hard start below 70 turns into no start.

85 maxim 700-X

carbs cleaned last summer, new plugs, no alcohol/ethanaol in gas. non synched carbs and valves sound okay, runs perfect once running. no issues at all since i got the new gas cap. . my battery was new this summer as well. been about two or three weeks max since i rode it around. and i put it in prime when i started as well.

all summer if i left it out in the sun it would start right up. then it got a little cooler, in the 70's, i would have to run the idle adjustment knob under the tank a couple three turns clockwise to make it start and it always would.

now that it's 50 and change, it's about 60 right now, i can turn that knob i'm guessing 3 to 4 whole turns and nothing at all. the very first time i hit the starter button it always fires like once or twice then that is it, it never runs. got to hit the idle knob. i was thinking the 'choke' wasn't moving far enough, but it seems to be maxed out. too many screws to loosen to move it anyway, i think one for each carb. i have not tried any starter fluid yet. i am confident that if the sun comes out, or i point my space heater on it for a while, that it will start. but something is wrong. can it all be carb synching or non adjusted valves. that is the one thing i havent done. sounds way too complicated for me with all the shimming. and the bike shop was too busy this summer to even think about looking at my bike.

sure enough. out in the sun about 15 minutes, i checked the spark, it looks very weak to me. not alot of voltage, but it did start without the choke on, ran about ten seconds and died, so it is going to start. yes. it is running right now, NO choke, then just went on up to 5000 rpm. i had no idea where in the hell my adj. knob was at. i just reset it down to about 1300rpm. it sounds great, as usual. letting the battary charge back up.

but anyway. this is the crap i have been putting up with for about two months. i had to hit the start button about 40 times. i'd give it a rest after five or so. so there ya go. any help massively appreciated!!!!

after about what? seven minutes it just kicked itself up to 2500 rpm. just turned the knob down so it was 1200 rpm. now i have to leave the bike here and go out with my wife. be lucky if i can ride it now.

 

had them all ultra-sonicly disassembled and cleaned last summer tho. been gone about 2 & 1/2 hours, bike not that warm, but still warm enough to start right up w/o messing with the knob.

when i push the choke lever the rpms go up at first, but then keep pushing all the way and it dies. is running now w/o the choke on at all

 

Definitely related. Getting the valves clearance in spec and synching the carbs is a must if you want it to properly start and run. Much of what you've described with turning the throttle knob shouldn't be necessary once it's properly dialed in. This forum is legit. All the help you'll need is here. I hope you take this advice and do what is necessary so you can see it for yourself.

Gary H.

 

I'd drop the float bolws and revisit the enrichment jets.

 

i'll call them tomorrow and pitch a bitch, but my race car friend uses them all the time and they ultrasonically clean them and said they put little drill bits thru all the holes, so i'll see WTF as far as that goes. thanks. i know this forum is legit, i've already fixed like a pile of things on my bike since i got it. and checked my rear brake shoes. just wish i could do other things too but right now, starting is big. the place that did my carbs does not have a carb syncher tho. i asked them last summer. seems like enrichement jet issue to me too since adding more fuel via the knob is one way to get it to start, if it's over 60 degrees tho.

can i drop the float bowls on all the carbs w/o removing them? i really had a bitch of a time putting the rear carb boots (new ones even) back on, and just the thought of doing that again blows.

 

They probably don't know that the enrichment jets are in the float bowls. Pulling the carbs gets easy with practice.

 

no, at this place the race cars all run bike engines

 

look at photos of your carb cutaway shows enrichment circuit on mikuni you should be able to spray into is and come out the plunger hole
http://www.xj4ever.com/inside your carbs.pdf

it could also be the well passage in the bowl is plugged up easy to over look

 

Probably not with bike engines that have Hitachi carbs that have been out of production for 20 years.

 

thanks very much for that, i will do just that. as well as put some seafoam in my gas. i talked to race boy today and he is mystified because my bike idles perfectly when it gets going. he seems to think clogged jet/port too but i cleaned EVERYTHING well, i did NOT clean or replace the fuel lines. and everything from the gas cap to the carbs and out was rustier than a crusty nail on the jersey shore. so i think that some crap was left in the lines cause he seems to think that although it could be sycning, that the ports are clogged and that could have only happened from the fuel lines. so he thinks maybe the seafoam will dissolve it, if not then i have to get the carbs synced at the dealer, then if it gets too hairy i could take the carbs out to him which i dont want to do. i really been there done that, and i had enuf of that. kinda like having sex with Bubba your cellmate at the State Penn probably gets easier with practice, but it's still one of those things i just don't wanna get good at. so yeah, if there is a way to blow out a plunger hole, i'm gonna be on that like a chinaman on a bowl of rice.... can i say that?

oh yeah ps, they are mikuni's.

