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Did some stuff and now I....

Started by GT @ oh., September 12, 2007, 04:56:22 PM

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GT @ oh.

have a few Q's....   I cleaned up the insides of my front brake system....shot it with brake cleaner... worked well on the darkish residue that was coating things :) used a mity vac system the do the bleeding and make the job go easy  ;)......way more lever now;D         I replaced the sightglass on master....digging out the old one was tough >:(.....and the new one I put in with epoxy...seems to be leaking under pressure... in a spot...... recoated should be fine.....but hindsight...... silicone seems to be a better pick.  Took the rear tire off shot out the drum with cleaner....no more sqeal ;) pads seemed to be worn thin.... like to a 1/16th in areas.   Swapped out the rear shock with the upgraded 83 .....job went well and during my brief ride I think I noticed a smoother more stable rearend....I'll let you know once I've rode on it a while 8).                                                   Here come the Q's  While it was apart I took a look at the carbs I've heard talk of a cone shaped spray out of your carbs....mine spray a stream staight down in ....is this wrong ??? ....does it need to be running ???            I could make out 135 on one of the air jets the other looked like 120........ but could be wrong.... it is small.....tried to remove mains but they wouldn't budge....what gives why so tight ???  I am wanting to check synch... via vacuum pressure gauge ...do I hook it up where the smaller hose goes from petcock to carb...... and on the other there is a plug???

markmakeitso

Good day

The accelerator pumps do tend to spray in a stream, it doesn't help the vision stumble when the fuel doesn't vaporize. Cleaning out the nozzles can help a little bit as can adjusting the stream to clear the butterfly, but don't expect a nice cone like an injector would give.

As for the stuck jets, soaking in carb cleaner or perhaps applying some heat could help. Make sure the screwdriver is a very snug fit in the jets or you'll risk destroying the jet.

Lucky has a good write-up on synching carbs. Apparently he's spent an hour or two working on these durn moorsicles.

http://www.xz550.com/tips.html

Sounds like you're on the right track, although a pressure gauge isn't going to work well :P :-*

Sable

Lucky has the less than $10.00 manometer instructions on his site. Pretty cheap to do and it works well. I use automatic transmission fluid in mine.

Good luck with it, I know it took me quite a long time to get 'em right.

~ John
1982 Yamaha Vision
1982 Motobecane 50V
1975 Kawasaki H-1
1972 Rokon Trailbreaker

YellowJacket!

I tried the vaccum gauges but there was just too much "jitter" in the needle to get an accurate reading.  Maybe oil damped gauges would work better.
I also saw a setup that aerostitch sells that is a "digital" meter that has several LED's.  Apparently when the carbs are synced, the green LED's in the middle of the bar light up.

I also saw a rig that fits over the top of the carb and measures the vacuum as air is being sucked down the throat of the carb.  You can either use it on each individual carb and get a measurement and then switch to the other or you can buy two.

David


Living the dream - I am now a Physician Assistant!!   :-)

GT @ oh.

I checked the air jet again and it is definitely 120 and 135....... I will swap out the 120 to 135 first chance I get......I checked synch with gauge and homemade meter and it seems to be ok. I'm thinking now that it could be leaky boots as they seem really cracked....... I'll liquid tape that as suggested.       A guy who works on bikes is suggesting it maybe that the float is set wrong and is running the bowls empty. What do you guys think??     Again bike idles and runs good..... till 7-8000rpms or half throttle......above this and it runs like crap >:(      Could my boots be leaking once the vaccuum is high enough to suck air thru the cracks or is this unlikely??? any other suggestions are greatly appreciated.  Thanks

Night Vision

first off, if the carbs haven't been dipped and cleaned at least once, start there.... only once? try try again

do you have that flapper mod?

there's a float height check method in the Haynes manual...

you might be running lean at the top end.. check your plug color, ... turn the pilots out 1/8, 1/4, 1/2 turns out and see what happens.. record the turns, ride some miles.... see if it's better or worse...

