Vacuum leak? crazy rpms, and now it won’t start.

So I am new to motorcycles, got an 82 XJ550 and have sunk a lot into it. I paid an elderly gentleman twice now who specializes in older bikes to do the carbs in August. I believe he did not change the throttle shaft seals but am not sure how to tell without taking them apart (he was hospitalized before he worked on it, and forgot to put some screws back after working on it). I don’t have any more money to take it back to him and now the bike won’t start up. Winter is here so I am winterizing the bike. When it was running I drove it a couple of times and when I was in my neighborhood, I had a new problem. When I pulled in the clutch the rpm would skyrocket. I thought the throttle might be sticking and double checked it and it was not. Only started happening when the bike was warmed up and the choke was off as well. I sprayed some starter fluid on the carbs and it definitely shot up when I sprayed the throttle shafts. Any advice would be appreciated. I love this bike when I ride it and now I’m not sure why I can’t start it up or keep it running without some fresh Hell happening.

 

You will have to replace the throttle shaft seals. The good news is that it sounds like the fella did a good job of cleaning he carbs othewise.
You should also verify that he set the float levls corectly.
The only parts you should need are the throttle shaft seals, which can be puchaced from member Chacal. Start a conversation with him.

IN THE CHURCH OF CLEAN

Replacing your Hitachi throttle shaft seals (Mikiuni carbs are simmilar)

Setting the fuel levels

There are more helpful links in my signature.
Take an MSF course if you have not already done so, and get a copy of Proficient Motorcycing by David L. Hough.
Be the Bunny, and ride safe.

 

Thank you for all of that, and I have been reading through and seen Chacal mentioned numerous times. Is it better to show up to the mechanic with the replacement parts already purchased by me?

 

NO!
You are the mechanic.


Sorry for shouting but seriously if you can open a peanut butter jar you can be your own motorcycle (XJ) mechanic... and you should want to be your own mechanic - it is your butt that will be swinging in the breeze when you get on those two-wheels. You sure you want to trust someone else to make sure that you are safe?

Read those links that Kmoe posted, start asking questions here... keep asking questions until you FULLY understand the answers.

 

On the upper right corner of page is xj4ever this is chacal page to catalog of parts. You can do your carbs all you need are a few simple tools a Japennese screw driverlooks like phillips but is not. Chacal sells them . A flat blade screw driver and that is about it. you have to pull carbs off the rack and remove butterfly plates to remove shaft you will need a 10mm wrench . After you put them back together you will need to doa bench synch with either a playing card or small paper clip.

 

+1 to the above comments.

I will add that if you want help, I do offer carb services. Just a few hours to the east of you in NY. Send me a private conversation if you want more info.

Dave Fox

 

I have tried to take the carbs apart to clean them and was extremely foolish and did not read the "in the church of clean" document before doing so. I would love to take them apart again and do the throttle shaft myself or even double check but they have supposedly been rebuilt (partially from my step dad and the older mechanic previously mentioned). I also don't have the right tools to sync them, I hear they are quite expensive.

 

Cheap as can be, and just as accurate for our purposes.
how-to-make-a-2-bottle-synch-tool.15650

 

So while I had the tank off of the bike this winter to work on it I came back out to the garage and noticed a basketball sized stain in the the ground. It appears the petcock has been dripping slowly. I did not have it set on prime or reserve tank so I thought it shouldn’t be leaking is that normal?

 

Should be no drips... it's not a Harley.
I highly recommend taking a sniff at the oil filler cap to find out if fuel has polluted the oil or not. If no smell of gas, that's good-- shoes your floats and fuel needles are good. If it smells gassy you have carb work to do, as well.

 

I know our petcocks are of the vacuum variety and I believe the petcock may have been rebuilt not 100% sure anymore. could it be due to the top of the tank having a bad seal or do they not work like that. or is it just the petcock and I should rebuild/buy a new one

 

This is it taken apart what are your thoughts?

 

Yuck

 

Rebuild the petcock.
Did you ever finish the carb work that was needed?

