Carb Trouble

I'm restoring my grandfather's 650 that has been laying on its side ever since he passed. So far the engine turns over, but the bike wont start. Each cylinder is compressing but no gas is pumping. I currently have the bike pretty ghetto rigged with a water bottle full of gas going to the carb (I'm a broke college student). I'm thinking that the carb needs to have a vacuum line connected to the petcock on the gas tank but I can't test my theory because the gas tank is completely rusted as is the petcock. This is my first decent bike I've worked on so any help would be greatly appreciated, especially good pictures of the inside and outside of the carb.

 

http://www.xj4ever.com/inside your carbs.pdf

http://xjbikes.com/forums/threads/the-information-overload-hour.27544/

Hope this helps.

 

you need to start by cleaning the carbs inside and out, ohm out your entire ignition system. take a spare spark plug and test for spark on each plug wire plug plug into cap and ground hit starter button see if you have spark,
if it has been laying on its side check oil level

 

The first thing I did was clean my carb out. I'm not too confident in the condition of my jets and float needle. I changed the oil and oil filters, but I'm a little worried that it is too full (could that play any role in causing it to not start?) and checked the spark plugs they all give sparks.
Could you give me more information on how to ohm out your ignition system?

 

What do you think is too full, Engine oil ? Carb float chambers? you really do need to clean teh carbs thoroughly (all jets out loads of carb cleaer aerosols etc..) It aslo helps to have a basic knowledge of how they work. The ignition should 'just work' Fuel delivery is the key to getting these engines running and that includes valve train (clearances etc..)

 

The oil level. When I changed the oil the new oil didn't settle as much as I thought it would. I plan on cleaning them again today

 

It does thanks a ton!

 

So I discovered that my main jet and air pilot jet were switched (shown in picture). Would that explain why no gas was being pushed to the
cylindersi254.photobucket [dot com] /albums/hh107/RickCoMatic/Yamaha/P5231436-1.jpg

 

Unless you followed the Church of Clean, you didn't really clean the carbs.

Is the petcock allowing fuel to flow on prime? On RUN?
Open the float bowl drains. Does gas come out?

I strongly suggest that you slow down, read the Information Overload Hour (link above) and only start work on the bike once you have an understanding of what needs to be done to each system to ensure that your machine will run reliably and safely.

The swapped air jets were a problem, but a bike will idle even when they are swapped, so your problem lies elsewhere.

 

I need to purchase a new petcock and gas tank because of rust. I currently have the gas fed by gravity through a water bottle until my next pay check so I guess no to your first question.
I can't seem to find the float bowl drain but I'm pretty confident that the float bowls is filling up because after I attempt to start the bike and then remove the carbs gas pours out.
I plan on researching my carb more so that I can understand it better so I can figure out exactly what is wrong with it once I can find the time after work. But for now I'm going through the process of the link you attached (meaning I'm going to completely break down all four carbs from the rods). I would like to know if the current gravity fed fuel system will work before I break the carb down and build it back together though?

 

I'm also wondering if its even important to sync the carbs up at this point if the engine isn't getting any combustion? I don't think that my diaphragms are bad but none of the pistons or needle valves are moving. I'm not sure how to fix this.

 

Do you have a breather hole in the water bottle? If not the gas isnt moving. Drain the float bowls to make sure gas is going in. Also are you getting a spark at the plugs?

 

are you trying to move them with your finger?
the diaphrams are vacuum operated they do not move with the throttle
if they are frozen in place you have to use cleaner to loosen them

 

should be able to set your petcock to pri to have fuel flowing freely if not take it apart and clean it ... simple idea is that fuel hose going to carby might be swelled or clogged

 

No breather for the bottle I'll try that however the carbs' float bowls still fill up so I don't think that is the problem. Yeah, every piston has compression and ignition but there isn't any combustion (no gas flows into the engine).

I've moved one while turning the engine over however nothing happens. They sound sealed and I think I hear gas flowing when I push them but I think that there isn't any pressure build up to move them. Thats why I was concerned if I should have a petcock installed for the vacuum line. I've extensively cleaned the diaphragms' pistons with carb cleaner so they should be lubricated enough to operate.

My petcock is beyond repair. Ordering a new one with a gas tank when I get paid.

 

your pilot jet and main jet in the bowl could be switched around on one or more or all carbies by happenstance i accidently did this with mine not knowing what i was doing causing it to run ultra rich and soaking the spark plugs

 

my advice to you if your a broke college student is to flog it off for whatever you can get for it by the time you overhaul it it will cost thousand or more to get it safe most likely have to replace the back brake pads cause they delaminate ..overhaul the front brakes new brake pistons and seals ..master cylinder rebuild .. new brake lines ...and by the sounds of it you need to replace a lot of rusted gear ...proberly by the sounds of it like mine you have a rusted frame along the lower kickstand side ..after its welded you will need to paint frame etc etc etc

 

I switched those already a would still run just fine even if they weren't switched.

Not really an option. I already knew it would cost a lot its kind of the point of getting a project bike.

 

$1000 is still cheaper than a newer used bike (that will still need work done).

 

Just in case my thread is relevant to anyone this diagram helped out extraordinarily