Venture Royale carburetor questions

[unwind80]

Hello everyone, I am the proud new owner of a 1983 Yamaha Venture Royale. I bought this bike from a co-worker that had ridden it up until about 10 months ago. It has since been sitting in his garage unused. He says that it was running kind of poor, so he did some 'fiddling around' with the carburetors, and then it wouldn't run at all. That's of course when he stopped riding it.

 

It was no surprise that it would not run for me when I got it home. I decided to give the carburetors an overhaul. I completely dismantled them, soaked them in carb cleaning solution, blew out all the passageways, and replaced all gaskets, o-rings and damaged diaphrams. After re-assembly, I balanced them by sight on the workbench and got them back on the bike.

 

I was relieved when the bike started, but after warming up, repeated attempts to take out the choke fail. It will run just fine with the choke on full up to 2500RPM or so. I read that these bikes don't like to run without the airbox, so I installed that and encounter the same problem. I have tried backing off the choke while very gradually increasing the idle via the idle adjuster, no luck. Any hint of throttle and this thing dies immediately.

 

I know about the seafoam fix, but I would assume that since I thoroughly cleaned the carbs, I shouldn't need to use the stuff. Even if I missed a couple of the passageways I would expect it to run better than this.

 

The only thing that I skimped on were the two rubber plugs at the bottom of each jet block. They were mostly hard, and probably not providing good seals. I couldn't find replacements for these, so I left them as-is. I haven't the slightest idea of why these are there in the first place. Could these be causing my problem?

 

Any other ideas? I am by no means a mechanic, so I could be missing something obvious. Thanks for any help you can provide.

-Dave

[CrazyHorse]

Hello everyone, I am the proud new owner of a 1983 Yamaha Venture Royale. I bought this bike from a co-worker that had ridden it up until about 10 months ago. It has since been sitting in his garage unused. He says that it was running kind of poor, so he did some 'fiddling around' with the carburetors, and then it wouldn't run at all. That's of course when he stopped riding it.

 

It was no surprise that it would not run for me when I got it home. I decided to give the carburetors an overhaul. I completely dismantled them, soaked them in carb cleaning solution, blew out all the passageways, and replaced all gaskets, o-rings and damaged diaphrams. After re-assembly, I balanced them by sight on the workbench and got them back on the bike.

 

I was relieved when the bike started, but after warming up, repeated attempts to take out the choke fail. It will run just fine with the choke on full up to 2500RPM or so. I read that these bikes don't like to run without the airbox, so I installed that and encounter the same problem. I have tried backing off the choke while very gradually increasing the idle via the idle adjuster, no luck. Any hint of throttle and this thing dies immediately.

 

I know about the seafoam fix, but I would assume that since I thoroughly cleaned the carbs, I shouldn't need to use the stuff. Even if I missed a couple of the passageways I would expect it to run better than this.

 

The only thing that I skimped on were the two rubber plugs at the bottom of each jet block. They were mostly hard, and probably not providing good seals. I couldn't find replacements for these, so I left them as-is. I haven't the slightest idea of why these are there in the first place. Could these be causing my problem?

 

Any other ideas? I am by no means a mechanic, so I could be missing something obvious. Thanks for any help you can provide.

-Dave

Did you clean out the small pilot jets (idle circuit) I had to poke a small wire brush bristle through mine to get them unplugged. To make sure they were clean I had to unscrew them and take them out. Be careful they are soft brass. They tend to plug up and will cause the bike not to idle without the choke especially if the bike sits. Mine were totally plugged, no amount of Seafoam helped. I dont know what will happen with rubber plug issue. I bet this is your problem. Also make sure the carbs are all seated in their boots both top and bottom.

Edited May 27, 2011 by CrazyHorse

[unwind80]

Which jets are for the idle circuit? I tried to remove the jets that are behind the rubber plugs in the block, but one was stuck and I broke one side of it off. It will still do its job, but it is a permanent fixture now. After my experience with that one, I left the others alone, and soaked them then used compressed air to clear them as best as I could. I didn't realize that it may need a wire run through it to complete the job. I guess I should disassemble and try again...

[Reddog170]

Did you replace the fuel filter? Seems to me if it has to run on choke then it is not getting enough fuel. Check the simple things first, may save you a ton of work. Shaun

[dingy]

The rubber blocks on the bottom of the jet block assy. don't seem like much but they are a source of low end & idle problems.

