Bike cutting out a little

[Beau254]

Hi everyone. I have a new to me- 1992 Vmax. I did a oil/Filter service on it recently & changed the Spark plugs.
I've noticed that it does fine @ idle & under throttle, But when you first start to to take off, it has a little mis/cut out to it, until the throttle pic up a bit. I know it sat 3-4 months prior to me purchasing it. Also, I was told by the previous owner that it has a Performance Jet Kit in it. I saw Pea Shooters Carb clean video on YouTube & was thinking of trying that this weekend. (Spraying out the Jets.) But just wondered if this was something any of you who may have a Jet kit installed has experienced? (If that’s normal?) Let me know if anyone has any other recommendations? (Other than a card rebuild/sync.) Which was done the prior year by the previous owner. Thanks!

 

[02GF74]

Other than a card rebuild/sync.) Which was done the prior year by the previous owner. Thanks!

Well you can guess what I'm going to say.
I bought mine just over a year ago, last time it ran unknown, cleaned out the carbs, pilot jets blocked solid, covid came along so wasn't allowed to use it, just under 6 months had to take carbs apart, pilot jets blocked again.

If I find i have to do this every 6 months then either looking at efi or cb1100rs.

 

[desert_max]

Two words: “Fuel Treatment”

 

[02GF74]

Yeah idid add additive but four words : 4 months too late.

Would turning the ignition on a couple of times a week so the pump fills the bowls work?

 

[Beau254]

Two words: “Fuel Treatment”

Ya, I got some sea foam. Going to do the jet clean out then Seafoam it.

 

[Beau254]

Well you can guess what I'm going to say.
I bought mine just over a year ago, last time it ran unknown, cleaned out the carbs, pilot jets blocked solid, covid came along so wasn't allowed to use it, just under 6 months had to take carbs apart, pilot jets blocked again.

If I find i have to do this every 6 months then either looking at efi or cb1100rs.

That sucks. Ya, I looked @ EFI too, but cha-Ching! $$$

 

[Beau254]

That sucks. Ya, I looked @ EFI too, but cha-Ching! $$$

Mega-squirt TBI system. But injectors can clog too. I’m betting it’s due to previous owner running Ethanol fuel. & then leaving it setting in carbs in off-use. If you do you gotta drain them. I get that Non-Ethanol Murphy gas. That way it’s not as big an issue. Can also use stabil. But that Ethanol will trash a fuel system. Especially when it sits.

 

[desert_max]

And that was the fuel treatment I was referring to. Treat the gas BEFORE an extended layup. Helps stabilize the volatiles that evaporate off leaving varnish behind. Seafoam is typically an attempt to clean that mess up. Better to prevent it in the first place.

 

[02GF74]

Agreed, draining them is an option but the screws are not that easily accessible and sods law that I'll drop one onto the engine never to be seen again.

For the now, I'll try the "turn on pump couple times a week" to keep the carbs full method.

 

[Beau254]

And that was the fuel treatment I was referring to. Treat the gas BEFORE an extended layup. Helps stabilize the volatiles that evaporate off leaving varnish behind. Seafoam is typically an attempt to clean that mess up. Better to prevent it in the first place.

I hear you, but this issue was already present when I purchased the bike. Setting was from prior owner. & Like I say, I only run non ethanol gas in it.

 

[Beau254]

Also, I’m getting crappy fuel mileage. Of course, I’ve been romping on it pretty good. Are you guy’s bikes this thirsty? I realize it has 4 thirsty carbs. But still. I used to have a Kawasaki Eliminator & it wasn’t this thirsty. Of course the Vmax has a Jet kit installed like I mentioned. The bike seems to be set up for racing.

 

[02GF74]

this issue was already present when I purchased the bike.

Also, I was told by the previous owner that it has a Performance Jet Kit in it.

Do you have part numbers/details of what was fitted?

Changing carb jets/needles needs to match other changes such as exhaust, air box, engine tuning mods etc.

There is loads of info and knowledge on after market kits on here, some work better than others.

 

[user 16790]

I cruise mostly but with an occasional dip into v-boost, my miles per tank are usually about 120'ish until the warning light shows, my mate had one and ran its tank empty in a little over 50 miles due to v-boost addiction

 

[Beau254]

Do you have part numbers/details of what was fitted?

Changing carb jets/needles needs to match other changes such as exhaust, air box, engine tuning mods etc.

There is loads of info and knowledge on after market kits on here, some work better than others.

No, I do not have the specs. Think the previous owner said stage 7 maybe. It also has a an aftermarket UFO Quadzilla exhaust.

 

[Beau254]

No, I do not have the specs. Think the previous owner said stage 7 maybe. It also has a ln aftermarket UFO Quadzilla exhaust.

Agreed, draining them is an option but the screws are not that easily accessible and sods law that I'll drop one onto the engine never to be seen again.

For the now, I'll try the "turn on pump couple times a week" to keep the carbs full method.

Now that you mention that. Where are the bowl drain screws located? You have a pic of the location maybe?

 

[Beau254]

The cut-out I’m experiencing is in the same throttle position every time. Right @ start of acceleration. Especially from a stand still take off.

 

[Fire-medic]

Now that you mention that. Where are the bowl drain screws located? You have a pic of the location maybe?

Arrows.

 

[Beau254]

Thought so. Thanks

 

[Beau254]

Well, I did the main Jet & choke Jet carb clean with spray carb cleaner with spray nosel spout while running @ idle & @ high idle. Then drained the bowls & sprayed them all out with carb cleaner as well. Then put in all fresh gas with Seafoam conditioner. Then went out & ran the Piss out of it. Lol.
Definitely is idling better now & running smoother. But it still has that low initial acceleration stumble. I’m thinking it’s due to how it’s jetted for top end. (Stage-7 Jet kit with aftermarket Quadzilla exhaust & K&N air filter.) Anyone else with a modified bike experience this?

 

[Fire-medic]

I have a UFO 4/1 (UFO makes the Quadzilla while Cobra makes the 4-into-4 slip-on, not a complete exhaust) and whenever I have a stumble off-idle, I check the gas tank, the fuel filter (replace it) and just remove the carbs, open them, and put 'em into the ultrasonic tank, and reassemble. The two brass jets have to come-out of each of the jet blocks' tunnels, and the main jets, too. Blow-out the passageways before reassembly, of course.