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Discussion Starter #1
So my buddy helped me pull out can clean my carbs on my 97 NV750. Prior to that, I pulled my petcock, flushed the tank, and soaked the petcock in seafoam for quite a while. My (car) mechanic buddy helped get the carbs cleaned then back into the bike, but we found that we should have taken more pictures than we did (as is usually the case).

Currently I am at 2 roadblocks before i can get back to riding...

2 hoses.... no idea where they go...

One hose is the hose that splits off at a joint and goes to both of the carbs. I know the other 2 hoses form the carbs go straight to the petcock, but the third.. I have no idea.

The other hose is a small 4" hose that comes out of the center/bottom of the petcock, and I see nowhere for that to connect.


Hopefully I can get this figured out quickly and get my bike back together. Ive been waiting 2-3 weeks to finish this carb job and ride again!
 

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So my buddy helped me pull out can clean my carbs on my 97 NV750. Prior to that, I pulled my petcock, flushed the tank, and soaked the petcock in seafoam for quite a while. My (car) mechanic buddy helped get the carbs cleaned then back into the bike, but we found that we should have taken more pictures than we did (as is usually the case).

Currently I am at 2 roadblocks before i can get back to riding...

2 hoses.... no idea where they go...

One hose is the hose that splits off at a joint and goes to both of the carbs. I know the other 2 hoses form the carbs go straight to the petcock, but the third.. I have no idea.

The other hose is a small 4" hose that comes out of the center/bottom of the petcock, and I see nowhere for that to connect.


Hopefully I can get this figured out quickly and get my bike back together. Ive been waiting 2-3 weeks to finish this carb job and ride again!
from your description the small hose goes to vacuum port on the carbs to open the petcock (even if in the on position no fuel flows without the vacuum)

the other big hose is a bowl vent that goes into the back of right filter housing to keep it out of the wind make sure it doesn't go to deep and bottom out,most on here cut it at an angle to insure it doesn't
 

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ok the first hose comes off a T between the two carbs and goes all the way up to the right side Ear or filter... the other hose goes from the vent nipple on the left carb to the petcock... hope this helps.
 

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denny beat me too it.... also if you go with the Yamaha petcock there is no vent line so you have to cap that one off.
 

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Linkmeister Supreme
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Discussion Starter #6
Awesome.... so when u say 'Dont bottom out the carb vent hose, what do u mean? Just dont bury it all the way into the hole?
 

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Linkmeister Supreme
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Awesome.... so when u say 'Dont bottom out the carb vent hose, what do u mean? Just dont bury it all the way into the hole?
Exactly. Even better, cut the very end of the hose off at a 45* angle and it can never get blocked off by pushing it in too far.:smiley_th
 

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Discussion Starter #8
As expected, nothing turned out as planned or hoped.

Still wont start. All the hoses are connected as they were before disassembly, and now it wont as much as TRY and fire. It cranks and tries to turn over, so now im off to get some starter fluid and see if that will help....

Any other suggestions?
 

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Wareagle1970
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did you take the carbs completely apart and check the jets? If so, and I know this is probably an obvious answer, but do you have the fuel on?
 

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Discussion Starter #10
Lol, yes. I tried it in both ON and RES, and neither made any difference...
Starter fluid did nothing at all, not even a single fire, though I'm going to try again maybe tomorrow after I jump the battery to be sure.
 

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Discussion Starter #11
Well I guess at this point my problem is much too vague or broad. I wouldnt imagine anyone would have any advice other than check the lines, since no gas is getting to the engine. It seems its not even getting past the carbs, since starter fluid didnt seem to help at all. The throttle definitely works as intended...


In maybe 2 weeks, if I haven't been able to figure any bit of it out, I'll just break down and take it to a shop.

If anyone has any other ideas for me to check, feel free to share any info you can.

Also, in case you weren't part of my last thread, the bleed screws on my carbs are stripped, so I cant drain the bowls to see if they are getting fuel. Kind of a crappy hole to be in at this point...
 

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Discussion Starter #14
When I took apart the carbs to clean them, I took off the caps, removed the float pin and diaphragm, and soaked the carb assembly one side at a time. Checked the jets were clear with a coat hanger (carefully), and scrubbed all the carbon deposits off every bit of metal.


