Another VOES question...
#1
Join Date: Nov 2010
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Another VOES question...
'98 Super Glide, stock.
I was out replacing my intake manifold to head gaskets and as I was taking the carb off, I noticed the vacuum hose (#7 here http://partsfinder.onlinemicrofiche....TCH%20ASSEMBLY )
had a bad crack along it and couldn't possibly be working properly for the VOES.
So, me and my heavy-handedness tried to take that section off the tri thing and naturally broke the nipple off the VOES *and* the part I was trying to get the hose off of.
Now, I need my bike to be able to work *ALL* the time, as it's my *only* transportation I own. My question now is...my bike is stock, can I just run a vacuum hose from the tank valve (on/off/res) to the carb and the bike will run okay, or will that not work and I have to buy a new VOES and that vacuum line to go with it? If I need to get the VOES to make this run, any idea what Hg I need? I'm a big man @6' 1" and 280, and can't find anything anywhere about what the stock Hg is for this bike
Thanks for any help as quick as possible with this, as I have a doctors appointment in 4 days and am already getting nervous.
I was out replacing my intake manifold to head gaskets and as I was taking the carb off, I noticed the vacuum hose (#7 here http://partsfinder.onlinemicrofiche....TCH%20ASSEMBLY )
had a bad crack along it and couldn't possibly be working properly for the VOES.
So, me and my heavy-handedness tried to take that section off the tri thing and naturally broke the nipple off the VOES *and* the part I was trying to get the hose off of.
Now, I need my bike to be able to work *ALL* the time, as it's my *only* transportation I own. My question now is...my bike is stock, can I just run a vacuum hose from the tank valve (on/off/res) to the carb and the bike will run okay, or will that not work and I have to buy a new VOES and that vacuum line to go with it? If I need to get the VOES to make this run, any idea what Hg I need? I'm a big man @6' 1" and 280, and can't find anything anywhere about what the stock Hg is for this bike
Thanks for any help as quick as possible with this, as I have a doctors appointment in 4 days and am already getting nervous.
#3
Join Date: Nov 2010
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Thanks, GOGOBECK! That's what it is, the stock petcock.
<WHEW!> This sure is a relief. I'd just brought this up too about the cost screwing with me and my fixed income. With any luck the bike will run fine without the VOES for a month, as come October I'm already broke (I may live on a disability check, but I'm responsible and pay *ALL* my bills *before* I get to have any fun, i.e. riding for just the heck of it, etc).
Again, thanks for the fast response and help.
<WHEW!> This sure is a relief. I'd just brought this up too about the cost screwing with me and my fixed income. With any luck the bike will run fine without the VOES for a month, as come October I'm already broke (I may live on a disability check, but I'm responsible and pay *ALL* my bills *before* I get to have any fun, i.e. riding for just the heck of it, etc).
Again, thanks for the fast response and help.
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tar_snake (09-23-2018)
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tar_snake (09-23-2018)
#6
Someone will come along and tell you what the vacuum switch point is (inches of mercury) for your bike.
They are color coded (the oem ones are color coded-not sure about aftermarket replacements) with a paint dot on them, and blue is 4.0 inches mercury, white is 4.0 also and those are for Evo Softails, FXR's, XL's and Dyna's. Red is 5.5 for Late evo FLT's, and no color code is 7.0 for early evo's FLT. Thats all the info I have on values and color codes.
They are technically adjustable but you need an ohm meter and a vacuum pump/gauge (a hand vacuum pump) to calibrate/adjust. There is an adjustment screw under a silicone plug to adjust them.
New ones go for about 40 bucks from reputable online parts places. BTW, make sure you unplug the violet (purple) wire coming out of the voes (or completely disconnect/remove it) while you wait for the new replacement part. You might not even notice a difference in how the bike runs.
There are two curves built into the stock module on your bike. There is a standard low vacuum timing curve for hard running, wide open throttle, etc, and there is a high vacuum advanced curve for for steady cruising, steady throttle, very little load on engine. When the vacuum is high, the voes kicks in the more advanced curve for better economy and less pollution. No VOES means your bike will not switch to the higher advance curve. The bike will do just fine running on the standard curve. Parts of the above VOES description have been referenced from "101 Harley-Davidson Evolution Performance Projects, 2nd edition". (gotta give credit where credit is due). YD
They are color coded (the oem ones are color coded-not sure about aftermarket replacements) with a paint dot on them, and blue is 4.0 inches mercury, white is 4.0 also and those are for Evo Softails, FXR's, XL's and Dyna's. Red is 5.5 for Late evo FLT's, and no color code is 7.0 for early evo's FLT. Thats all the info I have on values and color codes.
They are technically adjustable but you need an ohm meter and a vacuum pump/gauge (a hand vacuum pump) to calibrate/adjust. There is an adjustment screw under a silicone plug to adjust them.
New ones go for about 40 bucks from reputable online parts places. BTW, make sure you unplug the violet (purple) wire coming out of the voes (or completely disconnect/remove it) while you wait for the new replacement part. You might not even notice a difference in how the bike runs.
There are two curves built into the stock module on your bike. There is a standard low vacuum timing curve for hard running, wide open throttle, etc, and there is a high vacuum advanced curve for for steady cruising, steady throttle, very little load on engine. When the vacuum is high, the voes kicks in the more advanced curve for better economy and less pollution. No VOES means your bike will not switch to the higher advance curve. The bike will do just fine running on the standard curve. Parts of the above VOES description have been referenced from "101 Harley-Davidson Evolution Performance Projects, 2nd edition". (gotta give credit where credit is due). YD
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tar_snake (09-23-2018)
#7
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tar_snake (09-22-2018)
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#8
Yes, I noticed about 150 rpm drop in mine when I disconnected the purple wire just the other day. YD
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tar_snake (09-22-2018)
#10
I’m not sure I’d call the vacuum operated petcock “problematic”... but KG is correct in that if it goes out on the road, a tie wrap, tape or bailing wire won’t get you home... but I don’t know of it being a regular occurrence. Something like a points ignition or those crappy inline fuel filters are problematic in that you can lay odds you will be dealing with them on some kind of regular basis.
The issue with a on/off petcock is you better turn it off everytime you stop or you run the risk of having a siphon condition happen and gas starts running out of the carb. I was with a guy once that drained his gas tank while we were 20 miles from anything lol. Lucky it didn’t ignite.
I can always spot an old timers bike in a parking lot... even when it’s a vacuum operated unit, the petcock is always turned off. Years of procedural muscle memory or neurological plasticity!!
The issue with a on/off petcock is you better turn it off everytime you stop or you run the risk of having a siphon condition happen and gas starts running out of the carb. I was with a guy once that drained his gas tank while we were 20 miles from anything lol. Lucky it didn’t ignite.
I can always spot an old timers bike in a parking lot... even when it’s a vacuum operated unit, the petcock is always turned off. Years of procedural muscle memory or neurological plasticity!!
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