1946 bitsa project

[KenS]

Looking good, won't be much longer now before the maiden voyage!

[SEDoan]

Thanks Ken!

Here's a couple more pictures of the seat work. the first shows the stitching at the "darts" and the second the fit on the bike. I got the dart too wide on the left and the nose of the leather sits higher on that side so I later pulled and re-stitched to get it to lay down better. I'm happy with the way it turned out because it looks similar to an original cover but should be much tougher.

[SEDoan]

I had fit the tank when mocking it together but final installation was more work than expected. The tank sits further forward and a little higher than it should probably because it was made in India.
The key switch (electronic ignition) is held in the tank by a top hat shaped piece I turned from UHMW polyethylene. It is a sliding fit with two o-rings to hold it in place. Also had to make the steel knee grip mounting plates. Fortunately I had a pattern but getting them to lay flat was a fiddle.

Ready for the start! It took about a dozen kicks, mostly because I forgot to tickle it, but also because I'm not used to turning on a key!

video of it idling: https://youtu.be/pvsbdXj-I8M

I went around the block a couple times and it was weak on the transition off idle and hesitated mid-throttle so raised the needle. I also installed a snorkel airfilter using some plastic bilge pump hose. This hose is easy to stretch and form with a little heat so it now fits over the mouth of the carb and makes the bend over the oil tank. K&N mesh air filter is ziptied to the seat springs.

Rode it to the gas station and around the neighborhood so now it has 6-7 miles on it. It is the cold and wet season here so it is also now dirty. Might get a few more miles today if it dries up.

And here is a picture of where this whole project started.

[Julian Murphy]

Now, that just looks fabulous.

Well done, and thanks for sharing the story / progess on the way.

[Paul Slootheer]

That is looking realy great, congratulations!
Well done!

[KenS]

Shawn, congratulations! that is awesome! Certainly was a great project to follow and maybe I could load my 46 up then head up to the NW so we could go for a ride????
Again, great job.

[SEDoan]

Thank you guys! It's got a little over 80 miles on it now and it runs smooth and quiet and has lots of mid-range torque. It's a blast to ride with the higher bars and seat. It feels light and the brakes work well despite being a little spongy yet. But it's not all roses as it has been an absolute #@7H3%&KR! to start. I can't seem to wrap my head around this Concentric carb. It doesn't pop or bang unless it's tickled until gas is dripping and by then the plug is wet. There seems to be no happy medium between too lean and too rich. I'm about ready to put on an old 289 except it runs so well on the Concentric. And it's NEW! I've richened the idle mix, raised the needle and increased the main jet size to 210 (which is still lean by Amal's tuning guide). Tomorrow I'm trying a 230 main.

The only other bad thing is that it's been caught in the rain twice in 4 days. So no longer clean.

All that strife goes away when riding:

And Ken, if you make it up here - we will definitely go for some good riding!

[Simon.Gardiner]

Shawn:
Is this a Premium concentric, where you can get at the pilot jet, or one of the standard ones where the pilot passages are pretty much inaccessible?
I ran a concentric on the VH for years with very little trouble, also used one on the 650 for several years with no problems but recently that's become a real pig to start and it seems to have needed three or four bouts of carb cleaning to get it fixed (I'm still not happy that it's properly fixed but it 's back to being a more reliable starter recently).
While raking over all the advice on carb tuning I found that Burlen now specify a float height; as the carb has never behaved differently it might be worth checking this. (See 'fuel level' section on this advice: https://amalcarb.co.uk/technical/rebuil ... arburetter )
Up to 1/8 throttle only the pilot circuit should be involved, changing anyhing else shouldn't have any effect - although there's a tuning chart that suggests the slide cutaway and needle do start to get involved below 1/8.

Very nice bike!!

SG

[SEDoan]

Thank you Simon. It now looks like my carburation problem is actually ignition - or operator error! The Boyer instructions say their box can overheat if the ignition is left on too long. The instructions also say to wait until the unit charges before kicking (a few seconds). I read both instructions but only paid attention to the first so most of my kicks were in likely in vain. Will test this hypothesis after the holiday.
Merry Christmas!