Coo, that's running rough

Did the tappets, timing and a carb balance on the 400 Four on Monday.

God, it makes a difference, especially (I know this sounds silly) with
brand new throttle cables. Smoother, sweeter, more controllable.

Erm, until coming back from work today when it started running like
shite. Lumpy, engne racing, loads of clutch chunter, generally horrible.

Hm. Sounds carb-y to me. Off with the tank and let's have another look
at the balancing. Something must have loosened off.

Memo to self - ensure all locknuts on the carb adjusters are properly
tightened......

 

/me goes looking for errant locknuts on the DT's carb.

--
Ivan Reid, Electronic & Computer Engineering, ___ CMS Collaboration,
Brunel University. Ivan.Reid@[brunel.ac.uk|cern.ch] Room 40-1-B12, CERN
GSX600F, RG250WD, DT175MX "You Porsche. Me pass!" DoD #484 JKLO# 003, 005
WP7# 3000 LC Unit #2368 (tinlc) UKMC#00009 BOTAFOT#16 UKRMMA#7 (Hon)
KotPT -- "for stupidity above and beyond the call of duty".

 

Still idling fast?

 

What's the problem here? Because it rode fine when I, my neighbour, best
mate, and then Timo rode it.

Ah.

Timo.

All becomes clear.

 

What's the problem here? Because it rode fine when I, my neighbour, best
mate, and then Timo rode it.[/QUOTE]

Ivan's spent more time arseing about with the DT than I did
overhauling the Wing.

I think he's decided that because he's got a teenager's bike, he's got
to take everything apart to see how it works.

With predictable results.
--
| ___ Salad Dodger
|/ \
_/_____\_ GL1500SE-V/CBR1100XX-X/CBX1000Z
|_\_____/_| ..78868.../...19540.../..30836.
(>|_|_|<) TPPFATUICG#7 DIAABTCOD#9 YTC#4
|__|_|__| BOTAFOT #70 BOTAFOF #09 two#11
\ |^| / IbW#0 & KotIbW# BotTOS#6 GP#4
\|^|/ ANORAK#17 IbB#4 PM#5 WG*
'^' RBR Clues: 29 Pts: 485 Miles: 1967

 

Champ says...

He could tell you the square root of a packet of crisps, but not how to
open them.

 

'T'won't idle properly. Nor start. Then when it's going and
hot it idles at 4,000+ rpm for a minute or two before dropping back to
1500 rpm. The idle screw is in far too far -- it was bottomed out
originally.

After a short motorway burst (Maidenhead-Langley) during which it
ran onto reserve, it cut out at the first lights. Took me a while to
get around to pushing it -- it started immediately but wouldn't idle.
I've had the carb off and cleaned a couple of times, everything is
infuriatingly nominal. New plug, of course.

I discovered that the air-filter had been replaced with a bit of
knitted cloth (the type we used to pack smoked hams in), well oiled.
Neither removing that nor buying the proper foam element has made any
difference.

I'm at the point of checking the oil pump (when I get a spare weekend)
and then looking even more carefully for leaks in the intake manifold.
At some point I should check the exhaust, tho' it seems to be free enough.
After that? Crank seals, I guess...

--
Ivan Reid, Electronic & Computer Engineering, ___ CMS Collaboration,
Brunel University. Ivan.Reid@[brunel.ac.uk|cern.ch] Room 40-1-B12, CERN
GSX600F, RG250WD, DT175MX "You Porsche. Me pass!" DoD #484 JKLO# 003, 005
WP7# 3000 LC Unit #2368 (tinlc) UKMC#00009 BOTAFOT#16 UKRMMA#7 (Hon)
KotPT -- "for stupidity above and beyond the call of duty".

 

You peeps really know how to kick a guy when he's ...asleep!

