What have you done with your bike/s today?

[chaterlea25]

Hi RD
Are the Mikuni's fitted at an angle to the horizontal?
This will make setting the float level meaningless as I'm sure you know
It might be that the pilot circuit is being flooded? I would try removing the air screw to see if fuel flows out ?
Is this why racing and steep downdraught carbs have pilot fuel screws rather than air screws ??? I don't know
maybe talking bo**ox

John

[berger]

I have read a mikuni with a pilot jet and air screw doesn't like being tipped more than 20 degrees

[RDfella]

John - mine are horizontal - one each side, pointing sideways.

[berger]

what have I done with my bike today?? nearly set it on fire while waiting for a mikuni pilot jet I decided to fit the monoblock back on. well this caused a problem because I have piped the oil return across from the timing side where the filter is fitted and between the mikuni and cylinder head inlet manifold. with the monoblock being bigger I had to make a 12mm thick ally spacer to set the carb away from the crossover oil return pipe, all well and good up to now. BUT not thinking I hadn't got the bolt on pick up mag on the bike while messing with the gearbox I had dislodged the bottom pick up and hadn't seen this happen. so petrol on-- tickle carb jump on kick start and no go, tickle carb again jump on kickstart and bike starts on one pot. I start to rev the bike thinking I have a triple kwaker and middle pot will jump in shortly but nothing happens , so I look down and see flashes shining off the gearbox . I stop the bike to see what is going on and then discover a drip coming from carb thankyou for listening -- tomorrows another day----- got away with that one

[BigJim]

Thank you Berger, it's not just me at least!

[bsa-bill]

uummm I think fire is something we maybe don't about as much as we should

[chaterlea25]

Hi RD,
I would try two known carbs that work, take them off known running bikes
That will eliminate some unknowns, sort out ignition and other issues and then go back to sorting carb settings

John

[berger]

today i stopped the carb drip on the amal  and went for a little  run , she likes the std gearbox back in and I so do I , no whine in 3rd gear I hope the smaller pilot jet for the mikuni arrives soon because this old amal isn't getting my attention even though it is rich around tick over. played with it many times over the years and it just acts the fool when it wants to

[dave55]

Berger i feel your pain regards a fire as my pre monobloc dripped onto the mag and did burst in to flames over a year ago and only this week finished sorting it all out and getting it running again.

[RDfella]

Motorcycle fires? No problem. Used to have an old 50's Ariel on the farm. Sometimes it would spit back on starting, and set fire to the horsehair under the single saddle. Quick swipe with a cloth used to put it out, ready for the next time.

[Greybeard]

Today I gathered enough oomph to go and do some work on my bike. Last summer I found that sometimes when I pushed the bike backwards the rear brake would jamb. When I opened up the back brake drum I found that one side of the brake shoe end had broken off and the bit was rattling around doing orrible things to the linings. It's a sobering thought that something like that, especially if on the front brake, could kill you.

I cleaned out all the debris and used the bike until the end of the riding season. I ordered new Ferodo branded shoes from Fecked. Today I took it apart and am just about to fit the new shoes.

I have also ordered a pair of Mitas tyres for the bike today.

I understand that the Isle Of Wight BSA weekend, 18th to 20th September, may go ahead. I'd like to do that if I can.

[RDfella]

Bit more on the project. Ran it up on Sunday to make some inroads into carburetion. As apparently the pilot jet affects the whole range it makes sense to start with that, so warmed the engine up, stopped it, fitted new plugs and let it tick over for five minutes. Removed and examined plugs for colour. Looked fine – just a hint of tan. But the mixture screw made no discernible difference screwed in or out, so I’m going to fit the next size down pilot jets. Should be here in a few days, post permitting. Also, I found coming off idle the engine appeared rich. Hardly surprising, given my slides are 2 and most people seem to be running 2.5 or 3. So today was carb removal time and strip down ready for jet change and modified the slide cutaways to a tad under 3 whilst I was in there. 
Think I’m beginning to understand these carbs a bit, courtesy of much internet searching of other’s experience. Having said that, an old motorcycle mate of mine dropped around this afternoon for a bit of welding on a gearlever (he’s a Bultaco man). We discussed Mikunis and he recalled similar issues. Apparently he spent months with a pocketful of jets but never succeeded in getting it to run right. Too many variables.

[chaterlea25]

Hi RD,
If I had your bike I would try a 12 volt coil and battery, It should I believe provide a hotter spark which would help carburation problems
I have fitted several Mikuni's to unlikely motorcycles and within reason found them easy to sort out
I know there are dozens of jets and needles listed but you will find only a few of them are actually available anymore
(if they ever were)

John

[Colsbeeza]

I finally got the bottom end of the 1960 Flash assembled yesterday after about 10 or 12 attempts with end-float adjustment and interference issues. The new Conrod bolts (nuts) were striking the crankcase, so took some metal off them and the inside of the crankcase for clearance. Getting the shim stack correct was a nightmare. I used shims from 3 different suppliers to get the combination I needed (16.9'''). I had given up on receiving the shims from one UK source but they arrived after 6 weeks, no doubt due to the Coronavirus impact on postage. The NJ206 Driveside Roller bearing has turned out to be a good choice. The inner was so tight I did not use any Loctite.
A thin layer of Hylomar on the crankcase faces added about 0.4''' to the end-float. I now have 1.8''' end-float, a whisker more than my aim, but I am not taking it apart again. Some new 5/16" BCy nuts & washers for the crankcase studs look a treat.
I took quite a few measurements for interest. The sideways play at the small end of the conrod is about 0.5mm for each rod. I note that that question has been asked a few times on the Forum, so that is a good reference point for new ground bigends and new +0.10 shells. I know with wear, that 0.5mm can be much larger.
Col

[Greybeard]

Col,
Does 1.8''' mean 1.8 thou of an inch?