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Posted

Hey all,

I'm new here. I am getting horrible gas milage and always have (roughly 28 mpg). When on the highway (single up and have windshield on) my low gas light comes on at 120 miles. Around 15 miles I have to switch to reserve. I bought this bike used about 3 years ago from a dealership in CO. I always thought the milage issue was because I was riding in the mountains but now that I am no longer in the mountains I have the same issue. I have had my carbs redone (by a dealership) to get the gunk out of them because I was deployed for a year and there fore didn't ride it. they stated that whenever they do a carb job they also sync them afterwards. I have had an oil change done as well as the air filters replaced.

 

So, That was a very long way to ask if it is pretty ez to change out the jets for someone who isn't really mechanically inclined. I am ok and have taken the bike apart as far as the carberator but was unable to get the carbs out because I didn't have the manual (which I now do). Do you think it would be better for me to just take it into a shop to have them do it? Any insight is greatly appreciated.

 

Tx!

Posted (edited)

This doesn't really answer your question but.

My mileage is about the same as yours light comes on around 120 miles (I've never switched to reserve) I fill up and do the math I am around 29-31 mpg. I like you assumed it was my riding style/area (short trips most days 3 miles one way to work). My bike also was previously owned by a guy with too much money and was dealer maintained,(HAHA) including having the carbs off, cleaned and synched at around 10K miles, due to "Bad" fuel, by the receipt($425.00).

 

I was about to have the carbs off again and have the floats and jets checked, before that I did the following: complete oil change with synthetic oil ( I use the 10w-50 instead of the 5w, because its a little warmer here in good old FL) I also replaced the air filters with K&N filter chargers (fancy name for a high flow design) I also changed my driving style a little bit, Keep the rev's up!!! don't go into 5th at any speed under 55mph!! shift in to second much later, DONT lug the engine EVER!!. my around town mileage is up to 39-42 and my last trip (still stop and go did all back roads) closer to 50 MPG!!

 

I'm now on to my third tank since the changes, and this one will be all back and forth no excursions or little trips in the near future, wil see if the mileage hold up!

:backinmyday:

Edited by baylensman
cant spell worth a dang
Posted

Got to agree with baylensman. Before doing any changes first try running at higher rpm's. At 45 to 50 mph 3rd gear and up to 65 mph 4th gear is best. Unless I am running on pure flat ground I wouldn't even think about 5th gear until 65mph. These bikes like to run at a higher rpm. If you run them at a lower rpm it may sound like it is running at a better mpg but it is actually having to use more gas. Give the higher rpm running's and see if that doesn't help your mileage before doing any changes. It might save you some unnecessary money and you will get the advantage of some great riding time as you try different rpm settings.

Posted

i did the Ivan's jet kit myself when i had bike apart for valve adjustment. i didn't find the job too difficult. i did not see an increase in mileage but when i stop using the extra ponies i still get 35-40.

  • 2 weeks later...
Posted

Okay, I tried the higher RPM suggestion. I just did my calculations on two tanks of gas. Using the higher RPMs suggestion I now get less gas milage (25 on on tank and 26 on the other). I can't think of anything else to do other than change out the jets. Any other suggestions on the gas milage? MOst of my miles are city since I mostly do city driving with a commute to work of only like 3 miles. Thanks!

Posted
Okay, I tried the higher RPM suggestion. I just did my calculations on two tanks of gas. Using the higher RPMs suggestion I now get less gas milage (25 on on tank and 26 on the other). I can't think of anything else to do other than change out the jets. Any other suggestions on the gas milage? MOst of my miles are city since I mostly do city driving with a commute to work of only like 3 miles. Thanks!

 

I wonder, can you smell the engine running rich? I found that if your filters are clogged you will get bad mileage. Maybe you simply have fouled plugs causing low MPG? Also, I understand that if your valve clearances are off, you will get bad mileage.

 

I know it's apples and oranges but, I have a Dodge diesel and it had lost some of it's zoom zoom. Being that I only put 5k a year on the truck I just thought.. its 13 years old and... well.. its old.. Winter is on its way and I decided to give the old dragon wagon the once over. I had put bigger injectors in about 5 years ago and thought maybe they were part of the low performance/mileage problem. I was about to change back to the stock injectors when I started looking on the forums for advice. I read that the valves were supposed to have been adjusted at 150k.. DOH!! I'm at 209k... Thankfully, the adjustment process was pretty easy. As I was putting the valve cover back on I noticed the vaccume indicator for the filter was at 90!! That means the motor was starving for air.. SON OF A!! I NEVER let things like that happen! I popped the cover off and found that a mouse had built a house in my intake tube.. Long story short.. The old girl is back in prime form!

 

Anyway.. diesel or not the same principle applies. Engines need to breathe, after all they are just a big air pump, right?

Posted

One thing you might check are the vent hoses for the carbs....you will have one for left carbs, one for right carbs and they run forward past air intakes

and down into lowers.

 

If there is a blockage in the vent either in the carb or hose the carb will pressure up and run rich. Sometimes insects will plug the hose.

 

You might also pull spark plugs and see how they look.....might show one or two cylinders running rich etc.

Posted

Your gas mileage is a problem, and any jet change is just going to make it worse. When the carbs are clean and funtioning on a stock 2nd gen, the jet sizes are just perfect.

 

These bikes rarely get great fuel mileage - most people get mid to upper 30s. Mountains generally do not make it worse, since that often keeps the speed down. The only time I ever broke 50 mpg on my 05 was in the mountains!

 

Riding style makes a huge difference, and the biggest drain on economy is wind drag (SPEED). You should never get less than 30 unless you are riding at least 80 MPH and have a head wind. At high speeds and no head wind you should still get at least 32 mpg.

