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Post by pxguru on Sept 11, 2014 17:46:25 GMT
Way too rich if that was plug chopped from full throttle. Whats the carb and jetting?
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DR180
Sept 11, 2014 17:43:18 GMT
Post by pxguru on Sept 11, 2014 17:43:18 GMT
pottermod, bigger carbs need bigger jets to be the same. If you are happy that it runs ok on the 24/24, do a full throttle run for a few miles. turn off key, stop in a layby. And take a photo of the spark plug. We'll try and help
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Post by pxguru on Sept 9, 2014 7:59:42 GMT
A GPS speed of 54mph is 6000 rpm on the 20 tooth. If you could get that up to 7000rpm it would be GPS speed of 63mph. Or about 75mph on the vespa speedo!
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Post by pxguru on Sept 9, 2014 7:53:40 GMT
I do exactly similar but just with tippex white dots. This year even the MOT guy asked me the throttle marks were for. Obviously a four stroke man
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leak
Sept 8, 2014 17:21:03 GMT
Post by pxguru on Sept 8, 2014 17:21:03 GMT
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Post by pxguru on Sept 8, 2014 5:01:04 GMT
Yeh thats it.. It controls the amount of mixture coming from the idle jet circuit. And I tried something today, to block off the air feed on the idle jet at tick over. It made only minimal difference if any and it still ticked over ok The more I think about it, the more it makes sense. Now I just need to find my bag of idle jets to experiment some more. Good work Did you ride it blocked to see if you could feel it too rich?
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Post by pxguru on Sept 8, 2014 4:59:50 GMT
I've been told (by SIP) it's mixture screw in these SI carburettors. Wind it in gives leaner mixture. Wind it out gives richer mixture. The naming of the airscrew, didnt Shakespear write a play about that? Very good point though. In British we (me) tend to call everything airscrew but technically if the airscrew is after the progression diffuser (I say atomiser) it is then a mixture screw. On any carb if the airscrew is near the carb mouth it is a true airscrew and near the engine side it is a mixture screw. And just to complete the confusion, if you have a true pilot airscrew on your carb, it will work backwards too (wind out for weaker and in for richer)
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DR180
Sept 7, 2014 15:28:38 GMT
Post by pxguru on Sept 7, 2014 15:28:38 GMT
First put in a new B7ES spark plug and a bigger main jet (like 118) and tell us how it goes.
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Post by pxguru on Sept 7, 2014 15:09:16 GMT
Tuning by feel is certainly the best way. With a kitted or tuned engine the slow running must be slightly rich. Most mild tuning works fine with the standard jets but if disabling the autolube and putting oil in the tank instead, then bigger jets are required to allow for the oil now going through the jets.
When the pilot jet number is about right the airscrew will be responsive. From mid position, wind it in it will rev higher, not smoke, run terrible, then cut out and wind it out from mid and it will start hunting and smoke. The pilot jet air inlet number adjusts the mixture when the throttle is just open (one or two mm). Keeping the pilot jet number the same and reducing the air number until it splutters a bit (when riding it) at just open throttle, then increase the air number one jet to run ok. And thats it. The pilot jet will not need to be redone again if going on to change the main jet or main atomiser.
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Post by pxguru on Sept 5, 2014 18:34:40 GMT
the 55/160 is why it is running sooty. 55/160 is the standard idle jet for a non autolube P200E. Change it to 50/120 and it will all spring into life at low rpm. When the pilot jet is too rich the airscrew doesnt seem to do anything unless its wound right in. Get the 50/120 in and it will run better right away. This is the jet that should have been in yours from new. Vespasco: the 55/160 is richer at idle than the 50/120 and leaner through the progression stage. Just dividing one number by the other is just some some old wives tale. The SI pilot jet is acutally pretty smart. It does two jobs. The small number is the pilot jet for idle till just off the throttle stop. The large number (bigger is weaker)is top hole air inlet for the progression jet atomiser, which kicks in next, up until the main jet atomiser comes in before 1/4 throttle. The boring old SI is no dumb carb
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Post by pxguru on Sept 3, 2014 17:30:34 GMT
If it starts by 3rd kick when cold then the bore isn't that worn. Its still running too rich at low revs which is not the main jet. I would put the 120 main back in with that pipe. Even from new there might be some random friday afternoon pilot jet fitted. With autolube running yours should be a 50/120 pilot jet.
