Triumphrat

Mrsinister

Trying to get a 79 Bonniville 750 in running condition, and having problems getting the choke to stay down. Anyone with the same bike know if you have to hold it down when you kick it? or is there a problem because I believe its supposed to stick down. Also the gas seems to be staying in the resivoirs and not going any where else. My guess is carberator isnt getting any gas, because the plugs got a spark, it just seems like the gas isn't making it through the bike all the way.

Brian

jimmy bush

Has the bike been sitting a long time? If it has, there is a good possibility the carbs and tank petcocks are varnished up requiring a tear down and trip to the carb cleaner vat. If it hasn't been sitting long, have you tickled the primers until gas overflowed out of them? That is usually all one of these oldsters need to fire up. Most of them don't even have the choke installed anymore.

Mrsinister

it has been sitting for a long time. How long im not to sure. I know the dumby who owned it before me left gas in it for a bit and it was no good when i drained it out. Im pretty sure my bike has a choke on it, its right below the the left gas resivour. I've never had to get anything dipped to de-varnish, if that be the case what does that run?

jimmy bush

If you have any mechanical experience you can do it yourself. You can get a can of carb cleaning gunk (I use Berrymans) at auto parts stores. You might have to replace some carb gaskets but sometimes if you're careful and lucky you can disassemble the carbs without tearing up the gaskets. The gunk should have the instructions and a basket with it. Usually only takes an hour or so unless they are really gummed up. It helps to have a good shop manual to follow if you haven't tried this before. You will have to call a few bike shops to get an idea of what the cost would be for them to do it. If you choose to do it yourself, make sure the carb is completely disassembled and no rubber "o"rings are exposed to the gunk because it will ruin them.

Mrsinister

It depends on how bad it reallys is. THe bike is being stored at a friends how and we got as far as it was the carbs being backed up. IT was getting dark and cold (live in michigan) so we gave up for the night. And we havent started on it again since. But I imagine that the gaskets should be good, if not thats where are problems sits along with the gunked up insides. But The guy im working with use to own a harley shop, but isnt to confident about working on english bikes it seems.

happyray

Hi,

It sound s to me that you have 2 Problems:
1. No gas
2. Choke doesn`t work.

And we shoulda know what carb is fitted.
Taking the carb completly apart is always a good idea. That`s the only way to know what jets eg are fitted.

If it`s an Amal the choke-mechanism is quite a revelation lol.
With an Amal the choke works this way:
You pull the choke-lever , a piston inside the carb will be pushed down (by another spring) and decreasing the air-intake.
If the "choke" spring is broken or the choke-cable isn`t seated properly the choke is always in action = far too rich !
Some dealers are also selling choke-cables which are a tad too long. There should be an adjustment bolt for the choke-lever included. Wether the cable fits onto the carb-lid is another question as well grrrrr
And if the choke-lever isn`t tightened enough it won`t work again.
Took me some time to understand this thing.

Finally I got it all set up (750 Tiger) , kicked it to life, took a short cruise around the block...hmmm...hmmm..installed a "colortune"....hmmm....what the heck.....

After some hours I realized that the carb was a 928 instead of a 930!
Oh man, what a weekend it was lol.

ray

htown16

With all due respect Happy Ray, your describing an Amal Mark I carb, while a 79 should have Mark II's. On these carbs, there is a lever that connects to plungers on the float bowls of the carbs. These plungers have a rubber plug at the bottom that seals an air passage, richening the mixture for starting. To start one its lever down, throttle closed. The lever should stay down by itself to start and usually it helps to leave it down for a little while as the motor warms up. My 78 will not even fire without the lever down. However, if you kick it 4-5 times and it doesn't start its probably flooded. Then its lever up and throttle half open to clear the flood. The rubber parts are likely shot if they are original. I would go along with the other recommendations and disassemble the carb, soak in Berryman's cleaner. And when you put it back together put in new vitron tipped float needles and rubber choke plungers. Baxters in Iowa or Mitch Klemph in Minnesota are both good parts suppliers. Call them up and they'll fix you up with what you need. Also, I strongly recommend you get a factory service manual and parts book from them. Your going to need them if you hope to keep this bike on the road.
Good Luck
Mitch

happyray

Hi Mitch,
nothing to worry about. Course you`re right.

ray