BlueVenture87 Posted March 25, 2011 Share #1 Posted March 25, 2011 So, my 87 project is running a bit rough so I do what any shadetree guy would do and I look down the carbs when the bike is running. I noticed that all the slides are vibrating at different rates with some more active than others. It this a balance thing? Might be shot diaphragms but on a machine this old as soon as I open the carb covers to check for pinholes the diaphragms will be shot because I opened up the chambers. Is there a visual diagnostic other than pulling the slides that indicates diapgragm condition? Letting sleeping dogs lie and all that... Link to comment Share on other sites More sharing options...
mraf Posted March 25, 2011 Share #2 Posted March 25, 2011 I don't believe that the diaphragms will be shot just by opening them up. If they have never been changed in 24 years there is a good chance that they are bad. There are quick fixes to be found by doing a search on here if thats what you want to do. Probably could use a carb sync if nothing else. Link to comment Share on other sites More sharing options...
Snaggletooth Posted March 25, 2011 Share #3 Posted March 25, 2011 You won't hurt the diaphragms by removing the covers at all. Remove the covers and use your finger to press the slider to the outside while working the sealing edge of the diaphragm loose. If they are bad, they were bad before you opened the covers. Hold them up to a bright light and look for pin holes and tears. Should look solid. If not, new ones are in order. We have a supplier here that offers a very fair price on the diaphragms alone. A carb sync would most certainly help on evening up the action of the sliders if the diaphragms are good. Mike Link to comment Share on other sites More sharing options...
mlew Posted March 25, 2011 Share #4 Posted March 25, 2011 If the carbs have not been cleaned in a long time there is a good chance that old fuel gum and varnish is keeping the slides from moving freely. Also possible there is a bad diaphram. I would check the diaphrams then carb sync, if that does not help then remove and rebuild. Link to comment Share on other sites More sharing options...
Lassesand Posted March 25, 2011 Share #5 Posted March 25, 2011 I would be very thankful for any info about the supplier of diaphragms to the XVZ. I have three bad out of four that I needed to patch up or glue. Link to comment Share on other sites More sharing options...
Snaggletooth Posted March 25, 2011 Share #6 Posted March 25, 2011 This post has the contact info on the supplier for the diaphragms. I'm not sure but I think the price went up a bit but still.......way better than dealing with the Stealership. http://www.venturerider.org/forum/showthread.php?t=42124 This post has the walk though on the installation of them. http://www.venturerider.org/forum/showthread.php?t=19271 Hope that helps. Mike Link to comment Share on other sites More sharing options...
easternrider Posted March 25, 2011 Share #7 Posted March 25, 2011 I had a couple of leaking diaphragms, and when you remove the covers, you should know which ones are leaking. Without even touching them. When you remove the cover, if the face of the diaphragm is wet, it is probably leaking, as they should always be dry on the cover side Link to comment Share on other sites More sharing options...
CaptainJoe Posted March 25, 2011 Share #8 Posted March 25, 2011 When you depress the slide from inside the top of the carb with your index finger they should all return at the same rate and not snap back fast. One of my diaphram/slides was diirty and was returning at a slower rate so I just tore them all off and cleaned. I cleaned with carb cleaner then lightly sprayed with silicone. It cleared up the problem I was having with the RPM's hanging. Link to comment Share on other sites More sharing options...
BlueVenture87 Posted March 26, 2011 Author Share #9 Posted March 26, 2011 I know this motor can run better, looks like I'm goin' in! It also looks like I'm going to use alot of other peoples heads since this will be the first CV carb work I've done. "I'm not a mechanic, but I play one on TV!" -Jim Link to comment Share on other sites More sharing options...
mraf Posted March 26, 2011 Share #10 Posted March 26, 2011 Have at it! There are alot of "been there done that" people on this site that can answer any questions if you have any. Link to comment Share on other sites More sharing options...
