1985 maxim 700 won't start.

vern · Posted: Tue May 26, 2009 2:00 pm Post subject: 1985 maxim 700 won't start.

It's getting fuel, spark and compresion but it will crank and not start. What in the world could I be missing. Please help me

jayel · Posted: Tue May 26, 2009 2:50 pm Post subject:

pilot/low speed jets/starting circuit in the carbs probably plugged, fill a pump oilcan with regular gasoline, a small plactic squeeze bottle will work too, squirt some gas into the carb throats if it starts and runs for a short time the carbs need cleaned, low battery voltage is a problem too the starter will pull so much that the coils don't get enough to fire properly make sure the battery is at full charge

Russell · Posted: Tue May 26, 2009 2:59 pm Post subject:

Often when as Jayel comments battery a bit down they will fire readily with a 'bump' start.

vern · Posted: Tue May 26, 2009 4:50 pm Post subject:

thanks for the reply. Do you think all 4 carbs could have the same problem at the same time? It would run if only one or 2 ca Confused

rbs were the problem, wouldn't it??? Does it by any chance (now this is a shot in the dark) have some protection device that protects the engine when a carb goes down. Sad

jayel · Posted: Tue May 26, 2009 5:53 pm Post subject:

vern · Posted: Tue May 26, 2009 8:09 pm Post subject:

sorry I should have added more detail. The bike has been ridden the last two summers(that I know of). It had a starting problem last year, and the problem just disappeared. This spring he got it out, I believe he rode it a couple of times, went out to ride it one day and it wouldn't start. He brought it to me. I took the tank off, cleaned and inspected the petcock ( it worked good). Put it back together and it ran great. He took it home, rode it about 9 or 10 times with no problem. One day he took it out in the morning, came home, decided to go out again a few hours later and it wouldn't start. He brought it back to me. I took the tank off again and but a bottle of gas on the fuel line. Still wouldn't start. I checked the spark in all 4 cyl and spark looked good. The battery is new and it cranks over really well. with the bottle on the fuel line I was able to give the fuel a bit of pressure. That made it back fire only once. What is messing me up is the problem is all 4 cyls. Confused

What is the common denominator here. Is there anything at the bottom of that main fuel line? I can't see anything there. Oh ya I pulled all of the spark plugs and they are all exactly the same, Black, very dry tip but damp around the threads. Please tell me what you think Sad

650hardtail · Posted: Tue May 26, 2009 9:00 pm Post subject:

is airbox clear of obstructions ?? mouse nest etc .....

1 · Posted: Wed May 27, 2009 2:17 am Post subject:

you say your plugs are all black and wet? sounds like there fouled.
when was the last time the carbs were cleaned? valves adj'ed, do you have
an in-line fuel filter? hows your air filter?
these xj's afre pretty tough but they dont like it if you miss regular maint.
do you understand how the enrichment circut works? you can call it a "choke" but it
works the opposit way.
are your pilot screws still covered or are the caps off? if off how many turns out are they.
but back to plugs and carbs. thats usualy the #1 prob if all else is in working order.
you have the hitachi 33 set up and there easy to work on .
start with those plugs first. sounds too rich. could be the enrchment circut is not closeing completely
allowing too much fuel to the cyl.
also check your fuel petcock. sometimes the vac diaphram can go and fuel flows into the float bowls
(and then into the crankcase.)
check resistance on both coils, you can have spark and not fire the engine. if you test the spark
at the plugs they should have a blue tint.if yellow then your not getting enough from the coils.
get back with more details on the condition of the bike, the last maint work done etc.
i have the same bike so i'll help if i can...good luck Very Happy

vern · Posted: Wed May 27, 2009 7:29 pm Post subject:

Ok I checked out all the ideas. I got to the coils and they tested fine. I retested them just to right down the numbers and the left coil read open on the secondary windings. I am very careful and gentle with wires and stuff ( I like to fix up old stuff so I have learned this) I tried several times and it kept reading open. I then took the plug caps off of the wires and tested the secondary again. It was good. The #1 wire had been cut before and it was greenish. I cleaned it a best I could and put the cap back on. I inspected the other 3 and they were ok but I cleaned them anyway. I cleaned the spark plugs, hooked the wires all back up and it actually started. BUT it didn't run well and it stalled a couple of times. ( This is running off of a bottle of gas, the tank is not on it yet) NOW FINALLY MY QUESTION Do you think that it is fixed and the coil was the problem? It seems like it but could 1 wire prevent starting? Confused

If it is fixed it will probably run better after it is run a bit and clears all the crap out right?????? Please say yes Crying or Very sad

Russell · Posted: Wed May 27, 2009 7:37 pm Post subject:

Probably...earlier in this thread I was wondering what shape the top end of your motor is in?As compression drops away for all the reasons that happens then so it becomes more and more critical for electrics and fuel systems to be at peak. But there comes a time when even that isn't enough and they get really reluctant to start.
Having said that the engines in the XJ range are about as durable as motorcycle motors come so would need to have done a heap of work before it ran out of the stuff that makes them go 'bang'.

