gaz73

OK I fitted a new pilot jet and main jet: pilot was 36 now 40 main was 55 now 60 and theres no real difference in power, I tried the gunson colourtone and saw a nice blue flame but when i turn the screw lean it stayed blue and when I turned it rich i got the slightest flicker of orange every few seconds but never a constant orange. Does that mean the pilot is now too lean? it contradicts the increase in pilot jet. It seems like with pilot jet you need to go up or down 1 step not 5 like with main jet.

Thanks guys, yes its a 2 stroke 50cc scooter, auto choke and auto belt transmission etc and tutorials I find on tuning are only for manual gears/choke bikes so I cant do the tuning tests they talk about. I will look into the dyno run, sounds cheaper than I expected. Ive fitted a new main jet thats a few sizes bigger, slight improvement when I get to 20mph but it doesnt make sense, that means im running lean but im not getting lean spark plug readings or lean symptoms. Im about to try a gadget I have thats basically a glass spark plug so you change the mix until you get a blue flame, it sounds to me like a very accurate way of getting a perfect tune up.

I will get a new pilot jet, and a new main jet, throttle valve sleeve and probably a new needle, that's where this is going I think, from what im reading you need to change a few things when dealing with low to mid range. Today it was back to boggy but only when cold, it was slightly more pokey when warm but not much, also strong smell of petrol i think the float is too high, does the needle height affect the float level? Im amazed I need to do all this just after new rings its mental, I guess when you get a new top end you've gotta cross your fingers and hope you don't need to buy several sizes of each part.

Hi all I have a Dellorto PHVA 12mm carb and after fitting new piston rings it now runs very lean (bogs when applying power but doesnt stall) I raised the carb needle clip to maximum height and the mid to top range is good but the low end is sluggish until I get to 20mph. Ive read that I must keep the clip in the middle of the needle when running in and get a bigger main jet, another source said change the float height, another source said get a bigger pilot jet. I was looking for more ideas basically lol im not sure which road to pick here. Again theres no manual for this bike anymore, been looking for 2 years, I only have the service manual and the carb manual are nowhere near detailed enough for tuning. Thanks.

Just wanted to say a very big thanks to all that helped me here, bike is now running, its noisy compared to before and it doesnt stay at idle it stalls but I guess thats normal until run in. Cheers all

Thanks i was gonna make a compressor out of a can and some cable ties, ive heard some use a plastic bottle to prevent scratches.

Ive took a risk and gone for the 41.5mm rings because my bore measures 41.50mm at its maximum or 41.44mm at its lowest. I hope thats right lol so I guess ive got to hope the ring end gap is around 0.03mm then and im ok, or hope that it needs filing.

Thanks for that man, no the bike had a rebore 2 years ago and new piston and rings, I believe its still a 50cc not a 70cc because the piston has "50" on the top. I guess im knackered without the manual but there isnt one for this bike. BTW would you know what those numbers mean, is the 41mm the bore diameter and 0.50mm the ring gap? because i got some feeler gauges today and the ring gap I get is 0.05mm. I measured the bore diameter and its 41.44mm so I guess that means I need a 41mm ring?

I need new piston rings as I damaged one after removing it (no other damage to engine) and wanted to ask if I can just use a feeler gauge to measure the gap in the ring or if I need more measurements to make, when I look at the bikes manufacturer website they show rings that are 41mm/0.50mm and 42mm/0.75mm etc and im guessing the 41mm is the diameter of the cylinder and the 0.50mm is the gap you measure with a feeler gauge and thats all I need to know? Thanks guys.

Before posting here I searched for weeks and only ever found dead links to manuals, still looking now. Ive asked the guys at Italjet for help yesterday on torque wrench settings no answer yet, its all I need to know now but this manual you speak of would be nice.

Thanks, I removed the cylinder and theres no gasket and water and sludge is all over the piston and everything. the bike has been owned by such a moron in the past ive noticed a few things like this.

Hi all, I need to remove the cylinder from my bike and im a complete noob with no manuals, all I want to do is see if the problem is a crack, gasket or something else, do I need to make sure the piston is set at a specific place before I remove the cylinder? Thanks. the previous owner hit the exhaust hard forcing the cylinder upwards hard, its took 2 years of me riding not knowing this for it to leak.

