Well I just bought it from a guy that “says” he knew nothing about it. There’s no lid on the air box and it’s a K&N air filter. It’s a Mikuni carb but that’s all I know. Like I said I don’t know anything about the quad I’m just jumping right in.
So I have a 155 main and 25 pilot.... I didn’t do anything with the needle or fuel screw. It will only start with quick start and run for a second. Could that just be because the needle and screw need to be adjusted?I would put in a DynoJet 25 pilot, 160 main, adjustable needle on 3rd clip, and fuel screw 2 turns out. That should get you close, assuming that his info was accurate.
So when I first got it it didn’t have an air box or filter. I could get it to start but that was it. So I bought a box and filter and also put a 155 main and 25 pilot jet in it. Now I can get it to start and run if I restrict the air intake and feather the throttle to keep it running. Any ideas?Ahh, I see. If you need to use starting fluid, then you have other problems. Start with making sure you have a clean fuel supply getting to the carb. It should flow well on prime. You probably have good enough spark or it wouldn’t have lit off.
The other 2 big things with these motors are valve clearance and compression. If the clearance is out of limits, it won’t start. Search or go to the maintenance forum, there are some good how-to write ups there.
You’ll need to set the needle and mixture screw before trying again.
It won’t start unless I choke it and give it throttleHaving to give it throttle and restricting the air means a lack of fuel. It also raises the needle out of its seat to allow fuel from the main. So, the pilot circuit may be clogged somewhere behind the new jet, or the fuel screw needs adjusted out to let in more fuel in the pilot circuit. Is it easier to start with the choke on?
How do you check valve clearance?As I thought, the “choke” is just an enrichment circuit which dumps in more fuel. It isn’t really a true choke.
You really need to make sure the compression and valve clearance are good first or all of the carb adjustments you’re making will just be barking up the wrong tree. I’m stressing it because as the valves get too tight and get just outside the limit, it does exactly what you’re describing. Won’t start unless you give it about 1/3 throttle or more and dies as soon as you let off of the throttle. Sometimes won’t start at all. One or the other is a real probability.
Thanks a bunch for all the help.....really hoping it wasn’t the stinkin valves😔The manual also tells you how, but this is easier to understand. Fairly simple, don’t need to pull cams unless an adjustment needs to be made. Just put it at Top Dead Center, pull the valve cover, and check with feeler gauges.