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Post by scubadollar on Mar 10, 2012 4:38:07 GMT 1
Hi All,
My second post and main reason for searching out this forum is this.
My 1995 NTV 650 uses bucket loads of fuel and smells like Petrol at traffic lights.
I have read that it should get about 54 MPG US (65 MPG UK) but it is about half that running about the city and about 40MPG UK when running on the motorway for distances.
I have ruled out any leaks or other obvious reasons and can only assume there is a problem with the carbs.
Any ideas? Replacing the jets or the carbs themselves? Also anyone have any idea what the newest set of carbs I can swap them out with would be and where I might find a set?
Cheers in advance,
Paul (Expat in Berlin, Germany)
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groovylee
Sheene Gold rider. Nuff said
Member of the QA team
Posts: 648
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Post by groovylee on Mar 10, 2012 6:56:27 GMT 1
afraid my knowledge of all things carb related is a little rusty. but, stripping and cleaning the carbs would be a great idea, and doesn't take as long as you might think. from what you say about the petrol smell, but nothing about running rough, i would hazard a guess at a sticking float. not too bad a job to get the float bowls off and give it a good eyeballing / clean. i think there are a few guides knocking about in the tech section somewhere.
good luck, and welcome!
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Post by De Graaf van Salland on Mar 10, 2012 9:41:10 GMT 1
Hi Paul, Also welcome to this forum from me. The NTV can be very fuel-efficient. Mine normally runs about 23 km on 1 ltr of petrol (mostly secundary roads / 80 kmph), which translates to 64-65 mpg. But on motorways it's usually 19 km on 1 ltr. I agree with groovylee: I would suspect the floats first. It's not difficult to clean/check/replace these. If you're in Germany, I think you've already found the german forum: www.ntv-forum.de/. Perhaps a member of that forum (who lives close to you) could assist you. Good luck GvS |
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sear
Bad ass biker
Posts: 302
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Post by sear on Mar 10, 2012 9:44:33 GMT 1
If it smells of petrol then there must be a leak somewhere, if the fuel system was completely tight then there would be no reason for you to smell unburnt petrol.
The floats could be stuck, causing the carbs to continue filling and leak when you stop using enough fuel to displace what is pumped into the carbs, otherwise you just need to check the fuel system from start to finish. Construct a heirarchy of components of the fueling system, every stage at which petrol is handled, then form hypotheses as to points at which petrol could leave the system, then form experiments to test these hypotheses.
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groovylee
Sheene Gold rider. Nuff said
Member of the QA team
Posts: 648
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Post by groovylee on Mar 10, 2012 10:19:37 GMT 1
well, to add to this, having just put my fuels system back together ;D in this order: tank fuel tap fuel hose to fuel filter fuel filter fuel hose to pump fuel pump fuel hose to carbs carbs it is a fairly simple set up until you get to the carbs, but if you havent noticed any leaks at all, i would be looking at the floats. tip - when replacing the carbs, warm up the rubber boots with a hairdryer first  makes life easier. hope it helps, Lee |
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Post by rj2para (Bisto) on Mar 10, 2012 11:10:01 GMT 1
I fill mine to the top and fill up again evey 120 miles UK. May be ride style as it seems consistent in and out of town. Does not help your fuel smell but it shows a ranged of MPG, always good for a debate. I guess it depends how far you ride. Leaking fuel would be more of a concern. Good luck with tracking it down. |
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Post by gothitjulie on Mar 10, 2012 13:23:48 GMT 1
Agree with the others that it sounds like a sticky carb float (or both of them) from the description you give. Take apart, clean, measure the float, make sure the float isn't damaged (there should be air inside the float, if there's any liquid inside the float it needs replacing). Check the end of the float needle, usually there is a rubber bit on the end, make sure it seals in its seat position (too much ethanol in the fuel could have rotted the rubber).
To find if it's just one cylinder being affected, read the spark plugs, if one side is normal brown/grey & the other is black & sooty then you know the black sooty side is the one that's getting too much fuel through it. No point opening up the side of the carb that's OK.
Whilst you have the carb accessible, check the choke cable & linkages for free movement (the tank may have trapped the choke cable in the open position, a very easy fix.
To give you an idea of fuel consumption, I get between 55 (fast motorway) and 65mpg (sweeping country roads).
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Post by De Graaf van Salland on Mar 10, 2012 17:40:06 GMT 1
Also anyone have any idea what the newest set of carbs I can swap them out with would be and where I might find a set? Try otterparts.nl/You get a 10% discount because you're a member of this forum & he will send to other countries. I've never had any problems with the second-hand parts I bought from him. GvS |
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Post by scubadollar on Mar 10, 2012 18:48:43 GMT 1
Thanks all for the tips, links and ideas.
A ray of light has broken through the clouds and it makes now perfect sense. It has been so long since I have had to deal with carburetors I had forgotten the details of their function.
It does not run rough unless I am really in a lot of stop and go city driving, it seems to load up and the pertrol smell gets a bit worse. Not a single external leak. Runs great on the highway and the fuel consumption is much better but still not to expected levels. Sticky or badly adjusted floats make sense.
I shall check that out and let you know what I find.
Also thanks for the parts connection, I shall follow that up.
Cheers,
Paul
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makes life easier.
