I bought a used raptor 80 for my daughter. It has been a problem child since I bought it. When picking it up it would only run with choke on. The owner said it had not been rode in a year. It showed very low wear and is a 2004. The price was fair so I bought it.

First thing I did was drain carb bowl and gas tank. The fuel was really gross, dark orange and heavy. New gas did not do much for it. It would run with choke off but would not idle. So off came the carb. I soaked the 2 jets and blew them out with compressed air. Spray carb cleaner on the rest of the carb body. Carb now spic and span and back on the bike. Closed the Air-Fuel screw and opened it 11/2 turns adjusted the idle and now it will idle but it still sounds like it is missing. Starts off cold once choke turned off idling fair and then slows down and seems to search up and down for an idle speed, if idles for a a minute or so it will eventually slow down and stall, does better if you rev it every 15 sec.

Any ideas, where should I go from here. Obviously I am not a motorcycle mechanic but I am pretty handy if I have some direction. Any help would be appreciated.

Thanks
Doug

 

You may want to adjust the valves. Also look for any vacuum leaks around the carb and intake. Check your fuel lines and change any fuel filters and make sure your fuel tank is vented. Don't forget to clean the Air Filter. What color is the plug?

White = lean mixture
Black to Dark Brown = Rich
Tan to Brown = Right on

Just some things to consider.

Good Luck.

SB.

 

Thanks for the reply. Plug is tan so mix is good. Did service air filter and changed oil. If I have to do the valves I think I will need a manual. I don't see any access port on the crank case for finding timing mark and advancing to TDC.

Any knowledge on doing a valve job on these bikes?

Doug

 

As long as it is a 2004 Raptor 80 it is a four stroke. There should be some caps on the left side for TDC and one to turn the crank. It would be a good idea to get the manual. I would call the guy you bought the quad from, if he was the original owner of the quad he should have the manual. The owners manual is also the service manual.

Good Luck.

SB.

 

does it drive ok just doesnt idle?
try turnig the idle screw in a little which will give it more fuel at idle.if it runs better on the choke sounds like not enough gas.to adjust the valves you need to remove the case cover on the shifter side &the side cover on the head to get to marks.line the T-mark on rotor w/pointer on case ,and slot on cam sprocket w/pointer on head.on the end of the head there 2 caps remove those ,there are the valves.you need to bend the feeler gauge a little to get to the valve but fairly easy .there is an adjustment tool that holds the valve while you loosen & retighten the locknut on the valve but i used a very small openend wrench.

they are fine w/in this range
intake valve .05-.10mm(.002-.004 in.)
exh. .075-.125mm(.003-.005in.)

fairly easy to do i checked mine after 2yrs. of rough use and they were still in specs
good luck

 

Thanks guys for all the responses.

I was convinced by a buddy to who knows a lot more than I do that it still sounded like a carb problem to him. He gave the following reasons. Side tight valves usually make engine harder to start (not my problem) and tends to cause motor to run faster when warmed up (also not my problem) .

I thought I did a good job on the carb the 1st time, soaked both jets spray carb cleaner through every other part of the body.

Well reluctently this time I just dropped the bowl and pulled out the pilot jet. Soaked it again and then ran some very small copper wire through the main orfice, then blew threw it with a needle adapter for my air compressor.

Put it all back together and it idles like a brand new rig, very even steady purrrrrrr. Well I don't see any reason to tinker with valves now.

Live and learn.

Doug