dumb request

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bernie
Posts: 23
Joined: Sun Mar 20, 2005 10:18 pm
Location: Roma

dumb request

Post by bernie »

I don't know if any of you has had the same problem, but my nsr seems to have a strange behaviour in 5th but mainly in 6th gear. Carburetion was performed more than a year ago at 400m amsl and I'm riding in Rome which is almost sea level, so this might be a clue to the answer, which I still haven't figured out, anyway my engine revs up just fine in the first 4 gears, up to 9000 something with speeds of about 45mph in 1st, 68 in 2nd, 80 in 3rd and than I was too scared of the road to look at the gauges, but when kicking in 5th and 6th it seems impossible to pass 8500 and 7000 respectively with a read top speed of 111. Trying to pull full throttle at this stage results in what I can describe as a fuel starvation or stuttering. Also if I try to accelerate already in 6th from say 4/5000 rpm with full throttle, top speed is around 93 with the tacho stuck at 6000 or so, like the atac valve isn't working properly or working just above that limit, which for some unknown reason my bike can't cross.
I'd be glad if someone can point me to an easy solution ;)

Francesco

Alastair
Posts: 1796
Joined: Sat May 25, 2002 1:01 am
Location: Glossop U.K.
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Re: dumb request

Post by Alastair »

You can check your ATAC is working when stationary if you remove the lower linkage cover off the barrel and rev the bike up.

You say the carburation was done. Did you change it? If so, revert to standard and work from there.

bernie
Posts: 23
Joined: Sun Mar 20, 2005 10:18 pm
Location: Roma

Re: dumb request

Post by bernie »

I don't know, if any other than standard carburetion was applied, and I'll ask. Something was done as after 6 years without even been started I had cobwebs inside the carburetors and it took six different cleaning to have them working, while the top cylinder carb had to be cleaned with ultrasound. And forgive my english, but which is the lower linkage cover off the barrell?
Thank you anyway

gumball
Posts: 312
Joined: Sun Jul 20, 2003 1:01 am

Re: dumb request

Post by gumball »

Good day ) try checking if the stator is charging well. Had a similar problem, did everything, adjusted the bowls, changed cdi, computer box, etc...Please update us on your findings.

P.S.
Nice topic.
very catching )
HIGH RPM IS WHERE IT IS!
Tread With Caution

Alastair
Posts: 1796
Joined: Sat May 25, 2002 1:01 am
Location: Glossop U.K.
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Re: dumb request

Post by Alastair »

bernie wrote:I don't know, if any other than standard carburetion was applied, and I'll ask. Something was done as after 6 years without even been started I had cobwebs inside the carburetors and it took six different cleaning to have them working, while the top cylinder carb had to be cleaned with ultrasound. And forgive my english, but which is the lower linkage cover off the barrell?
Thank you anyway
Sounds like another good ultrasonic carb clean may be needed. I'd also do a leakdown test to see if your crank seals are ok.

ATAC linkage cover is item no 2 here http://alastair.ns400r.co.uk/E3.jpg

bernie
Posts: 23
Joined: Sun Mar 20, 2005 10:18 pm
Location: Roma

Re: dumb request

Post by bernie »

Still haven't serviced her good, but had a nice ride last tuesday with some friends. I still had the sensation of hiccups in 5th and 6th gear, so I tried to partialize the throttle till the hiccups would quit, but leaving still a little bit of acceleration, and I managed a whopping 100 in 5th and 110 in 6th (but there was quite a lot of traffic around the ring roan of rome). My friends told me my left cylinder would smoke more then the others while revving up whereas the right cylinder would smoke when idling. Last clue to this enquiry is I use 94? octane green petrol adding some lead additive, while on the last refill I used 98 octane green petrol still using the additive, but still haven't had anyone behind me to check on the smokes...
I still think the carbs needs a good servicing this winter (here it's still 24 or more during the day)

Thank you

bernie
Posts: 23
Joined: Sun Mar 20, 2005 10:18 pm
Location: Roma

Re: dumb request

Post by bernie »

and to be precise, while resting in the garage, my left exhaust pipe is oiler then the left one and drips small patches of oil on the floor. The leak seems from inside the cowl then running down to the lowest point in the line and falling to the ground. Grazie

Luciano
Posts: 156
Joined: Sat May 10, 2003 1:01 am
Location: Sweden, Malmö

Re: dumb request

Post by Luciano »

I'd be glad if someone can point me to an easy solution
Hi.
Look at your spark plugs. If they are black and oily then that is a clue. And ALL 3 of them has the same "coulor".
If the engine is OK and do not leak between cylinders AND your compression is OK.
Then look at your gasoline consumption.
If it is 1 liter/10 km or more and your plugs is almost black.
Then you have to make your bike to go leaner.

When you have to rich gasoline mixture >1/14 then the oil will not burn and therefor the bike will smoke more. And the unburned oil will stick everywhere on the inside of the pipes and you will have black sticky mess from the end of the silencer and everywhere.
(I assume the oil om the floor is black?)

The easiest way to make the NS to go leaner is to modify the air box lid (drill it). Maybe test with lid of but secure that the filter foam is in place. The noise will be higher ;) (Of curse it is then the main jets that needs to be changed.)
viewtopic.php?f=6&t=1989

The lead is not necessary on a 2-stroke it is for the valves in (old) 4-stroke engines... I have driven mine for many years on unleaded 95 octane. The higher octane is only necessary for if you have higher compression by skimming your cylinder head or playing with advance curves and several other reasons IF you alter something and go from the Honda setup. In other words a fuel that burn more slowly and do not ping that easily as 94 octane.
Best regards, Luciano.
Torque over the whole register.

bernie
Posts: 23
Joined: Sun Mar 20, 2005 10:18 pm
Location: Roma

Re: dumb request

Post by bernie »

Thanks a lot, I'll surely check all this and hopefully I'll thank you again sometime soon...

ducnomore
Posts: 163
Joined: Wed May 18, 2005 9:01 pm
Location: Ontario

Re: dumb request

Post by ducnomore »

Wow, lots of different answers. I had the identical problem which i cured with new spark plug caps. If your bike still has the factory caps they are probably corroded or worn out. If one pipe is colder as you say, then maybe that is the cap to change. Worked for me anyway.
:)
Image Image
1986 NS400R
2007 GSXR1000

Luciano
Posts: 156
Joined: Sat May 10, 2003 1:01 am
Location: Sweden, Malmö

Re: dumb request

Post by Luciano »

ducnomore wrote:Wow, lots of different answers. I had the identical problem which i cured with new spark plug caps. If your bike still has the factory caps they are probably corroded or worn out. If one pipe is colder as you say, then maybe that is the cap to change. Worked for me anyway.
:)
Yes you have a point there.
That is is why i wrote that "If the engine is OK and do not leak between cylinders AND your compression is OK.".
You have to check that all the systems (ignition, carbs, air leak and so on) is OK first!

And as I wrote that by looking at the spark plugs how they look and IF they all look the same that will tell you what/where (witch cylinder) lays the problem. But you see only the symptom. And the cure can be as duncnomore say spark plug caps or something completely different.
Best Regards, Luciano.
Torque over the whole register.

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