Need carb help PLEASE

[Guest Swifty]

86VR, was running rough on acceleration, took carbs off, professionally cleaned, new gaskets, I installed new diaphrams, replaced a frayed cable.

Acceleration problem solved. Engine runs very good! Engine idles very smooth.

The problem now is that the engine doesn't come down off revs fast enough. This creates obvious problems when shifting and coming to a stop.

The throttle grip moves freely, it springs back nicely; but the engine stays reving for 3-5 seconds falling down very slowly until it reaches about 2000rpm where upon it quickly falls to idle like it should.

I've checked that everything is property seated.

All hoses and caps are good, properly attached.

I've check for air leaks around the boots and the airbox.

I've triple checked the junction box, cables moving freely.

I've moved cable adjustments to each extreme and back.

Is this just need of a carb tune?

HELP!

[steve crossley]

this sounds like you are in bad need of a carb sync .

[Yammer Dan]

Or somebody missed pilot jets when cleaning. Sea-Foam Soak and hope they are only partly clogged.

[GeorgeS]

Sounds like you need to Sync the Carbs. Get the " Carb Tune Tool ". Money well spent. !!!!

 

Also, check your throttle Pull Cable, at the Left Fwd, Carb. Check to see if there is any free play, when moveing the throttle , before the Linkage starts to move.

Should be at least 1/16th to 1/8 inch of freeplay movement.

 

Also, Lubricate the throttle mechanical linkage parts. Just in case something is sticking mechanically.

 

Most likley you just need a Sync job. I would do that first, and go from there.

[warthogcrewchief]

I had a similar problem with my '89. It would rise up to 3K RPM, and sometimes idle high. After checking the throttle cables and syncing the carbs and it doesn't fix it, check the float levels.

[mrich12000]

Air leak some where.. Check the boots,air hoses ect..A propane torch with the burner

removed, install a hose on the brass end and search for the leak. The engine will gain rpm and then you have found the trouble..

 

Also a great carb and aluminum cleaner is Pinsol. Use it straight and immerse the striped carb block...Google it Honda forum AVD rider had a great story on it today(mechanics corner)

[Condor]

I've experienced the slow return to idle on several sets of carbs.... even after syncing. I've cured the problem by backing off all the sync screws, and starting from scratch. Amazing the difference in acceleration and response, and overall engine performance.....

[CdnDave77]

... take 10 mins and pull your plugs individually, see if any of them are real white/lean. That might help pinpoint the problem. I have found that almost all carb issues can be diagnosed by looking at the plugs.

 

From what you are describing, it sounds like a slider in one cab may be hanging open a little (slight bit of dirt/corrosion or the new diaphram may not be 100% seated .. who knows). If you pop the airbox off, you may be able to witness one slider staying open a little longer than the others (the gradually decreasing to 2000, then dropping normally). If it is not the sliders, I would also take a glance at all your enrichment plungers (chokes). If one is hanging open a bit, maybe you are getting more fuel to that carb ? It should bog when warm, rather than rev higher... but stranger things have happened.

 

If you don't have a synch tool, you are welcome to use mine... I am not that far. Just send a PM.

[Guest Swifty]

Thanks for all your replies,

in first post when I said I checked for air leaks, I DID the propane trick,

the plugs were fine, I should have said that in first post too...but thought that'd be a standard thing,

the cables were fine, I checked them lots, adjusting them back and forth to their limits.

AND SO THE PRIZE GOES TO THOSE WHO SUGGESTED CARB TUNING!

...which I was going to go anyway but had to wait to pick one up.

So this morning (instead of going to church to pray!) I went over to BradT's place and got the carbtune, hooked it up, #2 was UP IN THE CLOUDS, #1 wouldn't ever register in the tube. I found that amazing given how smooth the idle was...any explanations for that?

I cranked those screws 5-6 turns to get them in line, and right away any cranking on the throttle brought the revs back down immediately. Took it for a quick run and I knew it was fixed. I'm so happy I could kiss Tuckett's ugly face.

BUT I'll wait to have it all back together before I do that and maybe the feeling will pass.

[dogman]

Glad to hear it's running proper now.

Enjoy your trip when you leave.....soon.

[BradT]

If it is running so good why did I see it on a trailer ?

 

PS I glad the feeling passed by the time I saw you.

 

Brad