Quote from: mr72 on April 17, 2018, 06:34:55 AM
Of course, in TX the use of "deadly force" by citizens to prevent crime is justified in many cases where someone would be stealing a motorcycle. Most Texas homeowners have at least one gun on their property and a there's a substantial chance any citizen you encounter may be armed. If someone goes to steal a motorcycle in the nighttime, there's a reasonable probability they will be shot.

Really? Texas allows use of deadly force to prevent property crime? That seems a little extreme. Most states require there be a threat of imminent bodily harm to yourself or others before you can use deadly force.

Quote from: Bluesmudge on April 17, 2018, 10:33:06 AM
Really? Texas allows use of deadly force to prevent property crime? That seems a little extreme. Most states require there be a threat of imminent bodily harm to yourself or others before you can use deadly force.

Well there are certainly conditions. Usually it's robbery, aggravated robbery, or theft in the nighttime. But there are also special circumstances regarding your domicile or your vehicle. Considering how TX law ordinary errs on the side of the initial crime victim, I think it's unlikely anyone would be successfully prosecuted when using deadly force to stop the theft of their motorcycle. IANAL and all that of course.

So after a fair bit of fiddling with this i think its sort of right ish (enough for a test) at 2.25 turns on the mixture screws @ ~1200rpm. There is a slight hesitation on blipping the throttle from tickover and the engine isn't as smooth as i expect so I'll check the carb sync (now I've drunk two big bottles of corona, stupid me made a mamometer from plastic before realising, oh yeah, they crush...) and get that closer and see if that smoothes things over. then have another check of the mixture. It comes off choke a little too soon, maybe 5 minutes tickover @ 2.75 turns and blipping the throttle gave a bit of soot in the exhaust so if anything i think once sunk (synced? synched?) i should be able to back this off to 2 turns and have a nice setup.

Booked in for an MOT and new tyres (avon road riders anyone? ), bad time of year as i have to wait until middle of May for that...

plenty of time to clean the chain and watch the grass grow and get older i suppose.

Quote from: tobyd on April 20, 2018, 12:42:42 PM
There is a slight hesitation on blipping the throttle from tickover

Likely just normal behavior of CV carbs. There is a small time delay between when you open the throttle and when enough vacuum builds to pull the slides up.

If it's excessive delay it may indicate damage to the slide diaphragms such as pin holes or a vacuum leak.

Quoteand the engine isn't as smooth as i expect so I'll check the carb sync

Dunno what's meant by "smooth" but nearly always any running issues are due to lean conditions even if transient. Just FYI. Carb sync can't hurt and I'm told (although I have no direct experience) that the low-rpm/light-throttle stutter I have is related to carb sync.

sync'd the carbs, one side was out by a fair bit, adjusted it so the water level is steady, with slightly longer fuel lines it can be done with the tank still attached. Raised the idle speed to around 1800 to do the sync as per a guide somewhere. blue-tack worked surprisingly well as a seal.



Bike then ran appallingly. sigh.

Pulled the plugs (black, needs some on road action to clean them up), checked the gaps (one was slightly too tight) cleaned them off and reinstalled, might throw a new set on anyway since i have no idea how old they are. they dont look too bad.

bike still ran badly.

wound in the mixture screws and once again reset to 2.5 turns, set the idle speed to about an indicated 1500rpm, adjusted below 1500 rpm the bike is not running happily. at ~1500 rpm the throttle response is instant, no obvious signs of rich running, sounds ok seems quite smooth. Does the bike need some throttle adjustment for an idle? if i unwind the throttle stop completely is this suboptimal?

i have a suspicion the tacho isn't so good, it barely moved when i first got the bike going, was very sluggish. cleaned it up but it might not be so accurate at low speeds. or at all.

might have a poke around for air leaks, the intake boots aren't great.

Anyway, cleaned and lubed the chain and check the tyre pressures and scraped some crap off the wheels as a distraction.

Yeah the idle speed is too high. Back it down below 1200 when it's fully warm to avoid the dreaded hanging idle.

Made it worse today, ran it for a while, but wouldn't run off choke, below about 2000rpm its lumpy as anything and rapidly dies.
adjusted it up and down, checked over the cable routings and positions and they seemed ok.

then it wouldn't even start, made encouraging noises but would run for a second then die.

needing choke to work is making me think very lean. So i though "maybe its those ancient intake boots, where someones wobbed up the cracks with silicone?" que, dismantle process.



both have splits where the boot joins the metal backing plate, although one is really mangled and has been repaired*. Not entirely convinced the carb was sat in them properly either, nor were the clips doing a great job. stumped up for some replacements...

Will put some new plugs in too then at least i know they have been done.

rechecked the float heights and they seem ok, RHS is slightly below the gasket line and LHS is exactly on gasket line.

Might having 'wrong' O-rings in the idle mixture needle/screw assembly cause an overly lean condition?

I did replace them with ones that seemed about right but weren't as specified. I'm now wondering if 2 or 3 turns on the mixture isn't enough as the o-ring is thicker and isn't letting enough fuel through once off choke? I suppose letting it out to 4 or 5 turns and dialing in won't hurt?

Plugs and intake boots should be arriving tomorrow and I might be able to get it back together Wednesday evening but I'm wondering if swapping in 3.0mm ID x 1.0mm C/S orings in place of 2.6x1.2 might be closer to factory? Definitely seems to have gone from way-rich to way-lean after swapping them?

Quote from: tobyd on April 23, 2018, 04:12:28 PM
Might having 'wrong' O-rings in the idle mixture needle/screw assembly cause an overly lean condition?

