Carburator Issues

[Okie2ee]

I have an 86 VMax which has been sitting for the past 4 months. It was running pretty good when I parked it. Now it will not take any throttle opening at all when I start it, it dies immediately. I can get it to rev up if I keep it fully choked and work it up to high revs where it runs without stalling. I read some of the posts, I'm looking for the first plan of attack. The bike will idle so I could run some cleaner thru the carbs. I'm capable of cleaning and rebuilding if necessary. I look forward to learning alot from this forum. Thanks.

 

[naughtyG]

I had idle problems recently, and doing the 'shotgun' fixed it.

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

 

[one2dmax]

Do you have your airbox on when testing this - bike won't rev without it unless prepeed for stage seven or my kit? May have bad slides or try the other cleaning methods like peashooter or shotgun

Sean Morley

 

[Okie2ee]

I just completed the shotgun procedure and it helped a lot. However, I'm not quite there yet. My pilot screws were set as follows: RR - 2 1/4, RF - 4 7/8, LR - 1 1/4, LF - 3, does this sound OK. I have put 1/2 can of Seafoam into a full tank and will run that thru the carbs. I still need a small amount of choke to keep it run at low idle. It idles down to around 1,000 - 1200 without any problem. Hesitates a little when opening the throttle and seems to be fine at 3,000+ RPM. I haven't ridden it yet, need to bleed clutch ciruit. While idling with the air box on, the RPM surge slowly about 200-400 RPM. I think I will check for air leaks next with propane gas.

Note on the shotgun procedure, I couldn't get two of the pilot screws out of the channel. I used a vacuum gun to suck the needles to the opening, worked great, FYI.

Any ideas on what to check next? Thanks

Forgot to mention, that during the cleaning process I got a strong stream of fluid out of the main jets on the left side when blowing carb cleaner thru the upper opening, however, I didn't get the same action on the right side, just barely trickled out of the main jet opening. Any thoughts? Thanks Again

 

[dannymax]

Try syncing the carbs.

 

[Okie2ee]

I just completed a test ride. Does not want to idle below 1000 RPM, I still need just a hair of choke, and it is hesitant when opening throttle until revs get past 2000 and then everything smooths out. Purrs like a kitten from 3000 to 7000 RPM. I cruised down the road for awhile. Throttle response above 3000 seems to be very good. I hear backfiring when I let off the throttle to slow down. When run at low revs I also hear backfiring periodically when letting off the throttle. Any ideas on what to attack next.

Syncing the carbs requires the manometer tool. Where is the best place to pick up this tool? And what is the recommended brand and approximate price. Thanks.

 

[naughtyG]

I'm after one of those too. Best price I can find on a Motion Pro SyncPro is about $100 on eBay. (88.95 + 15.65ship) Then it seems you also need the 6mm adapters for Yamahas - another $15.95 + shipping.
You can also get a Morgan Carbtune Pro for about $160 here:http://cgi.ebay.com/New-Morgan-Carb...hash=item330269529942&_trksid=p3286.m63.l1177

Hopefully someone else can chime in to tell us if either is better, or any good at all. I wish I could borrow one from someone cos I just bought tires and can't afford it!

 

[maleko89]

I just completed a test ride. Does not want to idle below 1000 RPM, I still need just a hair of choke, and it is hesitant when opening throttle until revs get past 2000 and then everything smooths out. Purrs like a kitten from 3000 to 7000 RPM. I cruised down the road for awhile. Throttle response above 3000 seems to be very good. I hear backfiring when I let off the throttle to slow down. When run at low revs I also hear backfiring periodically when letting off the throttle. Any ideas on what to attack next.

Syncing the carbs requires the manometer tool. Where is the best place to pick up this tool? And what is the recommended brand and approximate price. Thanks.

Idle should be set to 1000 rpms. Anything lower and idle will suffer a bit.

 

[m-cman]

I have had sync tools since the 70's. Most were the mercury type. I now have the Morgan and wouldn't trade it for ANY other. It is the best I have ever used. Just my opinion...

 

[Shuriken]

i have had sync tools since the 70's. Most were the mercury type. I now have the morgan and wouldn't trade it for any other. It is the best i have ever used. Just my opinion...

+1

 

[dannymax]

+2 for the Morgan Carbtune. This spring I paid $114 delivered, from Exactrep in the UK
Their price hasn't changed but I'm not sure of current exchange rate

 

[richwrench]

If you want a cheap manometer, just make your own. I made one and it only cost me about 12 bucks - not pretty, but it still works great. There's an old link here somewhere, or just do a google search for homemade manometers - that's where I started.

 

[Redbone]

Here is place I found you can get the Morgan Carbtune Pro at. Shipping adds $14.18 shipped to 49715.

 

[Okie2ee]

Current situation is as follows: I tore down again for another cleaning session using the "peashooter" procedure and repeating the "shotgun" procedure. I discovered two things: 1. All the diaphrams have a small hole along areas where the diaphram flexes(wrinkled areas) - I made a repair over the spots with light layer of silicone type material. Drying right now. 2. While cleaning, I noticed that the RF carb does not have the same air flow out of PAJ2 when blowing compressed air into PAJ1 or into the idle screw passageway. All 3 of the other carbs feel about the same regarding air flow out of the PAJ2. I removed the brass jet and repeated injected Seafoam with no change in air flow. When blowing thru the idle passageway, the air will initially start and then stop in PAJ2. Any ideas on what this could be?

I assume the holes in the diaphrams would not affect the inability for the engine to idle with having the choke partially on. Before the above tear down, the engine will not idle at 1000-1200 RPM without the choke a little bit on. The plugs look good, just black probably from running to rich.

I have discovered the web site with the wealth of information on the VMAX and am now pouring over this information. I appreciate all the help and suggestions. Thanks.

 

[maleko89]

The PAJ2 opening is controlled by a coasting enrichener plunger. At idle it's normally closed. At off idle it opens up similar to the slides using vacuum.

 

[kx250rider]

The shotgun method sounds great!

Okie2ee's issue sounds exactly like the problem that my '85 is suffering. I wouldn't normally be brave enough to fool with the carbs, but I'll give it a try. I'm a Diesel engine hobbyist, and I've disassembled/cleaned/re-sealed many injector pumps, so this can't be any worse.

I recently got this bike, which had been in storage for a couple years. The tank and bowls were emptied and refilled by the original owner before he put it up for sale, but I'm sure that wasn't enough.

I'll post with results ASAP... I hope I have time in the next week or so, but the in-laws are coming to town this weekend and I probably won't have any time for myself :bang head:

Charles