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Post by pxguru on Sept 1, 2014 9:57:13 GMT
It should be running better than that but reading this a few things come to mind for you to try. A near standard PX200E should have a B6ES plug for normal use and maybe a colder B7ES if you do mostly motorway riding and only if the B6ES plug is showing signs of burning up. Second I am wondering how you set up your air screw. If you have one of those new fangled brass nut screws, a top tip is to take it out and hacksaw a slot in the top for a screwdriver This is how I do it on an SI carb. Start it up and warm the engine fully. Then with it not running, gently wind the air screw all the way in till it stops. Then out half a turn. Start up the engine. Adjust the idle so its revving a bit quicker than usual (about 1300rpm). Wind the air screw out a little at a time until the rpm picks up very slightly. Out a little more till its smooth, then Stop winding there. Adjust the idle back to normal. Blip the throttle to make sure it doesn't cut out (too weak). Rubber bung back in and thats it. Not so complicated edit: took too long with my quick reply!
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Post by pxguru on Aug 25, 2014 16:49:00 GMT
Sounds like you found where the seals were leaking from! Mixing Rally and PX/E casings is fine. I have done it before with no major issue. Important to check the base gasket surface. Between the halves it will not be exactly level with the crank centre and the barrel will not sit square. Check the lip on the gasket surface and make a thin half base gasket to sit on just one side to level it up
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Post by pxguru on Aug 11, 2014 6:31:15 GMT
Both of these have good mid and top end performance but would not recommend going for any stainless pipe, as they tend to crack.
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Post by pxguru on Aug 10, 2014 14:03:54 GMT
I have two motorcycles on the road, a 600 and an 1100. I still prefer to rider my PX. It's much more fun and so thrashable The first thing about porting any engine is deciding what you are porting it for Porting an engine is just changing the port timing. the simplest way to test the effect of the transfers is just to put a packer on the base gasket. If it goes worse take it off. No harm done. If you really like it get the barrel done by a pro.
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Post by pxguru on Aug 8, 2014 13:21:54 GMT
Wouldn't bother with the upgear kit, a lot of work and noisy as hell. Just use the 21 tooth clutch gear as has already been suggested, 10 minutes work and if you blow the kit 10 minutes to put back to standard. Agreed 21 tooth is the best way to go.
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Stand
Aug 8, 2014 12:42:39 GMT
Post by pxguru on Aug 8, 2014 12:42:39 GMT
Thanks everyone, that confirms it, my scooter is a Friday afternoon special It does have 3 slots in the frame and two spring holes in the stand but only had 1 big spring. I will get the two thin springs ordered and put it right.
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Stand
Aug 7, 2014 17:52:36 GMT
Post by pxguru on Aug 7, 2014 17:52:36 GMT
My centre stand spring broke today. So annoying It is the original one but I think this might be the wrong type of spring for my PX Disc. Beedspeed says it should have 2 thinner ones. Any ideas? Attachments:
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Post by pxguru on Jul 26, 2014 4:22:01 GMT
vespasco, I am sure you mean degrees F. Sounds to me your Pinasco is very cautiously jetted. Running hotter is more powerful but dangerous over 300F. Probably not a bad thing to be careful but measured at the spark plug, you could take it to over 200F round town and 250F on the motorway and still be in the cautious limit. It is important to check CHT accross all throttle positions carefully. Even running perfect wide open can still seize up when you shut the throttle at speed, if its lean in the middle.
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Post by pxguru on Jul 25, 2014 11:33:26 GMT
You will not regret having a CHT gauge. They are a lazy way to get the jetting right. And if you keep an eye on it, it might just prevent a seize up, dodgy fuel issues or forgetting the 2 stroke!
