Help Support VMAX Forum:
Does it have spark at the plugs?
ZackDaniels
Well-Known Member
Is it cranking but not catching or not cranking at all or? How old is the battery? Sometimes they read fine, hold a charge fine, but poop out under load.
tothemax93
Well-Known Member
Gas in the tank? Is gas getting to the carbs? Fuel filter plugged?
95spfldmax
Well-Known Member
As these guys already questioned......need to rule-out fuel or spark first....
- spark at plugs?
- fuel in bowls?
- spark at plugs?
- fuel in bowls?
1. Spark
2. Fuel
That leaves only one more thing to make a motor run: Air.
Oh, and I guess you gotta get them all in the right quantities, and at the correct time.
Have you checked the air filter?
If that is OK, you need to check your voltage WHEN YOU ARE TURNING THE MOTOR. The ignitor boxes on our maxes require a good, solid voltage in order to fire, and at the right times. Put a volt meter across the battery and see that you have a good 12v while cranking.
2. Fuel
That leaves only one more thing to make a motor run: Air.
Oh, and I guess you gotta get them all in the right quantities, and at the correct time.
Have you checked the air filter?
If that is OK, you need to check your voltage WHEN YOU ARE TURNING THE MOTOR. The ignitor boxes on our maxes require a good, solid voltage in order to fire, and at the right times. Put a volt meter across the battery and see that you have a good 12v while cranking.
wildweasel_pt
Well-Known Member
The million dollar question is... Is the spark strong enough? I had a rich condition and eventhough my sparks tested good outside the heads they were being fouled and i got exhaust backfire due to rear cylinders not igniting... The engine didn't start with all 4 plugs in (backfire) and it started on front 2 cylinders with rear plugs removed (so no rear compression)
Also, gas to the carbs doesn't necessarily mean the pilot jets, aka idle circuits, are not plugged up, and not giving fuel during the startup process.
Have the carbs been gone through and cleaned in recent history?
Have the carbs been gone through and cleaned in recent history?
tugla
Well-Known Member
w3as iut running before or been not running all year, like others said clogged jets. does it crank fast, good battery,its a must. are all the chokes being activated when you push choke lever? sometimes set screws fall out and its not even moving the plungers, have to look at them close.
95spfldmax
Well-Known Member
Sounds like you need to hit it with some starter fluid and see if it runs on that. If it does and then shuts down you know your fuel delivery isn't getting past the needles/seats or so.......if not running on the ether then your looking closer at your spark...........
We got the bike all straigtened out. When the new battery was put in it broke one of the p/u wires. We soldered a new one up. Also, the new $140 battery that was made in China was bad. So, went to Napa and got a good one for $70. Sync'd the carbs up and it's running great. Kyle is no longer crabby lol.
naughtyG
Well-Known Member
Awesome, Mark to the rescue!! 
+1 check choke linkage
Hello,
My cranking voltage is around 10.5, did recheck all spark at all plugs are present. I have drained the bowls and shot carb cleaner down the carbs with no response from the engine, but turning over well. The bike had been running fine, and one day the bike wouldn't start. I had the carbs cleaned by Yamaha about 6 months ago. The bike is getting fuel from the carbs, by opening the throttle full and cranking over, the aroma of fuel and spraying of fuel can be seen. I'm stumped at this point, I'm thinking about going back into the jets on the carbs, any help would be appreciated.
My cranking voltage is around 10.5, did recheck all spark at all plugs are present. I have drained the bowls and shot carb cleaner down the carbs with no response from the engine, but turning over well. The bike had been running fine, and one day the bike wouldn't start. I had the carbs cleaned by Yamaha about 6 months ago. The bike is getting fuel from the carbs, by opening the throttle full and cranking over, the aroma of fuel and spraying of fuel can be seen. I'm stumped at this point, I'm thinking about going back into the jets on the carbs, any help would be appreciated.
johnpclynch
Well-Known Member
How are your plugs? are they old/dirty? is the plug gap set correctly?
Try start the engine and when it doesn't - pull a plug and see if it's wet or smells of gas
How are the rubber carb mounts? If they're letting in air then you could be too lean to start
try spraying a squirt of starter fluid down the carbs while you're turning it over
Try start the engine and when it doesn't - pull a plug and see if it's wet or smells of gas
How are the rubber carb mounts? If they're letting in air then you could be too lean to start
try spraying a squirt of starter fluid down the carbs while you're turning it over
Could be a problem with the 'black box' ignitor unit. 10.5v while cranking is getting down there to the point an older ignitor box may not be firing right. That was the problem I was suffering 4 yrs ago. Looked like I had fire at the plugs, when visually testing w/ a plug hanging out, but the fire simply wasn't strong enough to lite the motor (apparently). Had me ready to sell the bike off.
