VTR Vacuum Hose problem.
 

Hey there
I need help with my 98 VTR.
I just switched back to original gas`tank from my race gas tank.
The race gastank had no petcock, so fuel was flowing straight into carbs.
Now I put back the petcock with the vacuum hose attach at the rear of petcock and to the front cylinder vacuum port (under the carb on the left side).
The bike runs great untill I get to arround 80-90 MPH and keep that speed for about 30 seconds. Then it starts starving and loosing one cylinder.

I have to back off the throttle and it takes about another 30 sec to get both cylinders back again.
It runs fine in the canyons and accelerates great.
It looks like it's not getting enough gas at continous high rpms.

My question:
is the vacuum hose conected the right way?
what's the open position for the petcock switch? it's hard to say from the "on" sign on it since it has no arrow and also it looks like it's not releasing gas withaout the vacuum off and is releasing gas with the vacuum on in all positions.

Thank you

Vtierry

Check for vacuum lock, try to open the gas cap, other than that the gas valve turned to full lock is either closed or fully opened, no where in between.
You may have a vac leak, check that vac hose for leaks, it need to run from under the rear carb from the head to the rear of the petcock

ok, I'll switch to rear cylinder!
 

ok, I'll switch to rear cylinder!

Yeah. I was confused by your original post. You said front cylinder/left side of bike. Vacuum nipple for front cylinder is on the right, rear is on the left, the one closer to the petcock.

Left/right corresponds to your body's left/right as you are sitting on the bike. Facing forward!;)

Vacuum hose
 

You and the hose are both right.
I guess I sipped to much gas trying to check that petcock...

I'll work on it tonight.

Also make sure that the vacuum line to the petcock is hooked properly. It should go to side of the petcock, not the bottom

LOL. I did that. I labelled all the hoses carefully, but put 'to tap' on the vac hose .... and refitted it to the bottom.

The tap let gas into the front cylinder carb, but not the rear.

Confused me for a while :confused:

Paul.

and after how many beers did this happen paul?:)