Starting problems when engine is cold.

[lee enfield]

Hi guys,
I just bought a 1982 XS400 maxim thats been stood in a barn for 14 years, it only has 25,000 kms on the clock, I changed the oil and filter, washed out the tank, cleaned the carbs, fitted new jets (carb kit), changed the plugs, new battery and solenoid, cleared mouse nest out of airbox (not kidding!) and fired it up, it fired but didnt want to start, checked carbs again, nothing! plugs were dry even after cranking over for ages, tried blowing down gas line into carbs until gas blew into airbox, she fired and eventually started, wouldn't rev until it had been running 5 minutes and was warm, ran and rode fine, started first touch on button provided it hasnt been stood more than an hour or so, if i leave it overnight it fires for 2 seconds then stops and wont start unless i blow down gas line again! HELP! i'm pulling my hair out! i've had the carbs off 20 times and everything seems fine but it just wont start when cold! any ideas?

 

[willem]

Welcome

did you watch bcware's videos on the carbs? could still be that you missed a passage somewhere, I know I did on my first few tries..

Did you set the float height? Carb sync? Have you adjusted the valve clearances? How's the compression?

 

[billday]

Just wondering why you changed the jets, because you don't mention changing anything else in the intake or exhaust. Maybe you should try putting the original jets back in.

 

[Lou Ranger]

Get an in-line fuel filter on there fast, just in case there is material coming down the pipe from the tank.

I assume you are using the enricher (full on) when it's cold. Is it hooked up and working properly though?

My Maxim would fail to start after sitting for several days to a week unless I turned the petcock to PRI first. It was fine overnight or even after 2 or 3 days, however, whatever that fault was, perhaps you have the same thing going on, only worse (using PRI every time is not a cure though, but a diagnostic).

 

[lee enfield]

Welcome

did you watch bcware's videos on the carbs? could still be that you missed a passage somewhere, I know I did on my first few tries..

Did you set the float height? Carb sync? Have you adjusted the valve clearances? How's the compression?

no i didnt see the vid yet but i will! not set float height or sync'd carbs yet, compression seems good but i need an adapter for my tester as the plugs are smaller than the ones on my GS750, valve clearances are next on my to do list as it does seem a little noisy! I put new jets in 'cause (a)they came with the carb repair kit. and (b) the original jets were gummed up solid! even after soaking in carb cleaner overnight and using a jet cleaner i couldnt get all the crud out! i think i may have missed the passage for the enricher after reading some of the earlier posts from you guys, Thanks to all you guys for your replies, its good to know i'm not on my own with this! I'll let you know how i get on

 

[Lana]

My 82 maxim is always hard to get warmed up. I have it on full throttle for about 1 min, then turn it down to about half, and let it sit for about 5-10 minutes before I can ride away, once going it's fine, and I can turn the throttle off, but if it sits for an hour or more, I have to wait for it to warm up again. Carbs all clean, new plugs, etc. I'm not mechanical at all when it comes to bikes, and this is my first baby, but it's annoying when going for a ride as a team or group, and I've got to get my bike started 5 minutes before anyone else, if we stop somewhere.

 

[Lou Ranger]

When you say full throttle then down to half, do you mean the fuel enricher (lever below horn button) or the actual throttle?

If you mean the former then your bike sounds pretty much like mine... provided that I could simply let the bike run for 20 - 30 seconds to ensure oil pressure then start to ride slowly away with the enricher still on.
Almost immediately I could turn the enricher down to half, then a third and then off because, at that point, I'd be using the throttle to maintain speed.

If your bike isn't able to be ridden away after 30 seconds with the help of the enricher, then I would say something is wrong - though unfortunately I don't know what. Likely carbs, although maybe the fault is with your enricher (which, I guess is still a carb issue - though a different one from the usual).
I found that if I let my bike sit and idle for more than a short while (say, while I put gloves and helmet on) it would actually run worse (though it would clear up after a couple of high rpm shifts) than when I'd start off after just 20-30 seconds.

 

[Lana]

Hey Lou Ranger,

Ok, what I'm calling the throttle in my post, I actually meant choke, and you call it a fuel enricher. The lever under the horn button. I guess I'll have to look this up in the manual.
Either way, yes, I start with it at full, and while I'm gearing up, I turn it to halfway, then after about 5-10 minutes, not seconds, I can finally put it in gear without it stalling out.

 

[Lou Ranger]

Mine was always fussy about starting on a real cold morning or after sitting for several days. But even on those occasions, once it fired up, I could ride it off withing 30 seconds on partial enricher, and then push the enricher in within the first km.

Something is definitely amiss with yours if it stalls under a light load after warming up for a full minute.