patience

There is significantly more vacuum present in the intake @ idle then when your on the throttle. (I know, its weird but true, velocity increases with throttle but vacuum drops.)

Starting a bike that has good compression can happen with a huge range of Air-fuel ratios. Again, it just does so starting doesnt really have much to do with running...

A small air leak changes the ratio just enough to be too lean, which in turn causes hanging throttle and surging (especially at high vacuum idle...)
If you were to just pull the carb boot off, it would likely stall, but with leaks, not so... it just revs.

The hotter the engine gets, the fuel requirements change. Thats why you try to make all adjustments with a good hot engine (unless otherwise specefied, like cam gaps.)
WEIRD EH! :laugh:



Do you know if float levels are ok?
Perfect carburetion is CRITICAL to bike performance.
SEAFOAM SEAFOAM SEAFOAM SEAFOAM SEAFOAM SEAFOAM SEAFOAM SEAFOAM

damn...I suck! I had no clue about bench synching etc...I will try out those little screws and see what happens then. If I can ride it for a little while like that I am happy. Once I can justify spending more money on the bike lol I will get the jet kit and do all of this bench synching and whatnot then.

9am53 wrote:

damn...I suck! I had no clue about bench synching etc...I will try out those little screws and see what happens then. If I can ride it for a little while like that I am happy. Once I can justify spending more money on the bike lol I will get the jet kit and do all of this bench synching and whatnot then.

Sometimes if the carbs have been tinkered with, then not synced, the bike can be nearly unrideable, even embarassing, especially at low throttle inputs. In your case though (i think you said you didnt play with them...) you "should" be ok.

You can always borrow a vacuum guage from someone and make a homemade restrictor just to check for peace of mind. or whatever...
and you can always check your float levels...

OR... just ride by my place and I can fix it all for you in an hour! :laugh:

I think your biggest issue is an air leak... once you have that corrected and the mixture screws close, then you should be ok to go for some time.

But, alas I am pretty far still, and you havn't even broke it in...

:laugh: We all just want to ride damnit!