Need advice on two starting issues

Astrolite

Astrolite

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1. One year old fully charged battery, based on specific gravity of cells, won't crank starter. A jump from my tractor battery or a booster battery cranks it just fine. Maybe battery damaged, not passing load test or too small?

2. Bike starts fairly easily, with kickstarter, when cold, but will not start when warm.

I have stock exhaust, air boxes, filters. The petcocks and carbs have been rebuilt, roughly bench synchronized. Cam chain, valves, points and timing all adjusted. Runs nicely down the road.

 
Have you checked the float settings and subsequent fuel levels in the bowls? Low levels can make for difficult starting. Here's how I found the fuel level in one carb on a hard starting bike I worked on .....

SightTube.jpg


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The other carb wasn't as bad but it was low too .....

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Setting them right cured the hard starting .....

SightTube6.jpg
 
I did set the float levels when I rebuilt the carbs, however, I'm sure I could have been off by a few mm, given the difficulty I had in reading the scale. So the correct fuel level is even with the line formed between the carb body and the float bowl as in your last picture? Two questions, (1) are the barbed float bowl plugs available somewhere? (2) To adjust the float, can you just drop the bowl, remove the float, adjust, reinstall and retest, without removing the carbs?
 
Yes, the barbed bowl plugs are available off eBay .....

https://www.ebay.com/itm/274881260720

They may seem a little spendy but it's a quality item that I use all the time, so I didn't mind paying that much. In fact, I bought two so I could do both carbs at the same time, lol.

Yes, you could just drop the bowl, remove the float, adjust, and re-install. That's all I do if I find them off. May take a couple tries to get them right but I think that's still easier than pulling the carbs off.
 
Yes, proper level is where the bowl meets the lip on the body, on the 650 BS38's calling for a 24mm setting anyway. The bowl extends up a couple MM past the bottom of that lip on the body, so the fuel level is actually below the top of the bowl. You want that or gas will eventually seep through the gasket if the fuel level was covering it.
 
5twins said:
Yes, the barbed bowl plugs are available off eBay .....

https://www.ebay.com/itm/274881260720

They may seem a little spendy but it's a quality item that I use all the time, so I didn't mind paying that much. In fact, I bought two so I could do both carbs at the same time, lol.
Click to expand...
Just ordered one, we'll give that a try. As for the battery maybe I can get it load tested. Can anyone recommend a good battery?
 
5t, do you know if those barbed bowl plugs will fit the bs34 carbs? I've been forever trying to find a way to set my floats this way. I believe the later ones came w a barb. Mine just have drain plug.
 
5twins said:
Yes, the barbed bowl plugs are available off eBay .....

https://www.ebay.com/itm/274881260720

They may seem a little spendy but it's a quality item that I use all the time, so I didn't mind paying that much. In fact, I bought two so I could do both carbs at the same time, lol.

Yes, you could just drop the bowl, remove the float, adjust, and re-install. That's all I do if I find them off. May take a couple tries to get them right but I think that's still easier than pulling the carbs off
Click to expand...

edit - just read post #12

with exchange and shipping will cost close to $40cdn. Maybe I don’t need one that badly. Lol.

just found this…. https://www.advancedfluidsolutions.co.uk/index.asp?uid=&function=CART&mode=UPDATE&id=1&qty=2. Not so bad
 
Last edited:

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