Problems with Hitachi Carbs.

I have a 82 XJ650 that I am about to drive into the river where I live. The piece of junk is really hard to start. It had about a gallon of gas in it but the bike wouldn't start so I put around another gallon of gas in the bike and it started but it will stall if I turn the choke (enrichment) off completely. It had brilliant blue spark. Compression as tested with a Mac Tools tester was 150 140 140 140. Had the tank off so I know the backwards petcock works. Fuel doesn't come out if the arrow down or to the front of the bike. If the petcock is on PRI the fuel flows freely. What else is there. But those garbage Hitachi carbs. I took them off the bike to clean them. Must have used 4 cans or more of carb cleaner in the worthless carbs. I used one alone on the stupid fuel bowls. I had carb cleaner flying 20 feet in the air. I blew cleaner through the other way. I even got the small hole that's in the thing that goes in the dumb jet in the fuel bowl. I tore these carbs completely apart but I didn't separate them. I cleaned the carbs twice and still have starting and idling problems. I just don't know where else to go with this. I have compression, spark and fuel. So what's the problem? I swapped a motor on a Honda CM250 and got it running. I put a 1994 ECM in my Lebaron that needed a security module to work. I got it to run even though the factory service manual said if you vehicle didn't have factory security it wouldn't work. I got it to work. Just hooked power to the module. Hooked the purple and white wires (CCD Bus) to the module and grounded the wire that went to the door key switch. When the ECM seen the security module on the CCD bus it restored the pulse width modulation. Without the security module the Pulse width goes to zero. I can figure this out but I can't get Yamaha XJ650 to run right. Sad. Just sad.

 

First and foremost is to check the valve clearances (which tighten instead of loosen over time). Classic sign of tight valves is the thing takes forever and then some to start and its the number one issue with these bikes and us newbies always clutter this forum up with posts wondering what's wrong just to have the legends yell at us to check valves.

 

Are the valve clearances within specs?

 

Being that you have an 8 valver instead of my 20 valver, its actually quite the easy job to handle, you'll need a new valve cover gasket, new screw boots that keep the tension on the valve cover, and a special tool to hold the buckets down so you can slide the shims out with the camshaft lobe all the way out. Search valve adjustment on here, you'll find bigfitz's article with excellent pictures showing step by step instructions.

 

Thanks for your help guys!! I just put a valve cover gasket on about 200 miles ago. I wonder if tight valves would cause poor gas mileage. The last time I took a trip I got 50 miles on about 2 gallons of gas. She's a gas hog. I didn't know I had tight valves!!!!

 

Can't find the article. Says no results found. I wish there was a force button.

 

When a Bike having a rack of Hitachi Carbs on it doesn't run unless the Enrichment Circuit is involved; you have a Fuel Delivery Problem.

I hope part of your Carb Cleaning included Scrubbing and Polishing Diaphragm Piston Bores.
If the Pistons drag or hesitate to rise properly; the Bikes need Choke gas.

The Main Nozzles.
Generally referred too as Emulsion Tubes.
The Nozzles need to be poked-out and Cleaned.
Inside, outside and all tiny Air Orifices verified fully open.

I have a Stainless Steels Cap Screw that has matching Threads to the Nozzle.
I stick the Nozzle on the Cap Screw ... Chuck the Bolt Head in a Drill ... Spin it while holding Carb Cleaner soaked patches of ScotchBrite Medium until they shine.

 

Wow. I thought I cleaned all the holes I could find and do it all. I took the emulsion tube and sprayed it for about 20 seconds. Spray was coming out of all the holes. Polish what? This isn't a $400,000 superbike. Why can't this bike have real carbs? With all the problems you would think someone would have designed a better carb. because hitachi's are garbage. I never had a bike that was this touchy.

 

Polish the Diaphragm Piston Bores.

Members have found their Diaphragm Pistons hesitating.
A few reported them stuck.


Scrubbing Bore •<>• Dremel Polishing •<>• Polished Bore

 

altlandf - I'm within 1/2 hour or so of you.... need a hand? I sent you a PM...