 

Partshark.com has them.

 

Also inside of the jet block assy, there is a 42.5 jet (on 83 & 84 only, 85 & up have a 37.5). This is harder than heck to get clean and not mess it up. Did you clean that one?

 

It is the one on left in picture.

 

Gary

 

http://i1007.photobucket.com/albums/af193/gdingy101/floatjetblock2.jpg

Edited May 27, 2011 by dingy
corrected jet size error

[MiCarl]

A carb soak won't do the trick. You need to completely disassemble and spray cleaner and compressed air through every passage. The emulsion tubes need to be removed and cleaned and make sure that every orifice is open.

 

The rubber plugs for the jet block are still available, I just had to replace a set of them.

 

The pilot screws need to be gently turned in, counting how many turns and fractions of turns, until they bottom. Then they need to be removed, the spring washer and o-ring under them need to come out, and those passages need to be blown with spray carb cleaner and compressed air. Upon reassembly you lightly seat the pilot screws and back them out to the count you made previously.

 

A carb soak is a very bad idea because it ruins rubber. There are rubber seals on the butterfly shafts that are not supposed to be removable. If they get damaged you are in a world of hurt.

[unwind80]

Redddog, I did check the filter and it is perfect. The fuel pump seems to be working fine too. I may have accidentally sprayed fuel all over the place when I turned the key on without the fuel line connected

 

Dingy, the 37.5 jet is the one that I broke with the screw driver trying to remove it. I did the best I could at cleaning all of these, but I just left them in the jet block. It sounds like that won't cut it I guess. Having broken that jet it will not come out of there...any tricks for this or am I looking at buying the new jet and block? I will get a new set of plugs as well.

 

MiCarl, I'm not sure where the pilot screws are, but I certainly didn't do the procedure that you described. Is that the same as the idle / air adjustment screws that are hidden under the metal plug? My carbs still have the metal plugs installed. I should probably remove them and clean those passageways.

 

Thanks guys, you have given me plenty to work on. I will let you know what happens!

[SilvrT]

...any tricks for this or am I looking at buying the new jet and block?

 

I dunno how some of the other guys on here will respond to this but I've rebuilt numerous carbs over the years and when those things won't "budge", I'll give the end of the screwdriver a whack with a hammer (not too hard). Make sure that you're using the correct sized screwdriver.

[MiCarl]

 

Dingy, the 37.5 jet is the one that I broke with the screw driver trying to remove it. I did the best I could at cleaning all of these, but I just left them in the jet block. It sounds like that won't cut it I guess. Having broken that jet it will not come out of there...any tricks for this or am I looking at buying the new jet and block? I will get a new set of plugs as well.

 

On the 83 that jet is a 42.5, so don't panic when you read it and it's not 37.5. It's got air bleed holes in the sides. It's gotta come out. A good fitting screwdriver is important. Let it soak with penetrating oil for awhile.

 

MiCarl, I'm not sure where the pilot screws are, but I certainly didn't do the procedure that you described. Is that the same as the idle / air adjustment screws that are hidden under the metal plug? My carbs still have the metal plugs installed. I should probably remove them and clean those passageways.

 

That's the guy. It's not an air or fuel screw, although it behaves similarly to a fuel screw - out is richer.

 

I remove the caps by drilling them with a 1/8" drill then screwing a drywall screw into them. I use pliers to wiggle and pull on the drywall screw. You have to use a light touch when drilling because the screws are brass and if you're laying into it you can ruin the screw slot. A nice sharp bit with little pressure is the way to go, and let go of the trigger the instant it breaks through.

 

I use an automatic center punch to put a mark on the carburetor body in line with the screw slot. A scribe or needle file will also work. You cannot use a pencil or marker because the carb cleaner will remove them. Then you screw in gently noting how many turns until it bottoms and record the number. When you reinstall you bottom lightly and back out the number of turns you counted (WRITE IT DOWN AND KEEP IT) and align the screw slot with your mark.

 

The end of that screw is a needle. If you over tighten it it will wedge on the sides and snap off. If that happens the carburetor is junk. I use just 2 fingers on the screwdriver to run them down. If you are using your wrist you can over torque them without realizing it.

