My son's Yamaha Raptor 80 has become very difficult to start. We had it on a trail ride last weekend and everything seemed normal. I filled it up with gas after we got back and ever since then it's been a real pain to start. It usually cranks without firing until I put some ether in the spark plug hole and crank it some more. If I crank it with the choke on for very long it floods. I replaced the plug to no avail. I'm starting to suspect bad fuel, but I put the same gas in my Polaris 500 and it starts and runs fine. The Raptor will run after I get it started but it won't idle until he get's it warmed up. It's getting fuel (it'll flood if I'm not careful) and I pulled the plug and checked for spark and I get good spark.

Any thoughts? I'm thinking about draining the tank and putting in some new gas.

Thanks,
SP

 

DieselTech wrote this about 5 pages back: Raptor 80 Carb Question?. check it out


"Actually, you could need a larger pilot jet - I think the stock one is a 12.5. Before you try that though, look on the left side of the carb for a small rubber plug above the idle set screw. Pop the plug out and adjust the pilot screw (you'll see it once you get the plug out). You will want to turn it counterclockwise (I think) to richen up the idle mixture. Turn it 1/4 of a turn at a time, and keep track of how far you turn it. Also, warm the machine up before you make these adjustments, and make sure the choke is off properly - these machines' choke levers actually can be turned too far towards the off position and it causes problems - you should turn it just until it hits the detent, it will go a little more than that , but that's too far.

No air leaks at the carb boots, right? The main jet doesn't meter fuel at idle, so that's not your problem. Rule of thumb for the pilot jet is that if you have to turn the pilot screw out more than 2 1/2 turns (from all the way in), you need the next larger size jet."

Hope this helps. Let us know how you make out.

 

Putter,

Thanks for the reply, and the reference. I tried adjusting the pilot screw (the one under the rubber plug) and it doesn't seem to affect the idle, or the ability to start cold. It starts OK and idles after it's been run, but when it's cold, it won't start without ether and it won't idle at all. It started and ran great about a week or so ago, in fact my son rode it about 50 miles over the weekend. I can't think of anything that has changed and nothing is obviously broken. We ran the gas out of it and filled it up with fresh fuel and still the same problem. Any more thoughts folks?

Thanks!
Shane

 

Mine is the same. Using new plugs helped a little, and keeping th ebattery charged did too, but the real fix is in the carb.

 

have you cleaned out the carb?
check with al at raptor80racing.com

 

Can anyone tell me what I have to do to check/adjust the valve clearance on this machine? The manual says it needs to be done periodically, and I've not done it in almost two years of running this thing. The manual says it should be done by a service tech and offers no advice on how it's to be done. I'm not a service tech by trade, but I'm suspecting this is a relatively simple thing to do. I appreciate everyone's help so far. I am having a VERY tough time getting this thing to start cold. Even with ether and a fresh plug (I double checked the plug gap) it's a bear. Once it's running and warmed up it's pretty well off, a little sluggish on the low-end perhaps.

Thanks again!
SP

 

i dont know,its probably the carb, but i would check the airfilter if the air filter is real dirty it might help,but if that dont work its probably the carb.

 

are you reading the owners manual??
or the service manual??

here is a link for the 50 raptor service manual (they are vertualy the same)

http://rapidshare.de/files/17459996/...04-06.pdf.html

 

Spraay, I have been running these things for over 40 years now. (Designs have not changed much on the low end machines)

I was a thumper follower before they were cool... I have abused these things beyond belief, and can honestly say I have NEVER adjusted the valves, and NEVER had an issue.

This is a marketing ploy and is the factory's way to get you to bring it in for "Ghost" servicing. The hope being that you will see a new bike that you just have to have in your garage and you will be tempted to trade up.

Change the oil, clean the air filter once in a while and replace the plug once a year, and ride the thing. Don't sweat it...

 

My daughter also has a Raptor 80 it is a 2001,we were riding 2 weeks ago it was running good,we loaded it up to go home,the next time we went riding it would not start,I changed the plug ,cleaned the carb, checked the wiring,sprayedether in the carb,it is getting compression, it turns over but won't start up,I tried everything to start it . If you figer it out please let me know and I will do the same. John