 

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

Part Deux: http://xjbikes.com/Forums/viewtopic/t=29209.html

Don't blame the bike for the fact that it hasn't been properly cared for.

 

altlandf, like Fitz said don't blame the bike. Be patient, meticulous and thorough when working on your bike. There is no machine that likes half maintenance or being neglected for 30 years.

If you run out patience don't run it off a bridge, feel free to drop it off on my driveway

 

Also, it's a vacuum operated petcock. you shouldn't have fuel flowing on ON or RES, unless the motor is spinning. (there's a vac line from the intake manifold to the petcock....) The vacuum from the motor opens the diaphragm in the petcock and allows the gas to flow.

 

My driveway is MUCH closer!!!!

 

lol. my xj 700n had same problem, i had visions of doing nasty things to it. would start with no choke,,idle horrible, (without me featherin it, it would die)..then when it got to operating temps she bogged out died at a light wouldnt start and when she finally did it would hesitate and dam near throw me off of it in a turn. first thing i did was come here, second ,cleaned carbs..( well i thought i did). put it back together, same problem but worse, cleaned carbs again and this time i cleaned them, bench synched them, screwed air/idle in..then put them back to spec checked air filter, checked spark,,checked tank, petcock, compression test, put a hotter plug in, i didnt do valves, they were done last season,,(seen the work order from previous owner), put it back together and i am gettin 240 kmh roughly to a tank compared to 60 kmh before,,and gained mass hp, however i did have a stuck spring on main idle screw that stumped me with high idle for a week,,(i will nvr forget that btw), but patience a few cold beers tunes,,and a saturday afternoon can accomplish alot, and it doesnt cost much,

 

if you need choke to run it..sounds lean to me, check color of plugs?

 

http://www.amazon.com/Zen-Art-Motorcycl ... aintenance

Seriously. How many 30 year old bikes are still running out there? Old bikes reward maintenance, and give you great service as long as everything has been covered. What you're dealing with is a bike that probably hasn't been consistently maintained by previous owners. If you keep attacking the process, calling quality engineering "garbage" and the bike a piece of junk, just get rid of it and get a newer model.

All of us here have been frustrated at times. Troubleshooting something this old when you are unfamiliar with it is a pain in the butt. So, my question to you is : Why are you doing it?

We've all had different answers to that question. Sometimes we get different answers based on the history of the bike we just acquired (see Ecologito for a nice variety ), but it still comes down to this...if you go in saying "I only want to spend this much time and money on this bike", you shouldn't go in. You can't control what previous owners did or didn't do, and they are the ones who decided what you'll have to do to be flying down the road on the XJ.

Here's a good summary of what you have to do when you get an XJ, most of it covering your butt for previous owners:
http://xjbikes.com/Forums/viewtopic/t=43470.html

The hardest lesson for me: XJs reward OCD. They don't reward ADD.

You got this, dude, just breathe a bit.

 

Dave - I'd still recommend you at least check your valves when you have some time.... that way you can be comfortable knowing that they actually are right. These bikes have insanely wide clearances compared to many newer bikes + cars. I'm working on a Honda rebel for my sis in law. valve clearances there are .003 in (.07mm), which is quite tight for an XJ.

Yep. It sure does.

 

ya this winter im going to for sure,

 

I have a notebook where I track what's been done to the bike and when (date and mileage). On the inside front cover I have a grid for recording valve clearances AND the current shim sizes. Having that info doesn't make me smarter, but I do feel more informed, and if I ever pass that bike to someone else, they'll catch up quick!

 

VERY GOOD ADVICE. I keep a log book on all of my bikes; and it can come in especially handy for things like valve clearance tracking, etc.

 

Yea... +1 on the log book too.... Knowing the current shim size makes valve checks go much easier + faster. no more pulling it out just to find out the size....

 

A friend asked me if it would be a good idea to try to "flip" some of these bikes. I told him that is out of the question. It is going to take time, money, and patience because it is a lot of neglected parts and pieces that were never serviced.

This has proven to be my "yoga" no rush, slow it down, do it once, do it right... It is taking me a little while to digest all this but I'm closer to Oogway