peteretep

When you guys are talking about setting your exhausts on fire, what is the reason for it? You have noticed a decrease in power or something, or maybe you feel like making clouds?

25 minutes ago, Adoom said:

CB900 got a second puncture in less than 4 weeks.   First one was ~1800km ago... but what a PITA.

 

new tyre each time? or repairable? 

I got a puncture on a 3 month old tyre a while back, no one would fix it so had to get a new one. At least it was only $80

I think I am almost there with tuning, I started writing notes and what the bike felt like, I have changed from one of the richest needles down to the leanest one I have in diameters, as well as dropping down a jet size. I have been quite surprised how changing a needle works out, they have made a big difference changing between 5 needles. If you get an aftermarket carb you really need to get pilot jets, needles and main jets.

I am getting to 190 degrees C on long periods of WOT which is pretty legit, and around 150 degrees at mid throttle positions. Take off is much better, I just need to finish tuning my clutch for engagement rpm and engagement aggressiveness, and maybe retune the pilot jet as the other jets have gone down, will check that tomorrow morning when its colder

running a 98 at the moment

12 hours ago, Truenotch said:

It sounds like the pilot circuit is too rich to me. 

Have you read this tuning guide? It's a pretty long read, but worthwhile IMO: https://advrider.com/f/threads/beginners-guide-to-two-stroke-jetting.1254185/

My summation of a rich condition based on that guide:

Symptoms of rich conditions

• Tends to get worse as the engine gets hotter
• Has a regular misfire, like a stutter.
• Mildly rich will fire every second cycle (four stroking), very rich every third or fourth cycle (six or eight stroking).
• Extremely rich mixtures will load the engine up to the point where it won't rev or will just die
• Usually the quickest way to clear a loaded up engine is to back the throttle off to just above idle
• Will usually respond OK to opening the throttle

 

I see what you mean about getting worse as it gets hotter, its definitely like that. But after fitting a couple of leaner needles starting actually became hard so I have enrichened the pilot air screw so it starts pretty easy again, so I am fairly happy with that, I have tested it and it is within the standard range on the air screw at 1.75 turns out now. This morning I moved the needle down to clip #2 to make it leaner at 1/4-3/4 throttle, bike is running reasonably well, when rolling it takes off sweet, but when at a complete stop it still splutters when I go to accelerate, at idle with no throttle it idles fine albiet maybe slightly too low now. I might have a bit of a play with the clutch, as engagement is 6k rpm and bite is soft, might try for a harder bite, will probably make symptoms worse but might make it easier to diagnose

I have a snap on set that supposedly repairs damaged threads, I use it quite a lot, they are like a gentle tap. I would have no problem using a normal tap to repair a thread though

5 minutes ago, SOHC said:

you could try a different carb slide cut away, 

Jeez man I already got every jet I could!! I can’t realistically play with slide cut always without it being a one way adventure. Carb is really too big for the motor so tuning is a bit hard, but I’m sure it is do-able 

Man every page or pdf I read has different data for how pilot jet, needle taper, needle diameter, needle clip setting and main jet takes part in the throttle operation. I am playing around with my street magic and can’t seem to get rid of the splutter at 1/4 throttle, I have reduced diameter on the needle twice now without any major difference which according to the most reliable PDF seems to indicate is the diameter zone. It works well when it’s cold, but after it’s warm it has a solid splutter down low, especially noticable when taking off at the lights

dang what is that thing? how fast is it?

Hey @Truenotch how does the oil system work? I see you have changed to premix but is the oiling adjustable, or some way you can see if it was working properly? I put a drill to pump oil on both my scoots to prime them/check them. My Suzuki has a non adjustable oil setup but the aprilia is adjustable

16 hours ago, mjrstar said:

Open vs close times may differ on a pneumatic solenoid operation due to the volume of the shuttle (unless balanced shuttle). Even then they wouldn't be exaaaacccttly the sane. 

 

It wouldn't surprise me if the times listed are plus minimum open deposit time. More like a design duty of the solenoid rather than something useful to start your calculations fron.

 

That sort of rate may also beat the daylights out of the needle seal and piston.

Also does a change in viscosity effect the actual cycle rate say a thin cold glue could be effectively be easier to apply quickly than a thickish hot glue. 

We use nordson glue gear (at a much slower rate) they seem reasonable, with the odd failure. 

 

Nordson is the most common in NZ, mostly as they have the best service really, just screw you over on pricing, plus everything is imperial

and yeah, does change depending on viscosity, but I dont have that info and I trust that whoever helps us set up the machine will set it for best results.

