'48 LS Engine rebuild

[fffcycles]

You are right Neil, easy enough to replace the pipe. Was just wondering if there is a source as I need to make a few others and would just cost less.
RDfella, I did not recognize the topic  correctly when I was searching. The centre stand on the long stroke bike has feet shaped different than the later bikes but I will figure something out. I have to as it holds the back wheel much too high at 3”. The concept has been proven and it looks easy enough.
Frank

[Greybeard]

You are right Neil, easy enough to replace the pipe. Was just wondering if there is a source as I need to make a few others and would just cost less.

Small copper pipe should be available but hydraulic brake pipe might be an alternative and would bend safely.

[Swarfcut]

  Getting the bike off the stand can be just as difficult. Plunger stands have a poor stop arrangement for the "Stand Down" position. The stand itself has two small ears which bear on the two flats formed on the  underside of the footrest mount frame forging. These parts wear over time, and the stand will  then allow the bike to sit lower when on the stand, hence the hernia inducing effort to lift it up and off the stand.  The ears can be built up with weld, as can the frame forging. Easy to do as a first restoration step, not so as a final overlooked detail.

  Good  unworn Plunger Stands have a fair value these days. I would be reluctant to put one to the axe. A low ride height will make using the stand harder to user, more physical lift required, so I'd only modify the stand as a last resort.

 Swarfy

[fffcycles]

So proud of having the original correct taps but despite new corks, boiling water, correct washers, etc ; they did not stop leaking. Okay, put another set of taps on and now that works better. Leaks at the base of the carburetor to float chamber,  replace seal washers twice then realize the float chamber collar where the banjo fits is not correct. Careful dressing of the collar top and bottom has the leak at the banjo bolt all sealed.
Now we are getting somewhere! Tickle the carb, kick, kick, many kicks, pull the plug and no spark. What? The mag produced lovely fat sparks when I spun it with a drill on the bench before installation. Clean the points, recheck the cables and try again but no joy. Thank God for the rain, I have an excuse to walk away and think about this some more.
Slip ring dirty? Brushes knackered? Need to check the ground again? It will be something I have done I am sure.
I love my motorcycles! Strange but true.
Frank

[chaterlea25]

Hi Frank,
If you blocked the hole at the base of the body where the fuel leaks out you will have trouble!! Ok so fuel leaks out but when the engine starts it acts as an air inlet
Look for a sectioned drawing of the pre mono 276 on the net

John

[fffcycles]

Oh, I have you on that one. The leak was where the banjo tightens on the collar that attaches the float body to the carb body (must look that up as there must be a proper name for it). The Mazak was dented and misshapen so cleaned that up and did not touch the breather holes (atmospheric vent holes?). But thanks for the reminder.
Today it will be a bit more valiant effort then the BBQ with the wife and girls. Good fun
Frank

[fffcycles]

A quick update, cleaned the ground brush and slip ring, new pick-ups with brushes and wires. A few kicks but no joy…. Ah yes, reverse the leads, tickle generously and second kick it roars to life, only ran 4-5 seconds then died. Tried a few more times with same result so I guess I will tear into the carb to do a few more checks.
I was doing a jig the as sign of life made me so happy. Oh yeah, found another small oil leak that will take a little fiddling.
Frank

[fffcycles]

Back at the bike yesterday, damn life gets in the way sometimes, oil line tightened, new washers on the banjo bolt then replace one of the tank taps. No joy, so checked for spark with left good and right nothing. Checked leads with a meter again, the plug cap on right is now showing open; new plug caps both sides, fill up the tank, tickle and the bike started on second kick!!! Ran pretty good, sounded right so after a minute or so turned down the idle adjusted the pilot and it was terrific for another minute or so then just stopped. Many kicks, pull the plugs and they are dry so I will clean the carb again, blocked jet maybe, and oh yes the oil line to the top end has another fracture so I will rebuild that completely.
Such fun, but it was encouraging.
Frank
ps I have been getting some riding in as the weather has been fair and my last rebuild, ‘71 Norton 750, is a pleasure.

[fffcycles]

And, it starts and runs fine at last! So glad it has come to life and sounds quite good. A few minor oil weeps causing a little smoke but now to get it out and get some miles in.
Frank

[fffcycles]

Now I am tearing my hair out fiddling with the carb. Starts well and did run quite well but now it is running much too rich just won’t accelerate worth a damn. The float just never quite stops the flow of gas and the excess is dripping from the atmospheric vent. Tried another float and needle but that does not help it seems and now to try a 1A body instead of the 1AT body the PO had on there and maybe a washer to modify the float level lower.
We will see in a day or so what is happening on this.

[Swarfcut]

 Frank you need to lower the float bowl in relation to the jet block. Experiment with fibre washers added between the base of the carb body and  float bowl mounting banjo. You can check the float valve works in isolation.  Fuel level  is just below the top of the needle jet housing in the carb body. Any higher and fuel will continue to overflow, dripping from any available orifice. Service Sheet 708 shows a cutaway and will help you get a handle on what's going on.

 276 Carb can be fitted with various remote float chambers, on later models the carb sits at a slight angle and requires a chamber which sits level at rest. It's all to do with the bowl casting used, they come with the mounting set to slightly different angles. So always a chance the bowl you have is not quite correct for your early type cylinder head and manifold if someone has fitted a carb from a later model.

 Swarfy.

[fffcycles]

Yes, I have to drop the bowl along with the correct model and I trust this will make it work.
Frank

[fffcycles]

Right, proper 1A float chamber, extra washer to drop it down, lo and behold the float works properly. One job done so on to starting which was third kick but running on right hand cylinder only. There is good spark, plug is wet with gas, compression seems good….. what is happening here? Cleaned the slip ring on the mag, tried another plug but no firing on the left hand.
Will check the points gap, install another set of plugs then I will consider this in depth.
Frank

[Greybeard]

... running on right hand cylinder only.

Some people want perfection. You'll be wanting the moon on a stick next. 😉

[Swarfcut]

 Could be a poor pick up/lead. Swap plugs over, together with the leads. Leave pick ups for now. If fault changes sides, mechanically it's fine, the problem is the lead/plug. Stays the same? Plug and lead good. Suspect pick up.  Sparks in the open air are a guide, HT does strange things under compression.

 Swarfy.