98 vmax seems to dog after 5krpm

[98blackmax]

My vmax seems to be staving for fuel after 5k more so in higher gears then 1-2. I dont know if the v-boost just isnt opening or what but it does seem like it randomly will come alive for a second if i keep the hammer down but its acting like a dirty fuel filter.

what can i check?
Plugs?
Wires?
Fuel filter?
clean carbs?:ummm:

would hate to cause a lean condition at 8k rpm and melt a hole :surprise:

Thanks
Kevin

 

[maleko89]

I'd start with what you listed. Plugs, wires, wire boots, fuel filter, intake boots.

 

[Robbarrie]

I'd also seafoam the carbs and then have carbs sync'd by a trusted dealer and go from there. Have you made any changes to your bike ? Like pipes, air box, ect... Can you hear the boost open and close when you turn the key on ?

 

[98blackmax]

Yea ill start with a basic tune up.

To sea foam the carbs do i just shoot the stuff down the throats while its running like i did to my dakota?

I only pulled the baffles off the pipes, didnt change them at all. I did this mod months ago (4000 miles ago) and it just started doging within the last 20 miles.

Thanks
Kevin

 

[Lew L]

Hi Kevin,
I also have a 98 Max. Sure sounds like a fuel filter to me. Get some extra fuel hose and hook it to the outlet of the filter and let the pump run for 10 or 15 seconds. Regular tune up stuff certianly can't hurt either.
Lew

 

[maleko89]

Yea ill start with a basic tune up.

To sea foam the carbs do i just shoot the stuff down the throats while its running like i did to my dakota?

I only pulled the baffles off the pipes, didnt change them at all. I did this mod months ago (4000 miles ago) and it just started doging within the last 20 miles.

Thanks
Kevin

You can, just a few drops and that'll clean the intake valves and manifolds pretty good. Otherwise, do the peashooter.
http://home.comcast.net/~onlyone12/carbs1.htm

 

[shawn kloker]

I would dump a bunch into the gas tank too.It will clean everything.I use it in all my gas tanks over the winter for stabilizer.

 

[maleko89]

I use it in all my gas tanks over the winter for stabilizer.

Shawn, your Vmax is running more than one gas tank? No wonder you get 200 miles per fill-up! lol

 

[98blackmax]

i tried cleaning the fuel filter last night, didnt help. Im gonna get a new one and some sea foam to clean the carbs cause the plugs are WHITE white=lean=bad

Thanks
Kevin

 

[98blackmax]

bike misses and backfires after 5k will spin 9k but not happily. Plugs are still white.

 

[vmaxinID]

Peashooter? 2-3 times

if no improvement

Shotgun

 

[98blackmax]

where are the brass plugs i have to drill out to get at them mixture screws?

Thanks!
Kevin

 

[maleko89]

It's the pink arrow on the left carb. That's where the plug will be.

Mark

 

[98blackmax]

thanks!

Kevin

 

[98blackmax]

ok i drilled them out and tried to turn them 3 of them turned 1 turn out before becoming hard to turn and one turned 2 turns no problem. Im going to try the pea shooter a few times even though they are only half way out. I put penetrating lube in them should i let it sit over night with the lube in them? Will they break loose then?

Thanks
kevin

 

[shawn kloker]

Its best to go in just a little ,try to clean the threads, then come out.They are very easy to strip out.

 

[98blackmax]

clean them with what?

 

[Buster Hymen]

clean them with what?

You try and clean them with the screw you are turning. Turn it out a little bit, then back in, then out, then in.... etc, each time turning a bit further out. When you feel it starting to bind, turn it the other way. This helps clean the threads and prevents you stipping the threads or breaking the bolt.

 

[shawn kloker]

Penetrating fluid and compressed air help too.

 

[Lew L]

With the white plug insulators you describe, it sounds like your ready for:
** a trip into the carb float bowns to check the mains.
** a flow test of the fuel pump.

Many moons ago I had a piece of wood stuck in the outlet of the gas tank. Back when they used to check the fuel level of gas station tanks with a long stick of ( you guessed it ) WOOD.

Good luck, Lew