And Loz, I'll let you into a secret about crisps. In Adelaide
they like their crisps broken up into ickle bits, so they kill two birds
with one stone, opening the packet by bringing a clenched fist down
sharply onto the new packet. <POP!>

--
Ivan Reid, Electronic & Computer Engineering, ___ CMS Collaboration,
Brunel University. Ivan.Reid@[brunel.ac.uk|cern.ch] Room 40-1-B12, CERN
GSX600F, RG250WD, DT175MX "You Porsche. Me pass!" DoD #484 JKLO# 003, 005
WP7# 3000 LC Unit #2368 (tinlc) UKMC#00009 BOTAFOT#16 UKRMMA#7 (Hon)
KotPT -- "for stupidity above and beyond the call of duty".

 

Ivan's spent more time arseing about with the DT than I did
overhauling the Wing.

I think he's decided that because he's got a teenager's bike, he's got
to take everything apart to see how it works.

With predictable results.[/QUOTE]

Ah, right, I see. No offence to Ivan, but I've never met anybody with
such an immense brain, who devoted so little of it to understanding of
things mechanical.... ;-))

 

Bizarre, because it did both perfectly when I had it.

That indicates running too lean to me. Have you done a plug chop?

It's not going to be the oil pump. Crank seals are possible but unlikely
- the sure-fire way to tell is if it smokes excessively and the gearbox
oil level drops, because that indicates shot seals as the gearbox oil
gets into the combustion chamber. A smell of petrol in the gearbox oil
is a ditto.

 

I still wonder if the exhaust is a bit clogged. Try a de-coke (caustic
and a potato (stand it upright in a bucket).

No doubt it can be done with YAG lasers too, Bond-style, but personally
I favour the King Edward for bung-ability. You don't have to weld the
two halves back together afterwards either.

Regards,

Simonm.

PS: If the timing was a bit advanced it would run OK-ish, but not tickover, and
it could well overheat. Your description sounds like it's overheating, and/or
lean. Does the plug looks rather unhappy after a run? You may yet have an inlet
air leak.

 

"TOG@Toil "

 

Thus spake Dr Ivan D. Reid unto the assembled multitudes:

Ah, those Awstralians have no finesse.

My favourite trick with crisps is to grip the unopened bag firmly with both
hands, and squeeze hard so that the top pops open with a nice loud bang.
With practice and skill, the bag can be opened in this way without crushing
the contents. I once nearly killed our elderly pub landlady doing this; she
thought somebody had been shot and nearly keeled over from the shock. Care
needs to be taken to ensure the *top* of the bag is the bit that opens, not
the bottom, which can of course lead to lapfuls-of-crisps misery. It's
also a good test for an airtight bag; any leaks are immediately apparent
and the bag with possibly contaminated or stale contents can be given back
to the landlord for substitution or refund (or a '**** Off' if the landlord
isn't very friendly).

 

Dr Ivan D. Reid came up with the following;:

Couldn't be as simple as the throttle cable either being not long enough, or
too long, and coming out of it's ferrule/holder on the carb top/twistgrip
and when it's opened, not returning fully, could it?

Or the carb throttle slide getting stuck up the bore when it's got a bit
warm, maybe having been ovalised/deformed slightly by someone dropping it
whilst changing the throttle cable?

Or, indeed, the mixture and tickover screws set totally, absolutely,
completely wrongly?

Might be worth, and I don't mean to be disparaging here, taking it to
someone who is good with two strokes to have a lookie-see.

 

Or even putting the slide in the wrong way round - something possible
on more than one bike I've owned.....

 

came up with the following;:

I dunno about that on a Mikuni ISTR they mostly have a quide groove down
them with a pin/dowel in the carb body to stop that ... though if it's
broken ....

 

The Older Gentleman says...

There's only oil on one side of the crank. If it's leaking air from the
alternator side it won't affect the oil level. It's more likely to be
the alternator side too, as this is the one that dries up because
there's no oil there.

 

TOG@Toil says...

Left crank seal.

 

Yes, good point.

Hmmmm.... how does one detect a shot crank seal on the alternator side?
Two-stroke mix around the alternator, I suppose.