I just realized I have a 400ex manual sitting around...

At correct idle speed, a timing light should show an F (6 degrees BTDC) in the window.

Increase RPM, and the F should move counterclockwise.

I agree, though, in that I would also do a compression test and/or leakdown test, and double check the valves first.

 

Have you checked the valves yet??? I'm sitting here in my physics lab with nothing else to do but wonder...

 

Nope, I'm at work, I hope I have time to check the valves when I get home. Prolly won't though cuz my wife's working tonight so I'm gonna be spending time with her. When she leaves for work, I'll be keeping my 1-1/2 year old. I may just let him run around and play in the yard while I work on it. It's scary doing that tho cuz we have an open ended culvert that leads to a sewer on one side of the lot and open access to the street in front of my house on the other...

 

Well I think you have enough to go home and check it out when you can. Ya make sure you don't get side tracked enough to lose sight of your little one!

 

Well, I got to do a little work on it this evening. Compression seemed fine although it was hard to tell cuz with the tester I bought, there was no way to fit a socket or anything to tighten it enough to know it was tight enough, so I just put it as tight as i could with my hand. I was getting about 6-7:1, but I'm almost sure it would be higher with a better seal on it. I checked the valves and they were very tight. I set them to where there was just barely any free movement in the arms at TDC (I've heard .005" and I'm probably just a little bit over that, but that shouldn't matter as much as it being too tight right? When they're tight, the valves never actually close). I tried starting it and we're actually getting somewhere! Besides just turning over, I could hear in about 3 consecutive turns a hint of firing going on! Woohoo! I just don't know where to go from here. I'm charging my battery as I type as it is getting low and could be the very cause of it not starting now. We'll see.

 

Spec is .004 intake, .005 exhaust. Make sure you are between the compression and power stroke.

 

HOLY FRIGGIN CRAP! I'M SOOOOOOOOOOOOOO FRIGGIN HAPPY RIGHT NOW! IT STARTED! IT STARTED! IT STARTED!

I had a 75% charged battery. It turned over like normal, I was thinking, o well, nothing. Then all of a sudden... POW! Freakin backfired. I was pissed. I decided, what the heck, I'll try it again... took it off choke pumped the throttle, let off throttle, pegged the throttle, tried everything. All of a sudden, I hear lots of firing going on. Next thing I know, wham!, she's up and running! It's a little hard on starting... takes about 4-5 turns of the motor, maybe a lil more, but hey, it starts so thats what really matters to me. I don't have rear tires and rims for it so I'm gonna put my 2009 grizzly's rears on there since they have the same bolt pattern and go giver her a spin tomorrow.

Thanks soooo much for all the help guys! I just want y'all to know that I love y'all! Haha, just messin. Dang I'm happy!

 

Get'er broken in and the rings seated before worrying too much about being a bit slow to start.

Anyway happy you got it running...

 

Good good to hear. If there is any kind of aftermarket ignition, they ususally won't start unless the battery is at full charge. I usually have to put a trickle charger on mine if the temp drops and pulls too many amps. Make sure you get your valves adjusted right and there shouldn't be anything you need to worry about. Yes you are right in that if they are too tight they will never close but that backfire thing is still making me wonder if it could be lean. O by the way, when you measure the compression, you are actually measing cylinder pressure. Compression ratio is always fixed depending on your piston/combustion chamber combo. So if you have leak-by or blow-by from rings or valves, the cylinder pressure will be poor. Good luck with it and keep it runnin strong to rep for the 400s!!!

 

This thing may very well have an aftermarket ignition... I'm the fourth owner.
It only backfired that one time right before it started. I guess it was flooded or something and the gas ignited somewhere other than where it was supposed to. After it backfired, it started almost right up and hasn't backfired since.
I measured the compression before I adjusted the valves and not since. Shouldn't the compression be lower if the valves weren't closing completely?
Man it sure sounds like it's running perfectly to me. I don't think I have any compression problems. It's running very strong.... once it starts anyway lol.
Thanks again everyone!