When I move the handlebars with the front wheel on the ground I still get the play, I can see that the front wheel isnt moving but the handlebars are. This is only very slight but its annoying, I dont know how much is too much basically. The front wheel does move slightly when off the ground but its like 0.1mm of movement and the bike doesnt have forks its a strange design, the suspension is totally separate from the steering.

2002 Italjet Formula 50 LC My scooter failed its MOT recently due to excessive play in the handbars. I bought a new steering arm for £170 and theres still about 20% play left which may still fail. My problem is I dont want to spend £50 more on the steering head bearing or more on a wheel bearing etc unless I know for sure the play is coming from there. The play is only present when you move the handlebars in the usual direction to steer, if I push or pull the handlebars in any other direction there is no play, so could it be that the play is coming from the wheel bearing end or is it most likely the steering head end? is there some test you can do to determine the most likely suspect? If I cant get help I would need to spend another £100+ and cross my fingers. Thanks very much.

Guys you are awesome thanks a lot, I was pushing the wires all the way down and they were making contact with the switch body. Now I can move onto the next problem lol

I have an Italjet F50 and bought a new stop switch for the right hand lever, it works OK when it is in my hand but when I screw it into the hole on the brake lever I get a spark and the fuse pops. This happens with the old switch too, is this a bad earth problem? if so where do you start to look? the problem came from nowhere ive done no changes to the bike other than remove the stop switch then suddenly I get a spark when I try to screw it back on. I have a multimeter but not entirely sure what to check, the readings I get from the stop switch wires is 12.16 volts so seems like the wires are healthy but is there anything else I should check? thanks guys.

Ive just spent a lot of money on my Italjet Formula 50 LC scooter but ive always had a problem ive ignored as it comes and goes and I usually just pull over and wait for the problem to go away after a few minutes. What happens is it bogs down (not the engine) as if there is about 30% brake being applied and at full throttle im getting 30 mph and i cant get up hills. I suspected the rear brake pads but the problem happens even when I dont use the rear brake at all or if I remove the pads, when i coast to a stop it feels just like a brake is slowing me down. Next problem that could be related is there is a strange scraping noise coming from the transmission when im moving along, theres no noise when im stationary, its most noticeable when coasting to stop with no throttle and the sound is very similar to those old and loud coffee peculators. Would anyone know what the heck this is? had this for the past 11 months now ever since I got it.

Yea my memory failed me there cos I already knew that from my first ever job and college, I never stuck with mechanics so ive forgot it all. Ive contacted Italjet and hoping for a reply, meanwhile just to deepen the mystery the diagram below shows a screw but mine doesn't have any screws, so ive got a part that doesnt match mine and a screw that doesnt exist.

Hey thats a clever thought I didn't think of that, no its not separate lol I checked their website and theres no separate seals, although that doesnt mean you are wrong, it could mean they dont stock the part anymore. I guess I need to contact them. btw for anyone interested the name of the joint in the first post I made is a U joint.

I posted help on the Italjet forum but its very dead there, I think you guys must have seen something like this before? I have no idea how to dismantle this other than to hit it hard with a hammer? After weeks of digging around all I know is I think its called a pivot pin bearing. The last picture is really confusing, because on my bike the bearings have 2 black ring seals either side exactly like in the last picture, but the parts provided by Italjet (3rd pic) dont have these seals

Thanks Ricky. Ive actually noticed that replacing these bushes has cured the wheel wobble over bumps but its not got rid of all the play, theres was an inch of play before and now theres about 1/4 inch, im worried it will fail the MOT again if hes not happy its enough, could do with finding out what the legal limit is or if its just mechanics discretion.

Just thought id update and finalise this problem. I ordered the black bushes and removed the old ones by drilling a hole at 12pm and 2pm and carved out that section then used a small screwdriver and got behind it and prized it out, greased the new ones and put them in and all good now. I was told by a guy at a bike shop that its a Chinese steering joint on an Italian bike and it cant be removed and that its far better to buy the whole assembly, that would have cost £170 but this fix cost me £17.

I considered that but you need to buy the whole steering arm assembly, £170.

Yea they are very quiet now, I posted there months ago about something and still not had a reply. I think ive worked it out now, you can buy the bushes (those black plastic seal things) so I got some on order, i will try the socket and hammer thing see if it works. Cheers.

I have no idea how its constructed, this is whats worrying me. I found these images online after hours of digging, sadly I cant reach the guy who did this. Im thinking maybe I just need a socket (of right size) and a mallet to hit the plastic seal out the other end, but I wouldn't wanna try it without knowing.