'92 Max dies after idle...

[Rayvin53]

Been riding since I was 16 (37 years ago), most recently a '95 Honda Magna VF750, and picked up a '92 VMax just yesterday. It's in nice shape, cosmetically, but has one major problem. Starts up easily at full choke, will idle nicely, but as soon as you twist the wick it dies out. I'm assuming the carbs are majorly gummed up as the guy who sold it to me had it sitting for quite a while and never ran it dry or added stabilizer to the gas. He claims it ran fine before the storage. So I added a half can of seafoam to tank and ran it awhile, blipping the throttle intermittently to try and work some of that stuff in there. Didn't seem to make any difference, so I rode it the 20 something miles home but had to keep the rpms up above 3500 or so so it wouldn't die out. It was a hairy ride, but as long as I had the revs up it kept running.
So I joined this forum last night and read some of the carb cleaning methods, like the peashooter and shotgun, but didn't come across anyone else with the exact same prob as me. I'm about to go outside and try the shotgun.
Any one have any ideas with this one? I'm guessing it has an idle circuit, a secondary circuit and a high speed one and the secondary one is gummed up, but can't wait to have it running right so I can really get on this beast and check out the vboost. I got a small taste of it on the ride home last night.
BTW, this forum is chock full of good info and I'm sure to be using it often.
Anyone else ever ride a Magna? It's quick for a cruiser and handles pretty well in the twisties, something I've heard the Max has a tough time with.
Thanks for any advice.
Vin

 

[Neil-3446]

First....Welcome to our world!!!

For sure sounds like a good cleaning is needed. If it runs okay above 3500-3700 or so, sounds like the shotgun is needed as the idle circuits are being left about those rpms.

If that doesn't work, a good rack out cleaning is needed. You must use enough psi when doing the shotgun to make it work. Just the pressure from the cleaner can, or a compressed air can will not likely work. Shoot em with 100+ psi in PAJ1 & 2

http://vmax.lvlhead.com/tips/shotgun.htm

Neil

 

[m-cman]

I had the same problem on my 97. Wouldn't run below 3000 rpm. Ran ok above that. I removed the carbs and completely dismantled each one individually and cleaned every part, all jets and passageways included. Replaced all replacable carb parts (o-rings, gaskets, hoses, etc) including the pilot screw sets and set the floats. Then synced after installation. Runs perfect now. Since I cleaned everything, I do not know what was the specific problem. Yours probably needs the same treatment as it sat for a while and is probably gummed up everywhere. Seafoam is great but will not fix a badly gummed up carb.

 

[Rayvin53]

Hey, thanks for the quick replies, neil and m-cman. I wound up going through the steps in the shotgun procedure, but the spot where the idel mixture screw is supposed to be is just what looks like a brass plug. So I passed that step and just ran through the rest, using only a can of carb cleaner and not the air. Once I find how to get to the idle mixture screw I'll do it right. I took off the whole air cleaner box, and when putting it back on, I couldn't figure out how to reattach what looks like a hose going back to the crankcase, located right on the bottom rear of the box. What's the trick for reattaching that thing?
All of this had zero effect on the problem, but at least I got familiar with that area of the bike. It's a hell of a lot like the setup on my Magna (which I get to keep for when the wife wants to ride on back-she's a bit intimidated by the Max) Also noticed that the rubber lip on one of the boots from the air cleaner to the throat of the carb was pinched and deformed, either came this way from the factory or the last time the air box was taken off.
So, what's the best way to get to my idle mixture screw?

 

[maleko89]

The mixture screws are behind the brass tamper-proof plugs. Just get a self-tapping screw and then pull out with pliers.

That hose is for crankcase ventilation. To put it back on just lift up on coolant reservoir and hang off to the right. Now it should be easy to get the hose back on. Be quick with the reservoir or a bit of coolant will drain fro the reservoir vent.

 

[Rayvin53]

You da man, maleko. Should I bother putting the plugs back in? What purpose do they really serve? Also, in another thread someone had mentioned picking up a universal fuel filter from an auto parts store--any idea which one to get, or should I stick with Yammie OEM?

 

[Rayvin53]

Can't seem to find a fine enough screw for that tiny hole in the plug...can I just drill it out?

 

[maleko89]

You da man, maleko. Should I bother putting the plugs back in? What purpose do they really serve? Also, in another thread someone had mentioned picking up a universal fuel filter from an auto parts store--any idea which one to get, or should I stick with Yammie OEM?