 

Correct. Brainfart on my part while at work.

Your bigger issue is that the tank needs the rust cleaned out and you need to install an inline fuel filter to prevent any crap from getting into the carbs. Seafoam won't dissolve rust.

I'm confused by what you mean by synching. Carb synchronization is a function of the throttle plates being adjusted to match the vacuum on each cylinder so they are all equal. It has very little to do with fueling issues. You can synch a carb rack even when none of the carbs have the same fuel mixture.

 

i have done both of the above and plasticoated the tank before i put the carbs back in. however, talk about brain farts, i did not flush out the fuel lines. i bought a new yellow one, it was too tight, i tossed it. i rebuilt the petcock entirely also, with a new filter also in the tank as well as in line. but this thing was so clogged up with rust that it just unbelieveable after only three years of sitting. i think that little bit is what desolved and must be cloggin my ports. is this rust something i would be able to blast out the plunger hole or holes? i hope?

i only brought up synching because it was something i didn't do and was mentioned in the first few posts. plus i don't know diddly about bike engines.

that, and because the race shop was confused as to why the bike, which he says uses the same enrichment ports to start as it does to idle, wont start, but idles perfectly. and i am also confused about why it seems clogged when it's under 60 degrees, but not when it's warmer.

 

Post deleted because the gas cap is new.

Gary H.

 

yes, gary, new gas cap one month old. and boy what a frustrating mofo THAT was to figure out. or try to as i still haven't got a good explanation of that in my head yet. that is a thread or two already. fwiw, $85 for a new cap from yamaha. still have them.! i did have that gasket go to shit and to be honest with you i cant remember if i chucked it before or AFTER i put the tank back on. frowny face with hatchet in the head

xj550 h, i hadda seca 550 one time, thanks for the link to the plunger hole. i have NOT tried it as of yet, but "Thank you XJ550! You're my only hope!" (sound of light sabre being turned on).

 

watched it and still clueless. man, never heard of a starter plunger before. starter plunger? i think i need a new one. plunger. i feel like i am unclogging a terlet almost. good grief, all those small passeges. gotta have sumpthin stuck in at least a couple of them. shit i get bigger specs of crap out of my ice machine. i drink'em, i dont know why my bike wont.

 

enrichment ports are part of the choke have nothing to do with bike idling. pilot jet and mixture screw are the idle control circuit.
different starting points in the carb bowl different ending points in the carb throat.

this thread explains the carb
THE SECRET LIFE OF CARBURETORS

read the plug chop also read it all
TALKIN' TECH: Various thoughts on various issues

 

Obviously the race shop dude is not familiar with these carbs sorry to say. It's really sad how some shops have mechanics that really don't know how some things really work and they BS the customers and charge outrageous prices. I'm not saying all shops are like that but there are some. You have to take into consideration that these bikes were made when some of these guys where wearing diapers or were not even born yet , the same goes for some owners these days. Carbs are a thing of the past and the cars these guys grew up with were fuel injected and they never had to deal with carburetor s like I did growing up in the 60's and 70's. cleaning and rebuilding carbs on all those old cars was just something we all did.

 

maybe the race shop dude should get himself an XJ and join the forums

 

yeah, he should. but he told me he actually isnt even working on any bikes or cars right now because his online minibike parts store has gone nuts. says it will stay that way for another two or three weeks.
anyway. THAT EXPLAINS why it can do what it does. so thanks at least, for Enlightenment on Enrichment!

Page 28 of that link shows the plug and the hole i will try to blow things out of. Mind if i ask w/o looking at the bike yet if those plugs are accessable to remove while the carbs are all still on the bike? and what about trying to remove all the bowls, and blowing air into the bottom of the enrichment tube that is hanging down into there? any of this doable w/o removing carbs? thx again.

 

if you can get the bowls off you can do it , that plate underneath makes it hard unless you did not reinstall the heat shield
it could be the sump in the bowl is what is clogged

 

If you really want to get it back running right and keep it thataway you should pull the carbs, church of clean them and learn them while you're doing it. Hope this helps.

Gary H.

 

I dont recall any heat shield. either before or after. i will check it out when it's light out in a day or two when i have time. thanks for all the input and the links. Greatly appreciated!

 

All the 550 carbs I have seen had a heat Shield installed that curved around under the float bowls. If you don't have one a PO must have left it off.

 

You say they ran small drills down all the passages. If they aren't familiar with those carbs they may have drilled out the enrichment jets in the float bowls. I did that some years back not realizing there was a jet in that passage. Then what happens is you instantly flood the bike when you turn on the enricher. You also say you need to turn up the idle speed screw to start it. That coincides with a rich condition.

