no engine speed

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hellogrish
Posts: 86
Joined: Mon May 26, 2008 11:14 pm
model: 750 Paso
year: 1990
Location: Poland

no engine speed

Post by hellogrish »

hello there,

got some problems with my Paso.

2 days ago when relasing the clutch
and accelerating GENTLY - the engine stopped.
(tried 2-3 times,
I have the sport exhaust and the engine sound was really quiet :)

so I gave more power while accelerating,
managed to shift to second gear,
but anyway when to give engine speed to about 4000 rpm
the engine stopped.

it was like not enough air.

today I tried to see how it looks inside.
the air filter looks great,
but the big pipe that comes from air box
was really in bad condition.
(i checked and the air was "leaking")

I replaced it with the new one and the engine came back to normal sound.
Tried to have quick ride, but the max speed I could get was 60km/h

please take a look:
http://imageshack.us/f/29/piped.jpg/

I replaced the big one,
but there is small one as well (red dot)
and it could have some leak.

(by the way what is for that big one air pipe?)

I ll try to replace it tommorow.
what else it could be? carburettor? spark plugs?


regards from poland
greg
angelix
Posts: 338
Joined: Thu Nov 29, 2007 2:38 am
model: 907 I.E.
year: 1990
Location: UK

Re: no engine speed

Post by angelix »

the one with the red dots is "irrelevant" to your problem.

That with red dots is just the crack case breather system and you can actually remove it (temporarly) and it will not effect the engine.

I think you might have rust inside the tank or a clogged fuel filter.
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paso750
paso grand pooh-bah
Posts: 5568
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: no engine speed

Post by paso750 »

As Angelix says the crankcase breather system has no influence on the carb.
In total you have 3 fuel filters. One is on the inner side of the fuel petcock, then the one in the fuel line and the Weber has one, too (positioned at the fuel line input, lower side. With the other filters before it this should be fine)

Did the bike run with that exhaust before or did the problems only start after you changed it ? I ask because I put an open exhaust on my Gilera 600 once and at 120km/h it started to have bad lean stuttering and the engine would almost cut out. This exhaust definetely would have required rejetting. With the old exhaust back on it ran nicely again to 170km/h tops.

G.
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scimmione
Posts: 65
Joined: Sun Jul 18, 2010 1:56 am
model: 750 Paso
year: 1987
Location: East Bay, SF Bay Area

Re: no engine speed

Post by scimmione »

It does sound like fuel starvation. Does it idle smoothly or does it require working the throttle to keep it running? I had an inductive pickup that was intermittently failing. Until it finally quit it was acting like a rev limiter over 4k rpm.

My 2¢
Wish I'd bought the 990 years ago
User avatar
hellogrish
Posts: 86
Joined: Mon May 26, 2008 11:14 pm
model: 750 Paso
year: 1990
Location: Poland

Re: no engine speed

Post by hellogrish »

paso750 - I got these exhaust for a long time

scimmione - the iddle is quite smoothly


I noticed some dust inside one fuel filter (this near fuel petcock)
can I clean it?

I got another fuel filter, - from previous Paso - so I can replaced it.
(this one has as well fuel pump + fuel pressure regulator)


I got advice to have a quick ride without air filter
(just to exclude the problem with air box), hope it wont harm my bike? ;)
chasaduc
Posts: 53
Joined: Sun Oct 24, 2010 6:55 am
model: 750 Paso
year: 1987
Location: Prospect, OH, USA

Re: no engine speed

Post by chasaduc »

I am no pro here but I did learn something on my bike. I learned this trick changing carbs and intakes. On the weber there is a line that goes from one carb to the other. It is rubber and covered in what looks to be nylon. It is the small one attached to lower side of where the carb and part of the intake manifold attach. Check that one.

All of your highlited pipes mean nothing. Again I said I am a newbey but I learned a lot. Your red tubes were elminated from my bike and were replaced by a breather filter at the engine.

I replaced my carbs and the intakes between the carb and the engine. My intakes had this thing protruding from them. like where a something should be. When they were open it refused to start. With electrical tape closing them it ran. Then i attached a rubber hose between them and it now runs great! of course when the battery isn't dead.

So I would check the hose and the clamps of that little tube that connects one carb to the other on the intake side between the carb and the engine.

Like I said Im learning here but I learned. if you need help let me know ill send you a picture tomorrow
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paso750
paso grand pooh-bah
Posts: 5568
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: no engine speed

Post by paso750 »

chasaduc what you mean are the screw nipples to connect the carb synchronization tool/carb balancer (whatever it`s called).
After the carb there should be no air leaks so of course these nipples must be closed or connected to each other with a tube or they will impact carburation.

G.
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streetsurfer
Posts: 217
Joined: Sun Jul 30, 2006 12:00 am
model: 750 Paso
year: 1988
Location: Chicago-NW Suburb

Re: no engine speed

Post by streetsurfer »

Could it be you are intermittently losing one cylinder due to weak spark? That's what it sounds like the way I read your symptoms.
User avatar
hellogrish
Posts: 86
Joined: Mon May 26, 2008 11:14 pm
model: 750 Paso
year: 1990
Location: Poland

Re: no engine speed

Post by hellogrish »

shame on me.
the problem was with spark plugs.
didnt have a proper key, so I replaced them only today.

(were NDK, replaced with champions)

thanks anyway!
User avatar
streetsurfer
Posts: 217
Joined: Sun Jul 30, 2006 12:00 am
model: 750 Paso
year: 1988
Location: Chicago-NW Suburb

Re: no engine speed

Post by streetsurfer »

If you experience further misfiring/dead cylinder, and find the new plug(s) are fouling in short order, then you'll want to follow up on checking voltage entering coils.

Were the old plugs oil fouled, gas soaked, or just worn? Thanks, and keep us posted. Enjoy the riding but stay safe until you get this sorted out for sure, then stay safe anyway......meaning don't take unnecessary risks in tight spots, realizing you might wind up with a dead cylinder at the most inopportune time.
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paso750
paso grand pooh-bah
Posts: 5568
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: no engine speed

Post by paso750 »

I wonder that you didn´t notice the engine was running only on one cylinder as it runs quite rough that way. Idle is low and the sound is also a different one.
However good that it´s running again.

G.
Mc tool
paso grand pooh-bah
Posts: 1974
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Riverton New Zealand

Re: no engine speed

Post by Mc tool »

Dianne had a wheel fall off her car . front wheel ( yes , the ones connected to the steering wheel .... that she was hanging on to ) The wheel nuts were still on the studs. The holes in the wheel had been flogged out enough to fit over the nuts ............................ and she swears on a stack of bibles that she heard or felt NOTHING. :banghead: Honestly , they would be piled hundreds deep if they didnt have @#$t's :lol: :lol:
An engine missing 1/2 its cylinders could be nothing to some one , and anyhow it aint always that easy to tell in the w/shop . The thing still sucks and blows , and if your exhausts have some sort of x over..........just sounds a bit slow :D
I wish I was young again............Id be heaps smarter than last time
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paso750
paso grand pooh-bah
Posts: 5568
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: no engine speed

Post by paso750 »

true, one probably has to have had the same issue already in the past to recognize it :)
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