Degreasing two-stroke exhaust flange ready for welding

[octo0072000]

looking good

 

[mangocrazy]

I've got the machined barrel back from the machinist, and it's looking pretty good. With the benefit of hindsight my welder could have added more material than he did, although at the time I was sure there was more than enough weld applied. This is a front-on picture of the flange:

I could pick a few little holes, but it's a million miles better than it was originally, and should work fine. This is a view looking down on the flange from above:

You can see where a bit more weld wouldn't have gone amiss, and I will need to do some clean up work with a carbide burr, but basically it will work, and save me the extortionate cost of a replacement barrel (or pair of). This is a comparison with the other undamaged barrel:

This shows most clearly where material is missing, but in use I really don't think it will be a problem.

 

[penfold]

It'll be reet.

 

[jordan1]

Personally I would take it back to be built up properly.

 

[Chris Stevens]

Looks a bit of a mess, and would only take 5 minutes to sort out. Wonder if the bore is still straight though? That would be my main concern.

 

[dannyp]

i'd say thats about right.

put just as much weld in as needed, that way it dose the job with minumum risk of distorting it, or you distrot it as littel as possible. belive me if you put more weld than absolutly nessasery and it distorts the customer bleets lots.

 

[mangocrazy]

The barrels were always going to be rebored anyway, so I'm not too concerned about any slight distortion. The mass of aluminium should have conducted heat away fairly rapidly. Once I've had chance to tidy it up with a burr I'll make a decision on whether to get my welder man to add more material or not. To be honest the only concern is cosmetic in my view. The barrel as is will do the job (once rebored, of course).

 

[jordan1]

I would have been happier with it built up fully, as you know this fixing is subject to quite a lot of vibration. A heat sink could be used to minimize any bore distortion I would have thought

 

[Jim Davey]

Did you give the welder the other undamaged barrel or exhaust flange for reference? Always easier to gauge how much metal you have to put back if you have something to work to.

 

[mangocrazy]

Take your points. I did give the welder and the machinist both barrels (as it were...) so that they had a reference, but it looks like something got lost in translation. I think I may take the repaired barrel back to the welder and get him to carefully fill in the missing bits, then get the machinist to re-face the flange. I can reprofile the edge and back of the flange myself.

 

[eSCHEn]

As much as an erse that'll be to fill in and re shape / profile, you'd be mad not to IMHO. It'll bug you every time you see it otherwise.

That said, still a very nice job on what is not the nicest material

 

[mangocrazy]

It certainly wouldn't have been a simple job to get the barrel set up and solidly mounted in a CNC machine to do the machining. They did the really tricky bits; machining the groove for the copper crush washer, machining the flange face flat and accurate and drilling and tapping the stud holes in the right place. I think I can manage the cosmetic stuff myself after the welder has had a second pass.

 

[mangocrazy]

Don't let anyone tell you that I take my time over projects. I know it's well over 4 years since my last post on this thread, but (amazingly) progress has been made to the point of the bike now being a runner... First of all, the state of the bottom end prior to starting the rebuild:

Another view of he general decrepitude:

The bottom end once it had been completely refurbished:

The barrel that was the original subject of this thread, being prepped for paint:

And the top end rebuilt and setting the ignition timing:

And lastly, the bike ready for its first MoT in 30 years...

It passed 200 running in miles and 20,000 miles in total last Friday on the A6 between Buxton and Bakewell...

 

[Woody.v8]

A credit to you sir, looks the mutts nutts

 

[mangocrazy]

Cheers Woody. The first photo above was taken on New Years Day 2020. It was my New Year's resolution to get the bike back on the road. It finally became road legal in the first week of September. A five week stay in the South of France (house-bothering) stopped any further progress until we got back, but I've been slowly increasing the running in mileage since mid October. It's weird going back to skinny tyres, rubbish brakes and two stroke powerbands after 30 years, but I could get used to it again...

 

[brightspark]

sandblast it with kiln dried sand

 

[Woody.v8]

sandblast it with kiln dried sand

I thought it looked good as it was