1983/1984 200X Won't Pull Fuel into Cylinder

[WickedX]

Hey guys, this is my first post.

I recently got a 200X put together using two bikes put into one. The engine has a stock bottom end (as far as I know), a slightly ported head, a 65.5mm 12:1 compression Wiseco piston with brand new Wiseco rings. It had 115 psi of compression last time I checked, the timing is spot on and spark is good. It has a stock 24mm Keihen with a fresh rebuild kit slapped in.

I've ridden it twice, and since then I haven't been able to get it fired back up. It consistently has a problem where it will not pull fuel. You can choke it, kick it 30 times, and the plug will be as dry as a 50-year-old skeleton. Once it pulls fuel, it fires right up with no problem.

I've been scratching my head for weeks wondering what might be the problem. I'm at a loss as I haven't much experience with single cylinder engines, and I rarely get off work at a time where I can have knowledgeable help.

[Rob Canadian]

These engines should be a 1-2 kick to start it if all set up. Did you rebuild the carb?

I would start with removing the fuel line off the carb. Turn the fuel on and watch for flow out of the fuel line. Should be a steady flow. This will tell you the vent,petcock and fuel line are OK. If that is ok looks like you are going to have to get into the carb. Get a rebuild kit. (Shindy carb kits are what most people are getting)

Tons of videos on YouTube on how to clean the carb. Oh and Welcome to the forum. I am sure more will chime in on their favorite way to clean the carb IF that is the issue.

[350for350]

He said that the carb's been rebuilt. Do you know what you have to do to pull fuel into the cylinder? If you exactly what that is, then it would start us on the right path. How long did you let it set between the second ride and this issue starting? If it sat for a while, then you may have to clean the jets, especially the pilot jet. 115 PSI is WAAAY too low for a 12:1 piston. The correct way to do a compression check is to have the throttle wide open while you are turning over the engine to check the compression. I tried it once on my old YTM225 and I gained 60 PSI by having the throttle open VS. having it closed at the idle position

[WickedX]

It sat for a few hours after the ride, about 4, then it wouldn't even fire. Not much was gained from wide open on the compression test, but that was before it had even fired up.

The way that we got it to pull fuel was to pull the intake boot off and cover the throat of the carb with the package the carb kit came in. Once we got fuel, we hooked up the spark plug and it fired right up. This was the night before the two times I rode the bike. It would fire repeatedly until I left for work. I came back on my lunch break and tried to fire it up, and nothing happened. I've tried pulling the plug wire off, choking the carb, and kicking the crap out of it, and no fuel was found on the plug.

[WickedX]

Update,
After being run and the rings having a chance to slightly seat, the bike now puts out nearly 175 psi of compression. Spark was found to be good. Timing was checked, and no change has occurred since the last ride. Still no fuel on the plug, even when choked and kicked numerous times.

[fieldy]

Was the plug a tan color?

[danbur55]

Have you checked the valve clearance?

[WickedX]

Valve clearance was set by feel. It's about the same clearance as our 185S, and that thing runs like a champ.
The plug is a little dark from the last time I rode it, but not black.

[yaegerb]

Have you changed our your petcock?

[fieldy]

When it's running will full choke kill it? Take the carb back off, put hand over intake and kick it over. Should feel if its trying to get fuel.
Mist a little gas in the intake and see if it fires immediately.
Can you set the valves by the manual with the high compression piston?

[Rob Canadian]

He said that the carb's been rebuilt.

I was wondering if he rebuild the carb. Basketcase but whatever. Open the throttle when starting. Mine likes a 1/4 to fire up on cold start.

[WickedX]

Alright, after a few months of sitting, I got the hankering to finally get it done right. I pulled the motor back apart and found that the piston to cylinder clearance was way too wide. I took another cylinder I had to a local machine shop and had it bored to the piston with .002" of clearance as per Wiseco's recommendation. It fires right up now. I haven't checked the compression, but in 40 degree weather it only takes about 5 kicks to get it fired up.

Also, I shaved the top off the piston some, and it now has around 11:1 compression. I didn't want to be completely dependent on race gas.

[350for350]

I'm glad to hear that it's running again. Have fun riding.