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Bike-Doc, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 671
Experience:  I have fixed & modified bikes for 35 yrs I'm now THE Mobile Bike Mechanic for S.LONDON since 1990
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I have a polaris trail boss 330 it turns over fine has spark

Customer Question

i have a polaris trail boss 330 it turns over fine has spark geting gas woulnt start with key but will with pull rope
Submitted: 1 year ago.
Category: Motorcycle
Expert:  Bike-Doc replied 1 year ago.

Welcome to JustAnswer

My name is***** am a professional here at

Does she crank rapidly when the trying to start her?

Sorry to have to ask what may seem like stupid questions, but it is obviously difficult diagnosing problems remotely, I cannot hear, see, touch or smell anything so I have only what a customer tells me to make a correct diagnosis.
Also I dont know how proficient a customer is or what they may have done already. So I need to ask stuff which may seem obvious or unrelated

Customer: replied 1 year ago.
never has started with the starter but always has with the pull rope turns over fine new piston and rings board over .50 gets spark gas everything it needs to start with starter but dont but will with pull rope the bike has alwas been like this
Customer: replied 1 year ago.
new batery cleaned all contacts
Expert:  Bike-Doc replied 1 year ago.

'always' do you mean from new?

Does she crank rapidly when the trying to start her?

Customer: replied 1 year ago.
bought it used it crank good not like timeing chain broke but yea fast sounds normal
Customer: replied 1 year ago.
cranks like my other trail boss
Expert:  Bike-Doc replied 1 year ago.


As she cranks fast enough it points to low compression but new piston, rings & a rebore should have sorted that

Have you checked & adjusted the valve clearances?

Have you done a compression test?

Customer: replied 1 year ago.
checked valves compression is 110 was 30 before
Customer: replied 1 year ago.
runs fine when pull started
Expert:  Bike-Doc replied 1 year ago.

Congrats with compression ! standard is 79 - 90psi

Does she start on the button when warm?

Expert:  Bike-Doc replied 1 year ago.

Have you checked for a spark while actually cranking (to eliminate rogue grounding of ignition) ?

Customer: replied 1 year ago.
no will not start unless pulled and its a old compression tester probably not totally rite
Customer: replied 1 year ago.
good spark
Expert:  Bike-Doc replied 1 year ago.

Purely for diagnostics :- Try spraying starter fluid into the airbox with the choke OFF & throttle open a crack. Does she fire up ?

Customer: replied 1 year ago.
just tryed it and no start
Expert:  Bike-Doc replied 1 year ago.

Did she not even cough or splutter?

Customer: replied 1 year ago.
just cranks it dont make cence
Expert:  Bike-Doc replied 1 year ago.

That suggests that there isnt a spark when cranking, are you sure that there is a GOOD spark while cranking & its not being grounded by the switch

Another way to check would be jump the solenoid poles, this will eliminate any starter lock-out

Can you try pls?

Customer: replied 1 year ago.
positive it has spark when cranking it with the key and already tryed jumping the solenoid a couple times
Customer: replied 1 year ago.
think there is a possibility of something with fuel pump
Expert:  Bike-Doc replied 1 year ago.

This seems to be a fairly common problem looking online

Isnt she carburrated ?

Customer: replied 1 year ago.
i just crossed the plug for the key switch like a diagram showed to check it and nothing
Expert:  Bike-Doc replied 1 year ago.

If she has a carb then the fuel pump is not the problem

Have you tried applying power straight to the starter motor, if still no joy then we have eliminated everything except the starter motor & clutch

All that is left is to to strip & clean the starter motor & replace brushes

Customer: replied 1 year ago.
well i will pull it in the morning and clean it n check it out but it turns over the same as my other trail boss. im at a loss something has to work i have a bad shoulder and with the compression that it has its to much on me now to pull start
Expert:  Bike-Doc replied 1 year ago.

I can sympathise with your shoulder problem

I broke the AC joint in my left shoulder 11 years ago & various operations have failed to fix it properly. It is 1 of the reasons that I sit at a computer more than contort my body continuously

Ive just had a good idea, turn the idle screw until you get the lowest possible tickover, then press the start button but dont touch the throttle at all, let me know what happens pls

Expert:  Bike-Doc replied 1 year ago.

Remember that the plug is liable to be wet after all this cranking! Keep it dry & clean

I keep finding more Trail Boss's of around that year with the same problem online, but no definitive answers yet!

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