Hi, I've had the Zip for six months and have been cleaning and painting etc. ready to ride on Sunday. On Sunday I could not get it started. It has started since I bought it and all I have done mechanically is to change both lock barrels. I have checked for spark and fuel and I can see no reason why the compression should be compromised. Suspecting old fuel, I have just checked the fuel tap and drained the tank and am about to dismantle and clean the carb. I was wondering If there may be anything else worth checking while dismantled? Thanks, Graham
if your getting a spark, I think you will find the problem with the carb, check the reed block and manifold while the carb is off, you have a similar engine and carb to me, so will help where I can, let me know how you get on.
Thanks for your advice CGC. Looking at my manifold, it appears to be fixed with two 'torx' type bolts. These bolts also have a raised peg in the centre, not come across anything like this before. I'll have to find a suitable tool. Be silly not to check it out whilst dismantled. I'm on the case. Graham
its an m6 thread, after I took mine out I replaced them with m6 bolts, just used a set of mole grips to get them moving then a pair of pliers after that
Thanks again CGC, handy information. Good to know that you've had success with the same problem. I'll certainly give it a go. Graham
Those stupid things in the manifold are security screws, you can get a set of the bits at Halfords for little money. Same as Torx bits but with the hole up the middle. As CGC says, get them out and replace them with standard M6 bolts. Or if you have a fine centre punch you can break the pin out the centre then use a standard Torx bit to remove the bolt.
Hi Steve, I tried the awkward bolts earlier with a mole grip and failed, luckily father-in-law had a set of the proper Torx security bits. So I have removed, checked the reed valve and found a couple of M6 bolts with 10mm hexagonal heads. Just the job. Thanks, Graham
Hi, Just a short update. One reed not seating so a new complete valve on order. Worthwhile checking. Carb opened up and was really clean. Removed the jets etc and blew everything through. But, My Haynes manual shows a third jet, a starter jet. I don't have one, just a brass tube that extends to the bottom of the bowl. My Zip is 2009 but the dealer I purchased from did say that he replaced the defective pattern carb with one from a 2015 model. Does that sound accurate? Graham.
yeah, same carb as me PHVA 17.5 some have the jet and others don't, you should maybe check the autochoke wire it straight to the battery and measure the length of the brass bit, but the smallest of things can block the jets even partially, and you wouldn't even notice it was there.
Thanks CGC and Stevep, Good to get your comments. I thought the carb looked right, with so many scooter models in the Haynes manual it's difficult to keep up with all the variations, as they appear. I've tested the auto choke and the brass pin extended from about 19 to 24mm, the resistance specs however didn't conform as it was 5 ohms measured, compared to the manuals' 20-30 ohms. I'm hoping this will be OK. Can't wait for the reed valve to arrive so I can get it back together and try to get up and running. Graham
think the choke will be ok, the default is on, and you would have had the scooter starting then flooding after a few minutes, hope all goes well when your reed block arrives.
Thanks CGC. See what you mean about the auto choke default, from what I have read, when extending, the needle reduces the petrol flow as the engine warms. I'm a little confused by a rubber elbow pipe exiting the deep inner section of the air filter box and another very similar pipe exiting the engine just to the rear of the reed valve. Both pipes are not attached to anything. Also there is a longer rubber pipe from the plastic cylinder head cover that just stops after about 4-6 inches. I've read about a 'secondary air system' in the manual and was wondering if I am missing some components?
yeah, I blocked off the one from the engine with some sponge which still allowed the transmission to breathe and cool, it was a catalytic system that ran from a junction in the exhaust downpipe, but most people remove it when fitting a new exhaust as all aftermarket exhausts don't have the junction. The tube from the cylinder cover would have went to a carb cover and would have helped cool the carb mine doesn't have this either as I was constantly working on the carb during the rebuild and I have it running good now (if its not broke don't fix it ) so its still in the shed. the rubber elbow I think you mean is the air intake, although mine is on the outside of the box, my airbox is like this one and the tube is at the back it restricts the airflow to the carb to a level the carb can cope with, I took it out once as a test to see if the system would benefit from more air, but it was too weak a mix to accelerate.
Thanks again CGC, That has certainly covered all my queries, I can see that you know your way around Zips. My exhaust is quite battered and there is definitely no junctions from the down pipe. I'll also try a bit of sponge in the end of the pipe, as you have, should help keep any dirt out. I get the message about tube from the cylinder cover. Oops air intake, should have realised that. Yes, my air box is very similar so following you advice I will leave it alone. Sorry if I am being a pain in the butt with my questions but scoots are new to me and the more I can find out the greater my confidence. I also really enjoy researching and understanding how things work as it makes it easier to fix, if necessary.
ask away, really glad to help, I got the piaggio in August last year, you are as me when it comes to restoring, I have posted a few pics of the restoration in scooter projects, all of the piaggio 2 stroke 50's from the same era have very similar engines, I think some of the frame mountings are different, and some zip gearboxes are different, as main differences though there are some which I haven't discovered yet.
We're on the road. Thanks to you guys who have helped me. I went for a short run, not straying too far from home, just in case. Seems that I need a fair amount of revs on before pulling away, then she's off like a bullet. Must ensure my chin strap is done up! Also noted that the engine bogged randomly at higher revs but does not stall. I'm thinking there may be some old petrol in the system that needs to be cleared through, so I will try a few more local runs. Thanks CGC for your kind offer. I will check out your restoration pics, still learning the forum search features Graham.
