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750 twin, no TDC when kickstarting
- gregm
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So I changed the oil and found a 18mm fine thread bolt to plug my tach hole. I rode it around last night and everything is back to normal. Tonight I go to kick it and it runs for a split second then shuts off and now I can kick the kicker all the way through the stroke without it stopping at tdc. I have spark. I took the plug out and can see valves and pistons moving. I can hear air going in velocity stacks. Another weird thing is when my clutch is pulled in while I’m gear it rolls very very hard. It rolls fine in neutral.
What the hell happened? Did I break a kicker gear?
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- DoctoRot
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- gregm
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- F64
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- 81-KZ440D2
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Use a ratchet just in case the engine suddenly rotates..you won't bust your hand open.
You may do a compression test as well..I'm thinking you may have a valve train issue.
81-KZ440-D2.
Louis Dudzik's GM HEI ignitor conversion installed 2015 s3.amazonaws.com/gpzweb/Ignition/GPZgmHEImod.html
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LIC, NY
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- gregm
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Compression is 90psi in both cylinders after adding a cap of oil. Full throttle, choke closed.
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- Mikaw
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gregm wrote: I have very little resistance at tdc when rotating by hand.
Compression is 90psi in both cylinders after adding a cap of oil. Full throttle, choke closed.
You need to have all the plugs out, throttle full open and choke “off”. Not sure if that’s what you mean with “choke closed”. You need to allow as much air into the engine as possible. There is quite a diverse appinion about adding oil or not. I’m in the not corner. Unless you using it to diagnose. Kick the engine as many time as needed to get highest pressure reading on the gauge. Ideally the engine should be warm it’s a more real life test.
1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
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- gregm
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- DoctoRot
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- M_a_t_t
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The compression tester needs to have a valve in the tip. Otherwise it will read lower than actual. I've always heard that if the cylinders have even compression (within like 10%) then it should run. It might be barely though at 60 psi. If valve timing jumped or something then it can cause low compression numbers because it won't allow enough air in, or allow it to escape early.
TDC is just a location of the piston. What TDC feels like is the compression of the engine. If it has low compression for any reason then the feeling of TDC won't be as obvious ("no TDC"). I don't see how low compression would be transmission related. Sounds like you have 2 issues. I've never messed with that specific bike so I won't be able to help much beyond general advice.
Good luck with the fix.
83 KZ1100A (shaft)
17 Versys X 300 abs
81 kz650h1
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90 Honda CBR600F (brother's)
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- Mikaw
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An engine needs 3 things to run, fuel, compression, and spark. I’d be thinking the same as Doc. The clutch might not be disengaging the trans and the extra mass is not allowing the engine to kick over fast enough to start. I’d check out the clutch. You have spark and fuel.
1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.
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- F64
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Check your valve clearance at tdc to make sure your valves are completely closed.
81-KZ440-D2.
Louis Dudzik's GM HEI ignitor conversion installed 2015 s3.amazonaws.com/gpzweb/Ignition/GPZgmHEImod.html
Motogadget m-unit blue installed 2017.
LIC, NY
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- M_a_t_t
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83 KZ1100A (shaft)
17 Versys X 300 abs
81 kz650h1
81 kz750e2
90 Honda CBR600F (brother's)
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