XJ1100 maxim running problems

I have an '82 XJ1100 maxim that has unending starting/running problems I seem to be unable to sort out.

What I have; very bad starting, sometimes it won't start, or it starts, then stops and will not re-start, or it starts, warms up, ticks over off choke but runs badly on the road, sometimes it will re-start, sometimes it won't, there is no rhyme or reason for this behaviour.

What I have done so far. Carbs of and stripped, ultrasonically cleaned, all jets cleaned with carb cleaner, all passages blown through, float heights set, new diaphragms fitted. Tank removed and cleaned out, taps stripped and cleaned, new fuel lines, new fuel filter, vac tap by-passed, checked valve clearances, valve timing, new plugs and caps, new ignition unit, check all wiring, in desperation remove and strip loom! all OK, new petrol with additive used, new battery, I also use a slave battery, all volt drop tests OK.

I spent all my working life as a Heavy goods mechanic, so all this is very embarrassing, can anyone out there help please? Ric

 

Your mechanical background is good but this may take some finesse.
Have you done a running synch and colortune?
What does "vac tap by-passed" mean?
Have you bypassed the vacuum line that runs to the petcock?

 

Hello from the UK Stumplifter,

I do have a colour tune, but didn't have a lot of success with it, perhaps I need to try harder. I have also spent hours with the bike on a remote tank adjusting the slow running again with little success. The trouble is you need to watch for overheating, again I may need to try harder. By "Running sync" do you mean balance the carbs? yes I did that. I also checked the auto advance, which works OK. The other thing I replaced were the carb to head rubbers

"Vac tap bypassed" means I re-routed the fuel pipes and plugged the vacuum line, just to see if that was a problem. I think I have thought myself into a corner, fresh thinking is a good idea.

Thanks for the reply, Ric.

 

Did you clean the carb bowl enricher wells?
Did you remove the mixture screws?

Have you tested the ignition coils/stator/pickups/etc...

 

The carbs have been off and stripped several times, no dirt anywhere, plus they have been in the ultrasonic cleaning tank. I have had the mixture screws out and replaced the O rings, the small metal washers are in place.

I have also checked all the engine electrics as per the book. The only thing is my book is a Clymer manual for the XS1100, not the XJ and there do seem to be some differences, I can only use my common sense, such as it is.

I have a bad feeling I am missing something really obvious, so all ideas will be gratefully received. Ric.

 

Have you physically blown air through all passages to verify they're open?
Have you physically blown sir through the jets at the bottoms of the bowl enricher wells, and shown a light through to verify they're open?

What are the voltage numbers on the battery.... Standing, vs. cranking?

 

check your inbox for factory service manual

 

Check your side stand/neutral safety circuit, it may be intermittently cutting off ignition and starting . The relays are directly above the carbs.

 

I have a compressor and have blown air through all jets and passages. Can't remember the exact voltage numbers, I will check again. I had the motor apart and cleaned it all up when I sorted the gearbox out.

A good point about the relays though, I hadn't thought of that. I will have a couple of shed days at the end of the week and post the results then, many thanks, Ric.

 

Thank you for the service manual. Ric.

 

Did you chck the rsistances of the ignition coils and th spark plug caps, and check the condition of the plug wires (by spraying water on them).

 

+1. There's a intermittent connection somewhere .

Gary H.

 

I'm still wondering about battery voltage numbers

 

This is what you look for--- lol

( on one of the maximX that I recently picked up). I took a video, too..... It was arcing all up and down the boot-- this is obviously just a single screenshot.

 

Wanted to take 650 out for a spin last week. Turned the key...horn was blah, signals blah, all lights dim.Volt tested battery prior to charging. Volt test@ 12.6. Put battery back on bike and had a hard time starting (much like what ric described). Rode it a couple miles without turning it off. It felt like power was going in and out. Got back home and realized the license plate bulb wasn't lit. I thought it was in the bucket then I remembered the ground wire male bullet connector under the seat I keep saying I'm going to extend because it just reaches the female connector. Pushed in the connector, turned the key, thumbed the button...Varoom, varoom!

Gary H.

 

Best to look for it than to feel for it. The feel ain't no fun. lol.

Gary H.

 

thats very odd

 

Wow, hogfiddles' picture looks like one of those mini Tesla coil lightning generator doohickeys you see in science museums! Could that be used as a RoboCop style bike security system?

 

Funny..... That's' really what it looked like when it was running-----the purple sparks were dancing all over

 

Now I had to go watch that again. Thanks for that.

For the uninitiated...

MagnaVolt - Lethal Response

/No embarrassing alarm noise
//No need to trouble the police
///...and it won't even run down your battery!

 

Having received service information from this very helpful site I had a look at the old girl today. First the battery voltage; S.G is 1.260, open volts 13.5. On engaging the starter the voltage dropped to 10v. Strangely enough, although the choke wasn't on and it is a cold frosty day and the tank was off the engine fired up, but not for long. The general opinion is electrical problems, so now having the necessary info I can go through it properly.

First thing I found was the boost sensor is no good at all, plus it has a vacuum leak inside. I could try Ebay, but this can be a gamble, does anyone know of a good dealer or website to get new/second hand parts from? New parts over here in rip-off Britain are available but at eye-watering prices.

I now have two clear days in the shed and will go through the book and check everything electrical, I will post the results after.

Cheers, Ric.

 

I'm still going with the battery.
It's too low.

You're lucky it started, but I think it's distracting you.

It started out of luck.
The Enricher wasn't on, so it's not going to run long when that cold without it.
It wouldn't start again because:

The battery is too low, and
The fuel mix isn't right, temporarily, because of the un-enriched cold-start attempt, and
It's the bike is too cold

Dave

 

I've got a boost sensor which won't break the bank if you're interested. PM me.

 

I would be very happy to buy your boost sensor if I only new what PM meant, and how it works. Sorry, I'm still living in the 1960's.

 

Click on FJ111200's icon, you should see an option for Start Conversation - also known as a Private Message (PM).
This will allow for exchange of personal details without telling the whole world (home address, phone numbers, etc).

 

Your inbox is full apparently, so I can't leave a message.

 

Sorry Ric, should be all sorted now. I've sent you a conversation or a PM as it's known.

 

Hello! The plot thickens, I have been spending many happy hours in the shed checking out bit by bit the electrics (XJ1100Maxim). I also check bought two brand new coils off Ebay, at a very nice price. They turned up still sealed in polythene, the thing is on checking the old ones out the secondary resistance measured 11kv and the primary's 2.7, OK as per the book. My nice new coils have a secondary resistance of 17k will this matter? The primary resistance is spot on at 2.5 ohms.