Dies at prolonged top speed?

[Smerft85]

My brother and I went for a top speed run, him on his trike, and me on my ken-bar streaker. His top speed was right at 45 with a degoverned and stage 1 predator 212cc, my top speed was 39 with an only degoverned predator 212cc, the run was from my sisters house to mine, about a mile and a half. In that mile and a half my streaker cut out and died a total of three times, but would start up first pull. Only thing I can think of is maybe I'm using the fuel in the bowl faster than it can fill? Both engines are a couple months old, and both will cold start within two pulls, very slim chance of carbs being gummed up, and his traveled the entire trip with no issues. I'm wondering if a bigger jet may solve the issue, but wanted to gather thoughts before I start buying stuff to throw at it blindly, in short bursts, say a quarter mile, I can run wot with no issue, and off road itll drift, jump, powerbrake, and run wot no problem, just seems like a long run is the only time it has an issue.

 

[mckutzy]

I'm a proponent of doing a proper plug test..
Since the road is long an able to hit a high speed for the engine..
Do one at as highest it can ... shut off and brake safely to a stop, hop out and check the plug while hot.. see what the colours are...

That will be the best check off hand to see if the jet is right..

 

[Smerft85]

I'll do that later this evening, itll be the first time that plug has been removed so could be interesting to find out.

 

[Brianator]

If you suspect the fuel bowl is drying up a larger main jet will make that happen quicker...

Is the fuel tank in the original location? Have you checked the screen in the fuel outlet of the tank? I've had issues with a couple similar carbs that didn't flow as much as they should've because of poor casting/moulding of parts of the fuel system

 

[Smerft85]

Tank is in original location, casting all looked good last I had it apart, but may not hurt to check with my attention looking for an issue. The screen I have yet to pull for any reason, but I'll do that as well, sounds like I need to go ride tonight and use up some of the fuel.

 

[Brianator]

I can't believe I didn't think of this earlier.... is the low oil sensor unplugged/removed?

Carb issue I had is not only didn't the fuel shutoff not open all the way but the slot on the underside wasn't as wide as the holes in the bottom!

 

[Smerft85]

Oil sensor is always the first thing to go! I'm thinking there is a restriction of flow in the fuel somewhere.