The little XJ650 that could - Which to Tackle First?

Is there anyway to check and see if the siphon tube and the metering port are clean and clear? I can't tell if the carb cleaner is getting through or not.

thanks

 

Re: The little XJ650 that could - Carbs (siphon tube)

Take the tube that sticks out of the carb cleaner spray-can and stick it right down the hole in the carb base. Give a good squirt with the can button. If it's clean and clear, watch out......it'll squirt out the bottom hole and right into your eyes so make sure it's aiming a different direction. DAMHIKT

I also stick the tube end into the little hole at the bottom to make sure that it will spray up out of the well, too.

The siphon tube......I use a couple different sizes of guitar/mandolin strings to feel the inside of the tube. When it's finally good and clean, I can hold the end of the spray-can tube tight against the pickup tube, spray, and see carb cleaner running all over from other holes in the carb body.

If it's not running from somewhere, then it's not open yet.

Dave F

 

Re: The little XJ650 that could - Carbs (siphon tube)

The Main Jet Emulsion tube?? - - gets removed and scrubbed, then a small wire poked thru each hole, then scrubbed again.

The Siphon Tube that sticks out of the carb body and into the float bowl body?? - - I found crud blocking the very bottom (or "top" actually) of this tube by poking a single bristle from a wire brush in there, and don't forget to clean the little side port.

There is advise on this site to clean ONE carb at a time, so the inexperienced don't get lost or overwhelmed, and have an assembled carb for reference.

However, if you have all 4 apart at the same time, you can compare the carb cleaner "blasts" and results from carb-to-carb, which helps you verify that a given passage is indeed "clear".

Don't forget the "hidden" jet that's INSIDE the float bowl.

 

Re: The little XJ650 that could - Carbs (siphon tube)

Another question. Is there a trick to getting the main jet back into the emulsion tube? Now that it's clean it wants to spin with the jet, thus not sitting down in the treads.

 

Re: The little XJ650 that could - Carbs (siphon tube)

Assuming it is engaging the emulsion tube threads and that the emulsiuon tube is at least partly seated, try this: use a philips-head or other screw-driver with a "well rounded" handle-end, and put the handle-end down the piston so that the handle-end seats on top of the emulsion tube -- press down as hard as possible on the screw driver handle while engaging the jet threads. It was my experience that once they begin to tighten, the jet thread pulls the emulsion down with enough force to seat it and hold it for a modest amnout of tightening through the jet.

 

Re: The little XJ650 that could - Carbs (siphon tube)

That did it, thanks boss!

 

Re: The little XJ650 that could - Carbs (siphon tube)

Note that the above ONLY applies to our Hitachis; Mikunis don't have the issue.

The Mikunis have a locating pin in the bore that engages a slot in the emulsion tube; you have to be aware of it so that it doesn't get damaged.

 

Re: The little XJ650 that could - Carbs (siphon tube)

Ok, I cleaned and put the carbs back together! They look a little out of place on the old bike, being that they are clean now. Unfortunately, a new problem has arisen.

Before I took out the carbs the starter would turn over, but now it won't even crank. The green light goes on and when I hit the starter the red oil light goes on. The spark plugs are not getting electricity. Is there something wire I might have forgotten to reconnect? Any insight? My voltage on the battery reads 11.8Xish, could this be the problem?

Thanks!

 

Re: The little XJ650 that could - Won't crank after carb rebuild

The easiest Test is to simply "Short" across the Solenoid's two Main Terminals.

Use a beat-up, Plastic-handle Screwdriver.
Select and confirm that the Bike is in NEUTRAL.
Place the Shank of the Screwdriver on one of the High Amp Posts on the Solenoid.
With the Shank on the one Post; ... Touch the other one.

The Starter should Spin.

::: Use CAUTION if you are Charging the Battery. The Arc will ignite Hydrogen Gasses from a Battery on Charge ... especially if the Overflow Hose is missing. :::

 

Re: The little XJ650 that could - Won't crank after carb rebuild

Your battery is flat or you have a loose/bad connection somewhere.

Start with the battery.

 

Re: The little XJ650 that could - Won't crank after carb rebuild

First off I wanted to say thank you RickCoMatic for your carb rebuild guide.

Secondly, when I shorted the solenoid the starter turned over. I guess it's time to start tracking down the loose/bad connection.

 

Re: The little XJ650 that could - Won't crank after carb rebuild

If your battery is only reading 11-ish, you need to either charge it or replace it.

Dave F

 

I have been slowly working through an 82' maxim. It didn't start when I bought it, so I started with the battery and replaced it. Hit the starter and it turned over but didn't fire. Compression left to right 125, 130, 90, 130. Pulled carbs and cleaned them according to Rickcomatic's guide. Changed the fuel line and vacuum line to the tank.

I now have several problems and I'm not sure which to tackle first:
Starter no longer causing engine to turn over

No spark at spark plugs

Gas not getting into the engine... I'm not even sure its getting through the carbs - which probably means another tear down.

Petcock leaking in ON and RES, this is a new development after I changed the fuel line.

Any idea suggestions where to start? I think I'm going to take out the Carbs again on Thursday when I have time, but where should I go after that?

 

Start in the order you listed those problems. Compression and spark are essential BEFORE fuel gets into the engine. Then work on the carbs - check float height, clean fittings, and rebuild your petcock.

Figure out the starter. Is it the solenoid? Short the high current poles to test it. Check battery voltage OFF and while pressing the start button. Is there an unusually high drop?

 

I might suggest you get the valves in spec and re-check compression. That 90psi cylinder doesn't bode well for trying to get the carbs adjusted.

 

Just to be sure the valves you are referencing are the ones found in your post about Airhead Valve adjustment or this post:

http://xjbikes.com/Forums/viewtopic/t=14827.html

 

I began work on the Valve Adjustment. When I opened up the head there was standing oil around the valves... I'm betting not a good thing. I need to go get a gaping tool that can handle such small measurements. The smallest gap I have is .254mm. That being said I couldn't get it to fit between any shims/cams. I also need to get a new head gasket, mine is cracked, and donuts. Any It's by birthday today so all will be done tomorrow!

Just one last thought: I'm correct when I say that because I can't gap with the .254mm I will be going down shim sizes? ie 250 --> 240

 

Read the thread on "How to check and adjust Valve Clearances". It is a good write-up. It will explain exactly what to do to get those clearances in specs. You'll also need a shim tool. Oh...and if your cover gasket and donuts are leaking that might be some of that 90psi compression problem. The donuts harden over time and can only tighten so much before replacements are necessary. They are the only thing applying pressure to the cover as it comes under a lot of pressure when the bike is running. I don't know much, hopes this helps.