996thehawk

I did a quick search, found some similar issues but no conclusions.

A little about my bike.

All stock except Staintune Exhaust and dreaded K&N Air filter. New stock plugs, always ran 93, aftermarket fuel filters. About 21k miles.

The first winter it sat which was about 2 years ago, I started the bike and it ran good. Out of nowhere it started to stall out and run rough. Wouldn't hold an idle. Seemed like it was running on one cylinder. After warming up it ran fine. Didn't think much of it.

Then I ran out of gas last year. Had a buddy top me off and started it up and it did the exact same thing. Ran rough as if it were running on 1 cylinder ago. After getting aggravated I just rode it home. After hitting 2nd gear around 4-5k rmps it cleared up and ran perfect all summer.

Then, late last year it started doing the same thing out of nowhere. I was riding normal, cruising down the street and it started again. I parked it, changed the plugs, cleaned the air filter, changed the fuel filters and it ran good again for a few hundred miles until I parked it for winter. Always with a full tank with Stabile.

Yesterday I take it out for my first ride of the season. Running beautifully for about 10 miles then it began. I nursed it to where I was going and parked it. Went back out an hour later and the exact same thing. Couldn't get a ride home so I just rode it. After about 10 miles of stalling, back firing and people giving me weird looks I opened it up and went through the gears. Out of no where it cleared up and ran perfect for the next 5 miles until I got home.

I thought I fixed the issue with clean filters and new spark plugs but obviously not. This all happened over the course of a few thousand miles, since I got the bike. When it runs good its good.

Any ideas of where to begin with this issue? Intermittent issues are the ones that stump me.

thetophatflash

I'd check fuel flow and the spark color to start. With exhaust and the K&N and no rejet, you are running lean.

996thehawk

I forgot to mention the jetting. I have no idea if it is jetted or not. I thought Staintune bragged that no tuning was necessary. There was one time that It was running rough and I pulled the tank, the one fuel filter was bone dry. I'm assuming a fuel issue as well. What would prevent fuel from flowing though? If the petcock was bad, would it prevent fuel from flowing to both fuel lines or possibly just one? Is it even possible that a K&N could cause an issue like this? I know everyone hates them, but I've had them in everything I've ever owned with the exception of my John Deere lol and never had a problem. Thank you for the reply.

Wicky

As standard there's only a fuel filter in the tank attatched to the petcock. Or do you have in addition aftermarket inline fuel filters on both the fuel hoses?

With a K&N and freer flowing pipes you'll need dynoing and rejetting.

After storage / having the tank off - Have you switched the petcock back on and attached the vacuum hose correctly?

Re fuel filters. Were they primed to allow flow. checked that they aren't gummed up? I fitted a pair for a friend on her VTR as extra insurance after she had a respray and they could wet lock up preventing fuel flow unless primed.

smokinjoe73

My bet is crud in your tank. You should never let a bike sit & then just start it up. Condensation will cause water, then tank scale etc cause debris.

Save yourself a lot of labor and drain your tank to totally empty. Remove the petcock if possible or at least shake it upside down. You should also clean the carbs at this point but a clean fuel supply goes a long way to making your life better.

Another lifesaver is inline fuel filters. Its pretty easy for the heartache it saves. I posted a thread on here somewhere on doing mine.

You should for sure clean the carb jets as they are small & don't get cleaner on their own.

I don't see any possibility that you don't have crud in your jets. Even if it clogged then cleared up, its only a matter of time.

BUT, with an old cruddy tank, no amount of carb cleaning will help since more crud and water is on the way downstream.

AndyMX47

agree - jetting and a K&N may cause poor or weak running, but not likely deathly stumbling one minute and decent running the next.


clean and dump the tank, clean the carbs. Use caution when cleaning the carbs to not intermix parts - the needles are different from front to rear, and sometimes they may have different needle height settings.


Check the float needles when you are in there too. A sticking float will make it run like crap for sure.

996thehawk

I'll be replacing the K&N either way. Seems it does more harm than good.

There are aftermarket NAPA fuel filters in each fuel line going to the carbs.

I never turned the petcock off or disconnected any of the fuel/vacuum lines during storage. So it is definitely not that.

I thought that the aftermarket fuel filters were possibly restricting fuel flow. Would anyone recommend going back to stock fuel lines w/o filters?

I guess I'm looking at a carb and tank clean. I will get to this asap and check back. Any other advice while I'm in there would be greatly appreciated. Thank you all for your help.

8541Hawk

I would suggest removing them.

Some folks like them but I have seen issues in the past by running them.

To me, the filters are designed to be run on a pressurized system (something with a fuel pump) and in a gravity feed application they might cause a flow issue.

I have only run the tank screen in my bike. Bought new 9\97 and have never experienced any issues with getting gunk in the carbs.

Of course this is just my opinion and YMMV.

smokinjoe73

I think that similar to saying "I never got a flat so you should be fine". Just sayin.

CruxGNZ

FYI, my tank has see through Mr. Gasket #9748. There is a thread about it here. Give it a read.

In that thread, I found the previous owner removed the stock (plastic & brass mesh) filter on my petcock. If you decide to remove those aftermarket fuel filters, make sure the P.O. of your bike didn't do the same thing as mine did.

996thehawk

I've decided to start with new fuel lines, new stock air filter, and I'm going to pull the petcock out and clean or replace the screen. I will check back if I come across a solution. Thanks again for all the help.

8541Hawk

Using that reasoning you could say you guys are similar to saying "I'm so scared of getting a flat that I'm going to fill my tire with patches, just in case"....... just saying.

I gave my honest opinion that the filters could be causing an issue.

I have never heard of VTRs or Honda road bikes to have an issue with gunk coming from the tank.

So IMHO putting aux filters inline is fixing a problem that doesn't exist and adding extra places you can get a fuel leak.

When was the last time you had to clean one of those filters?


So do whatever makes you happy but I'll stick with the tank screen that has worked without fault.

Cadbury64