or you might be running rich...stick you finger in the ends of the exhaust and see if they come out black? wipe them out... ride some more and recheck.... adjust the pilots in and see what happens

coat your boots if you can't afford new ones... new wires / caps / plugs might help.....

try the cheap fixes first....just keep at it...
if it ain't worth doing it the hard way....
it ain't worth doing it at all - Man Law
;D


if it ain't broke..... take it apart and find out why


don't give up.... don't ever give up - Jimmy Valvano

QBS

Go with new caps on the old wires.  Not absolutley certain, but strongly suspect that new factory plug wires will be hard to find.  Besides as Lucky has said, copper doesn't wear out.

h2olawyer

New caps are cheap.  Just do it.  Bulk wire is cheap as well if you want all new plug wires & caps.  I spent less than $20 on plugs, caps & wire earlier this summer.

H2O
If you have an accident on a motorcycle, it's always your fault. Tough call, but it has to be that way. You're in the right, and dead -on a bike. The principle is not to have any accident. If you're involved in an an accident, it's because you did not anticipate. Then, by default, you failed.

Tiger

Quote from: h2olawyer on September 28, 2007, 08:11:04 PM
New caps are cheap.  Just do it.  Bulk wire is cheap as well if you want all new plug wires & caps.  I spent less than $20 on plugs, caps & wire earlier this summer.

H2O

... 8)
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well-preserved body, but rather to skid in sideways, body thoroughly used up, totally worn out and screaming HOOOOYA lets go again baby !!!!!!

'82 Vision, Pearl Orange finish, lots of up-grades!!!

Rick G

remove the plug caps by winding the counter clock wise until they come off. You can clip the last  1/4 to 3/8   off  as the wire does tend  to erode where the threaded spike  screws into it. You can get real copper wire (not crappy automotive carbon core stuff) at some  auto parts stores and all lawn mower shops . Thats where I get mine  when working on old bikes with raggedy plug wires.
Rick G
Go soothingly on the grease mud, as there in lurks the skid demon
'82.5 Yamaha XZ550 RJ  Vision,
'90 Suzuki VX800, 1990 Suzuki DR350.
'74  XL350   Honda , 77 XL350 Honda, 78 XL350 Honda, '82 XT 200 Yamaha, '67 Yamaha YG1TK, 80cc trail bike

GT @ oh.

Thanks for the tips guys......I really think its in the carbs......it does seem to have a nicer hum to it now that I've set the synch......I will fiddle with the pilot setting to see if it helps..... and swap out the 120 air jet....was the 120 what the factory used to modify??? ...just curious how it came to be a 120.              If pilot screws don't help I guess the carbs have to come out for rebuild........Just another thought here....... when I was synching..... and having to use the vacuum port used by the petcock.....the bike kept stalling out ....because (I believe) the carb kept going empty.....I had to keep putting it on prime to get it going.....it would idle a while between stalls.....I don't know if this helps you guys diagnose my problem ....but something doesn't seem right........or does that always happen with the port not connected to the petcock to assist fuel draw???...............also what about a diaphram rebuild???....... are there kits???..................Oh yeah.... the 83 shock is a great improvement ;D

h2olawyer

The vacuum to the petcock is what alows the fuel to flow when the bike is running.  When you synch, you need to leave the petcock set to prime because you have eliminated the vacuum to the petcock, thus shutting off the fuel.

The 120 pilot air jet is not original.  On 82 carbs, the stock size was a 130.  My guess is that someone has been into the carbs & tried to eliminate the stumble - or had extra jets on their workbench & was careless in replacing them.  The airbox modification kit came with 135 air jets.

H2O
If you have an accident on a motorcycle, it's always your fault. Tough call, but it has to be that way. You're in the right, and dead -on a bike. The principle is not to have any accident. If you're involved in an an accident, it's because you did not anticipate. Then, by default, you failed.

GT @ oh.

Ok H2o Thanks............ now I'm thinking the air jet maybe my problem then......any thoughts on this probabilty???