1 · Posted: Thu May 28, 2009 2:10 am Post subject:

can't say yes just yet. you need to check the coils with a multi-meter and find what the resistance is.
i dont have the numbers in front of me but i"ll get them and will post if you need. haveing continuity is not enough.
but the good news is it started....and after your description of the plugs before being cleaned is a hint.
you need to pull them again and check the color. tan or gray is fine. white and clean-lean.black or wet-rich.
we have to find where the prob ends so we can backtrack. a whole lot can be wrong in between the fuel and the plugs.
but again we need more info-detailed-about the last time the carbs cleaned and synq'ed (if at all), the valves adjusted,
(you cannot sync the carbs if the valves are too far out of tolerance. they need to be done every 18000 miles or so at a min)
if the valves are fine,the spark is fine,then the fuel delivery is the most likely source of the trouble.
the jets,pilot,enrichment circut passeges are very tiny and it only takes a little dirt to block them.thats why you add a in-line fuel
filter besides the one in the tank.
BUT TAKE HEART Very Happy

i know this all sounds complicated but in reality its pretty easy...THERE ARE NO SHORT CUTS.
at least not if you want to ride instead of fix Laughing

if you can get her to run in the next few days with a bit of tinkering all is well.
if not i'll be happy to guide you through ( as best as i can that is Laughing

) all the steps to getting her to run like a "raped ape".
and these little 700's will do it.
one of my riding buddies has a harley 1500 and can only just keep up, and thats more then twice the motor.
also i forgot to ask..is the bike stock?

sorry to you and everyone else for the long thread. just trying to think and tap at the same time Embarassed

vern · Posted: Thu May 28, 2009 9:01 am Post subject:

Ok I tested the coils. and they were close to what they should be (off by a couple of numbers) The plugs are wet now. It has been over 3 years since the carbs have been cleaned. We don't know how much over 3 years. It is stock. I am hoping that I can get it running again and it will clear itself out. I believe it needs new plug wires. (one is green at the boot. and it is stretched to reach the plug) Can the wires be changed or do you have to buy the coil?????

1 · Posted: Thu May 28, 2009 10:45 am Post subject:

ok, wet plugs means the fuel is not burning off.
the green is corrosion and of course will limit spark,however the other cyl' should still fire.
i forgot to ask about timing! have you checked to see it the pickup coils are working?
if your coils are firing and your getting fuel then check to see if they may be firing at the wrong time.
as for the wires, the wires are sealed in the coil and cannot be replaced(bad design by yamaha).
the options are new/use stock coils, after market high performance is a good choice but you need to modify
the mounts (not too difficult) or....they make a connecting plug that allows you to spice new wires to old.
they run about $25 a piece plus the new wires. or you can go the the salvage yard,find a BMW,or other
high performance car as they use top end stuff, buy those wires and splice them in.
i have the same trouble with mine. i snipped the ends which made them abit short but i cannot yet afford
the new coils. at least not while shes running so good Very Happy

you SHOULD hear a tapping coming from the valves. if not the shims are too worn down and the valves
are not opening all the way-if at all-a very very bad thing unless you like bent valve stems.
xj valves get tighter as they ware out.
beside the prob getting her running,at some point you'll need to pull the carbs and do a THROUGH cleaning.
but thats another day.
i hope others will chime in as my knowlegd in these matters is very limited and bow to the more experienced
wrenchers on this site Very Happy

vern · Posted: Fri May 29, 2009 8:26 am Post subject:

I tested the coil resistance and this is what I got. Left side primary is 9.1 ohms. secondary is 26.1 kilo ohms The right side primary is 9.4 ohms and seconary is 22.70 kilo ohms. This is with the caps on. The other day I tested the caps and they seem to have some resitance that's why I say this. So what do you think. Is that Ok. And if it isn't. Is it enough to cause my problem?????? I have a manual for my own bike which is a 1982 yamaha Seca 750 and it covers Maxim 650 1980 and 1981. And Seca 750 1981 and 1982. Many things apply to the '85 but the coil spec are pri 2.5 ohms and sec 11 K ohmes. the specs for the 81 must be different right????

vern · Posted: Fri May 29, 2009 12:21 pm Post subject:

Ok I put it all back together and it won't start. Won't even try. It just cranks and cranks. Crying or Very sad