last ditch effort

Heynow,

I'm very close to putting my 85 xj700 up for sale. I have enjoyed tinkering but the bottom line is that I want a bike to ride and spent a good portion of last season taking carbs apart. I learned a lot and was feeling pretty accomplished until...

I took the bike for a 60 mile ride the other day and now, whenever the bike is warm, it struggles to 'get out of the hole'. If I am on a hill at a stoplight it will sputter and I'm lucky to get it to move. As a result I took my carbs back apart, cleaned them (4th time) and replaced the #41 pilot jets with the original #36.5 which I had replaced as a result of the bike having totally clean plugs and a hunting idle which would result in stalling. I was hoping by switching the jets back to stock I could eliminate the possibility that the bike was actually running too rich. I may have been successful in that, but the bike is still lurching out of first gear and missing at idle. New plugs, new plug wires, tested coils, petcock functional, good compression, new air filter, colortuned...total confusion. I don't even know if the symptoms are a lean or a rich condition. If anyone has any ideas I would appreciate it, else keep a lookout for the bike in the classifieds.

Thanks for all the help.

Marshall

 

Have you tried running it on "PRI" for a bit to see what happens? A petcock with a hole in its diaphragm can cause all sorts of erratic behaviour, especially if the problem is bad enough for the petcock to be allowing fuel down the vacuum line. Also, have you checked for intake air leaks?

 

sounds rich, go for a ride, pull the plugs & post a picture.

 

I agree with Bigfitz. pull the vacuum line on #3 intake boot and see if there is raw gas dripping out. #3 plug will be black and maybe wet if thats the problem. Scope it out and get back to us. Good Luck

 

I agree with BigFitz, check for intake leaks. These will give you a lot of low end problems and are common on these bikes.
Best way I have found is to let the bike idle and using a small propane torch with the valve open but NOT lit, move the end of the torch around each carb boot, any change in idle speed indicates a leak.
This may sound dangerous but in fact is FAR safer than spraying a flammable fluid on a warm engine!!!!!

 

Some tests with the voltage meter tell me that this whole problem is probably electrical. My battery is reading 11.6 and then dropping to 11.2 or 11.3 when the brake light comes on. My battery then failed a load test. Regulator seems good along with alternator brushes. Could there really be an easy fix? We'll see....

Thanks for the advice

 

it might not fix the problem, but your battery is toast anyway.

 

I can actually watch the voltage drop on the meter accompanied by the engine missing at 11.4 or 11.5 volts. I have been doing a lot of tuning at idle and I suspect there is just not quite enough reserve power to run the components and the ignition system. It is possible there is an underlying problem that is draining the battery. The misfiring at idle when the brake is applied is what was leading me to believe I had a rich mixture problem. I remain hopeful.