GT @ oh.

Does anyone have pics of the top of the carbs??? ....because i noticed that on the tube just in front of the air jets ....my front has a blocked top (like a ball bearing maybe).....and on the back I see nothing...no (ball bearing)....is this the correct setup???

h2olawyer

An air jet that small would make a noticable difference in performance.  As for the blocked off tube, I just can't recall.  I remember seeing the block you speak of, but don't remember if it is present in both carbs.

Who knows what blockage lives in the carbs of Visions?

Lucky does.

H2O
If you have an accident on a motorcycle, it's always your fault. Tough call, but it has to be that way. You're in the right, and dead -on a bike. The principle is not to have any accident. If you're involved in an an accident, it's because you did not anticipate. Then, by default, you failed.

GT @ oh.

Well it doesn't seem to have been the jet.....135 in both now and same problem......does anyone think it could be the rev limiter wire issue to blame???

h2olawyer

I took three tries to get my carbs clean - dipping them in Berrymans every time.  Third time was a charm.

You can try disconnecting the rev limiter to see if that's the problem.  You can either unscrew it from the back of the tach, take the connector out of the plug at the TCI or just clip it.  If you choose to disconnect it at the tach or at the TCI, wrap the bare end with some electrical tape.

H2O
If you have an accident on a motorcycle, it's always your fault. Tough call, but it has to be that way. You're in the right, and dead -on a bike. The principle is not to have any accident. If you're involved in an an accident, it's because you did not anticipate. Then, by default, you failed.

jasonm.

#17
GT, If you really want to clean your carbs. Nothing works better than a real "DIP". These are gallon cans with a basket inside. All decent auto parts places have this type of cleaner.You should remove all rubber and gaskets you can. 
  Also what you describe at half throttle + or past 7000 is what my '82 did and what JoeVac's did as well> It was fixed by sliding the diaphragm that opens the air box "door". Loosen the 2 screws. Slide it till the door is just open ~1/16" or so more than the little rubber bumper. Nightvision saw us fix Joe's bike this way. If this fixes it...Then you were running rich. My '83 I have mine slide till the door is as open as possible before the diaphragm starts to move. YES, it's likely you are rich up top. These bikes use the biggest pilot jets Mikuni makes. Plus the accel pump can really squirt quite a bit in there. Including removing the gas tank. This fix will take you no more than 10 minutes. Now why this happened to Joes after many years is unclear. He is the original owner. He has a good airfilter and all else checked out. ALSO the only thing I have yet to figure out on these carbs is. WHAT the HECK the mini "filter" on the right of the front carb is for? Service bulletin says it's a filter that does not require any service. Maybe this is getting clogged after many years? I just don't know.
As long as both accel nozzles are squirting. I bet you will have this going great in no time.
  PLEASE TRY the fix.
looks aren't important, if she lets you play by your rules

Night Vision

#18
Quote from: GT @ oh. on October 02, 2007, 12:27:25 PM
Does anyone have pics of the top of the carbs??? ....because i noticed that on the tube just in front of the air jets ....my front has a blocked top (like a ball bearing maybe).....and on the back I see nothing...no (ball bearing)....is this the correct setup???

yes, that is correct IF you have the modified front carb with the mini filter and the hose going to the modified air box with the vacuum flapper....

I'm not sure if I got an answer to my question: have your carbs been dipped at least once? twice?
if not, you're chasing your tail... only then you can think about jets, flapper settings, and pilot screws
if it ain't worth doing it the hard way....
it ain't worth doing it at all - Man Law
;D


if it ain't broke..... take it apart and find out why


don't give up.... don't ever give up - Jimmy Valvano

GT @ oh.

I will try the flapper diaphram then...I did try to once but the screws would not budge.......as far as the cleaning....... the guy who got it running at the dealer says he took it apart dipped and blew it out a couple times before it would run...... but if the screws to open the flapper doesn't work....... I'm taking the carbs off and apart .....Thanks I'll keep you all updated.