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Discussion Starter #1
As most of you know this bike has given me trouble right from the get go. Recently it was taken apart for some repairs(coolant in the oil) so i split the cases to give it a good clean and make sure everything was in tip top shape. New mech seal , new gaskets all round etc. I had it running before i took it apart so this has left me stumped. Right here goes. Went to start the bike after the rebuild and nothing. Cranks and cranks with the odd shotgun bang 😁 ( scares the **** outta me everytime). But no start. Battery is brand new mf battery, timing is spot on 305* as i wont make the same mistake twice. Everything lines up with all the marks. Starter is perfect. Good blue spark from the plugs. My carbs do need a little work (float stuck i think) but there is fuel in the bowls after i prime them. Here the funny part. After cranking the plugs still look dry. So next step. Try starter fluid. Few squirts of starter fluid and still nothing. Anyone any ideas why it wont start. Im at my withs end with this bike. Im at the stage of just getting rid of it. Any help much appreciated.
 

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Was going to say, get fuel into it, but you did and starting fluid too.

Airbox clogged with old filter foam?

Getting good compression?
 

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Discussion Starter #3
Was going to say, get fuel into it, but you did and starting fluid too.

Airbox clogged with old filter foam?

Getting good compression?
the bike has the ear shave done to her. So get this. Just went out. Took tank off last night and drained the bowls. Sprayed starter fluid into it and she ran for about a second. Put a small bit of fuel in the bowls, gave it a shot of starter fluid and she fired up. But only with full choke and full throttle. Even then it sounded like she was bogging down. Any ideas what could cause this. Im lost to be honest. But at least it ran even if it was bogging
 

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Sounds like it's just not getting enough fuel. Make sure the petcock is flowing.

I'll put gas in a Windex bottle and force feed if I have to. Have to watch those lean backfires though.
 

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Discussion Starter #5
Sounds like it's just not getting enough fuel. Make sure the petcock is flowing.

I'll put gas in a Windex bottle and force feed if I have to. Have to watch those lean backfires though.
yeh it was backfiring like crazy. Could it be all down to a carb problem. Plugs were wet when i checked just after she ran
 

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Well getting it fired may have gotten the fuel flowing.

Backfires can be due to being lean, opening the throttle and giving it too much air, and low voltage to the CDI can cause backfire.
 

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Discussion Starter #7
Well getting it fired may have gotten the fuel flowing.

Backfires can be due to being lean, opening the throttle and giving it too much air, and low voltage to the CDI can cause backfire.
ok thank you spockster. Im going to rebuild the carbs anyhow so we will see what happens. Thanks for you help.
 

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Discussion Starter #10
Ok so a range of new problems arised. Got the bike starting first push of the button after i squeeky cleaned the carbs. Now the bloddy thing wont rev passed 2k. It started by firing only on the rear cylinder but once i got this sorted and running it startrd popping like crazy. I also noticed that the vacuum slides are vibrating like crazy. I have a leaky petcock but even with the tank off and just the fuel in the bowls it does the same. It idles fine for a bit but if i even look at the throttle is dies. Any one any ideas?
 

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Not sure, but description of the slide action makes me think, diaphragms. Like an all out leak, make sure they're seated correctly and not damaged.
 

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Discussion Starter #12
Not sure, but description of the slide action makes me think, diaphragms. Like an all out leak, make sure they're seated correctly and not damaged.
its the first thing i checked. I have never seen this on any bike ever so im completely stumped
 

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Vibrating slides? Diaphragms good?

Have to think about leaking valves. Do you have a vacuum gauge to get a reading?
 

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Discussion Starter #14
Vibrating slides? Diaphragms good?

Have to think about leaking valves. Do you have a vacuum gauge to get a reading?
No thats one thing i dont have. I doubt its the valves as they were lapped during the rebuild. The first time lol. I will have to thinker with it again. I might switch slides and see if that makes a difference. I could have mixed them up when i took them apart. Not sure if that would make a difference or not tho
 

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The difference in slides is the needle on rear is a smaller diameter/taper, to make rear cylinder a touch richer/cooler. Wouldn't want the needles switched.

Valves can still leak if not tested.

The diaphragms are seated on the tab?
 

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Discussion Starter #16
Yep the diaphragms are seated. The needles are correct because i checked that this morning. Could a leaky exhaust have something to do with it maybe?
 

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No, shouldn't affect it much.
 

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Can you describe what the slides are doing a bit more?

If you can see the slides, they don't usually run well with air filters removed.
 

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it is normal for the slides to be dancing up and down, the pull up on the intake stroke (vacuum generated across the carb venturi due air flow.) more throttle, the higher they pull up, and pull the needles with them.
 
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