 

Under that screw is a spring, then a very small flat washer, then a small o-ring. The spring is easy to get out but the washer and o-ring are probably stuck. I made a small hook by soldering a bristle from a wire brush to a piece of electrical wire. Then I put a 90 degree bend about 1mm from the end of the bristle. It takes some digging.

 

When you reassemble put the spring, washer and o-ring on the screw. The o-ring will hold it all together while you put the screw back in. If you just drop the pieces down the hole they'll never line up properly.

 

You also need to set the float levels. Your service manual will detail how to do that. If you don't have a service manual stop until you get one.

[Oldseadog]

If you don't have a service manual here is a link to one

http://labs.trunkful.com/vrmanuals/index.cfm

[dingy]

On the 83 that jet is a 42.5, so don't panic when you read it and it's not 37.5. It's got air bleed holes in the sides. It's gotta come out. A good fitting screwdriver is important. Let it soak with penetrating oil for awhile.

 

Whoops, sorry about the wrong size, I should have known that.

 

But it does gotta come out like Carl said. This one has an extremely small hole in it, very easy to plug up.

 

Gary

[unwind80]

Thank you everyone so much for all the information. I rebuilt an '85 Suzuki Madura last year, and the Madura forum was (and is) a wealth of information filled with guys willing to spend their time helping a Schmoe like me. I thought that group of guys may have been unique, but here you are proving me wrong!

 

 

I took the carbs back off the bike, and am working on getting that 42.5 jet out of the #1 carb right now. Just letting it soak for a while in penetrating oil. Thanks for the link to the service manual. I have an old paper copy, but it is nice to be able to look it up on the computer. I need to order those plugs tonight and wait for them to come in before I will put these back together. It might be a couple weeks before I know what happens, but I will be sure to post back here with the results.

-Dave

[barend]

It might be a couple weeks before I know what happens, but I will be sure to post back here with the results.

-Dave

 

In a couple of weeks you might not be able to post anymore unless you become a supporting member ........for a mere $12........... Hint, hint

[unwind80]

In a couple of weeks you might not be able to post anymore unless you become a supporting member ........for a mere $12........... Hint, hint

 

Done! I didn't even realize my inferior status

 

I managed to get three of the four 42.5 jets out of the block, but the last one is a problem. You guys were right, every one of them was blocked. One was severely blocked...it took some digging to see light through it.

 

I am going to try and figure out how to get that stubborn one out. Its not going to be easy. My screwdriver isn't catching anything when it turns down there. I tried hitting the driver with a hammer to make some kind of impression, but nothing. Maybe I can make use of the Dremel, but that would be pretty difficult. At this point I am sure I will end up buying a new jet, but I'd rather not have to buy the $66 block also.

[mlew]

Once you have ruined the screwdriver slot on the jet there is not much to do other than drill it out. I use left turn drill bits(regular bits turn right) to get them out. It works every time. You can get them at some auto parts stores or hardware store. Drill the first hole with a 7/64 then follow with a 1/8, this will allow the larger bit to grab the broken jet and turn it out. Drill bits are cheaper than a new block. Of course you will need to replace the jet when done.

[Venturous Randy]

I would try to run the same wire through the stuck jet. You may be able to do that and be ok. I may have a block I can send you.

RandyA

[unwind80]

Once you have ruined the screwdriver slot on the jet there is not much to do other than drill it out. I use left turn drill bits(regular bits turn right) to get them out. It works every time. You can get them at some auto parts stores or hardware store. Drill the first hole with a 7/64 then follow with a 1/8, this will allow the larger bit to grab the broken jet and turn it out. Drill bits are cheaper than a new block. Of course you will need to replace the jet when done.

 

Great idea, I was thinking about trying to drill it out, but I didn't realize that they made left handed drill bits. I will pick up a couple of those. Along with the new jet.

 

I would try to run the same wire through the stuck jet. You may be able to do that and be ok. I may have a block I can send you.

RandyA

 

Thank you for the offer. I would be more comfortable with a new jet in there, I think I saw them for about $5. If for some reason I can't make this work I will contact you.

[dingy]

One more thing that would be helpful when you ask questions in future would be to put your bike info in your user info.

 

http://www.venturerider.org/forum/showthread.php?t=58880

 

Gary

[greg_in_london]

Back to the original post.

 

You rubber bungs are absolutely essential.

 

Without them you are bypassing the main jet and providing unmetered fuel directly to the emulsion tubes. The effect is the same as if the main jet had unscrewed and fallen off.