Nah, throw the plugs away. They're supposed to keep putz's like us from richening them up a bit....it's an emissions thing.

For the fuel filter just get one of these...it's a Purolator 806. Go to Advance auto and they can cross reference the part number. Make sure both ends are for 3/8 fuel lines.

 

[maleko89]

Can't seem to find a fine enough screw for that tiny hole in the plug...can I just drill it out?

Yes, but drill carefully. You don't want it to suddenly give and damage/destroy your mixture screw. The plug is only 1/8 of an inch thick at the very most. Just drilll and then thread any old screw in and pull with a pliers.

 

[Rayvin53]

Plugs are out--exactly 1/8" thick--going to pick up that purolator fuel filter and do the shotgun. Mark, thanks again for the quick advice.

 

[Rayvin53]

Ok, new plugs, fuel filter, did the shotgun...low speed is slightly better but still have to have choke partially on to keep bike from stalling out at low rpms. At highway speeds, I can take choke completely off and it runs beautifully (now I know what a rush this bike is--holy sh*t, you really have to hang on), so the problem still seems to lie in the idle to 3k area. When I get off the highway and I'm coming to a stop sign, it stalls out unless I keep the revs up. When it does stall, I have to use lots of choke to get it running again.
Got seafoam in there, did the peashooter, no real effect, still stalls when coming down to low revs.
Is my next step pulling the carb bank and breaking it all down? Or should I give the seafoam more time to work?
Thanks in advance for all the help here.
The newest VMax fanatic in the neighborhood,
Vin

 

[shawn kloker]

Ok, new plugs, fuel filter, did the shotgun...low speed is slightly better but still have to have choke partially on to keep bike from stalling out at low rpms. At highway speeds, I can take choke completely off and it runs beautifully (now I know what a rush this bike is--holy sh*t, you really have to hang on), so the problem still seems to lie in the idle to 3k area. When I get off the highway and I'm coming to a stop sign, it stalls out unless I keep the revs up. When it does stall, I have to use lots of choke to get it running again.
Got seafoam in there, did the peashooter, no real effect, still stalls when coming down to low revs.
Is my next step pulling the carb bank and breaking it all down? Or should I give the seafoam more time to work?
Thanks in advance for all the help here.
The newest VMax fanatic in the neighborhood,
Vin

How much did you put in?I use half a can when it is the first time.It will cough and sputter for about a mile then clean back up.We have a big hill to get out of town about a mile long.I like to go up it WFO when tuning!

 

[shawn kloker]

How much did you put in?I use half a can when it is the first time.It will cough and sputter for about a mile then clean back up.We have a big hill to get out of town about a mile long.I like to go up it WFO when tuning!

Did you do the shotgun?The peashooter mainly cleans the air circuts.

 

[Rayvin53]

Hey Shawn. Initially put 3/4 of a can in the tank before I bought and flew it home. Haven't added any more to the gas tank, just via doing the shotgun and peashooter. Should I add some more to the tank? One other thing I haven't done is check my float levels--going to do that sometime today.

 

[Rayvin53]

I'm no expert here, but is it possible my symptoms indicate an air leak somewhere or does the the fact that it seems to run great at higher revs rule that out?

 

[Rayvin53]

Here's another symptom that should help me to isolate my problem--when trying to adjust the idle mixture screws, I set them all the 2.5 turns, but when I screw one in to hear for the engine slowing down, it has no effect at all. This is the same for all four carbs. I'm guessing that's because I'm still running at partial choke...does this make sense?

 

[maleko89]

Correct. IF you close choke and it still doesn't affect the running then it usually means out of sync or idle is set too high.

 

[Rayvin53]

Mark, it won't even stay running if I don't use any choke, so I guess I'm yanking the carbs today and will check the boots and all the rubber for cracks. What are some of the common places to check for vacuum leaks?
Thanks.

 

[maleko89]

Are you sure your idle thumb screw is set high enough? If you put sync gauges on does it read really high? If there was a vacuum leak it would still run. It sounds like your pilot circuit is dirty.

 

[maleko89]

You know, I take that back. It MAY run with a vacuum leak. If you remove the rubber caps from the sync port it won't run. When my carb boots went bad it just sounded weird. I would take a spray bottle with water or even WD-40 and spray around the boots. If the engine stalls or sounds different then that's the problem.