bongobobny Posted March 26, 2011 Share #11 Posted March 26, 2011 Have you tried the "Seafoam" cure yet?? A half can in a tankful of gas can work wonders, or a full can if you want to change your plugs immediately after! That stuff can work miricles! Drain your gas tank, and your fuel bowls in the carbs as well, then fill up with a good gas and the seafoam and go on a nice long ride, preferrably at highway speeds! The more agressive you are with throttle twisting, the better! After that, try balancing the carbs and see if it runs any smoother. I also would recommend replacing the plugs before doing the vaccuum balance. Also, if the wires are the original ones, it is most likely time for a new set, they don't last forever. Easternrider has a god point, if one of the diaphragms is torn you wil see wetting on the outside. It doesn't hurt to remove the sliders and give them a good cleaning to get any dirt or contamination off the plastic. Also clean the bore they ride in as you could have crud built up on the walls. As Mr "Backwards Farm" states, there is a lot of knowledge here and we can supply you with more info than you caqn handle!! Also, when you remove the security torx screw from each cover, replace them with regular phillips screws to match the other 3 per cover, and save you or the next person a hassle the next time they come off!! There is an excellent video that is for sale on ebay that gives step by step instructions for rebuilding the carbs. It is based on the vmax carbs, but the procedure is exactly the same. The only thing you probably won't be able to do is use a sniffer to fine tune the mixture screws but chances are if you rebuild them right, they wil be close enough that they will work just fine! Link to comment Share on other sites More sharing options...
easternrider Posted March 26, 2011 Share #12 Posted March 26, 2011 When you take the covers off, do it slowly. There is a very small O-ring which usually stays on the carb, but make sure you don't lose it. Also check the others to see if there is any missing, cause that can cause problems. The O-ring is about this big [O], seriously, but fatter Link to comment Share on other sites More sharing options...
BlueVenture87 Posted March 30, 2011 Author Share #13 Posted March 30, 2011 OK here is where things are. First, things arent really good enough in for the seafoam to take hold. (other problems) I managed to get the covers off and found the diaphragms largely good. One has a single pinhole in it another has a small thin spot that wants to be a hole so I'll order 2 new diaphragms. The big queston for today is the needle on each slide sems to flop around ane are rather loose. Is this right? There is a screw slot inside the slide. This tightens the needle? Maybe adjusts something? Don't know. Thanks to all so far! -Jim Link to comment Share on other sites More sharing options...
bongobobny Posted March 30, 2011 Share #14 Posted March 30, 2011 There is free play in the needles, which is spring loaded. Those "Screws" youn see are plastic, and should be snug. If you take one apart you will find the spring behind it. Hope that helps... Link to comment Share on other sites More sharing options...
skydoc_17 Posted March 30, 2011 Share #15 Posted March 30, 2011 Here is the procedure for the replacement of the Carb. Diaphragms from the Tech. Library: http://www.venturerider.org/forum/showthread.php?t=32121 Here is the Carb. Sync. Link from the Tech. Library: http://www.venturerider.org/forum/showthread.php?t=56723 Because of the material that the Aftermarket Carb. Diaphragms are made of, you are going to WANT to replace ALL 4 Diaphragms, or the return rate will be different between the old Diaphragms and the new Diaphragms. Just an FYI. Have a look at the Idle Mixture Screws as well. Earl Link to comment Share on other sites More sharing options...
timgray Posted March 30, 2011 Share #16 Posted March 30, 2011 When you depress the slide from inside the top of the carb with your index finger they should all return at the same rate and not snap back fast. One of my diaphram/slides was diirty and was returning at a slower rate so I just tore them all off and cleaned. I cleaned with carb cleaner then lightly sprayed with silicone. It cleared up the problem I was having with the RPM's hanging. Oh that is a good idea.... silicone wont get washed off easily from gasoline so it should stay "lubricated" fora while. Although adding some MM oil to the gas regularly helps with lubricating the moving carb parts... Link to comment Share on other sites More sharing options...
twigg Posted April 1, 2011 Share #17 Posted April 1, 2011 This post has the contact info on the supplier for the diaphragms. I'm not sure but I think the price went up a bit but still.......way better than dealing with the Stealership. http://www.venturerider.org/forum/showthread.php?t=42124 This post has the walk though on the installation of them. http://www.venturerider.org/forum/showthread.php?t=19271 Hope that helps. Mike Current price is $69.99 plus $6 Shipping. I ordered a set today. Link to comment Share on other sites More sharing options...
BlueVenture87 Posted April 3, 2011 Author Share #18 Posted April 3, 2011 Balanced the carbs today and they were really off. Things are better now and I have a direction for improvement on the drivability front. Of course new issues came up as usually happen when working on neglected equipment. I'll save that for a new thread. Thanks for all the help and providing me the confidance to open things up! -Jim Link to comment Share on other sites More sharing options...
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