 

Without pulling out the diagram I can't visualise the effects of the second bung, but I think you will be messing up the emulsion tube's function. It doesn't really matter though - those bungs are available and not terribly expensive - you need to take the carbs apart and replace them.

 

There are different jets recommended for different models/markets. I'd put the carbs back together without leaving any parts out and then see if you want to make any adjustments, rather than thinking about jet sizes at this stage.

 

[EDIT - I just re-read the post and realised that you did re-use those plugs - hopefully they were a tight fit. You might check that the previous owner didn't switch two jets - I never tried this myself, but apparently two of the carb jets - the main and one other have the same thread and can be swapped accidentally. Sounds like a basic mistake though, as otherwise it would not affect all carbs and it would run, but badly on some pots.]

Edited May 30, 2011 by greg_in_london
misread post

[unwind80]

After taking the carbs apart again, the rubber plugs were soaked with gasoline. The gasoline actually seemed to soften the rubber. Also, the plugs were a little tighter in their spots. I think they are making a decent seal, so I will continue without replacing them. They are $5 a piece, and I cringe at the thought of paying for all 8 of them for no reason.

 

I'll be working on the bike again this weekend, but I won't have my new jet until sometime next week.

[MiCarl]

You also might try a bit of heat on the jet block. The brass has a similar coefficient of thermal expansion to the aluminum but the heat might soften any varnish gluing them together.

[Daveand Barbie]

To share some personal experience....I read on the Nighthawk forum of the success of using Pine Sol as a soak for gummed up carbs. Since it doesn't attack rubber, you don't have to worry about damage. I tried this on 3 sets of carbs so far and it worked great. I washed them after a 24 hour soak with hot water and blew them dry.

 

For cleaning clogged jets, I have used a tip cleaner for a gas welder. They are cheap at the welding supply store and come in a fold out handle with about 20 in it. Each wire is slightly knurled, so you can easily feel when you are approaching the maximum size usable.

 

I know you are near completion of the project but thought it might be useful information in the future.

Edited June 2, 2011 by Daveand Barbie

[mbrood]

On cleaning the TINY 37.5 pr 42.5 jet:

 

These are TINY, and the orifice is a highly calibrated opening, any ream that removes even a tiny bit of brass changes the opening. The crud that builds up there, reduces the fuel flow (requiring choke to idle). I finally resorted to taking my parts to an auto speed shop who tossed them in an utrasonic acid bath with a bunch of "their parts"... cost was about $15 bucks but the parts came out looking totally clean and revived. If in doubt, replace the jets. The other jets have fairly large orifices and cleaning is much simpler... but oh those tiney ones are so important to a good idle and low end mileage !!

 

As was said, those rubber plugs are crucial, if in doubt, replace them, no sense getting in there any more than needed, right?

[unwind80]

I almost gave up and was going to ask the kind member if I could buy his jet block when I thought to myself, if I'm buying a new block, I might as well go far enough to ruin the old one to make sure that I tried everything.

 

I had been heating it up with a propane torch and then using the left handed drill bits with no luck. All that was left with was a very thin wall of brass on the threads inside the block. I never heated it too much though, I didn't want to deform anything. Just being overly cautious I guess. So I went back for one more try and heated that block for like 5 min with the torch. I then took my modified screwdriver and scraped away at it. Wouldn't you know it, I got all the rest of the jet out of there. I think the heat did the trick. I tested the threads with one of my other jets, and they don't seem to be damaged. I think the block is still in good shape.

 

Now its on to the pilot screws while I wait for the new jet to come in.

 

Thanks for the advice! It is coming along...

[V7Goose]

Glad you finally got the bad jet out. You have received lots of good advice in this thread, and I only want to re-emphasize a couple of things.

 

The symptoms you described (won't run off choke, won't accept throttle) are absolute CLASSIC for blocked pilot jets.

 

And one caution: poking anything harder than a broom straw into a jet is the worst thing you can do - those jets are very soft brass, and any other metal will damage them instantly. Just pull the jets and soak them in a small amount of spray carb cleaner for an hour or so, then blow through them with compressed air - repeat as necessary. You can tell when they are clean just by looking through them to a bright light - clear jets will be a perfectly circular little spot of light. If you think that light spot looks a little flat or funny shaped, then it ain't clean - repeat!

 

Goose