Ok guys, I'm new and already I need help.

Hey everyone,
I just graduated from Vespa 150 to an Xj650 and I'm thrilled at having that kind of power (not to mention how bada** they look). However,
I'm not as mech-savy as I'd like to be and already I'm in need of help.

The guy I bought it off of rode it over to meet me...I rode it around the block, loved it, and bought it. When I got home and got it off of my truck it didn't want to start. I didn't turn the fuel line off when I was transporting it, and I was afraid I'd bounced it around enough that it was just flooded. (also, the battery was a little weak). After a good nights charge, I went out and started it up no problem...except now it won't idle (it just dies) and it won't rev up past 2 or 3000 AND it's backfiring quite a bit. Im almost certain I've let it warm up enough that it should hold an idle.

What should I start checking?

oh...and the Carb intake filter (number 4) nearly blew off when it backfired once.

I'd be grateful for whatever help anyone can offer. This forum is great and everything I've read so far makes me think that even though it's running rough...i've made the right choice in buying this bike.

_Wayne

 

Howdy Ode!
Have you checked your oil level? Sometimes when the fuel floats don't seat right or a fuel petcock doesn't work like it should, fuel will flow into the crankcase. Real problem that is, you'll hear it time and again when you start hanging around here.
As for the idle, my recommendations would be to pull the plugs and look at them. Are they tan or black and sooty?
Odds are not in your favor that the P.O. did regular maintenance and the carbs will probably need to be cleaned out so MY recommendation to you is to first source a service manual for your bike. It will pay for itself the first time you use it. Factory books are the best of course but the aftermarket support isn't too bad either.
Let us know what you find on your plugs.

 

Hey,
Thanks for replying so quickly.
I bought the manual today and pulled the spark plugs....every one of them completely black with oil. I cleaned them off, re-gapped them and put them back in the bike...now it runs even worse.
I checked the petcock and the fuel line into the carb...both clear. But...when the bike finally did start, and I backed the choke off, i didn't see any fuel running through the line.
Is it something with the vaccum fuel system maybe?
Thanks again for your words of help, Robert

-Wayne

 

I would check the vaccum line from the petcock valve to the #3 intake manifold port. Any leaks? What shape is the vaccum line in? Any cracking, even on the ends? Is it hard? If either condition exists, I'd replace it. Now back to the problem at hand. I'll confess up front that I'm not a whiz with the carb/sparkplug magic so I hope one of our more learned/experienced brothers (or sisters if they are out there) will jump in and guide us accordingly.
Any chance that your air intake boots are still not sealed up correctly? Bike won't run for squat if there are leaks. Is your air management system the stock box or have you got individual filters?

 

Wayne:

When you get a new ride ... there's things you GOTTA know.

The first thing you got to know is:
"How's the Compression?"

Follow the instructions in the Manual and do a Compression Test on ALL four holes. If you don't have the Compression Testor ... borrow one or buy one.
(Some AutoZone Stores lend them to customers)

In the mean time ... use the Signature Feature in your "My Account" and fill-out the Signature line with "Thumbs" on your bike ... like this:

__________________________________________________
Year - Model - Total Mileage - Stock or Mods** - Known issues.

**Pod Filters

We'll work with youi to get you straightened out.

 

Ok. Vaccum line is hitting intake manifold port #1. The manual mentioned it going into 3 as well. There's a small crack on the end, but the tube looks/feels fine. I may snip off the end and reseat it. Although if I wanted to switch it to #3 I'm going to have to get a longer hose.
There are individual air filters on each carb. One's got tape on the end of it and one other's end is about done, but they're not clogged. These filters mostly look like they're not designed to do a whole lot. They're pretty flimsy and transparent. (as in they're only there to stop great big tree leaves from being sucked into the carb.)
I've never done a compression test before...but then again, I've never owned a streetbike before either. I'll do it.
Thanks again guys. I'll report back as soon as possible.
-Wayne

 

ToBob, did that bike happen to fall over when you were loading it?

sometimes if it falls just right you can end up with a float stuck open (now how do I know that?)
(something to do with when I smacked my knee on the cruise peg!)

Damm peg!

I'd check my petcock to be sure it doesnt drip if the fuel line is disconnected in the run or res position.
Note; that it SHOULD run freely in pri position

Could be that before the float problem you never noticed the leaky petcock.

Good Luck

 

Hey Guys,
Guess what! I replaced the spark plugs and changed the oil (which did smell a little of gasoline) and that puppy fired right up! Guess it's about time to change that old "biker wannabe" up to something like "Top ace mechanical genious"...right guys?...guys?
Anyway, I haven't done a compression check yet, but I'm planning on driving it around the block to american motorsports and seeing if they'll lend me the tool.
I also took the carbs off and cleaned them out a little bit (mostly just familiarized myself with them). (I think) everything looked fine in the float bowl sector.
Thanks again guys for all your help and words of encouragement.
I'm glad to be here.
-Wayne

 

It's not just "The Float Bowl Sector"

The Emulsion Tube that holds-in the Main Jet ... pops-out of there through the top ... when the Main FUEL Jet and washer are removed.
You have to take-out the Diaphragm Piston to give it room to be pushed-out.

There are up-to 16 -to- 20 tiny Air Metering Ports that need to be open and clear to give you middle and top end acceleration.

 

Yeah,
I knew I wouldn't actually know what I was looking at when I removed the carbs. Are the carbs not being set/clean one of the factors that would cause the bike to run really rich? (as in...those spark plugs that I put in are already black with oil - after one run around the block).

I guess for now I'll stay at "biker wannabe".

-Wayne

 

Yes. Major factor.

Don't be ashamed for not knowing that. Getting to fully understand Carbs takes a whole lot of trial and error.

You try a lot and error a good deal.
But, when you finally get those puppy's where they need to be ... you be having ... fun, fun, fun 'til yer old lady says put the XJ away!