Just the float valves? Now this?

Hi.

Thanks for taking the time to read this. I have a 1981 XJ650 that was running fine until the Float Valve in cylinder #3 started to fail causing gas to drip out of the Air Filter.

I bought a Kit that had the new Float Valves and I installed them without incident.

I'm all happy getting to ride my bike again (it's been almost a week) and I look down at the engine by the Carbs and I see gas that starts on the starter and because of forward motion, worked it's back to the rear wheel.

I notice the Clutch starts to feel strange, so my first thought is "Do I have gas in the oil?" Sure enough, I look into the bubble only to see what appears to be a lot more liquid in the crankcase than before, so I take it very easy on the way home.

After taking a better look in the Window, I'm pretty sure there's gas in the oil. My question is:

What would have caused this? Did me installing new Float Valves do this? I'm hoping I'm not in for a major repair.

One other thing I should mention is when I got the bike, it didn't have an air box. I was told it was not driven this way, so I went and bought the individual air filters that attach VIA hose clamps onto the air intake of each carb. This makes the Crankcase Breather hose open on the end that usually connects into the air box. I started the engine and ran it for 30 seconds, and I noticed the air coming from the crankcase VIA the breather hose smelled strong of gas, further confirming my suspicion of gas in the oil.

Any help on this would be appreciated.

Also, I just received a Haynes Manual on the bike. Maybe I should read it!

Thanks!

Gynotai

 

float heights need adjusting.

 

Yep. Or one (or more) may be sticking or hanging up for some reason. You said it was "running fine" was it rejetted for the pod filters? Also, if you're going to stick with the pods, the breather should get a filter too. They are available, it looks like a miniature air filter and clamps on the breather.

 

If you had gas dripping from your air filter prior to your repair it is likely that is when the gas got in the oil. A failed needle valve will dump gas in the cylinder (lots if your petcock is bad too) and from there is goes into the engine. You need to do several things:

Verify your petcock is working properly - it is vacuum controlled - no gas should come out if the engine is not running.

Verify all your needle valves are closing properly

Verify your float heights as suggest above

Change/flush your oil to get rid of the gas. I have been there, what worked for me was I changed the filter and added some cheap 10W40 oil. Ran 10 minutes or so under NO LOAD. Remember fans to cool your engine. Then drain and change filter again - refill with your normal oil.


Lastly pay attention to Bigfitz's queries about pods and rejetting etc...

 

Hi.

Argh. I replaced all the float valves because of the one that failed. I had the naive assumption that all I would have to do it replace them. I hope I didn't get into more than I'm able to handle.

With regard to jetting the Carbs; nope. Didn't do any of that. All I mainly did was clean everything up. I bought the other air filters because they were $28 for the set of four, and were a lot less expensive than the air box's I was finding on eBay that were in thrashed condition.

I started reading the book last night (and I have it with me today to read more) about the technique using a piece of hose to determine the levels in the float bowls. I guess I'm going to have to guess at this. I see you have to make the adjustments VIA bending the little tab on the float bowl which means having to take the carbs off many times, and... Again; argh!

In hindsight, I should just cleaned the old ones and put them back!

If anyone has their own technique on how to do this, I'm all ears!

Thanks for reading,

Can't wait to be riding again!

Gynotai

 

Check the thread on dry setting the floats. It will get you very close.Then you have to use the tube to ensure they are right.

I just did my carbs and while setting float heights I had issues with the needles sticking when first filling the bowl. Had to tap the bowls to insure they seated but no problem after that. Also while tube checking 2 hints.

2 screws should hold the bowl with no leakage and if you do get a carb to overflow and have to tap it drain some gas and let it refill. I went nuts because no matter what I did the level was high, well duh on me it had overflowed and there is no place for the gas to go. After I figured that out I had the floats set pretty quick, wasted an hour though. I'm a slow learner.

 

Hi.

Thanks for all of this information! I just went out and pulled the carbs off my bike. Would it be a good idea to change the oil before I test the newly adjusted carbs? If so, I guess I'll run the risk of contaminating it again if they're still overflowing.

I also read that the petcock is vacuum controlled and that gas shouldn't come out of the fuel line unless the engine is running? The Petcock has a diaphram on it and a smaller (second) line that connects to the intake
of one of the cylinders. Is this correct?

Thanks!

Gynotai

 

Set the float heights with the carbs upside down (off the bike, obviously) at the following measurement:

from the carb body base ridge (where the gasket would sit, but without the bowl gasket in place, and NOT on the raised rib that is in that area) measure 13/16" upwards, and adjust the float so that the MOLD LINE in the float (at the end of the float, not at the pivot side of the float) is at that 13/16" height.

Then double-check with the "clear tube" method, but that 13/16" measurement should get you pretty much dead-on...........


P.S. the above information applies to Hitachi carbs only!

 

Hi.

After readjusting the Carb floats, I'm no longer getting and gas in my oil. Thanks to everyone who responded.

