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Cleaned Carbs Now Won't Start
- 650ed
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1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- chconger
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1977 KZ 1000-A
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- Lmmduramax
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650ed wrote: Does it backfire only at idle, or does it do it at higher rpm? Ed
Seems to only do it at lower rpm
1981 KZ440
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- Lmmduramax
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chconger wrote: Did you bench sync the carbs while you had them off again?
No didn't even think of it :dry:
1981 KZ440
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- 650ed
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Make sure the vacuum caps are tight on the carb holder nipples.
Warm the engine up to normal operating temperature.
Temporarily set the idle as low as possible without stalling the engine. It should be down below 1000 rpm. The lower the better because when it is set low the carb slides are closed (or nearly closed) and this raises the vacuum level in the carb holders. The combination of the increased carb holder vacuum level and the very low idle amplifies the effect of the leak test.
Once the idle is set low, spray carb cleaner around each of the carb holders where they bolt to the cylinder head and where the carbs attach to them. If there are leaks, the vacuum in the carb holders will suck the carb cleaner in and this will affect the idle. It may cause the engine to stall. If the leaks are at the carb holder / cylinder head mating surface you need to replace the holders. If the leak is where the carbs attach to the holders you may be able to tighten the clamps enough to seal the leak. Some folks use starter fluid or other substances for the test, but carb cleaner works best as it doesn’t evaporate too quickly like ether and leaves no residue on the engine like WD40.
If you do need new holders just bite the bullet and buy them. Trying to seal things up with some kind of sealant or goop will only lead to frustration as it will at best only last a short time. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- Randombeat
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1980 KZ750H LTD-- pods-- vance & hines 4-1 --speedo/tach/blinker/switch deletes -- brat style
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- Lmmduramax
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Tightened the clamps on the carb boots a little more and it seemed to fix the backfire out of the carb . But still backfires pretty bad out the exhaust
1981 KZ440
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- Nebr_Rex
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Lmmduramax wrote: You guys are a huge help for all us newbs thanks !
Tightened the clamps on the carb boots a little more and it seemed to fix the backfire out of the carb . But still backfires pretty bad out the exhaust
Check your valve lash.
.
2002 ZRX1200R
81 GPz1100
79 KZ1000st daily ride
79 KZ1000mk2 prodject
78 KZ650sr
78 KZ650b
81 KZ750e
80 KZ750ltd
77 KZ400/440 cafe project
76 KZ400/440 Fuel Injected
www.dotheton.com/forum/index.php?topic=39120.0
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- Lmmduramax
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Nebr_Rex wrote:
Check your valve lash.
.
Sorry not sure what you mean by valve lash ? Also it takes a little while for it to idle down ...very slowly drops. Having trouble to keep it running it just wants to die sometimes when I give it a little throttle.
1981 KZ440
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- Lmmduramax
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1981 KZ440
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- SWest
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- 10 22 2014
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When it runs better when cold, that can be a symptom of tight valves.
Steve
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- TexasKZ
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Lmmduramax wrote:
Nebr_Rex wrote:
Check your valve lash.
.
Sorry not sure what you mean by valve lash ? Also it takes a little while for it to idle down ...very slowly drops. Having trouble to keep it running it just wants to die sometimes when I give it a little throttle.
Valve lash is the distance between the camshaft base circle and the valve follower. If there is too little or no distance, the valve can be prevented from closing when the engine is at operating temperature. The factory service manual explains the procedure pretty well, and even has some pretty pictures to help out.
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
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