Author Topic: HOT engine valve check  (Read 5904 times)

BettinANDlosing

  • Hero Member
  • *****
  • Posts: 2235
  • Carter Merz
    • View Profile
    • Columbia Scooters
Re: HOT engine valve check
« Reply #15 on: December 07, 2014, 08:29:00 PM »
Yes, B&L. I searched through several manuals, online, offline, paperbacks and so on and so foth, but the more I researched the web, the more different values for the same bolt I got....
Kymcos weak point is that they don´t have and don´t offer proper workshopmanuals, and most the others throughout the web go the easy way and "copy and paste" Kymcos faults into a new manual....
Some other use more fantasy and vary the values here and there.... What´s better? I leave it up to you.
Cyclepedia is also not the holy bible. More a copy shop.

Cyclepedia is not a holy bible, the Kymco Factory Green paper manuals are the holy bible of Kymco Manuals. They are written by engineers in Taiwan from Kymco. Cyclepedia and Haynes are the same thing, they have a shop and open up bikes and do write up's on how to put things together and service etc. Cyclepedia has better pictures than Haynes and more detailed info. I have never had a problem with torque values from the OEM Kymco Shop Manual, if you have issues with online info order yourself the paper Kymco manual and everything is in there. What zombie was talking about is that almost all bolts have a standard torque value I.E. a 10mm bolt has such and such torque and a 8mm cap nut has such and such torque. The torque value of a fastener is actually the stretch of the threads measured by the torque wrench. So a bolt's torque can be determined by the size, because it has a given amount of stretch for whatever the diameter is. 
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

zombie

  • You never know do ya!
  • Hero Member
  • *****
  • Posts: 13870
  • Close enough to get the idea!
    • View Profile
Re: HOT engine valve check
« Reply #16 on: December 07, 2014, 08:29:15 PM »
Sorry Zombie, I neither understand what you mean in your first sentence, nor do I understand the bolt torque chart in your second sentence.

So how is international understandability for joe sixpack defined and determined?  ;)


The torque is rated by the fastener. Meaning it's the bolt/nut size that determines how tight it should be. The way it works is, the threads slightly distort when properly torqued to "lock" that fastener in place. Too loose, and things fall apart. Too tight, and fasteners break.

If you are attaching two flat pieces of metal together w/ a 1/4 x 20 bolt, it will be the same torque rating as if you were attaching a carb to a manifold w/ that same bolt.
 There are very few exceptions... Mainly on cylinder head bolts where a specific torque is met, and then another 1/2 turn of the fastener is required. This is not the case w/ Kymco engines.
All the torque settings can be found on-line using a fastener torque chart.

I hope this helps some...
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

zombie

  • You never know do ya!
  • Hero Member
  • *****
  • Posts: 13870
  • Close enough to get the idea!
    • View Profile
Re: HOT engine valve check
« Reply #17 on: December 07, 2014, 08:32:38 PM »
LOL... I just looked up, and saw B&L said the same thing.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

Stig / Major Tom

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 14693
  • Rural Ohio
    • View Profile
Re: HOT engine valve check
« Reply #18 on: December 07, 2014, 09:56:20 PM »
I do not own a good torque wrench - but an OK one - that I use only to snug up CVT nuts.
I certainly do not trust it when working in alloys and smaller fasteners.
So, I use a few decades of experience working on alloy VW engines.....and 'snug it' by feel and size of the fastener.
If I did much wrenching I'd buy a very good wrench.

I suspect there might be a lot of fellows out there like me, working on their scoots and being careful.

A question - seems like somewhere recently I read about tightening a (spark plug maybe?) and then reversing the item a quarter turn - or was it forward a quater turn. No, it wasn't an oil filter - I'm pretty sure.
Any one know what I'm talking about here?
Thanks, Stig
Boston Strong
Rural Ohio

And, I'm feeling a little peculiar.

BettinANDlosing

  • Hero Member
  • *****
  • Posts: 2235
  • Carter Merz
    • View Profile
    • Columbia Scooters
Re: HOT engine valve check
« Reply #19 on: December 07, 2014, 10:00:55 PM »
I do not own a good torque wrench - but an OK one - that I use only to snug up CVT nuts.
I certainly do not trust it when working in alloys and smaller fasteners.
So, I use a few decades of experience working on alloy VW engines.....and 'snug it' by feel and size of the fastener.
If I did much wrenching I'd buy a very good wrench.

