4 stroke quad bike problem

[terravista]

Hi
I purchased sort of by mistake unseen a Polaris 500 Sportsman (4 stroke) quad bike at an auction being sold as "parts only".
It was in about 40 pieces but most of appeared to be there. The obvious missing part was the fuel pump, which has now been sourced.
I took it to Polaris to have it reassembled and to see if it was useable.
After a couple of hours of work, they have it running, but the exhaust gets "red hot", so the service technician thinks it is a fuel injector problem.
In my extremely limited knowledge, this does not sound like a feasible reason that would cause an exhaust to overheat.
Do any of our knowledgeable members have an opinion on this prognosis or alternative theory?
Cheers
Ian

[Slo1]

Yep sounds like the bike is running very very lean, could be blocked fuel filter, kinked fuel one or partially blocked injector

[terravista]

Thanks, that may make sense if leanness can generate heat as the fuel line came separate as a loose item and looked a bit suspect.
The fuel pump came from a wreckers off a bike that must have been running at the time of  impact but could still be damaged.
As a seperate query though, why does running lean generate heat?
Cheers

[terravista]

Google was my friend.
Apparently it all relates to stoichiometric mixture.
Shoulda guessed that.
Cheers

[mato]

Yes running lean
It may have a blockage or if the pump came from a wrecker it coukd have a blockage.
But also cleaning an injector should be ease. Just depends hiw hard it is to remove.

Sent from my SM-N920I using Tapatalk

[tomo]

hi
Fuel pressure and flow on the bike check
tests for leaking injector ,leaking pressure regulator ,fuel pump function
change the filter
remove and cleanout tank check for rust inside the tank
compression wet and dry
valve clearance check
timing belt or chain stretch
air vacumn leak inlet manifold
air leak exhaust
check charging voltage ,sometimes high or low charge causes running issues
Remove injector and have pattern and volume checked
 tomo

[Footy Shorts Shane]

Does it have an engine temp gauge, or do you have an IR temp gun?

Shane.

[terravista]

Does it have an engine temp gauge, or do you have an IR temp gun?

Shane.

Negative to both. I think I will give the alleged Polaris expert a few days to see what he claims is the problem.
General concensus so far agrees with the technicians guess.
Cheers

[Footy Shorts Shane]

Negative to both. I think I will give the alleged Polaris expert a few days to see what he claims is the problem.
General concensus so far agrees with the technicians guess.
Cheers

OK, hope it goes well for you.