Top Cyl & Top Pipe not smoking as much as other 2

Bike running like a dog? This section might well answer your questions. Posting restricted to registered users.
Post Reply
Straycat
Posts: 86
Joined: Sat Feb 18, 2012 7:37 pm
AntiSpam: No
Location: Canada

Top Cyl & Top Pipe not smoking as much as other 2

Post by Straycat »

Hi Guys, Ive not torn into the new-to-me NS yet, but i just fired her up for the first time since bringing it home 3 weeks ago (finally above Freezing here). I noticed that the top pipe, from the top cylinder isn't smoking as much as the other 2. I see a trace/odd puff of smoke but no where near what i see from the other 2. Rev'd up or at idle its always less (alsmost nil). anything particular I should look at ?, or is this just a case of tear it down and check the carbs?

the top pipe is getting warm/hot, but the inside of the silencer isnt warm like the other 2.

Seemed to be running ok when I bought it.
1986 Honda NS400r
1985 Yam RZ500
1990 Yam RZ350 YPVS
1987 Suzuki RG250
1988 Suzuki RGV250 VJ21
1989 Yam FZR400
1986 Honda TLR 200 Relfex
1986 Honda VF500F Interceptor
1985 Honda VF500F Rothmans
1985 Hond VF1000R (x4)
2014 Honda VFR800

luggy
Posts: 614
Joined: Sun Feb 28, 2010 7:11 pm
AntiSpam: No
Location: Austria
Contact:

Re: Top Cyl & Top Pipe not smoking as much as other 2

Post by luggy »

if it is on tickover, it may just be a synchronisation problem, ie , the top is not pulling on stand as the other two !
gravity is an extreme painful thing !

Alastair
Posts: 1784
Joined: Sat May 25, 2002 1:01 am
Location: Glossop U.K.
Contact:

Re: Top Cyl & Top Pipe not smoking as much as other 2

Post by Alastair »

The top pipe should be hotter than the other 2 because it is faired in. Mine has always smoked more on start up after a week or 2 from the top pipe. soon settles when the engine has been run.

Straycat
Posts: 86
Joined: Sat Feb 18, 2012 7:37 pm
AntiSpam: No
Location: Canada

Re: Top Cyl & Top Pipe not smoking as much as other 2

Post by Straycat »

Yes, top pipe is definitely cooler than the others,

I pulled the air box cover off

element has disintigrated, there is foam dust in the Carb throats, center carb may be plugged up some. new filter element is on order now

I gave the center carb a squirt of gas and it came to life, got more smoke out of that top pipe, as long as i had some fuel squirted in it..

Carbs are coming off, getting a good cleaning and we'll see what that does

the top cyl plug cap is also ripped, the rubber coating is torn (although there is a hard plastic cap underneath.

Ill need a new cap.

Question.... aside from the ATAC valves on the front 2 cylinders, are there any other exhaust valves on this bike ?

Is it also possible that the foam from the filter has clogged the reed valve on the center cylinder ?
1986 Honda NS400r
1985 Yam RZ500
1990 Yam RZ350 YPVS
1987 Suzuki RG250
1988 Suzuki RGV250 VJ21
1989 Yam FZR400
1986 Honda TLR 200 Relfex
1986 Honda VF500F Interceptor
1985 Honda VF500F Rothmans
1985 Hond VF1000R (x4)
2014 Honda VFR800

Alastair
Posts: 1784
Joined: Sat May 25, 2002 1:01 am
Location: Glossop U.K.
Contact:

Re: Top Cyl & Top Pipe not smoking as much as other 2

Post by Alastair »

You'll need to sort the faults which might be causing a weak spark which won't help.

Clean the carbs, test the compression. Maybe do a leakdown test. Foam is highly unlikely to damage the reeds. it'll just get pulled through the motor. Might make a sticky mess as it burns though!

Straycat
Posts: 86
Joined: Sat Feb 18, 2012 7:37 pm
AntiSpam: No
Location: Canada

Re: Top Cyl & Top Pipe not smoking as much as other 2

Post by Straycat »

Thanks.

Pulled the Carbs out today and cleaned them (removed all the jets, used carb cleaner, compressed air etc). nothing obvious, though the Pilot/low speed jets were iffy (clogged) on a couple. will put carbs back on tomorrow

Interestingly, when i last ran the bike, with the fuel tank off, i let it idle until it stalled out, ie all the fuel in carbs ran out -.....well.... when I drained the carb bowls during removal, 1 and 3 were pretty much empty already as expected, but, number 2 was still full. clearly fuel is being delivered to the carbs, but it wasn't making it out of carb number 2 into the cylinder. This makes some sense, since when the bike was running, i couldn't even smell fuel from pipe 2, it would also explain why pipe 2 got some signs of smoke when i squirted some fuel into the carb throat. Hopefully the cleaning did the trick

Reeds on 1 and 3 are clean, number 2 i'll inspect tomorrow, now that i have an inspection mirror to see inside.

will do a compression test tomorrow too, for good measure.
1986 Honda NS400r
1985 Yam RZ500
1990 Yam RZ350 YPVS
1987 Suzuki RG250
1988 Suzuki RGV250 VJ21
1989 Yam FZR400
1986 Honda TLR 200 Relfex
1986 Honda VF500F Interceptor
1985 Honda VF500F Rothmans
1985 Hond VF1000R (x4)
2014 Honda VFR800

Straycat
Posts: 86
Joined: Sat Feb 18, 2012 7:37 pm
AntiSpam: No
Location: Canada

Re: Top Cyl & Top Pipe not smoking as much as other 2

Post by Straycat »

All good now, were firing on all 3. Just crap in the cabs
1986 Honda NS400r
1985 Yam RZ500
1990 Yam RZ350 YPVS
1987 Suzuki RG250
1988 Suzuki RGV250 VJ21
1989 Yam FZR400
1986 Honda TLR 200 Relfex
1986 Honda VF500F Interceptor
1985 Honda VF500F Rothmans
1985 Hond VF1000R (x4)
2014 Honda VFR800

Post Reply