1 hour ago, Testament said:

physically what are the glue guns, how do they work? are they piston things with variable stroke, is there a pressurised supply of glue behind them, or mystery under the blanket operation?

until measured with a high speed recorder or something I would probably question the accuracy of most of those timings anyway - so may just have to take a stab at it and adjust from observed production result anyway

there is pressurised glue in line feeding the guns, the times relate to the pneumatically operated solenoids which open the valves for the pressurised glue lines. We can measure everything pretty accurately as the cardboard is moving via servo with encoder feedback. Problem with that is we need to buy a machine to test it, costing $25k

holy shit I thought there was going to be death at the end of that video

Hey guys I have a work related question, I am designing a machine that applies hot glue to cardboard. The cardboard is moving pretty fast so I need fast acting guns & associated equipment. We have an automatic glue gun that we often use with a solenoid that claims to be able to cycle 8000 times/minute, or 133 times/second, or once every 7.5milliseconds, with a minimum bead deposition time of 2milliseconds. How does the 2ms relate to the 7.5ms? It takes (7.5-2)/2=2.75ms to open, 2ms minimum open time, then 2.75ms to close?

An alternative product can cycle 120 times per second, or once every 8.3ms, with a minimum open time of 5ms, so does that mean it takes (8.3-5)/2=1.65ms to open, stays open for 5ms, then takes 1.65ms to close? So its faster to operate between positions, but must stay open for longer once open?

The outputs from the PLC are high speed, 0.5ms on, 1ms off

timeline for gun 1

0 - tell PLC to operate solenoid

0.5ms, signal received at solenoid, starts to open

3.25ms, solenoid open

11ms, solenoid has been open for 7.75ms, it will take 1ms to send signal to close, so send signal from PLC to high speed output

12ms, solenoid starts to close 

14.75ms, solenoid closed

timeline for gun 2

0 - tell PLC to operate solenoid

0.5ms, signal received at solenoid, starts to open

2.15ms, solenoid open

9.9ms, solenoid has been open for 7.75ms, it will take 1ms to send signal to close, so send signal from PLC to high speed output

10.9ms, solenoid starts to close 

12.55ms, solenoid closed

so if I never need to operate less than 5ms, then gun 2 is arguably the better choice? Or have I mixed up how this works?

42 minutes ago, MopedNZ said:

Looks rather attractive. Nice work!

I destroyed my soul removing the old tyres, took 500kg + of hilux weight to push the tyres off the beads

Ah i thought I had entered this, will get onto it. Edit: entered

Put new tyres and bearings into street magic, will ride it to work the next few weeks to make sure it’s reliable

I got a 6mm neodymium  magnet and drilled a bit into the heads of the brake rotor bolts, then epoxied the magnet in

gave it a bit of a lick with a diamond burr plate today, and will try it with a stone tomorrow, looking reasonably positive so far

yeah warming to the idea, will get it looked at first though

in similar news, got the bearing off the shaft, its looking a bit sad, will take it to work tomorrow and see if one of the fitters can make it happy. It's picked something up on the shaft seal surface which is a bugger

norice how the ball hokder is skewed?

Pulled bike apart, turns out I had water in the carb which was causing it to dirA, but also had a busted stator aide bearing, properly pulled apart now, but anyon e know why I have so. Much crud on this bearing side? Maybe I should get a shielded bearing next time and only take off a cover on one side 

What is the run time of an electric bike like that? And do they design for quick changing of battery packs? I tried googling but all the faggot electric bike/car blogs dont like talking about the downsides of of electric stuff

hey guys, I lost about 10-15kph top speed on my street magic, seems to take off ok, but straight away you feel a slight loss in power all the way up to its now top speed of around 70-75kph. I have so far taken apart the exhaust, taken off the cylinder to inspect, replaced the spark plug, checked the reeds, intake filter, checked variator, replaced drive belt, and now I have taken off the torque driver to see if thats particularily sticky. I have not found a big problem with any of the things, but given them a clean and made sure they are still sweet. The torque spring was more 'sticky' than I thought it should be, so I put a tiny amount of lithium grease where it moves. I am pretty sure the rear gears are fine, so I will take the carb apart next, but any other ideas?

I was thinking of getting this to make the spring rotate easier, but I am not sure it will fit, @Raizer ?? the spring is smaller than my aprilia

https://www.scooter-attack.com/motoforce-torque-spring-seat-racing-minarelli-105mm-mbk-booster-nitro-mf84-105-39.html

dang 13bhp, nice way to make some sweet power