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???
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 :-*
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
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
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
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...
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.
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
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)
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.
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
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
Ok H2o Thanks............ now I'm thinking the air jet maybe my problem then......any thoughts on this probabilty???
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???
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
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???
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
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.
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
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.
Update.......flapper adjusted all the way.....gained a little more throttle and r's..... up to maybe 9's ....but seemed to suffer a bit at lower r's..... and still wont climb nicely to redline.........checked to make sure the mains were correct and clean .....they are......soo I guess the carbs have to come off >:(... and apart :(.......again >:( .....I guess if you want something done right you have to do it yourself......I'll probably wait till the season is over...... since that is pretty soon........ and its still running well enough........any other options at this point I should know about???
The disk shaped filter for the modded carbs is there because the passage in the top of the carb is blocked off if you look at the tube type holes in the top of both carbs you will see that the front one is closed off with a brass B-B.
the passage is drilled an taped with a fitting & goes to the disk filter.
Yamaha decided not to take air for the main on the front carb from the airbox with the update, but instead to take it from outside, hence the filter. perhaps the air was too unsettled or low pressure because of where the flapper is, or maybe because there was blow-by oil getting into the main, dunno why...
--Lucky
I would says its running about 90% now......3/4 throttle and getting a solid 9k rpms ...which is basicly time to shift.....so it seems to have been running rich......I have the pilot screws set in CW as far as they could and still idle nice......seems to be best setting.......I'm considering putting this 120 in the front and putting the front 122.5 in the rear.......what do you guys think???.......I'm wanting better gas milage truthfully..... not speed......since I hear numbers like 180's till reserve...... and I'm more like 120-130 (two aboard)......seems worth a try :-\.....but would like your advice :).
I hit reserve once at 110 miles, but that was while I was doing lots of carb fiddling. Quite a bit of idling time. I normally fill the tank @ about 100 miles. Went to 135 once this summer & didn't hit reserve. I have always seen 43 MPG with my V ever since I bought it. Doesn't seem to matter how I ride it, either. Sedate, go for it, stop & go traffic, highway cruising. On the highway, going around 65 - 70, it does a little better, but still definitely under 50 MPG. Your 120 - 130 miles before reserve isn't uncommon - especially two-up.
I tried smaller jets in mine once. Got a real bad stumble I couldn't get rid of. However, I'm at 5,000 ft. elevation & 99% of my riding goes up from there.
H2O
I gassed up a block from home and rode up I 5 past Portland accross the Columbia river and headed east to the Motocross track at Washougle WA. On the return trip I went back doem I 5 (running 65 mph ) and got off I5 and used back roads (went on reserve just after getting off the freeway) Just as I came to the only stop sign in Sublemity OR .town next to where I lived in Stayton) It went on to 1 cylinder . I chugged accross the street and filled up 4.2 gal. and 211 miles not quite 50 mpg.