My road bike runs fine from one fuel tap.
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78 XS650e build
- Thread starter Zmccleary7
- Start date
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
Positive news! The Helicoils worked flawlessly. gas tank holds gas without leaking a drop.
now with every good there's a bad. When I finally hooked everything back up and flipped the petcocks over, no fuel is making it down left carb, and then the right carb fills then just POURSSS out the bottom overflow. We got the bike to kick over and idle for a few moments before dying out.(I assume because there's no fuel in one carb and is flowing straight out the other, although I did put some fuel line on it and push it up so what fuel does pour out it goes back up and stops when it reaches about where the floats stop in the carb,) it reached a point where it only flows fuel when on reserve so to save wasting more gas I haven't tried anything else.
now with every good there's a bad. When I finally hooked everything back up and flipped the petcocks over, no fuel is making it down left carb, and then the right carb fills then just POURSSS out the bottom overflow. We got the bike to kick over and idle for a few moments before dying out.(I assume because there's no fuel in one carb and is flowing straight out the other, although I did put some fuel line on it and push it up so what fuel does pour out it goes back up and stops when it reaches about where the floats stop in the carb,) it reached a point where it only flows fuel when on reserve so to save wasting more gas I haven't tried anything else.
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
Nearly a month later and we finally have the carbs!! Easily enough to install and look stunning. The petcock output is smaller than the carb receiver so I’ll need to play with that to get a good clean fit. We got everything hooked up and the bike still only starts and bogs down
Next guess is either old spark plugs(which they are) or old failing coils(which they are old
) so thats that.
Now the confusing part. The throttle cable came pre-installed so after routing it up to the throttle assembly and putting it on the bar, no twist.____. So I pulled her off to see what was wrong and well she was back to normal. Throttle back and spring forward. I put the throttle assembly back on the bar and now it throttles forward and springs back while “catching” or “lagging” for lack of better terms?? Ill work tomorrow longer but any help or recommendations would be amazing!!
Wishing you all a Merry Christmas and a fruitful New Year
Next guess is either old spark plugs(which they are) or old failing coils(which they are old) so thats that.Now the confusing part. The throttle cable came pre-installed so after routing it up to the throttle assembly and putting it on the bar, no twist.____. So I pulled her off to see what was wrong and well she was back to normal. Throttle back and spring forward. I put the throttle assembly back on the bar and now it throttles forward and springs back while “catching” or “lagging” for lack of better terms?? Ill work tomorrow longer but any help or recommendations would be amazing!!
Wishing you all a Merry Christmas and a fruitful New Year
Even a new cable needs lube and make sure your throttle sleeve is installed in the clamp correctly.
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
The issue seems to be the throttle sleeve, I bought one pf the cheap universal ones off TC bros, she looks pretty but I’m gonna go a different route and get one of the nicer ones
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
Battery died.___. I came out today to keep working on the throttle and she would NOT start. Started diagnosing and well no lights turn on and when we took the plug caps off there was no spark. I didn't leave the key in over the past days nor was any of the lights actually turned to the on position. Is there something else that would've killed my battery???
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
So this could be a dumb question but I'm honestly unsure.
I Recently upgraded to a Murrays carb kit and I'm running non-vacuum petcocks. Do I need to plug the vacuum ports on the VM-34's or is plugging the vacuum port only necessary with the OEM bs38s? Fuel seems to run fine but She still wont stay running for longer then a minute or so.
Thanks for any help as always!
I Recently upgraded to a Murrays carb kit and I'm running non-vacuum petcocks. Do I need to plug the vacuum ports on the VM-34's or is plugging the vacuum port only necessary with the OEM bs38s? Fuel seems to run fine but She still wont stay running for longer then a minute or so.
Thanks for any help as always!
As a general rule of thumb, any vacuum port on any carb needs to be closed. So, either by connected to something requiring vacuum or by plugging it.
Can you give us a pic of what port you're talking about? VM's also have vent ports. You don't want to plug them.
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
I'll have to snag those photos for you later this afternoon for more/better angles. I found this image online though.
The port I'm referring is just up-left from the fuel intake. What confuses me is there's another one identically on the other side and bottom of the carb(although I learned real quick with the old ones that the bottom is for fuel overflow)
The port I'm referring is just up-left from the fuel intake. What confuses me is there's another one identically on the other side and bottom of the carb(although I learned real quick with the old ones that the bottom is for fuel overflow)
It's a vent. If it was a vacuum port, it would be closer to the engine side (further forward) on the carb body. They may exist, but I have personally never seen a VM34 with a vacuum port (?).
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
That is a relief to hear. Or at least a relief to hear its one less thing that could be causing poor idling/running. Regardless ill still take and upload a couple phots here after 6 MST, if all else because who doesn't like looking at bike parts
Hope this might help. Attached are photos of my left and right carbs; float bowl overflows are on the bottom as you've noted, vents and fuel line connections are both on the left sides of the carb bodies on my set, with no other fittings on the right sides (ex. air & idle screws of course).That is a relief to hear. Or at least a relief to hear its one less thing that could be causing poor idling/running. Regardless ill still take and upload a couple phots here after 6 MST, if all else because who doesn't like looking at bike parts
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Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
So I got the photos of my carbs on the bike and then the old ones. It does seem the new ones don’t have the nipple on the inner side of the carb. The old ones have what I imagine is the vacuum ports but they were never sealed(which would explain why the PO complained about poor running and put it in his shed)
)Attachments
I will preface this by saying I am not a carb expert by any stretch of the imagination. That said, I do not think either of those ports on your old carbs are vacuum ports...they are just not in the right position, and if you look at the body casting detail behind both of them, it looks like they tap into a passage leading to the float bowl...vents(?).
Your new carbs from Murray's are like mine. If you look at the photo of your left carb and look further to the "left" of the vent hose, you will see a little casting detail on the intake side near the manifold; this would be where a vacuum port would likely be if there was one i.e. this location would be drilled & tapped for a nipple (or one would be pressed in).
Your new carbs from Murray's are like mine. If you look at the photo of your left carb and look further to the "left" of the vent hose, you will see a little casting detail on the intake side near the manifold; this would be where a vacuum port would likely be if there was one i.e. this location would be drilled & tapped for a nipple (or one would be pressed in).
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
Hey any bit of knowledge is beyond helpful the two prior ports make sense to lead into the gloat bowl, there positioning is just too obvious. You’re right. At the end it nice to eliminate the vacuum from thought since its not there(thank the lord).
the two prior ports make sense to lead into the gloat bowl, there positioning is just too obvious. You’re right. At the end it nice to eliminate the vacuum from thought since its not there(thank the lord).
Yeah, the only drawback to not having a vacuum port on the carb or intake manifold is that you then can't vacuum sync the carbs, and instead, have to do it in a more manual, generally less accurate way. I'm in the same boat.Hey any bit of knowledge is beyond helpful
Zmccleary7
"Not all those who wander are lost" J.R.R Tolkien
Yeah that does suck. Thankfully murrays advertises syncing and tuning from factory so its more or less plug or play. Now do I fulllyyyyy believe I wont have to mess with/tune anything, no not at all.
Yeah, I read that on their site some time ago, and while I think they provide a high quality kit, the only thing they can do is manually/mechanically sync the carbs i.e match throttle openings, which of course is easy to do. The only problem is that it doesn't take into consideration the dynamic, running differences between cylinders.
So, as in almost all cases - as you have said - it will likely require some tinkering.
