cant get carbs to adjust properly, need advice

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Timothyblythe240z
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cant get carbs to adjust properly, need advice

Post by Timothyblythe240z »

my original problem was that the vacuum line going to the tank was not hooked up.
before i knew this i had the carbs off multiple times and cleaned everything.
the front carb choke screw broke but i ended up fixing it with a brass fitting i had in the garage.
now the bike will only run with the choke on, and is hard to get running.
when turning over it will fire but not run and after turning over many times finally fires and runs at 3,000 rpm then lowers down to around 2,000. the engine will start surging and after a few mins will just die.
if i open the throttle slightly it will pick up idle a little then start bogging, if the throttle is open fast it will die.
i can get the bike up to high rpm by feathering the throttle, but it will back fire and sound way out of wack.
if i cover the rear carb the idle picks up a lot for a few seconds then start surging again.
there is little to no change when adjusting the carb sync, i have not messed with the fuel mixture screw at all, only the idle adjuster and sync.
is there something more going on here? im sure it possible that the choke srew i had made is causing some of the problem, but i made sure that it was the same length as the original.
any help/suggestions would be appreciated
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lloydie
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Re: cant get carbs to adjust properly, need advice

Post by lloydie »

Sounds like fuel starvation .
Where have you got the vac pipe connected ?
And have you connected the tps ?
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leevtr
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Re: cant get carbs to adjust properly, need advice

Post by leevtr »

Timothyblythe240z wrote:my original problem was that the vacuum line going to the tank was not hooked up.
before i knew this i had the carbs off multiple times and cleaned everything.
the front carb choke screw broke but i ended up fixing it with a brass fitting i had in the garage.
now the bike will only run with the choke on, and is hard to get running.
when turning over it will fire but not run and after turning over many times finally fires and runs at 3,000 rpm then lowers down to around 2,000. the engine will start surging and after a few mins will just die.
if i open the throttle slightly it will pick up idle a little then start bogging, if the throttle is open fast it will die.
i can get the bike up to high rpm by feathering the throttle, but it will back fire and sound way out of wack.
if i cover the rear carb the idle picks up a lot for a few seconds then start surging again.
there is little to no change when adjusting the carb sync, i have not messed with the fuel mixture screw at all, only the idle adjuster and sync.
is there something more going on here? im sure it possible that the choke srew i had made is causing some of the problem, but i made sure that it was the same length as the original.
any help/suggestions would be appreciated
Really sounds like you've reconnected the vacuum hose in the wrong place mate. Its meant to go on the connector thats on the back of the left hand side of the fuel tap ( as you sit in the bike ). Sounds like you connected it to the one pointing downwards. I did that and got that same symptoms. 2 minute fix.
" It was 2 minutes 5 minutes ago "
Timothyblythe240z
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Re: cant get carbs to adjust properly, need advice

Post by Timothyblythe240z »

The Tps is connected.
Vacuum Lin is connected to the tap on the back left
There are two lines coming com the tank valve, the one pointing strait down is connected to drain hose.
The other connects to a port on the head below the rear carb
Timothyblythe240z
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Re: cant get carbs to adjust properly, need advice

Post by Timothyblythe240z »

I took both carbs apart at the same time if memory serves me correctly, I was looking around and found that the main jets are not the same, if they are mismatched would that be the problem?
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Wicky
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Re: cant get carbs to adjust properly, need advice

Post by Wicky »

Doesn't seem right - Some pics might help

Vacuum hose should connect from back of fuel tap to a take off from rear cylinder
Then the two drain/overflow hoses from the two spouts on the base of the tank are routed to near the lower front of the bike.

Make sure the front cylinder take off is plugged and both carbs have no airleaks where they mount.


Timothyblythe240z wrote:The Tps is connected.
Vacuum Lin is connected to the tap on the back left
There are two lines coming com the tank valve, the one pointing strait down is connected to drain hose.
The other connects to a port on the head below the rear carb
It may be that your whole purpose in life is simply to serve as a warning to others.

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Wicky
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Re: cant get carbs to adjust properly, need advice

Post by Wicky »

They should be slightly different. Did you by any chance mix parts from front & rear carbs when reassembling?

Carb set up > http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=28922

Carb tuning > http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=14214

VTR1000F (Superhawk) Firestorm Service Manual PDF > http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=18025
Timothyblythe240z wrote:I took both carbs apart at the same time if memory serves me correctly, I was looking around and found that the main jets are not the same, if they are mismatched would that be the problem?
It may be that your whole purpose in life is simply to serve as a warning to others.

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AMCQ46
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Re: cant get carbs to adjust properly, need advice

Post by AMCQ46 »

there is still a risk that teh choke is not closing and this is overfueling the engine.

did you manage to route all the cables and hoses back the correct positions?
AMcQ
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lloydie
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Re: cant get carbs to adjust properly, need advice

Post by lloydie »

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Timothyblythe240z
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Re: cant get carbs to adjust properly, need advice

Post by Timothyblythe240z »

Wicky- it is probable that they are swapped as I did not take thought into which tube went to the front or rear carb, I will check that.

AMCQ46-one thing I had noticed with the choke cable is that the front cable ( the one that broke) was sticking open and wouldn't close easily unless the cable was pulled by hand.

I will be sure to post some pictures of the vacuum houses and where they are connected.
Timothyblythe240z
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Re: cant get carbs to adjust properly, need advice

Post by Timothyblythe240z »

I took the carbs apart, the tubes were in the opposite carb. Swapped them over, runs a little better.
What I have noticed is that if I cover the middle port on the top of the rear carb the idel goes down and there is throttle response. My guess is there's something going on with the rear carb.
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lloydie
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Re: cant get carbs to adjust properly, need advice

Post by lloydie »

Are you running it without the airbox ?
It don't like that
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Wicky
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Re: cant get carbs to adjust properly, need advice

Post by Wicky »

You'll need to get it back to standard, carbs and hoses to get a running baseline. Maybe get a 2nd set of carbs that are known to okay from fleabay.

Put your location in your profile as there might be someone near to you who could help out.
It may be that your whole purpose in life is simply to serve as a warning to others.

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Stratman
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Re: cant get carbs to adjust properly, need advice

Post by Stratman »

I'd start by replacing the choke cables and fittings with originals. The kit is quite dear for what it is, but after I broke one I made up a new nut for the carb (not as good as the brass ones you can get from a member whose name I forget) and it ran OK, but never quite crsiply at the bottom end. Replaced the bodged part with the new and hey presto. Don't try to find something else at fault before replacing what you know to be broken.
Two bikes, still only four cylinders!

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Timothyblythe240z
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Re: cant get carbs to adjust properly, need advice

Post by Timothyblythe240z »

I replaced the carbs with a second hand set, as luck would have it they came with the choke fittings.
This has fixed the peoblem, thanks for all the help
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