Author Topic: Discrepancy in Service manual. What to do?  (Read 1063 times)

Faber32

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Discrepancy in Service manual. What to do?
« on: April 16, 2022, 03:07:47 PM »
Hi everyone. I'm about to reassemble the front fork and wheel. In the service manual I found two different values for the front axle torque. One is 20 Nm (which I believe is correct), the other 65 Nm. I don't know if someone has already done the job on a People Gti. Do you think 20 Nm is plausible?
And also, for the two small M6 screws (pinch bolts) do you think the range 10 to 14 Nm is correct? It already cost me a new shock because I overtorqued the pinch bolts.

In my opinion a torque of 65 Nm would be correct if the axle had a nut. But in my People Gti there's no nut on the other side. It goes into the shock.
Do you think the M6x1.0 screws indicated in picture are the pinch bolts?
I learned a lesson: for pinch bolts never use a torque wrench. If the grease of the axle gets the threads wet, you overtorque them breaking the shock.

Thank you for help
« Last Edit: April 16, 2022, 03:11:51 PM by Faber32 »

CROSSBOLT

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Re: Discrepancy in Service manual. What to do?
« Reply #1 on: April 16, 2022, 03:32:34 PM »
You already stated you learned your lesson with a torque wrench! The Kymco manuals are full of errors so take what they say with a skeptical view. Go to an industrial torque standard for thread size to see which Kymco factor is way out. That is to satisfy curiosity.

Then use your "feel" to bottom the front axle then put about a quarter turn and no more. The pinch bolts are just that: to prevent (hopefully) the front axle from coming loose. They are small threads. Just tighten enough  to squeeze the opening slightly.

Check often by backing the pinch bolt(s) then trying to tighten the axle. Cinch the pinch bolts back if the axle does not move. Put more of a turn than the first time if the axle moves then cinch the pinch!

Stig, others and I use the feel method because most of the torque wrenches available to us are uncalibrated unknowns.
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
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Faber32

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Re: Discrepancy in Service manual. What to do?
« Reply #2 on: April 16, 2022, 03:43:08 PM »
I'll use your method. These manuals are full of mistakes. I also found a manual in which in the picture was indicated 27 Nm for the pinch bolts, and it cost me a lot of money.
Anyway do you think 20 Nm is a realistic value? Between 20 and 65 there's much difference.
I think 20 Nm is the correct one.

I was thinking about using this procedure to align the shocks perfectly: I put the axle (still not torqued and with pinch bolts loose but inside), I compress 3-4 times the front fork to make the shock go in the "relax" position, and then tighten the pinch bolts. Is it correct or can I damage the shock around the pinch bolts region if they are loose during fork compression?

Thanks again  :)

Ruffus

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Re: Discrepancy in Service manual. What to do?
« Reply #3 on: April 16, 2022, 07:33:41 PM »
@Faber, good way go fasten your front shocks as you describe.
BUT: DO NOT RELY ON FIGURES IN MANUALS
WHY: Different material fatigue, different users, different lubrication...etc.
Use att. torque schedule to train yourself on a non critical piece of mechanics to see jow much i.g. 0.5 kgs are.
Happy and safe scootering, Ruffus

CROSSBOLT

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Re: Discrepancy in Service manual. What to do?
« Reply #4 on: April 16, 2022, 07:41:49 PM »
I'll use your method. These manuals are full of mistakes. I also found a manual in which in the picture was indicated 27 Nm for the pinch bolts, and it cost me a lot of money.
Anyway do you think 20 Nm is a realistic value? Between 20 and 65 there's much difference.
I think 20 Nm is the correct one.

I was thinking about using this procedure to align the shocks perfectly: I put the axle (still not torqued and with pinch bolts loose but inside), I compress 3-4 times the front fork to make the shock go in the "relax" position, and then tighten the pinch bolts. Is it correct or can I damage the shock around the pinch bolts region if they are loose during fork compression?

Thanks again  :)
I would recommend the essence of your procedure but tighten the axle first, pinch bolts loose. Plunge the forks 3-4 times, put on the centerstand without any front braking then snug the pinch bolts.

I finally consulted a metric thread torque chart and a nm to ft-lb converter. 20 nm is too light. 65 nm is about 48 ft-lbs. 14 mm fine metric thread is good for way over 100 ft-lbs so 60-65 nm is probably the most reasonable value. You check for yourself to make SURE I did not have an old guy brain glitch!
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

Faber32

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Re: Discrepancy in Service manual. What to do?
« Reply #5 on: April 16, 2022, 07:48:58 PM »
Thank you guys :-) I know well the conversion from Kgm to ftlbs to Nm.
When I removed the axle the first time it came easily, so I suppose it was tightened to only 20 Nm. This value (20 Nm) even if it's low, it's the value I see the most in the manual. I saw the 65 Nm value only once instead. But as you correctly say, it's an M14 thread so it could bare higher torque.
Honestly I don't know but it's my life in this value, if I go wrong I could kill myself.
I'll search in other manuals, but for now I think 20 Nm is the correct one, being in the table at the beginning of the service manual.
« Last Edit: April 16, 2022, 07:54:39 PM by Faber32 »

CROSSBOLT

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Re: Discrepancy in Service manual. What to do?
« Reply #6 on: April 16, 2022, 08:47:52 PM »
Thank you guys :-) I know well the conversion from Kgm to ftlbs to Nm.
When I removed the axle the first time it came easily, so I suppose it was tightened to only 20 Nm. This value (20 Nm) even if it's low, it's the value I see the most in the manual. I saw the 65 Nm value only once instead. But as you correctly say, it's an M14 thread so it could bare higher torque.
Honestly I don't know but it's my life in this value, if I go wrong I could kill myself.
I'll search in other manuals, but for now I think 20 Nm is the correct one, being in the table at the beginning of the service manual.
Try it and check it periodically.
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

Faber32

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Re: Discrepancy in Service manual. What to do?
« Reply #7 on: April 16, 2022, 08:51:12 PM »
If you don't hear from me, I lost the wheel along the street

leomagnus

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Re: Discrepancy in Service manual. What to do?
« Reply #8 on: April 18, 2022, 07:52:36 PM »
Faber, send me an email at modenaf1360@yahoo.com. I have a full maintenance manual from my old 300 GTI on PDF

Dean
Rome, Italy
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I have minor knowledge on basic maintenance based of many conversations with scooter mechanics in Rome, Italy.

Warwick, RI, USA
'12 Kymco People GTi 300
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Faber32

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Re: Discrepancy in Service manual. What to do?
« Reply #9 on: April 21, 2022, 01:18:13 PM »
In the end I torqued the pinch bolts by hand by feel with a 1/4 ratchet. I suppose at around 10-12 Nm. The wheel hasn't come off so I think it's all right.
Thanks to everyone

CROSSBOLT

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Re: Discrepancy in Service manual. What to do?
« Reply #10 on: April 21, 2022, 07:04:51 PM »
In the end I torqued the pinch bolts by hand by feel with a 1/4 ratchet. I suppose at around 10-12 Nm. The wheel hasn't come off so I think it's all right.
Thanks to everyone
Yeah, baby! Ride on!
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

Faber32

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Re: Discrepancy in Service manual. What to do?
« Reply #11 on: April 21, 2022, 07:05:58 PM »
 :D

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