i tried to fix it and made it worse

Umm, this threads not going to make me look clever, so there's no point in hiding it lol.

My bike is a B reg (84?) Maxim X. I've been having problems getting it to go.. it started ok, but wouldn't idle and didn't want to rev very high.
So, someone told me to take the carbs off and clean/inspect them. I was really careful and looked at every part to make sure it was working and put together properly.. but now it won't start.
It makes massively loud backfires (local dogs love me) and there's black puffs of smoke coming out.
Can anyone think of a stupid thing I could have done?

 

Did you take any jets out? Make sure you didn't switch your main jets for your idle jets when you put the carbs back together.

 

Welcome to the site !!

There's quite a number of things that can go wrong during a carb "cleaning".
Floats installed upsidown, jets reversed, diaphragm dislodged. . .
Then there's your valve adjustment, which is a pain on the "X".

You could start by checking your float/fuel level by putting "pinky" up on the centerstand and using a clear tube on the bowl drain. The fuel level appears in the tube 3 MM below the bowl gasket surface (unless it's different on the "X" ).

Have you done a compression test?? Post the numbers

 

According to some folks the Haynes book shows those air jets for pilot and main backwards. Not sure what picture or diagram they meant so look at the picture rickcomatic posted to be sure you got yours correct.

 

Ty for all the ideas
I didn't take the jets out, so can't be that. I'll try the tube thing and see how that goes
Umm, compression what? lol. No idea, have to find helps methink

 

maybe you removed the plug wires and returned them to the plugs out of order?

 

Well if you didn't take jets out, I would doubt just how "clean" you really y your carbs really are. What did you do to clean the carbs? I'm not too familiar with the Maxim-X's but check out RickCoMatic's "Whole 9 Yard" carb cleaning post to see what it takes to get them really clean. A rough idle and hesitation COULD be carb related, but to fix these problems by cleaning the carbs takes complete disassembly and thorough cleaning of all jets, passages, and associated bits.

Note that you may have some minor issue keeping you from starting...but carb cleaning has to be done right to be effective with these carbs.

 

Did you actually clean them - or just inspect them?

If it is a "B-reg" are you in the UK like me?

It's possible something else is stopping the bike from starting but if you only touched the carbs - then it's the carbs.

You could try spraying some "Easy start" into the air filter inlet and then see if the bike fires up.

 

more ideas, fankyoo.. hmm where to start,
ok.. don't think the leads are wrong cos it did start once (for about 5 secs and sounded really bad).
Spose i did inspect more than clean, cos they actually looked really good, so I decided to leave alone.
I asked a friend and he seems to think there's too much fuel (?) But why?

Oh, & I am in the uk too *waves

 

Stuck float valve probably.

 

Stuck float valve probably.

 

+1

 

I was under the impression these motors used a "wasted spark". Meaning -- firing order doesn't matter so much since they spark on EVERY stroke.

 

One coil sends spark to #1 and #4

The other Coil Sends spark to #2 and #3

 

It sounds like the carbs will have to come off again. I'm sure there is a carb cleaning sticky and there are also some reasonable youtube videos of how to clean them. Everything tends to get blocked or gummed up with age. The only way to tell is to strip and clean them fully.

Probably not the answer you were hoping for!

 

http://cycles.evanfell.com/2008/09/how- ... right-way/

for carb cleaning.
Also, Chacal's advice, too.
(Replacing any worn seals, gaskets, etc. as part of your standard "cleaning")


Also also, Hi xjbikes forums!

 

I have an update well, maybe not a big smiley update cos it still won't go.

I got some help and it's all in bits again. Apparently there's a bit that plugs a hole when the float bowl is put back (?) Anyway, it might be leaking so i've got some cleaning to do.

Also.. apparently my jet size is a little extreme. I searched here and it seems the standard size is 107? I have a 152.5 - is that way too big?

