Starting Problems. Compiling List of Checks.

[bamarama]

Ok, so the bike I bought last weekend ('95 750) is consistently getting harder and harder to start. The bike has a jet kit and ignition advancer on it. When I hold the starter, you can hear it turning over, but it's not catching. It may pop a little here and there, but won't start. Choke it and it still does the same. Eventually I got it to start. The latest time I took it out, the bike cut out on me as I was pulling into the gas station (I don't believe I accidentally shut the switch off). After filling up with gas, it took me a good 3 minutes of cranking to get that bitch to start up. I got it to start once, got to 1000 rpm and applied throttle, then died. A minute later and it started up choked (Also, full choke causes the RPM's to set at 3000-4000, normal operation?). I'm going to work on diagnosing this problem this week, and I am compiling a list of things to check. I know that the addition of the ignition advancer and jet kits result in the need for tuning of the engine, but the previous owner talked as if he'd been running the bike with these modifications for quite awhile. If yall have any suggestions, please let me know.

1. Battery voltage - checked out at 13 volts.
2. Battery voltage after key turned (current draw) - will check tomorrow morning. Also, I didn't really see any fluid line within the battery (didn't remove it, so couldn't see the bottom), meaning its either empty or completely full right?
3. Choke/Throttle cables - not really sure what to look for here. I guess just make sure they are moving freely.
4. Beyond these I'm gonna wait until I can get my centerstand (supposed to be here monday) so I can work on the thing without fear of dropping it on its side. Then I will start checking for spark, check out the spark plug gaps and condition, and as a last resort.......brace yourself............dive into the carbs for inspection (I might have just dumped a little in my pants).

Any other suggestions yall?

Thanks,
bama

[The CyberPoet]

Probable causes:

Bad gas -- if the fuel in the tank has been there for over a month or so, it may be the cause -- or if you used fuel with too high an alcohol content, such as E85;
Fouled plugs (ran too long on choke or bad carb settings);
Overly thick oil for your current weather (20w50 in temps lower than 50 degrees);
Carbs' idle circuit partially blocked by dried fuel residues (run Techron fuel cleaner through the fuel) or deposits/rust (check tank for rust, see CyberPoet's how to deal with gas tank rust if you find it);
Bad start button (intermittent) -- open & clean with WD40 or electrical contact cleaner, possibly emory cloth, then goop up with dielectric grease to prevent future issues;
Vacuum leak (vacuum line is dirt cheap -- simply replace if in doubt);
Blocked fuel filter (clean/replace/ensure it's downhill from the petcock to the carbs);
Excess resistance in the battery cables (corrosion - clean/replace);
Blockage in the exhaust side of the equation (mouse nest, water, etc);
Low vacuum in general due to lack of blockage at the air filter (esp. aftermarket air filters, like the emgo).

Cheers
=-= The CyberPoet

[md86]

Sounds like crappy plugs for whatever reason . Check and clean em and see what happens . And an advancer doesn't require you to change your jetting or anything else except MAYBE the gasket on the ignition cover if you mess it up . Check plugs and see what happens , then check them agian for good measure in a few days to make sure they ain't getting all blacked-up too fast , indicating a possible problem .

[bamarama]

Well the past two days and the bike's started up with little effort. Choke it all the way, hold the button for maybe 10 - 15 seconds, and it fires right up. A couple of seconds with choke on then choke off and revs high for 20 seconds or so and the bike runs like a champ. It was 32 F this morning and the bike started easier than it did yesterday. I'm guessing that at some point late last week I didn't unchoke all the way in my glorious noobishness, and it probably took a good long ride (which I took yesterday) to clean off the spark plugs.

bama

[Black_peter]

plugs!!

Mine started one morning, warmed up..
1 hour later wouldn't start...
Checked 1/2 million things then checked plugs.. new plugs, fired right up no choke!!

runs like a champ..

[md86]

Wow , 10-15 seconds to get it started is a LONG time . Mine only turns over 3 or 4 times MAX (just a couple seconds) , even in winter . If it ain't running by then , it ain't running .