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General => General Discussion => Topic started by: terravista on March 10, 2016, 07:13:22 PM

Title: 4 stroke quad bike problem
Post by: terravista on March 10, 2016, 07:13:22 PM

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

Title: Re: 4 stroke quad bike problem
Post by: Slo1 on March 10, 2016, 07:19:54 PM

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

Title: Re: 4 stroke quad bike problem
Post by: terravista on March 10, 2016, 08:39:34 PM

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

Title: Re: 4 stroke quad bike problem
Post by: terravista on March 10, 2016, 09:24:18 PM

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

Title: Re: 4 stroke quad bike problem
Post by: mato on March 11, 2016, 07:12:14 PM

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

Title: Re: 4 stroke quad bike problem
Post by: tomo on March 12, 2016, 12:11:52 AM

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

Title: Re: 4 stroke quad bike problem
Post by: Footy Shorts Shane on March 14, 2016, 08:24:27 AM

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

Shane.

Title: Re: 4 stroke quad bike problem
Post by: terravista on March 14, 2016, 09:41:16 AM

Quote from: Footy Shorts Shane on March 14, 2016, 08:24:27 AM

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

Title: Re: 4 stroke quad bike problem
Post by: Footy Shorts Shane on March 14, 2016, 12:57:09 PM

Quote from: terravista on March 14, 2016, 09:41:16 AM

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.