1999 TRX300 Starting issue

[KJINTF]

Been slow in starting up, in the recent past it would start up in <1/2 second of the button press with a snap. Now it takes several seconds of cranking to get going. Once going runs as it always did. Replaced the plug no change. battery is good.

Before I tear it apart and look things over was hoping others might have had the same experience and have a quick fix for me

Thanks in advance for any and all suggestions to get this old machine starting quickly again as it has for 20 years.  

[Frank Angerano]

Probably needs a valve adjustment would be my guess.   You can check this by taking a simple compression test. I would also check the fuel delivery system. Maybe a little bit of dirt caught up in the needle where the float is. This could cause The gas from getting up into the intake port of the carb.  

You could have gotten some bad or dirty gas.

Hows the gas in the bike fresh ? Is the tank clean and maybe a fuel filter if you clean the carburetor. 

Last thing is make sure there are no leaks on the intake boot where the carburetor is mounted and make sure your vent hose on the gas cap is clear.   

[KJINTF]

Might be a valve adjustment - don't believe its ever been done - Will try a compression and leak down test this afternoon

Always used fresh gas with NO alcohol - only thing is that it's 91 only way to get no alcohol around these parts 

Will also take a close look at the carb

Anyone know what the KV of the spark should be?  I have a Pico Scope with the pressure transducer for so can easily see the compression, spark amplitude, dwell, etc..  

Strange this starting issue happened almost overnight about a week ago - Guess it's time to get my hands dirty 

[Frank Angerano]

My guess would be a fuel delivery issue that can be solved with a good carburetor cleaning and add a fuel filter as well.   But I’m sure a valve adjustment is long overdue.  

As far as spark goes if you can clearly see a good spark when you pull the plug and test it then you don’t usually need to dig deeper into that.  

Might as well double check your timing as well while your adjusting the valves. 

[Old Guy]

Our 1990 Fourtrax 300 starts instantly in less than a full crank. But our 1985 250 cranked on and on but it would start quicker if we shook the machine. It ended up being a plugged screen in the sediment bowl on the bottom of the fuel shutoff valve. It wasn't getting a good fuel flow to the carburetor. 

[Charlie Garcia]

I agree. A good carburetor cleaning could do the work.