 

definitely in need of a rebuild kits are pretty cheap , I think I paid like 20$ for mine .... I bought a used petcock and rebuilt it as P.O. fitted an after market petcock that was ON/OFF/RES ....I love the vacuum feature on the stock petcock no more forgetting to set to off ( I'm paranoid about fuel leaking past needle valve and getting engine filled with gas ) .

 

if fuel leaks past the needle valves you have some carb work to do

 

I made a 4 carb running carb synch manometer for about $25: http://www.xjbikes.com/forums/threads/carb-synch-manometer.114770/#post-573818

 

Hey guys it’s been a while but now that school is taking a back seat I am taking the carbs apart. Going to end up buying a ton of new screws since some were rusted in place but I finally have the carbs apart. The throttle shaft seals... are those typically stiff and not as flexible as the o-rings? I assumed that was my main vacuum leak but am not sure because they don’t look as bad as the other o-rings. I also bought some carb rebuild kits and they came with this little metal donught piece and I cannot find where it goes in the carbs... any ideas?

 

The throttle shaft seals should be supple and flexible. Yours are done. Get new ones.

Post a pic of the 'little metal doughnut piece"

 

I think the little metal donut is a washer for the mixture screw, there should be one for each carb and a corresponding 0-ring.

 

It is pretty thick as far as washers go... and I haven't been able to find a part like that in the carbs

 

I got really worried that i took the carbs all apart for nothing when I saw how unworn they looked, they do bend a little. They aren't as dried out as some of the other o -rings i came across so thanks for the clarification. also should I replace the cover plunger cap? can those cause vacuum leaks as well?

 

The enrichment plunger covers are just there to keep crud out. They do not provide a vacuum seal; the enrichment plungers do that themselves.
That is not to say that you can't have a vacuum leak at the enrichment plungers. If you do, then the solution is to clean the plungers and seats thoroughly, and use jewler's rouge to re-lap the plungers to their seats as well as making sure that the springs are pushing the plungers closed and the lifting linkage isn't binding and keeping the plungers lifted (not even a little).

 

Do you have any thoughts on the little doughnut piece I was talking about? I posted the picture a few posts ago.

 

The aluminum one? That's a replacement anti-tamper plug for the idle mixture screws. You can junk it.
If you want the hole covered Chacal sells rubber plugs for that application.

[EDIT] Matti, don't

 

Thanks for telling me that it was driving me crazy! so now that I have the carbs fully stripped down, is there some type of carb path I can toss the parts in minus rubber ones and let them soak? I have been reading through the church of clean. Also do I need to check valve clearance on a bike that has only 4k miles on it? I plan on getting a professional sync and color tune after I redo/check the electrical components. but I believe I found a decent guide here on how to check it I am just nervous about messing it up.

 

1. I prefer Berryman's CarbDip (comes in a gallon bucket), but other people like other things. Just be sure to follow the directions on the can.
2. You should check the valve clearances, and even take the time to see what shims it has. Clearance checks are to be done every 6,000 miles, and knowing what shims it has will save time when it comes to adjust the clearances (you can order ahead and swap them out on a pre-planned non-riding day instead of waiting).
3. If you don't mess stuff up you won't learn anything.

 

Berryman’s has a gallon with a basket. Looks like a paint can. Put parts in basket and soak. Keep all of carb 1 parts together, all of carb 2 parts together, etc.

Ifyou have not checked the valve clearances then go ahead and do it, order a new gasket first, cause that 30 year old one will most likely be toast. https://www.xjbikes.com/forums/thre...valve-adjustment-with-pics-parts-i-ii.116006/ This is a good task to take on that will start to build your confidence in doing your own work.

The sync and color tune should be done by yourself also. Sync can be done on the cheap with a home made manometer or done easier with a nice Morgan Carbtune.

 

Do you have any idea of chacal’s part number for the gasket? I don’t want to order the wrong thing.

 

HCP863 standard bowl gasket

HCP18412 hi-performance bowl gaskets

 

Thanks a bunch!

 

The easiest way to order is to just tell Chacal what you need, and for what machine. He will give you a parts list, including the choices (if any) and a full price quote.

