Did an oppsie on highway, need help diagnosing

[Robby]

It may just need the idle turning up, should be a knob on the carbs to do it.

It does sound noisy at very low engine speed, but that could just be because it's running too slow and trying to stall. Sounds fine on choke.

[stinkwheel]

I wonder if that's clutch rattle? Does the noise go away/change when you pull in the clutch?
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Nobby the Bastard]

The fact it starts on the button like that makes me think there's not anything mechanical wrong with it.

I would go with my usual standby of coil(s) failing cause stalling after a couple of minutes but as it didn't use to need the choke to start and now it does I'll go with something fuel related.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[stinkwheel]

Don't divvies have an oddball mechanical fuel pump? I wonder if the tank's getting low and the pump is misbehaving. You could try it with a full tank and see if the problem goes away.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[GfromLT]

Cant remember now about pulling the clutch and the noise, will check tommorrow. Filling up the tank is no biggie.
Someone suggested that I use a screwdriver to listen where the sound is coming from.
I had filled up gas only once, a week before "the incident". I dont know how long the bikes been stored before I purchased it and I ran it on reserve for a few times. Could there be a posibility, that the violent shock of my dumb-ass gear change shook up all kinds of shit in gas tank and now the pumps/filter/carbs are clogged?

[Nobby the Bastard]

That would mean it would run like a dog all the time. As soon as you turn on the choke it pursts into life quite happily and seems to run cleanly so I suspect not.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[stinkwheel]

[Nobby the Bastard]

Can't see a vacuum tap or any sort of pump being bothered by crap in the fuel but openingthe choke fixing it.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[stinkwheel]

[Bhud]

OP, if you're absolutely sure it's firing on all cylinders at idle in that last video, then I strongly suspect it's the famous Diversion clutch rattle. If so, it's nothing serious and nothing to worry about. Sounds like rod damage/engine death, but it's absolutely nothing.

Step one: get your carbs perfectly in sync. I expect that this will significantly abate the unpleasant noise.

Step two: investigate the gear behind the clutch basket. Remove the clutch basket. You will see that a gear right behind it is retained by a little metal dowel about 10mm long. This should have absolutely no play in it. If it does, you'll need to make a new one (use a section of HSS drill bit - you may need to file down a 4.5mm or 5mm or 5.5mm or 6mm - depends on your particular case). Press/force/drift the new dowel in firmly. It should have no play in it.

Speculation/mythology: the price of these extremely robust-engined bikes may have been kept down by people who couldn't figure out the source of that clutch noise (which often appears at around the 30-40K mile mark), and who were driven to artificially advancing the auto cam chain tensioner by one click to deal with the noise (don't do that) and then flogging it. However, I can't say that for sure.

All I can tell you is - basic things first. Get those carbs in sync. I expect you'll come back and say the noise has gone away. If you don't , then whip off the clutch basket.

[GfromLT]

[bugeye_bob]

Once started even on choke, give it a thrash, see if that clears your carb issues.

[A100man]

Hi one other idea..

The older XJ engine like the one in my 550, I'm told has a hydraulic primary chain tensioner, mine also sounds sh!t at low revs - maybe the Diverson is the same - they do share some parts like the sump

You have to make sure the oil level is close to the upper limit and turn the idle up a bit for the noise to quieten down.
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[WD Forte]

I believe it has an electric fuel pump as in the second 002 vid
you can hear it priming (sort of a soft buzzing sound)
when the starter button is released.

In vid 003 it does sound a bit lumpy, do I detect a bit of
an exhaust leak?

Whatever it is, it doesn't sound fatal just an old bike in need of
some attention.
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bikers smell of wee

[GfromLT]

I played around with the bike today trying different scenarios. What I noticed was:
- When cold bike starts up okay-ish with choke half-way pulled. Giving throttle makes engine go VROOOOM.
- putting it in gear, without releasing the clutch, makes RPM go down 1.5-2k (wtf?)
- Idle rpm isnt stable (when fired up with choke, 3k rpm, going up and down +-300rpm.
- I left it to idle for as long as it could. While engine is hot, it doesnt wannt to start even with choke, If it does start, rpm rises to ~4k because of how much choke is pulled and then start falling, falling, and stalls in like 2 minutes of total idling
-While RPM is falling, twisting throttle kills the engine.


https://www.youtube.com/watch?v=fpa-yIf46hg

Tried to push bike in different gears, there is some free play, but gears are there. Engine knockin indeed is clutch rattle. Didnt find anything metal in engine oil.

At this point it has to be the fueling?

[WD Forte]

I don't know the bike from personal experience but shouldn't normal tickover be around say 1100 -ish?
and fast idle, using choke, say 500 rpm ish faster?
3000 seems way to fast.
Fairly sure those carbs have rubber diaphragms in as Yamaha use them a lot and they can go hard or crack with age.

I'd have the carbs off for inspection and give it a general service otherwise you'll just keep guessing
Buy a workshop manual off Ebay if you cant find an internet freebie.
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bikers smell of wee

[Bhud]

It's overdue a service. It does sound like there are a number of minor issues that need to be put right. Your engine races, and behaves differently when warmed up. When you pull in the clutch the revs go down when you shift into first. That's most likely your carburettors out of balance but you may also have a vacuum leak. A holed exhaust is another possibility. I would just go through everything one thing at a time. A proper service will solve things.

[mentalboy]

Checked that tank breather yet?
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