Nope.

Quote
I did replace them with ones that seemed about right but weren't as specified. I'm now wondering if 2 or 3 turns on the mixture isn't enough as the o-ring is thicker and isn't letting enough fuel through once off choke? I suppose letting it out to 4 or 5 turns and dialing in won't hurt?

No, it doesn't work that way. The o-ring keeps the fuel in the passageway from leaking down the screw shaft and out of the carb. It basically isolates the fuel from the atmosphere. And turning it out more than 3 turns is useless, the needle is all the way out of the jet by then.

The big problem wth putting in the wrong o-ring is that it may not fit in the prescribed space, causing it to bunch up or fold, or rattle around (if it's too thin/small, unlikely). And then when you screw the needle in you may munch the folded o-ring and ruin it. Also this would cause the needle to not "bottom" in the right spot, so it may be too low (too far out of the jet) when you start adjusting so maybe you go 2 turns out but the needle's in the position that it would be at 4 turns out if you had the right o-ring. Then the more annoying problem is that the wrong o-ring will probably get stuck in the carb when you remove the needle to try to replace it, and you'll have to make a tool to "pick" it out of the carb which is easier said than done. BTDT. Not worth risking with the wrong o-ring. And FWIW I couldn't find ANY off-the-shelf o-ring that was exactly the right size. I could go put a micrometer on one of those original o-rings and give you approximate dimensions but why? You can get them for like 50 cents each from http://www.thisoldtractor.com/for_sale_dr350_orings.html ... 13295-29900 ... just get the right ones and stop worrying about it.

Quote
Plugs and intake boots should be arriving tomorrow and I might be able to get it back together Wednesday evening but I'm wondering if swapping in 3.0mm ID x 1.0mm C/S orings in place of 2.6x1.2 might be closer to factory? Definitely seems to have gone from way-rich to way-lean after swapping them?

Order some of the right o-rings and while you're at it intake boot o-rings from the same place, do it right and don't worry about it any more. FWIW some sources say that o-ring is 1mm x 3.5mm so your o-rings are in fact too fat.

I re-read your last couple of posts and don't see any indication it's running lean. In fact your black plugs make me think it's rich at idle, and likely because the o-rings are too big. But if you had leaks in the intake boots it would run extremely lean above idle both because it's leaking air in behind the jet and also because it reduces vacuum a lot and therefore never lifts the slides to pull the needles out of the main jet.

Getting the o-rings wrong on the pilot needles will cause all kinds of troubles that are hard to track down, but it's 90% at idle where these problems manifest. Once you are running off idle or above like 2K rpm and with more than like 1/4 throttle you should be mostly on the main jet and then you have to suspect vacuum issues as the primary cause of what's wrong. You know the intake boots are knackered. Fix what you know is broken and don't fret about other stuff until you can rule out the obvious.

If you must go through the cycle of take-apart-put-together many times, then go ahead and ride it with suboptimal idle util you can get the right o-rings. But if you don't have new intake boot o-rings then don't bother putting it back together IMHO. Just get fresh intake boot o-rings and new/correct pilot needle o-rings and be done with it in one shot.

BTW I don't know what your float measurement was referring to but incorrect float level will look and feel like mixture problems at conditions besides idle. Check here: http://gstwins.com/gsboard/index.php?topic=26604.0  ...

The boot o-rings were replaced when I was ordering some other parts, the boots weren't concrete hard but weren't supple. The replacement boots came with replacement O-rings amd arrived today so i'll put those on and swap the plugs over. I'll try the 1x3 orings, i bought at the same time as the 1.2x2.6 ones in place if they look messy. I'll go out and pull the carb now and have an investigate since i have to move the bike for something else anyway.

Sadly, its the shipping from the US on those that will be a problem. I doubt i'll have enough time to get them ordered and the thing sorted enough for mid may. Perhaps i'll get a set later I'm the year depending on how things go.

I'm fairly happy with the float heights. Measuring them as per the diagram isn't the most accurate thing i can think of anyway since you need need to have it 'just so' and there are no convenient flat surfaces to get anything accurate in a nice position. the drain tap + hose method seems sound enough.

edit: so the 1.2x2.6mm O-rings are snug on the needle shaft, the 1x3 O-rings are loose, about the same as the washer. the RHS needle came out as a complete assembly, the LHS needed the oring removing.

Sounds good, forgot which side of the pond you are on. You'll work it out for sure. But I still don't think you're lean.

right again, replacement washers and new plugs in started up. sounded bad, very sluggish. was just on the reserve level so sucking air and petrol. flipped on reserve cheered it up.

i'd set it to 2.5 turns out and 1 turn of throttle. wasn't running great on that, got it down to mostly off choke and it wasn't great still. gave it a bit more throttle and it cheered up, backed the mixture screws down at half turns and around 1.75->2 turns seems best, bought the idle down to approx. 1400, i think its a little lessthan that since my tacho isn't great. anyway, throttle is sharp and returns quickly, exhaust seems clean. engine is a bit tappety but aren't they always? might need the valves re adjusted once I've got some miles on it. i'll need to re-torque the head bolts in a few hundred miles so will check then.

i don't think its 100% but i think it'll do for the MOT and then i can get it properly warmed up and set. might see if i can find some 3.5x1 orings and try them out. the 3x1s dont appear to be leaky yet. i dont mean to do this-old-tractor out of a job but having the measurements would be great as a general resource, most ebay seals seem to arrive the next day.

thanks again mr72!