All the parts store had was spray starter, so I sprayed into the air intake on both carbs... Should I try it in the plugs?
 

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Linkmeister Supreme
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Spraying the starter fluid directly into the carb air intake is fine.
But not getting any engine response indicates no spark to me.

Pull the plugs, snap the plug wire boots back on tight and rest or hold the plug base against the engine (with an insulated tool).
With a fully charged battery, crank it over to test for spark.
Should get big fat blue sparks.
 

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Discussion Starter #16
Spraying the starter fluid directly into the carb air intake is fine.
But not getting any engine response indicates no spark to me.

Pull the plugs, snap the plug wire boots back on tight and rest or hold the plug base against the engine (with an insulated tool).
With a fully charged battery, crank it over to test for spark.
Should get big fat blue sparks.
So just to be clear, you are saying to pull the plugs, put them back into the wire that connects to them, and test each one on the engine block to see if it sparks?

I dont see any reason why i would suddenly lose spark after messing with the carbs. Before pulling the carbs, I could get it to fire on occasion...
 

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So just to be clear, you are saying to pull the plugs, put them back into the wire that connects to them, and test each one on the engine block to see if it sparks?

I dont see any reason why i would suddenly lose spark after messing with the carbs. Before pulling the carbs, I could get it to fire on occasion...
If you never had it running before,just firing occasionally,you may have had a combination of problems to begin with.New plugs and proper cranking speed is crucial to firing off this engine ,You may have fouled your plugs while trying to start it before. make sure it is cranking fast because if it is turning slow with a battery that is trying to fire 2 coils and turn over the engine , your battery may not be up to the task.

New plugs and a jump off a Known good battery,may fire this thing right off,use good cables and listen to see if cranking speed when pushing the starter button,if it starts you know there was a low voltage problem and or fouled plugs.

If it starts fully charge your battery and then see if it still cranks as fast ,you may need a battery too.
 

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Discussion Starter #18
So, i realized that starting new threads everytime my problem changes might not be the best idea, since ppl may not know the past on this bike.

When i bought the bike about a month ago, it ran. It didnt run anywhere near as powerful as it should have (topped out at 70, in 3rd - 5th gear, anything above 50% throttle had literally no effect) but it still ran.

When i got the bike, i immediately replaced the original battery. The spark plugs were brand new when i bought the bike. Before i bought it, my friend verified proper compression on all 4 plugs.

So that leaves me where im at now... after flushing the tank and cleaning the carbs, the only thing left I can think of is to replace every single fuel line... I'll check the spark when I get home and jump the battery just to be sure.




Also, I doubt this is the issue, but i may as well check... I know that higher octane fuel is less combustible. I put the highest octane fuel in there (93) and then added about a 3rd of a can of Seafoam to clean the bike out, as it hadf been sitting before i bought it. Could the seafoam have possibly diluted the already-less-combustible fuel, and that be the reason its not firing? (before i drained it, the bike would still occasionally fire with the exact same fuel i recently recycled into the tank.)
 

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Sounds like your prob is with the carbs. High speed jets I bet? (at least where your original prob described?)IMHO, I think you should R&R the carbs and clean & CK the high spd needles. I believe there's a diff between the left and RT carbs. AND by all means, Maybe even before you pull the carbs ck that rt AF housing, the rear to be exact and see if there's a hose in the back. Make sure it's not in so far as to be touching the back(bottomed out). (But, Others here have already mentioned that.) That hose alone can drive you crazy! Believe me, I know!!
No cough with starting fluid=no spark/timing.
 

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Discussion Starter #20
Yeah I checked to make sure the EGR hose isnt bottomed out. From what I hear, if i just pull it out completely it should at least start and run, though not at its full potential...

And I pulled the carbs already and cleaned them to the best of my ability...
Other than soaking in carb cleaner, scrubbing the carbon with a paper towl, and checking the jets with a coat hanger. what/how else would you suggest for cleaning the jets or anything else. Keep in mind im still technically a newb, and other than my two previous bikes, I have not done much in the way of mechanical maintenance.
 
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