 

It runs again

ok, end of the 's.. cos it runs badly . Now it has 110 (?) jets and seems to make more noise. like the air sucking in is louder, maybe it's me?
using the choke makes the air noise much louder and it stops almost straight away. It still hates revving, just like it did with the old stuff in. Strange

 

What's been done to this bike? You mentioned the bike and year, but are there any intake or exhaust mods? Pods perhaps?
Did you properly clean the carbs? http://xjbikes.com/Forums/viewtopic/t=2 ... +sync.html
Do your slides clunk?
How did you set the pilot mixture screws?
Have you checked your valve clearances? http://xjbikes.com/Forums/viewtopic/t=1 ... valve.html
Did you do a bench synch? http://xjbikes.com/Forums/viewtopic/t=6 ... +sync.html
Have you compression tested the engine? http://xjbikes.com/Forums/viewtopic/t=1 ... +test.html
Do you have spark?
Have you searched for intake leaks?
(all ^^^ not guaranteed to be the same for water cooled engine, but some with an X can chime in and give the differences)

You have taken a bike that doesn't work, and probably sat for years. There will likely be multiple issues with the fuel delivery system, and they will be nearly impossible to troubleshoot. It's best to work through the proper steps to restore you intake, filter to engine. If you do everything right putting it back together, then the troubleshooting can begin. My experience is that these things will "run" pretty easily...but running "right" is a whole different story.

 

+1 on Manbot- - have a cigar !!

K.J.S. have you thought that if someone installed a 152.5 jet where a 107 belongs, that the same person may have screwed up your floats, messed with the pilot or main needles, or other mayhem and chaos thru the carbs?? You will need to look at everything, and clean every passage while you're in there.

And how about pictures?

 

oh, I'll get some piccies up soon. promise

 

4 filters = pods = reason for large fuel jet. This was an attempt to make up for the lean condition the pods create.

If you don't know what pilot jets are, then you haven't cleaned the carbs yet, and didn't read Rick's "Whole 9 Yards" carb cleaning post (search for it).

Without checking valves (I think this is more "fun" on an X) or compression, you could be trying to revive a dead engine (or not...but this is a quick way to figure out where you are actually starting from).

Clogged pilot jets would make it really hard to start (b/c it's using the pilot circuit of the carbs).

Consider getting a proper air box...if you don't want to troubleshoot and tune forever (and since you already got the proper jets)

 

any progress on this? If you are going to go with a stock airbox I might be willing to take those pod filters off of your hands for you as well as the larger jets you have. I could even pull my stock airbox and new air filter and we could work out some sort of a trade.

 

I'd jump at the opportunity to get back to a Stock Airbox and Carb Jetting.

Sooo much easier to get within the "Window of Fine Tuning" with the Intake Air and Carb Jets Stock.

Whatever happens here ... DON'T Wreck The Airbox.

 

Yeah, I'm still up in the air about what I want to do

 

OK.
I know it's a tough decision.
Paper. Plastic.
Classic Rock. The Classics.
Win. Place Show.
Less Filling. Tastes Great.

Air Cleaner Pods are a totally cosmetic Modification which inevitably causes difficulties inn Fine Tuning which have not been solved, to date, for over 30 years by Legions of frustrated owners having Constant Velocity Carbs. You will enter the arena where endless experimentation will resolve nothing and the bike will remain unable to be Fine Tuned for a variety of issues.

Stock Airbox and Rubber Joints.
Various degrees of Fine Tuning can be achieved and maintained without too much difficulty within a few hours of Fine Tuning.

 

I'm sold.....the stock airbox will be staying put as long as it doesn't get in the way when I go to hardtail it. That's not going to be until next year at the earliest though, so I'm good. Thanks

 

Yes, a little
It starts really well now, just needs a tiny twist on the throttle (no choke). It idles really high for a while, then drops and stalls. It doesn't like to idle unless it's too high.
Riding - it doesn't like to rev from about 3000-9000 rpm (it's slow and i can hear popping noises). Beyond that it's fine - before everyone panics, I only tried once for the sake of testing.
I looked at the mixture screws they were all 2.5 turns undone.
I did that revving to 5k for a bit and turning it off. The plugs were black.

 

You need to synchronize. See my gallery for a synchronizer.

You should adjust your valve clearances before you synchronize.

My bike would not start well nor take throttle well.

RickCo's carb cleaning instructions followed by valve clearance adjustment and finally synchronization made my bike a joy to start and ride.

You have to do all 3, carb clean, valve clearance adjust and then synchronize.

Anything else is half a loaf.