 

Keeping the revs at a reasonable level is important, but it should never make your fuel mileage less in normal riding, and it CAN improve your economy if you have been riding the bike like a v-twin.

 

Running on only three cylinders certainly will give you the problem you describe, and believe me, the average person who does not already have a lot of experience with one of these bikes CANNOT tell they are only running on three! Do the fingertip test on cold headers to see if all four are at least hitting when first started.

 

If all four cylinders are firing properly, then your problem is definitely in the carbs. (which includes the full air intake tract). Good luck,

Goose

Posted

So, I did the fingertip test, or at least what I thought it was. I ran the bike on idle for about 2 mins, periodically putting my hand on the cylinders to check for heat. They never got to hot, that is to say, I was able to leave my hand on each one for an extended period of time. They all seemed about the same temperature. I am hoping that is what was meant by the fingertip test. :D

 

Ha I just read a thread on here that explains the test in more detail, about touching the mufflers right at the headers. hehe I will try that once the bike cools down. hehe

Posted

Goose,

Your fingertip test seemed to show that the front right cylinder is not working properly. I was able to keep my finger on that pipe while the rest were hot and I was only able to touch them quickly. So can anyone tell my how to fix this? Is it as easy as a spark plug or is it something else? Do I have to take the bike into the shop to fix it?

Posted

rule out the easy stuff first, check plug cap resistance and plug or coil to make sure you have good spark before yanking the carbs:detective:

Posted
Goose,

Your fingertip test seemed to show that the front right cylinder is not working properly. I was able to keep my finger on that pipe while the rest were hot and I was only able to touch them quickly. So can anyone tell my how to fix this? Is it as easy as a spark plug or is it something else? Do I have to take the bike into the shop to fix it?

 

 

Pull the plug and ground it with the bike running and see if you get a spark. Good spark, make sure the cylinder is getting fuel. Bad spark (likely) check the plug, cap and coil.

 

Careful not to get shocked!

Posted
Goose,

Your fingertip test seemed to show that the front right cylinder is not working properly. I was able to keep my finger on that pipe while the rest were hot and I was only able to touch them quickly. So can anyone tell my how to fix this? Is it as easy as a spark plug or is it something else? Do I have to take the bike into the shop to fix it?

The fingertip test is just the first step of this problem. Since that test only checks how fast the pipe heats up at idle, it USUALLY points to a clogged pilot jet. Unfortunately, that is probably not your problem, since a clogged pilot jet only causes mild problems at speed where your fuel mpg numbers would be most affected. But it does give you a pointer on where to start.

 

If the the #4 cylinder is not heating up at idle, then maybe it is not running at all - in that case, the problem is most likely ignition, either (in probability order) plug cap, bad plug, bad coil, or ignitor. The most simple check on any ignition at all above idle is to just rev the engine a bit while still doing the fingertip test - if the problem is only a plugged pilot jet, the pipe will sizzle quickly as soon as your raise the revs. that will keep you from wasting time running down ignition problems when you simply need to clean the carbs.

 

But no matter what else you find, I would strongly suggest you do two things - change the plugs (or at least switch the two right plugs so you can easily see if the problem follows the plug or stays with the cylinder), and take off the plug caps to measure the resistance. High resistance due to internal corrosion on these bikes is common - look for more details in older threads. You want to see about 10,000 ohms on each cap (just going from memory here); anything above 12K is a problem.

 

Do those additional tests, and we can tell you where to go next.

Goose

Posted (edited)

I did do the spark test while running the bike and I did have a constant pulsating spark. The plug was pretty black (I think it was carbon cuz it wasn't wet). I cleaned it and put it back in. I just replaced my plugs in Mar or Apr. I will try the switch with the plugs. Hopefully I get to work on it some more tomorrow and if not I guess it will be Sunday. I will try the other thing with the ohms as well after doing a search on here on what to do. Thanks all for you help thus far!

 

Also, Can I purchase just plug caps? I haven't changed the plug wires since I bought it in 2011 so not sure if maybe they are due to be changed as well.

Edited by hoochster
Posted

On my 1st gen the wires easily come off the coil so it is easy to swap in new wires. I believe it is different on your bike. In any case the old caps will come off, you can clip a little off the end of the wire and replace with new resister caps.

Posted

So I plan on checkking the resistence tomorrow. I do have a question about that. I plan on using a home multi meter, Do I plave the tip on the outside rubber part of the wire or directly in the wire (inside of the cover)? Also does a multimeter work for this or is a special tool needed?

Posted

Brian,

 

We just dealt with what you describe with one of our Houston members bike at our maintenance day last weekend. He was getting 25 mpg, the bike ran good, but horrible gas mileage. He decided he was going to put the Ivan's jet kit in it, and he did. He also pulled the carbs off and what we found were floats that were WAY out of adjustment. I set his floats to the manual specs and when he rode it home it went from 25 to 41 mpg. I'm not saying this is your issue, and I would definitely do the easy stuff like plugs and caps 1st. Many of the dealers do not have a clue how to work on the Venture little own a carbureted bike....just my :2cents:

Posted

Thanks Squidley, I will keep that in mind. I also wanted ot mention that when I did the fingertip test yesterday morning when the bike was completely cool I found that the whole right side wasn't working correctly. I found that while the left side was hot the right side front remained pretty cool and the right back was just warm. Not sure if that matters but that is what I found.

Posted

Remove all 4 Plug caps, and do a Resistance check of all 4, ( number them ) to keep track of which cylinder it came off, of.

 

Make sure all 4 are about the same resistance. You can take them apart and remove the internal Resistor. If this is a high milage bike. I higly recommend you get a new set of NGK, plug caps.

And of course a new set of plugs can't hurt anything.

 

Also, you might have a failed, or failing Ignition coil on that cylinder.

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