drewpy

you're correct in assuming the pipe seals are to blame as that will produce the backfiring you are experiencing. You should have a gasket there, but it may be compressed and does look at first to be part of the cylinder head. try cleaning around the exaust port and check for a gasket (they can be metal copper or steel concertina shape) hope that helps, if you seal the exhaust and it still backfires, then timing or fuel mix is to blame.

erm..no thimble full at most there's no seal there, maybe try tightening the case bolts. 8mm = 2.0 - 2.4 lb ft 6mm = 0.8 - 1.2 lb ft ps I am talking about the left side of the bike (as you sit on it) as the engine only takes 2 litres (2.3 with new oil filter) so hopefully your not removing the clutch side?

this a great gathering organised by the LE velo club. Its situated off the east Lancs road. Lots of different bikes attend and there is a great (free)museum housing one of the largest steam engine winders in the UK. 11am to 4pm directions here

LT is left timing for the valves on that side RT is the right timing for the valves on the right make sure the piston is at TDC by removing the sparkies and feeling compression with your thumb. inlet (carb side) is 0.08 - 0.12 mm exhaust 0.16 - 0.20mm A little oil does come out and my engine has only 2k since rebuild

check fuel flow from tank and it is venting (replacing the space left by the fuel with air) then check float heights in each carb

you obviously got too much time on your hands. Very nice bikes, hats off to you!!

great, that wheel is off a custom model

Mr Cadbury and Miss Rowntree met on a Double Decker, it was After Eight. She was from Quality Street , he was a Fisherman's Friend. On the way they stopped at a Yorkie Bar, he had a Rum and Butter, she had a Wine Gum. He asked her name, "Polo, I'm the one with the hole" she said. "I'm the one with the nuts," he thought! Then he touched her Milky Way. They checked in to a hotel, and went straight to the bedroom. Mr Cadbury turned out the light for a bit of Black Magic. It wasn't long before he slipped his hand into her Snickers and felt her Cream Egg. He fondled her Flap Jacks then he showed her his Curly Wurly and Tic Tacs. Miss Rowntree wasn't keen to have any Jelly Babies, so she let him take a trip down Bourneville Boulevard via her Party Ring. He was pleased as he always fancied a bit of Fudge. It was a magic moment as she let out a scream of Turkish Delight. When he pulled out, his fun size Mars Bar it felt a bit Crunchie. She wanted more, but he needed Time Out, however, he noticed her Pink Wafers looked very appetizing. He did a Twirl, had a Picnic in her Sherbet Dip and finished off by giving her a Gob Stopper! Unfortunately, Mr Cadbury then had to go home to his wife, Caramel. Sadly,3 days later his Magnum lolly started to drip. It turned out Miss Rowntree had been with Bertie Basset who had Allsorts!!!

take off your spark plug and it should stink of fuel. this will also bore wash your oil and wear your engine quicker.

Welcome to the forum

I'd check the earthing lead from engine to battery and also check live connections from battery via starter solinoid to starter. ensure the battery is fully charged. all else fails your starter brushes are worn. Get a manual for the bike, this will pay for itself in no time

Feel the kick lever getting harder, this is when it is on compression. depress the compression lever so the piston goes over TDC. let go of compression lever and jump on the kick start. try different amounts of choke and twist grip when engine cold. No choke hot. could also be flooding the engine and creating a hydraulic lock with the fuel. ie over fuelling the bike

contact gaps (if fitted) ignition timing valves adjusting coil parameters check carb on that side all gap info is previously posted, use the search facility

already discussed in this forum. please do a search before posting Q's

some thing like this Item number: 170122928169 will fit, but i don't know about the jetting. Why don't you buy an eliminator and tell us if they work

oil low and frothing at higher revs?

I'd start with stock and run on a dyno to get the fuelling curve. then you can optimize the flow with new jets if need be.

same thing happened to mine, I got a friend to look at them and he pushed them through from the top. It enlarged the hole but you just screw in the pilot screw in more!

Wow those carbs were gunky!! Mine were no where near as bad and i still had a severe blockage in which you describe. Had to soak over night and use a fuse wire and jiggle till i got compressed air through the bowl. Then i sent off to JRS to have them cleaned. Looking at my manuals, the pilot system can't be fed direct from float chamber as it has a blanking plug over the jet so would seem to come off the starter system!! The fuel filter you have is the same as mine. I thought they had a paper element at the top part!!

Watch those balancer chains and tensioners, and keep the oil clean as the top end gets starved of oil easily

I just used a small inline paper filter. Just because they are ultrasonically cleaned, doeasn't mean all the crud is out. Some swear by using a carb additive in the petrol tank and that clears out the gunk

on my xs400 the timing marks are called RF for right LF for left. The LT/RT etc is for the valve timing. just a thought

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yep, pilot jets blocked ( a recurring theme in xs400 threads)

redwhite is the + feed from ignition swtch and connects to both coils. Grey and orange go to the conacts via condensor. the connector must be faulty or just needs some contact cleaner as they can get verdigri and prevent contact.