Purchased an 87 VR a last week (named it PV1... cause I actually bought two VRs... this one, and an 86 (named PV2)). Normal story with PV1... been sitting a while... has some carb issues.
I've pulled the carbs (twice, so far). First time was to fix an overflow issue with carb #2 . Float tab had pulled away from the float needle. Easy fix. Got it started (without pouring fuel out the overflow)... but running poorly. Pulled the carbs a second time to clean every every nook and cranny in it.
Bike starts easy now. Idles good.
Problem: Bike does not throttle up worth a hoot. Running at least 1/4 to 1/2 choke helps tremendously. Assuming this is a pilot circuit issue (though I cleaned the pilot circuit very good) or possibly a vacuum issue. I've read several forum posts where folks have had to go through the carbs multiple times to get them right.
Things I've done:
-disassembled carbs (one at a time) and cleaned.
-used Seafoam Deep Creek; Carb Cleaner; compressed air; one pilot jets was totally clogged; some gunk in the bottom of a couple of the bowls;
-all jets were sprayed and cleaned several times. I also ran a carb orifice cleaning tool through everything... and ran a small wire through the pilot jets to clean them out. I had good round circles in all jets when holding them up to a light. Sprayed carb cleaner and compressed air through every hole I could find.
Reassembled carbs... bike still did not throttle up worth a hoot.
-Sprayed carb cleaner all around looking for a vacuum leak. Didn't really find anything.
-I filled the pilot circuit with Sea Foam Deep Creek and let it sit over night.
-Disassembled diaphragm ends and all rubber is intact and looks good. Cleaned and shined the slides. Sprayed jet.
-removed pilot adjuster screws (screw/spring/washer/oring). Cleaned good. Ends looked good. No deformity.
Bike still won't throttle up worth a hoot.
*Note: I did not replace any orings or gaskets in the carb.
Things I've noticed:
-vacuum ports on the intake boots do not have individual hose caps on them. Carbs 3 and 4 are connected together with a short tube (port to port). Carbs 1 and 2 are connected to a tee which splits off and goes north to the boost port (not sure what the boost port is. I've not researched that one yet).
Question: Is that configuration okay? (Note: I've tired reconfiguring it to have individual caps on them. This did not change anything).
-Right side carbs (3 and 4): If I remove the vacuum line from either port (Remember, those two carbs have a joined vac line).... the motor immediately tries to die unless I add throttle.
-Left side carbs (1 and 2): If I remove the vacuum line from either port... the motor speeds up a bit. (Remember, those carbs have a common vac line that also goes to boost).
-Right side carbs: With the airbox off... if I spray carb cleaner into the throat of either carburetor the engine starts to die (quickly).
-Left side carbs: If I spray carb cleaner into the throat of either carb throat... nothing happens. (I mean nothing! Engine does not speed up).
Question: Why would the two sides respond differently?
Currently, engine starts and idles very good. Slides pulse when I try throttling up... but, no power and it just bogs down. If I turn the choke on... of course Idle goes way fast... but, it will rev. I've added choke and rode the bike a little distance and it runs okay. Without choke... it can't even find enough power to climb my driveway.
Next Steps:
-My plan is to drain the carbs and fill it full of Sea Foam... turn it over a little bit and let it sit a day or two. Then drain Sea Foam and see what happens.
Also... I've NOT sync'd the carbs yet. I don't have a vacuum gauge (yet). Could this be the issue? (I would not think so... but, I refer to those with more carb experience).
I welcome your Thoughts? Suggestions? Additional questions?
Thanks all!
Paul