Tune out accel pump on 2001 Virage 700 to fix acceleration bog?

[casey67]

I am having the same issue on a Virage 1200! Installed new cylinder heads/pistons over the winter after one carb ran lean and melted one piston. I believe there is suppose to be some pressure on the fuel tank maybe ~1psi, I have noticed when I open my fuel tank I don't have any pressure so am going to look at the fuel cap seal and fuel tank venting this weekend. I also see that hot products sells return line restrictors to help with throttle response. Maybe this would help. See page 150 of their catalog.

Thanks for sharring your experience, but the tripple carbs you have are a bit different from this single carb.
Yes there should be pressure in the tank, that is controlled by 2 valves. Pretty sure it's covered in the tech section. And of course leaks any where in the system will cause the lack of pressure.

The Mikuni carbs use in-line restricters to control fuel pressure. These Keihin carbs have it built into the return circuit in the carb. Increasing fuel pressure will mask other issues like pop-off, but increasing will also cause issues at cruise, running rich where it's not needed.

[rfitts]

I am having the same issue on a Virage 1200! Installed new cylinder heads/pistons over the winter after one carb ran lean and melted one piston. I believe there is suppose to be some pressure on the fuel tank maybe ~1psi, I have noticed when I open my fuel tank I don't have any pressure so am going to look at the fuel cap seal and fuel tank venting this weekend. I also see that hot products sells return line restrictors to help with throttle response. Maybe this would help. See page 150 of their catalog.

[Bluedmax]

Thanks for the tip K447

[K447]

Try these...

https://www.youtube.com/shorts/UJlEDyKbIsk

https://www.youtube.com/shorts/Oj6PP_Plm9s

Tip: To convert YouTube _shorts_ to normal YouTube links, replace /shorts/ in the URL link with ‘/video/

https://www.youtube.com/shorts/UJlEDyKbIsk

https://www.youtube.com/video/Oj6PP_Plm9s

[Bluedmax]

Could you send the videos again I do not see them. I'll see if I can help out. I have had very good luck using the dual carbs with accelerator pump from the older slt sl 700s. Very responsive. No jetting changes. I may have a set, let me take a look tomarrow.

Try these...

https://www.youtube.com/shorts/UJlEDyKbIsk

https://www.youtube.com/shorts/Oj6PP_Plm9s

[Bluedmax]

Thank you very much Ryan!

[car22car]

TX, here's a couple videos I took of the accel spray (hopefully the links still work).
This one the ski is on the trailer and obviously the engine is off... https://www.youtube.com/shorts/UJlEDyKbIsk
This one is with the ski running in the water (which is why it's hard to keep the camera steady and do everything at the same time)... https://youtube.com/shorts/Oj6PP_Plm9s?feature=share
Do either of these help to tell if the spray is normal or not?
Do you happen to know where I could find a good used carb to either try or buy? Ebay is expensive for an unknown part and seems like a crap shoot. Beernutz suggested above car22car might have something available but I'm struggling to find him.

Could you send the videos again I do not see them. I'll see if I can help out. I have had very good luck using the dual carbs with accelerator pump from the older slt sl 700s. Very responsive. No jetting changes. I may have a set, let me take a look tomarrow.

[HiPeRcO]

If you're on Facebook, this is his profile.

Mike Lang | Facebook

I've summoned Mike to this thread.

[Bluedmax]

TX, here's a couple videos I took of the accel spray (hopefully the links still work).
This one the ski is on the trailer and obviously the engine is off... https://www.youtube.com/shorts/UJlEDyKbIsk
This one is with the ski running in the water (which is why it's hard to keep the camera steady and do everything at the same time)... https://youtube.com/shorts/Oj6PP_Plm9s?feature=share
Do either of these help to tell if the spray is normal or not?
Do you happen to know where I could find a good used carb to either try or buy? Ebay is expensive for an unknown part and seems like a crap shoot. Beernutz suggested above car22car might have something available but I'm struggling to find him.

[TxVirageTx]

The brass nozzle check ball not sealing will cause that issue,I had a ton of old carbs and would just replace the entire brass squirter.had to do that on a brand new never run set

[Bluedmax]

I should clarify it was working before I took it apart but thought it was taking too much of a squeeze with the throttle before it would actually squirt (like 3/4 to full throttle to make it squirt). After going through the circuit and putting it back together, it still performed the same. So I’m guess 3/4 to full throttle squeeze is normal to make it squirt.

[Bluedmax]

Thanks TX. I saw one of your older posts and took the circuit apart during the winter to check everything out. Also installed the metal check ball as you mentioned just in case. At first I thought I made it worse because it wasn’t squirting, then got it to work after “priming” it with several pumps.

[TxVirageTx]

The accel pump circuit works like this,the nozzle check ball prevent air from being drawn in that way when the chamber fills,the chamber check ball stops gas from being pushed out that direction.I use to remove the plastic check ball from the metering block chamber with a steel one,fixed a lot of them that way

[Bluedmax]

Thanks K447. I've thought the same thing and have done the following...

Ignition timing - I transferred everything over to the new engine as it. Not sure how timing would change as the shaft / balancer is keyed and nothing moved. I could double check it but would need to learn how to.

I've tried multiple sets of spark plugs (BPR8ES), both old and new.

I've performed the ignition coil test (which I reported on a separate post). Manual says reading should be 0.35 and I measured 0.50. Never received a reply if this is ok or not??

I replaced both complete wires (SBT).

I've checked for engine air leaks (both pressure and vacuum) by plugging off the intake manifold on one end and exhaust pipe outlet on the other end. Had a "slight" leak under pressure only at front housing gasket but have since resealed and no improvement to the issue. The retest with manifolds holds both pressure and vacuum no problem now.

I appreciate the ideas, keep them coming if you have more...

[K447]

It is entirely possible that something else is going on at the same time. Do not assume the only change was the engine swap, or that the only problem cause is the carbs.

Check all the basics, including actual ignition timing.

Correct spark plugs installed.? Perhaps install another known good set of spark plugs.
Sometimes new spark plugs are bad right out of the box, sometimes they xan be counterfeit.

Check ignition coil ohms. Check ignition wire ohms, Check plug wire ends. And so on.

Recheck for air leaks in the air intake/carb system.
More work, but sometimes the engine itself has an air leak.