Running bad bad bad

[user 5302]

Hello all. It was suggested that I come here for help with my '92 Max. Declining health has kept me off two wheels for some time now and I finally pulled the Yammy out of the shed for some tinkering. Here is the story. I bought the bike about three years ago and it never seemed to run quite "right." Seemed like it was missing on one cylinder but was still rideable. Last Summer I washed it and water got into some of the plug connections. This in turn fried the CDI box. I bought a replacement (aftermarket) and by the time I installed it the carbs had gummed up. A few weeks ago I bought 4 carburetor rebuild jits and new rubber carb mounts. The pilot jets on all 4 were clogged tight. Everything was cleaned and rebuilt but the bike would only run on three cylinders. Fuel and spark were getting to all four but the left front header would remain cool. A compression test revealed that three cylinders would hit approximately 160 psi but the left front was only about 65. I poured some Kroil in it and let it soak for a few days. It now reads 160 psi like the others. New plugs were installed but It still runs poorly. At Idle it seems like only three cylinders are hitting and if the rpms are held at 3-4k there is a continuous popping from the left tailpipe. After running for a minute I took a laser thermometer and found that three head pipes were around 150 degrees but the left rear was 230. I also notice that the lights tend to flicker when the rpms are up. Any suggestions short of scrapping the bike will be most appreciated.

 

[naughtyG]

Hi and welcome.

Unfortunately there are so many possibilities here..

The obvious things to me from what you said:

- lights flickering point at a dead battery / poor charging system. Max will NOT run good with a dead battery. Try two things: a] put jumper leads on from a car battery known to be in decent shape, if it helps your battery's dead (very likely btw). b] put a voltmeter across the battery with the engine running. At idle you should see at least 12.5V, revving should bring it to around 13V, if not it's not charging properly. Do a search here for 'the crimp fix'.

- have you sync'd your carbs? The Max service manual calls for this to be done monthly. Max always runs like shite when carbs are not in sync. It's dead easy to do (5mns literally) but you do need a vacuum gauge of some kind.

 

[user 5302]

I'll try your suggestions about the battery and Carb synch. Just have to get out tomorrow and pick up a vacuum tester. The crimp fix was done when I first got the bike. Thanks.

 

[gamorg02]

whats kroil?

 

[user 5302]

whats kroil?

A brand of penetrating oil.

 

[one2dmax]

Don't tell me you bought the ebay or other "Keyster" carb kits. If you did that's part of your problem.

Sean

 

[user 5302]

I used K&L carb kits. How could a few small gaskets and o-rings cause trouble?

 

[one2dmax]

The gaskets aren't as much a problem as the brass is. Did you reset the float levels and do a carb sync?

 

[user 5302]

Okee dokie. I pulled the carb rack again and set the float levels. I blew compressed air through the jets to make certain they were still clear. Fresh gas was put in the tank and there is just a slight improvement. The left rear cylinder is really hot though. About 40 degrees hotter at the head than the other three after only a minute or two of running. Still sounds like a really regular misfire too. I have not sync'd the set yet since I haven't had an opportunity to get a manifold gauge but I wouldn't think a slight sync adjustment would affect the idle. Or would it? I'm grabbing at straws here! The person I bought the bike from three years ago said that he didn't think it had the power it should so I think he was aware of some problem. He said that there was an oil leak at the middle gear cover gasket that he had repaired twice by the same shop and it still dripped. After pulling the cover and cleaning massive amounts of sealant I found that the shifter shaft seal was bad. Replaced it and the cover gasket and it's dry underneath now. The reason I relate that story is to explain that there are some real jackleg bike shops around here and perhaps one of them screwed something up. Any thoughts? Ideas? New suggestions? Thanks.

 

[one2dmax]

The sync will greatly affect how the bike runs and is really noticeable at idle. Get it synced and see what it does for you.
Sean

 

[woodsman30]

Okee dokie. I pulled the carb rack again and set the float levels. I blew compressed air through the jets to make certain they were still clear. Fresh gas was put in the tank and there is just a slight improvement. The left rear cylinder is really hot though. About 40 degrees hotter at the head than the other three after only a minute or two of running. Still sounds like a really regular misfire too. I have not sync'd the set yet since I haven't had an opportunity to get a manifold gauge but I wouldn't think a slight sync adjustment would affect the idle. Or would it? I'm grabbing at straws here! The person I bought the bike from three years ago said that he didn't think it had the power it should so I think he was aware of some problem. He said that there was an oil leak at the middle gear cover gasket that he had repaired twice by the same shop and it still dripped. After pulling the cover and cleaning massive amounts of sealant I found that the shifter shaft seal was bad. Replaced it and the cover gasket and it's dry underneath now. The reason I relate that story is to explain that there are some real jackleg bike shops around here and perhaps one of them screwed something up. Any thoughts? Ideas? New suggestions? Thanks.

Thats a fact listen to what the guys say here there is a lot of info and you will get the help you need. Most here have worked through all kinds of issues and this is the place to be unk:

 

[vmax626]

You also might wanna check the A/F mixture screws too,
turn them out to 3 turns each and go from there .
inward = leaner
outward = richer.
Good luck my friend,
<<Dave>>unk:

 

[user 5302]

Played with it again today. Made a home-built manometer and tried to sync the carbs. What I found is that #2 still seems to be dead. I took a propane torch (unlit) and shot gas in the carbs as it was running. The engine sped up when shot into 1,3 and 4 but did not even notice when shot into #2. Since #2 is the cylinder that the others are adjusted to match, I was dead in the water. This thing really has me baffled! I have a few other bikes that I tinker with but two of them are ancient HDs and are as complicated as a lawnmower so keeping them running is not a problem.
A little background about myself to explain some difficulties. I have stage 3 polycystic kidney and liver disease so my kidneys are about the size of basketballs. I am no longer able to work due to pain and exhaustion from loss of kidney function. The heat in my area has been near 100 degrees for the last 2 months so my time in my little workshop is limited to maybe an hour before I have to go inside to cool off. I am not asking for simpathy, just trying to explain why I may not be the sharpest knife in the drawer when it comes to fixing this thing quickly. As I stated earlier, I lusted after a V-Max the year they came out. That year also happened to be the year I got married and bought my first house so gratification had to be delayed. I finally found this '92 about three years ago and I'd love to get it running well enough to take a fair trip on it while I am still somewhat able. Enough whining!
Tomorrow I will play a little more and then I guess I'll take it to a local indy for his diagnosis. :bang head: