Two miles and it died

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Hotspur
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Main scooter: Lambretta LI175
Location: J24 M25
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Took my restored LI out for the first time today, and it died after two miles. Symptoms were it felt like it was holding back, and the more throttle I gave it, it just slowed and came to a halt along with a burning/hot smell. Pushed it home, it's got good compression, a good spark, plenty of fuel but it refuses to start. I've changed the plug (old one a nice chocolate colour) taken the carb apart and cleaned it. Checked the fuel cap for a blockage, fuel is flowing well. I wondered if anyone out ther can point me towards something I've missed. Spec is as follows.

Andy Frances iron barrel 175 with Asso piston brand new
22mm Jetex with Dellorto jets (main is 125) and 200 slide brand new
42mm AF Clubman brand new
Indian 12v stator and CDI reg etc brand new
New wiring loom

Cheers
Pete
goldeneye
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sounds like the barrel might be a bit tight. careful running in needed, use cheapo mineral oil for first 500 miles. and fit a fast flow fuel tap. lad round here had same symtoms, over 30mph, kept cutting out, he tried easing the throttle to get to 40mph, but the same. stuck a fast flow fuel tap on and cured it. same set up as yours, 175, clubby, 22 jetex, electronic. good little set up when ran in. still loadsa lads round here running iron 175"s.
Hotspur
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Main scooter: Lambretta LI175
Location: J24 M25
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Cheers Golden eye. I've already got a Camlam rear exit fast flow, and using Tesco mineral oil (Don't come much cheaper than that) But it still won't start
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coaster
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If the tap is flowing fuel then it can't be that preventing it from starting and would also eliminate the breather in the cap being blocked. You say it your first ride on it, do you mean following a re-build or just sincwe you got it?

Sticking with the fuel issue, is the plug getting wet? if not, is there any fuel in the float chamber, it's worth stripping the carb and blowing through all the jets and passages with carb cleaner, have a very good look at the float needle and seat.
bristolmod
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Main scooter: Lambretta TV175 S3- what else!
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"the more throttle I gave it, it just slowed and came to a halt along with a burning/hot smell."

symtomatic of a heat seizure I'm afraid.

What clearances did your reborer give you?

I'd be inclined to:-

1) temporarily replace the Jettex with another KNOWN GOOD one to eliminate the fuel side.

2) If that fails, then strip the top end and see what the damage is (ring/s possibly stuck in groove??)

3)Is the exhaust OK? I had an Ancilloti powdercoated a few years back and it somehow sealed the innerds= bike cut out and wouldn't run)

Chris
Scootering since 1968.
Hotspur
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Joined: Sun Sep 05, 2010 7:56 pm
Main scooter: Lambretta LI175
Location: J24 M25
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Thanks for your advice guys. To answer your questions, it wasthe first time out since I did a full nut and bolt rebuild of the whole scoot. So new crank, bearings, seals, clutch, gear selector, barrel, piston, head, stator, flywheel and on and on and on. As for the bore clearance, I bought it new, but I didn't measure it. (That may be a big mistake) The plug does get wet, and I have cleaned out all the jets. The float bowl is filling OK, and the needle valve seals. Just a thought, does anyone know how to measure the float height ?
bristolmod
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Main scooter: Lambretta TV175 S3- what else!
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try your flywheel/ keyway/ timing

If it has heat seized, then the rapid lock up MAY have sheared the Woodruff key resulting in the timing now being way out.

The fact that it ran for 2 miles indicates that the carb/ fuel side is probably OK but as its a Jetex......

Chris
Scootering since 1968.
soosh
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Running in on cheap mineral oil,has this been proved over the years?
bristolmod
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Main scooter: Lambretta TV175 S3- what else!
Location: Bali-Hai bar, Locarno Ballroom Bristol, 1967!- mines a Brown Split!!
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soosh wrote:Running in on cheap mineral oil,has this been proved over the years?
all we ever had in the 1960's, and TBH, seizures after a rebore were a rare occurance. BUT......the fuel was better then, so who knows.
Scootering since 1968.
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Diablo
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I don't think you can beat having the bore taken to a decent old school engine reconditioners for a precision hone. I don't fit any barrels untill they've been to cylinder rebores in Nuneaton. It greatly reduces running in time as well.
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