 

Well it has been a while but I am finally putting in some good work in the bike. I have checked the shim clearances and 6/8 were out of spec. replaced the gasket and the doughnuts as well. really helped to build my confidence. I have the carbs completely disassembled and the parts just ordered. I am curious as to how long I should dip the carb parts for? I have seen some people say from as little to 30 minutes and as much as overnight.

 

30 minutes to an hour will do it the longer it sits the darker gray the carb bodies will get

 

the carb kits fit other bikes. That is why there are extra orings. also one may be for the drain screw some of them have an oring seal there will be a groove on the drain screw

 

Thanks I ended up finding that they were the caps, my bike had them removed from the PO.

 

So once that is done I dry them off and run compressed air through them correct?

 

ues compresses air work well to get passages clear. i also use spray cleaner into all the holes, I use little caps with the red tube stuck through them to seal holes for most pressure through the passages. sand end of red tube so it fits into carb bowl hole in the bottom. spin it in sand paper into a cone shape. and finish with air.
heat shrink works good to build up tube .
if you have an old set of jets those can be made into tube holders with a drill to fit red tube 1 jet for will fit main and pilot jet. .
when doing emulision tube screw in jet and block the other end after spraying down inside of it it will clear holes. then install it cover needle hole and flush up through air jet. pilot jet will also flush through the air jet and mixture screw hole so cover jet hole and mixture hole to flush out little holes in carb throat. confirm all holes emit spray
goggles eye protection required

I read about using shrink may be the jet thing too in the info overload IIRC guess I will have to read it again and the xj4ever catalog for all its little tidbits of knowlage. It is getting dark early these days.
also all the non catalog links in the XJ4Ever - Supporting Vendor thread.

 

Yes

 

so I am putting together the carbs and cannot find the photos of the springs on the throttle shafts!!! I am not sure of the proper positioning! does anyone have some good quality photos of the positions!? I am searching the sight and keep finding ones that appear to be blurry

 

Hey Guys, I got the carbs put together and back on the bike and now I cant get the bike to start. I bought a new battery and tried spraying starter fluid through the air intake and nothing. it almost sounded like it started when I let go of the button but that was it. I benched synced the carbs, turned out the fuel/air mixture screws 2 3/4 turns out and there is definitely gas in each carb bowl. I am at a frustrated loss right now.

 

You might turn the idle knob in a full turn , I rebuilt a set of spare carbs, had same issue turned up idle ,fired right up . While I bench synched idle was to low I guess. One other thing do you have the choke and throttle cables installed in the correct position ,?

 

Thanks for the advice, I will check that out! And correct position as in what? Not having them connected to the wrong thing?

 

Yes , if throttle is connected to choke and choke connected to throttle ...this is possible as they look the same and it has happened before.

 

No I set those up correctly haha!

 

so my floats are in spec but the fuel level is still only 10mm from where the carb body and bowls meet!!! I also replaced the fuse box. I am fiddling with bending the tang but that's all I have for tonight

 

I saw the title of your thread and was hoping you had found a solution by now. I'm having the same problems. As of now my xj650 '82 is running but it shoots up to 7-8k at idle. From your description of the problem you said your bike only revved crazy in neutral and I have not tried taking it OUT of neutral, so I might try that. I got my bike last summer and there was a point when it wasn't running. I messed with it for a long time before it ran, I'll check my notes and get back to you about what did the trick. Could you tell me a bit more about your issue with the rpms going crazy? Did you notice when/how it started? I've torn apart the carbs (church of cleaned, rejetted, etc) time and again and still having issues. Sometimes it seems my bike will spring up new issues without reason. What have you tried so far in terms of fixing it?

 

Also do you have an airbox or pod filters? stock or aftermarket exhaust? These things can make a significant difference in how the bike runs

 

Please start a thread for your bike. Same symptoms does not equal the same root cause.

 

And you expect it to start? Some hope. Get the fuel levels to spec. And don't be fooled by comments about filters and exhausts, they make no difference to whether the bike will start.
Sort the fuell levels, make sure the battery is good, you have sparks, open the enrichment and if the engine sucks, squeezes, it will bang.