But I now have another question:

The bike rides ok. Not that hot at lower RPM's, (2K and under) and a lot of the time the bike has a high idle (2000-3000 RPM). Sometimes revving it once makes it come down to normal idle (800-1000 RPM).

What causes this?

Thanks!

Gynotai

 

Sticking Slides Did you do the clunk test?

 

Clunk Test Failure.

http://xjbikes.com/Forums/viewtopic/t=1 ... clunk.html

 

Or a vaccum leak somewhere......

 

you have to remember guys he said he had pods!!! So your under 2 k you really need to add more fuel for the air flow by either bigger pilot jets or bigger pilot air jets whichever is the best option. Chacal can get you what you need and they are easy to replace although you will be taking the carbs back off. Also if you search plug chop you may get by with just tweaking your mixture screws. but very warned if they haven't been pulled and cleaned they have a tendancy for the head to strip on them. THen you are drilling on your carbs not a fun thing to do. I suggest before y ou even think about moving them put a drop of wd-40 or the like right on top of the screws for at least a day or two to help free things up.

 

Hi.

I'l have toi give the "Clunk Test" a try. I thought they were free, but I'm not sure they were that free.

I took it to work this morning, and it was HARD to start! Sounds like it was starting, then right after I let the starter button go, it stopped.

I did see rebuilt ones on eBay for $150.

Keeps me thinking...

Gynotai

 

Hi.

Does anyone have any suggestions for me with regard to the hard starting in the morning? Might that have anything to do with the Float Valves I replaced? If not, what might be the cause of that? I'm going to pull the carbs off again this weekend and if anyone has any suggestions on what to do I'm all ears.

Thanks

Gynotai

 

charge the battery & chech the coils.

 

Step 1) check and adjust the valves

Step 2) remove the carbs from the bike

Step 3) clean the carbs thoroughly, INSIDE and out, until they are zestfully, surgically, computer-chip-assembly-lab clean. This includes every internal passage way, starter jet bowls, etc.

Step 4) Set the float levels properly and the bench synch settings correctly.

Step 5) Start the bike, do a quick synch, and then using your ear or---even better, a colortune plug---set the idle mixture settings.

You are quickly going down the same path that so many other people follow.....by trying to "cut corners" and do the absolute minimum to "get the bike running" on the carb service, you are going to end up doubling/tripling/quadrupling your time and effort and expense in doing a real tune-up to your bike.

And although I know absolutely nothing about the carbs on eBay that you are referring to, my gut reaction is that there is NO WAY you are going to be getting a set of rebuilt carbs for $150. No way. Not possible. Even with rock-bottom, discount-quality parts (never mind all the special tools, or the 8-16 hours in time needed to properly rebuild a set of 4 carbs), there's almost $150 worth of PARTS ALONE that typically need to be replaced.

Please understand, I'm not trying to rain on your parade, and while it is true that normally SOMEONE gets lucky and win the one big powerball lottery prize, well.....this might not be the winning ticket.

 

Great Advice from Chacal I cleaned mine 2 times before I did it right (complete rebuild in my case) and now that it's done and tuned what a difference!

Take your time - get it surgically clean, replace whatever needs replacing and you won't be sorry.

 

Hi.

I admit, I'm trying to cut corners, but it's only because of my lack of knowledge about it. (you should see how through I am when I repair electronics)

I'm also a little gunshy when it comes to taking it all apart; not that I don't think I'd be able to get it back together, but if I break something off, or ruin something in the process. Then a simple cleaning turns into something major.

At this point, I'd rather pay someone to do this for me, because I know if I screw something up, it'll make things even worse, and at the hands of someone who knows what they're doing, it'll be correct.

One thing that I did learn about the carbs in general: the cleaner, the better!

Ok, I'll stop complaining now.

Gynotai

PS with regard to the carbs on eBay, it's for a completely rebuilt set from an "experienced" carb rebuilder, and it's $150US with your old unit as a core.

 

The ebay guy is discussed in a couple of threads. Parts cost for a rebuild is just under $100 so you get what you pay for. Also who knows what you are getting in terms of condition when you send in your carbs?

I'm no mechanic but I can handle tools. I'm a programmer and electronics guy. I had no problem doing the carbs - dive in.

Take your time. stay very organized.

 

Hi.

Bill, you have a point. I'll give it a try.

One question (Just one, yeah, right!) I have is I noticed the new Float Valves I installed had spring loaded pins in the center of the plungers. Do I measure the floats at 17.5mm with these springs compressed, or not compressed? I did my float adjustment with them compressed. Wonder if that would explain the hard cold starting because the bike needs more gas to start cold?

Lastly (see, there was more than one!) should I just take each carb apart completely, then clean and reassemble as I go? Or is there any part of the carb I should leave alone (not take apart) Lastly, what do you recommend as a good cleaning fluid?

Thanks!

Gynotai