Problem starting my 81 Yamaha XJ 550 Maxim - 9000 miles

Message

szerwa · #1 Unread post by **szerwa** » Mon Oct 24, 2005 8:08 am

This is my first bike and first time working on one, so all the help you could give would be awesome. Here's a breakdown of what's going on:

Problem:
Battery is turning the engine, but after 10 seconds of holding the ignition switch there just won't be any combustion. The bike was riding fine in the summer, but if I didn't ride it for a week it would have some trouble firing up. All I would have to do there was to pull the choke all the way back and it would start after a couple trys. The first time it didn't start was after that week long monsoon we had up here in the Northeast (I'm in Philly). At that point, the bike had been sitting for a week. It was covered and out on the street.

Since then I've tried multiple things to get it working:
Ignition - checked the spark plugs and they were in good condition. Each one was producing a good spark. I went ahead and bought new sparks anyway and installed them. Tested the new ones to make sure they were sparking and they were. When I was replacing the 4th cylinder spark, I put my hand over the hole when I hit the ignition switch, and I felt a gust of air come from the cylinder. Didn't check the other three for this, but I assumed they are working fine since I'd be hearing a different noise if the pistons were stuck.

Petcock - Removed the vacuum and fuel lines at the petcock. Set the valve to Prime and the gas poured out. Attached the vaccuum line back to the petcock, put the valve in the "ON" position, cranked the engine and gas was coming out. Therefore the vaccuum line and the fuel lines are ok.

Airfilter - Replaced

Carbs - Took them off today thinking I'd find the problem there, but they were extremely clean! Still removed the jets and blew them out with cleaner. There were no apparent obstructions. Cleaned it up, lubricated joints, and reassembled. Put the petcock on Prime for 5-10 seconds to fill the float bowls on the carbs, switched the valve over to "ON" and tried starting. No luck.

So what could be left? One thing I did notice was that on the middle side of the 2nd and 3rd cylinders, where the cylinder body meets the top cam cover, there are some wet spots coming from the gasket. Would this prevent the bike from starting? Any help would be greatly appreciated. If you need anymore info, let me know. Thanks!

Alex

niterider · Mon Oct 24, 2005 12:49 pm

Have you tried spraying a little bit of carb cleaner or either into the air inlets?????

Mottoxfox · #3 Unread post by **Mottoxfox** » Tue Oct 25, 2005 6:20 pm

In your float bowls there is a choke hole in each one. It starts wiith a hole at the top by the gasket and runs down inside to the bottom of the float bowl. It is very hard to get clean and you should try and clean it using a very very smal stiff wire. Like a strand of a smaller cable or better yet a K+L carb cleaning tool much like a welding tip cleaner. Blow contact cleaner through ech one and see if it comes out the opposite end.

szerwa · #4 Unread post by **szerwa** » Wed Oct 26, 2005 4:24 am

Thanks for the responses. I haven't tried spraying carb cleaner into the air intake just yet, but will try it tonight.

I think I sprayed some carb cleaner in at least one of the carbs. It was so small that I hadn't even noticed it until the last carb. When I sprayed it, cleaner came through the the hole and into the bottom of the float bowl. I'm not sure about the other ones though. In general, the carbs were very clean before I took them apart.