I suspect there might be a lot of fellows out there like me, working on their scoots and being careful.

A question - seems like somewhere recently I read about tightening a (spark plug maybe?) and then reversing the item a quarter turn - or was it forward a quater turn. No, it wasn't an oil filter - I'm pretty sure.
Any one know what I'm talking about here?
Thanks, Stig

Thats a spark plug technique. 5/8" plug tighten snug then 1/4 turn past, 13/16" plugs tighten sung then 1/2 turn past.  Oil filter some people use this also, I've NEVER had a filter come loose after screwing it on as hard as I can by hand (I can get them pretty tight!!)
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

Stig / Major Tom

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 14693
  • Rural Ohio
    • View Profile
Re: HOT engine valve check
« Reply #20 on: December 07, 2014, 10:10:27 PM »
Thats a spark plug technique. 5/8" plug tighten snug then 1/4 turn past, 13/16" plugs tighten sung then 1/2 turn past.  Oil filter some people use this also, I've NEVER had a filter come loose after screwing it on as hard as I can by hand (I can get them pretty tight!!)
Thanks B&L....it was one of those things I saw on the web.....then could not find again for the life of me! (I think it was re. a Denso spark plug - but couldn't locate the comment again)
I need to take notes....
Naw, I'll never do that.
Thanks, Stig
Boston Strong
Rural Ohio

And, I'm feeling a little peculiar.

zombie

  • You never know do ya!
  • Hero Member
  • *****
  • Posts: 13870
  • Close enough to get the idea!
    • View Profile
Re: HOT engine valve check
« Reply #21 on: December 07, 2014, 10:34:08 PM »
That same method is used on alloy cylinder blocks, and most diesel engine cylinder heads.
The reason is the compression gaskets used. (same as on a spark plug)
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

BettinANDlosing

  • Hero Member
  • *****
  • Posts: 2235
  • Carter Merz
    • View Profile
    • Columbia Scooters
Re: HOT engine valve check
« Reply #22 on: December 07, 2014, 11:36:45 PM »
That same method is used on alloy cylinder blocks, and most diesel engine cylinder heads.
The reason is the compression gaskets used. (same as on a spark plug)

Oh yeah zombie you reminded me of another one, the drain plug! Not the oil screen plug but the side drain plug, with a new crush washer tighten then go 1/4 past. But only with a new crush washer, after one use it'll be flattened and not crush any more and that 1/4 turn will go towards stripping the aluminum haha
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

zombie

  • You never know do ya!
  • Hero Member
  • *****
  • Posts: 13870
  • Close enough to get the idea!
    • View Profile
Re: HOT engine valve check
« Reply #23 on: December 08, 2014, 03:57:46 AM »
See there... I just learned something. I never knew that.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

2wheelfun

  • Hero Member
  • *****
  • Posts: 710
    • View Profile
Re: HOT engine valve check
« Reply #24 on: December 09, 2014, 12:43:19 AM »
Answer this. Do you adjust any automobile engine valves when hot? Maybe liquid cooling makes a difference? Bikes are 50/50 both.

zombie

  • You never know do ya!
  • Hero Member
  • *****
  • Posts: 13870
  • Close enough to get the idea!
    • View Profile
Re: HOT engine valve check
« Reply #25 on: December 09, 2014, 12:53:59 AM »
Actually yes.

ALL high performance engines are adjusted hot (running temp). The only cold adjustment is to get it within running spec.
The only mainstream exception is modern overhead cam engines where there is no adjustment.

It surprised the hell out of me when I learned Kymco has no procedure/spec for adjusting hot.
I had to experiment, and create my own.
I've never done this on anything larger than a GY 6 150 but I see no reason the method will not work if the work is done quickly to ASSURE the engine is at running temp.
Ie: have the plastics removed, and the tools handy when you stop to do the work.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

An Error Has Occurred!

Call to undefined function split()