 

MN, it's a 700. RW, hey could be, but if they were drilled out that seems to me it would be hella rich. when i turn the knob to start it when it's not starting it, i am turning it the direction that makes the idle go way way up. that means i am enrichening, so although that is something they coulda done, i dont see how that is doing this... these guys work on lots of bike carbs on the race cars. i can't tell you what all those guys are running, but they are using carbs off 700's alot on smaller bike engines that have been hopped up.

anyway, no heat sheild however have a water hose coming out of the block and under the right two carbs that look like they would stop me from removing them on the bike. starting to look like this is going to be a "have to take the carbs off again" madcap misadventure.

 

I'm not sure what knob you are turning but if it is the idle speed and you turned it to a higher idle speed then you would lean the engine during starting. The reason for this is the carb butterflies are open farther and the engine is turning very slow so less suction is generated at the idle and enrichment circuits. I have a SR500 and it has a special knob you push that opens the carb just a crack to lean it out for warm starts. I hope I explained the opening the carb vs mixture good enough. If not I will try to reword. Good luck.

 

thanks again RW, that does explain it a lot! and dragsta, is that U visible anywhere on this link i got from XJ550? http://api.viglink.com/api/click?format=go&jsonp=vglnk_144630751457510&key=d8c39b2fbbccc31101b087881dc732d5&libId=igfa536h01000ajf000DAakfnoaby&loc=http://xjbikes.com/forums/threads/hard-start-below-70-turns-into-no-start.74639/&v=1&out=http://www.xj4ever.com/inside%20your%20carbs.pdf&ref=http://xjbikes.com/forums/threads/hard-start-below-70-turns-into-no-start.74639/page-2&title=hard start below 70 turns into no start. | XJBikes - Yamaha XJ Motorcycle Forum&txt=http://www.xj4ever.com/inside your carbs.pdf


i see the 90 that's there. also (enrichement ckt starts on pg 25) the starter plunger is on the outside and looks like it can be removed and blown out, but would that work? AND, can those enrichment jets be removed from under the carb with the bowls off? or somehow attach air to the bottom of the jet and blow it out that way? i guess either way i would just be moving the crap that is in there around and it will just come back into the jet and clog it again, no? that rust was just everywhere when i got the bike. the whole tank was a total wreck inside, the carbs bowls were full of it. but it couldn't have run like that. still, apparently there was enough crap left in the old fuel lines to do this to me.


BUT, now that i look at this, the fuel is going IN to the small port, which i think would make any crap in there exit out the larger end. so in view of THAT, do you think it is more than likely that crap is stuck on the outside/bottom of that port and i could just wipe it off with the bowl off?

 

when ever possible you should blow out holes in the oppisite direction of flow

 

Bullheimer, After reviewing the link with the carb cutaways I see the Maxim X carb doesn't use an enrichment passage that runs through the float bowl wall. It was a 650 I was working on that had them. Therefore disregard what I said about the drilling out an enrichment passage may have ruined a jet. I do own a 700X that I had to go deep into the carbs. The problem I had there was the main jet had been drilled larger but was not obvious or they had pilot and main jets swapped. It may have had both problems, I don't remember. I have worked on a lot of carbs and what seems simple to remember isn't always so easy. Anyway keep examining the carbs little details and consult pictures and advice and you will get it. This is the stuff that will make you a good mechanic and is so rewarding in the end.

 

i'm gonna be 60 in a couple weeks. being an ace wrench on bikes is not on my bucket list. when i bought this pos it was "a running bike". about like i could run a marathon.
i want to clear this one thing up tho. when i said they used a small drill to clean out the passages, they did not chuck the bit up in a drill motor, they just used them by hand. still wondering how this can work fine in 70 degrees and not at 60. but still thinking i am doomed to have to remove these carbs again. this time i will try to do with boots left on the motor and the air box. new air box boots will make it easier this time,, but i still have 30 year old stiff front boots to deal with.

 

Maybe you know this. When pulling the carbs, remove the battery, loosen the air cleaner mounting bolts and slide the air cleaner back. That will give you the clearance you need to pull the carbs. Leave the boots connected to the engine.

 

the one thing i DO know is last time i did it wrong. i took the boots off the engine one by one, which was ok, but then after a month or two the back boots were hard as rocks and seemed to have shrunk. i tried the water pipe union trick and that was a complete FLOP. so then i had to buy new air box boots and had to put them in afterwards cause i already had the front boots tightened up. sticking my hand down into the airbox to push those little Fer's in total sucked. from what i have read the easy (my a$$) way is to remove all the clamps on the carbs and rotate them front down, back up, at least, so says the guy that claims he can do it in five minutes, anyway.