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Help needed - 1983 KZ750 L3
- Injected
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19 May 2023 15:29 - 19 May 2023 15:31 #884944
by Injected
Seems low for that engine according to FSM. Low compression makes for cold pipes (dropping cylinders) weak spark is also a culprit. You want to be in around 160-180PSI or more hot, these small motors don't run very well at 120-130PSI.
Replied by Injected on topic Help needed - 1983 KZ750 L3
5 month old compression numbers?? Hot or cold?
Plugs are wet but #2 and #3 seems darker.You should go back and check the basics (fuel, compression, spark, timing)
Are the plugs wet? (fuel) What is the compression on all 4?
If you have a OEM Kawasaki electronic ignition the Igniter box can often be the issue putting out weak spark (happened to me) - there are ways to check the spark output.
Sounds like you have a vacuum leak somewhere (negative spray test)
I took compression in january and it was not so bad. From memory, 3 cylinders were at at about 135 psi and one closer to 120 psi.
Thanks!
Seems low for that engine according to FSM. Low compression makes for cold pipes (dropping cylinders) weak spark is also a culprit. You want to be in around 160-180PSI or more hot, these small motors don't run very well at 120-130PSI.
Last edit: 19 May 2023 15:31 by Injected. Reason: sp
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- Claude.
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21 May 2023 07:26 #885023
by Claude.
I will take compression again this week.
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
Replied by Claude. on topic Help needed - 1983 KZ750 L3
Yes, 5 months old compression numbers. But the engine did not run since then as it have been on my work table since about last november. In fact, this engine did not run in about the last 20 years. So, number are for a cold engine.5 month old compression numbers?? Hot or cold?
Seems low for that engine according to FSM. Low compression makes for cold pipes (dropping cylinders) weak spark is also a culprit. You want to be in around 160-180PSI or more hot, these small motors don't run very well at 120-130PSI.
I will take compression again this week.
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
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- Claude.
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21 May 2023 08:41 #885027
by Claude.
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
Replied by Claude. on topic Help needed - 1983 KZ750 L3
Just took compression. Cold engine, no spark plugs, no carbs and no carb-to-head rubbers.
#1 = 155 PSI
#2 = 135 PSI
#3 = 140 PSI
#4 = 150 PSI
A bit low but surely acceptable (?).
#1 = 155 PSI
#2 = 135 PSI
#3 = 140 PSI
#4 = 150 PSI
A bit low but surely acceptable (?).
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
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21 May 2023 09:41 #885028
by gordone
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).
Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine
Replied by gordone on topic Help needed - 1983 KZ750 L3
Spray start gas around the inlet rubber, if the engine change sound, you have a vaccum leak?
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).
Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine
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21 May 2023 10:15 - 21 May 2023 10:16 #885029
by Claude.
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
Replied by Claude. on topic Help needed - 1983 KZ750 L3
Gordone, as I originally wrote, I already did this. New carb-to-head rubbers are already ordered. Thanks!
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
Last edit: 21 May 2023 10:16 by Claude.. Reason: Typo
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21 May 2023 11:30 #885037
by gordone
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).
Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine
Replied by gordone on topic Help needed - 1983 KZ750 L3
sorryGordone, as I originally wrote, I already did this. New carb-to-head rubbers are already ordered. Thanks!
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).
Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine
The following user(s) said Thank You: Claude.
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- Claude.
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07 Jun 2023 13:01 #885745
by Claude.
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
Replied by Claude. on topic Help needed - 1983 KZ750 L3
Finally received and installed new carb-to-head rubber adaptors. Looks like the engine now turns pretty well!!
I'll have to ride a a bit in the small streets around the house to be sure everything is OK. If it is, this bike will be for sale!
At first, because of the condition of the OEM rubbers (they had no cracks and were still softish), I was quite skeptical. I now know I can't underestimate the experience of you guys!! Many thanks for your help!!
I'll have to ride a a bit in the small streets around the house to be sure everything is OK. If it is, this bike will be for sale!
At first, because of the condition of the OEM rubbers (they had no cracks and were still softish), I was quite skeptical. I now know I can't underestimate the experience of you guys!! Many thanks for your help!!
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
The following user(s) said Thank You: Wookie58
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- Claude.
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08 Jun 2023 18:49 #885797
by Claude.
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
Replied by Claude. on topic Help needed - 1983 KZ750 L3
Short ride taken this afternoon and I confirm the bike works great!!
Thanks again!
Thanks again!
2017 Versys 1000
1982 KZ1000J2
1983 KZ1000J3
1982 GPZ1100
1983 KZ750L
1982 KZ1000J2 (another one!)
2017 Yamaha FZ07
The following user(s) said Thank You: Wookie58
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