Low Gas + High RPM on hills = Thud??

[dodgeram18]

yesterday i ended up running low on gas from what my gauge was telling me(notoriously inaccurate gauges) and whenever i had it to the bar going up hills i would get a consistent thud. thud. thud. at higher rpm. i ended up just feathering throttle to lessen the thud unsure of what was causing the noise. has anyone else had this issue on low gas levels on their sled. high rpm pulls going down hill was flawless. my belt seems good also but i still might swap belts to be sure i eliminate any culprits to the issue.

 

[takethebounce]

Where was the thud coming from? Sure it wasn't just the track ratcheting?

 

[dodgeram18]

The thud was coming from engine bay. Top end was rebuilt 5 rides ago bottom end has about 2k on it and primary clutch was inspected 2 rides ago all is good. I was just wondering if anyone has had similar thud/noise issues when low on gas when in demand of power on a hill. I started thinking crank but kinda ruled that out when the the thud was only every second and not more rapid as I would suspect a crank issue would be at 7-8k rpm.

 

[aocbiz]

I would check your track tightness first.....sounds like it could be jumping driver teeth (ratcheting), as the way you describe it - it only happens when your torqued out climbing.

 

[dodgeram18]

track is tight, I had no problem for the first part of the day with steeper climbs and harder vertical demand. the thud started shortly after my gas light came on.

 

[aocbiz]

It doesn't make sense that low fuel would cause the thud. If it was anything like low fuel you would be surging and feel the loss of power.
Just going to throw out some thoughts.....
Partially frozen intake? But u should feel loss of power too.
Frozen cap vent on fuel tank?

If you figure it out let us know.

 

[team-x]

was the thud possible detonation due to ****ty gas at the bottom of the tank? Only thing I can think of that would be related to the amount of fuel in the tank

 

[dodgeram18]

I inspected the drivers and they are in good shape no teeth rounding like it was missing from loose track. I also tightened the track a bit more just to be safe. I am going to swap out my belts and start with a fresh belt. Im pretty sure the thud was fuel related, either low fuel or crap from bottom of tank. ill test it out friday with a full tank and see if the problem is solved before making a trip to golden for sat and sunday ride. ill let you guys know how friday goes if that has resolved the issue.

 

[dodgeram18]

update - I found out what the notorious thud was. my track is toast. popped a big hole right in the middle and my idler wheel was thudding when it would roll over the hole.

 

[aocbiz]

ahhh bummer! at least you found it!

 

[dodgeram18]

yeah it sucks i need a new track but at least it failed on the trail ride down with 6km to go and i was able to limp it out and load it on the truck no issues. it could have been worse, it could have shredded when we were at 7800ft. overlooking area 52 in quartz that wouldn't be a fun tow out.