Only run's with choke on

[Jason Schmidt]

Hello guys. I'm new to the forum

Just bought a '85 VMax. I was sitting for a year.

Start right up but will only run with the choke on. Dies when you try to increase the throttle or turn off the choke.

Seams like a carb problem.

Ran Seafoam through it on idle for 15 min's and did the shotgun. Nothing changed.

Am I going to have to do a complete rebuild and if so is there a kit?

 

[maleko89]

Check your fuel filter and float levels first.

Most likely your pilot fuel jets are plugged. Try the Peashooter:
http://home.comcast.net/~onlyone12/carbs1.htm

Otherwise, you'll need to break open the float bowls and remove the jet block. Remove the rubber plugs and remove the pilot fuel jetand clean it thoroughly. There are 2 rubber plugs. The PFJ is behind the rubber plug on the side....not the center tube.

http://www.vmaxforum.net/attachment.php?attachmentid=1009&d=1180028722

Mark
#1098

 

[one2dmax]

of course the main question is: are the slides even moving freely?

Sean

 

[maleko89]

Slides don't have an affect on idle or off idle response. You can take the slides completely out and it'll idle just fine.

Mark
#1098

 

[85Max]

Can you check the float level with the carbs on the bike?

 

[maleko89]

Yep, just need some clear hose from hardware store that'll slip on those black hoses coming out the sides of carbs. On one end of hose, make a mark 17 mm from the end. Open the drain screw and hold the end of the hose with the mark to the measuring line on the carb.

Mark
#1098

 

[85Max]

Okay, I tried the Peashooter and shotgun. Still only runs and choke and dies when I increase the throttle.

Bike is 21 years old and carbs are probably in need of a good rebuild. Are there step-by-step instructions on how to do this? I was an Aerospace Technician for 10 years in the Air Force, I mechanically capable of doing it. I just never dealt with carbs. Mostly worked on diesel and jet turbine engines.

 

[maleko89]

Look at getting a Clymer manual for the Vmax. There are several on Ebay right now. The procedure to break the carbs apart and clean them is detailed nicely in there. If you have any questions from there, we can answer you questions. If necessary, I can call you up...my dime.

Mark
#1098

 

[85Max]

Man thanks for the offer for the call. I got my hands on the service manual.
Got the carbs off. Most of the screws are very tight. Had to tap them with a impact driver to get the float bowl screw off. The drain screws don't seem to want to budge, I'm afraid to break them. Are these float bowl drain screws something I will need in the future and should I make an attempt to break them loose?

Jason

 

[85Max]

Mark,

I do have a few more questions. Would you rather chat online or over the phone?

Jason

 

[maleko89]

I'm in the chat room now.

Mark
#1098

 

[85Max]

Okay,

First, this site has been a life saver, good job.

Carbs are off.

Drain screws are stuck show I try to break them free and risk breaking them?

What do you clean the carbs with Sea Foam, Gas, Carb Cleaner?

Is there anything I need to look at while carbs are off, like the V boost?

Do you recomend a K&N air filter over the stock (mice ate mine)?

I set the floats at 1.07 inches, right?

And last, is there a good inexpensive carb sync gauge?


Thanks.
Jason

 

[maleko89]

Try spraying some PB Blaster penetrating spray on the drain screws. Otherwise, might need an extractor to get them out. You can also tip the carbs over and drain them through the float bowl vent tubes.

When I rebuild carbs, I use ONLY Honda Carb cleaner...that's the best stuff. I've used a 1/2 dozen other brands and they all leave a residue and don't clean nearly as well. I get it from the local Honda dealership for $3.99 a can. For routine maintenance, I do the Peashooter with Seafoam....I also put a few ounces in the gas tank every couple of months.

While carbs are off, check crankcase vent hose and make sure no cracks and that it's not plugged. Also, sync and adjust vboost as noted in manual. I also unplug the fuel pump connector, turn the key on and then shut it off when the vboost cycles all the way open. Then, I stick my middle finger on either side of the vboost valve to make sure it's completely open. I'm good with the middle fingers....especially when Morley whee-lied passed me last year.

Remove the four intake boots including clamps and inspect boots for cracks.
Also, remove the manifold fastening bolts to the #1 and #4 carbs and remove the manifolds. Loosen the clamps to the vboost boots (4) and then wiggle the vboost butterfly assembly free. Inspect the boots. The reason for only removing #1 and #4 manifolds is because of the blind bolts present in the other two manifolds. Oil will seep up....this method prevents the mess and you don't have to re-seal those holes. You might as well get some cable lube and lubricate the vboost control cable and throttle cables.

I replaced my stock air filter with K&N (before I went to Morley's kit). You don't really gain anything besides the re-usibility of it.

Setting floats to 1.07 inches will set the fuel level to the rich side of things. I was recently corrected to shoot for 1.125 inches. This will ensure the level to be pretty close to 17 mm.

For carb gage, cheapest would probably be Motion Pro through either Denniskirk.com or you can give University Motors a call and see what kind of discount you'd get.

Mark
#1098

 

[85Max]

Just wanted to give you a big thanks Mark.

Put the carbs on last night, started right up & ran great! (Will need to sync carbs of course)
Went for a small ride, have all the trim off and primed getting ready to paint this weekend. Not a show bike but I'll post some pics when it's painted.

When I was cleaning I noticed one of the Coasting enrichment
valve assembly's was worn. Two small holes. Was going to replace it right away but the only dealership here didn't have one and they wanted $50, twice what it is online. Still ran great. I guess I should replace that soon?

Thanx again.

J

 

[maleko89]

Awesome! For the coasting enrichener, put a dab of Permatex Black to cover the holes. I did that when I rebuilt mine a few years ago and they're still fine.

Mark
#1098

 

[4gasem]

Mark,

I do have a few more questions. Would you rather chat online or over the phone?

Jason

Hey Jason,

I would recommend you edit your post and remove your phone number...

It's not usualy a good practice to put personal info on threads... I would use the a PM in the future...

Glad you got it running right again!:banana:

Buy some Seafoam and use it every so often and always when storing for long periods...

Cheers,
Chris

 

[serrow]

Jason, did you gas mpg improve after the cleaning of the carbs?

also, anyone have a stepbystep to remove the carbs..

 

[motorhall]

As a postscript to this thread, anytime a bike has been sitting for a long time and will only run or idle with the choke on, the most likely problem is plugged pilot jets. As the fuel deteriorates and evaporates it leaves behind a varnish, and it doesn't take much to plug the tiny holes in the jets. Only good solution is to take the carbs apart and clean the jets.

As far as draining the float bowls, I'm paranoid about stripping expensive aluminum parts, so I've found it quicker and easier to just flip the carb assembly over and let the fuel drain out of the vents into a pan (or onto some unwanted weeds).