I also go by 300F as the maximum with the sensor on the spark plug. I think this to be quite hot enough for the road. I have the SIP speedo one and have the sensor on one of the head bolts which is a bit cooler than the spark plug but doesn't get broken quite so often.
Here is the theory bit. The basic idea of a Carburetor, is to supply a constant ratio of fuel air mixture regardless of the position of throttle or quantity of air drawn through it. The ratio of fuel to air determines how hot the flame will burn. More fuel to air (bigger jet) will make the CHT colder and less fuel to air (smaller jet) will make it run hotter. This might be opposite to what anyone first thought.
When you find the right one and have the CHT gauge all set up, try riding at each of 1/8, 1/4, 1/2, 3/4 and full throttle for at least 30 seconds or so each. And you are looking for better than 250F and near to 300F across all the throttle positions. This is especially useful with a needle carb where there are many more adjustments.
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Post by pxguru on Jul 20, 2014 14:16:57 GMT
Normally bogging down is when running too rich. Try a turning the mixture screw in to 1 turn out. If its any better you might need a smaller pilot jet.
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Post by pxguru on Jul 10, 2014 11:26:37 GMT
Henri, I beg to differ. Ring area is smaller but the force is smaller by a similar amount. Spring force of the ring is not as strong on a thin steel ring and the ignition blast pressure force is directly proportional to surface area inside the ring. That aside you only really need one of these pistons if you work your engine hard most of the time or have ported it to rev higher. In reality the fat rings wear rapidly with high rpm and the thin rings don't as much. The thin ring piston can handle a very much wider exhaust port too. I have used the thin ring 68mm piston in standard barrels with great success
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Post by pxguru on Jul 10, 2014 11:06:17 GMT
Maintaining the keep it simple theme, the nut has been removed from the back already, hasn't it? Just to be sure
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Post by pxguru on Jul 9, 2014 4:38:07 GMT
The BE5 is the second richest atomiser and the BE3 is the second weakest. Which would be ok if there was only 4 of them but there are 6. If it was running rich in the mid range for a long time, that old exhaust could be choked up. Put that other exhaust on for a few weeks to eliminate it. The other thing might be compression. Does it feel ok?
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Post by pxguru on Jul 8, 2014 12:25:34 GMT
Bryno, just a few more questions first. Is it completely standard PX200 engine? What exhaust and how old? ignition timing on the A mark (23 degs)? What number main jet 118 or 120? and atomiser BE3?
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Post by pxguru on Jul 6, 2014 11:26:13 GMT
"Have to be bonded in" is just opinion and experience Without bonding in there is a risk of leaking or falling out. Both of which don't happen to mine or others scooters anymore. I think when they fit the metal seals from new they are put in with a press or some tool. They never seem so tight after the original seal is changed.
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Post by pxguru on Jul 5, 2014 17:30:09 GMT
Metal brown seal is my one of choice. The best for long life at high rpm. They do have to be fitted with bonding liquid tho. Henri, I use Loctite 603 but there are a few others that will do just as well I suspect you are losing some oil rould the back of the seal. You may be able to take it apart and pop it out without damage but better to get a new seal and bond in properly. The good news is that if its passing oil you are losing power
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Post by pxguru on Jul 5, 2014 6:48:32 GMT
The COSA clutch can't handle the stress of wheelies and burnouts like the MK1 clutch but for normal riding a COSA clutch is better
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Post by pxguru on Jul 5, 2014 6:18:29 GMT
Need a bit more info. How many times you filled the gearbox oil in 400 miles? What make/colour of main oil seal did you fit? What sealer do you use to bond the seal in the casing?
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Post by pxguru on Jul 3, 2014 15:25:43 GMT
Just for "touring" eh? Depending on your ability with the spanners you may have a lot of options. A Malossi 210 is not the best choice for touring, as they can do it but are more suited to higher rpm. A Polini 208 or 221 (even better) gets my vote. Exhaust SIP road 2.0 Whatever you decide you won't need a 30mm carb for touring, the 24/24 and autolube will be fine for that
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