Maintenance & Technical > KX500 Original

Torque wrench

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BDI:

--- Quote from: BDI on March 11, 2009, 04:26:02 PM ---
--- Quote from: martinfan30 on March 11, 2009, 02:48:19 PM ---The lapping in idea is a good one. Just as I was scraping the gasket off with a razor blade, I noticed high spots around each head bolt hole....

Using crows feet will reduce the torque, just like using an extension, so i always add a few ft. pounds to the mix to compensate.

--- End quote ---
Laping is a must but it has to be done correctly. As for the crows foot thing I'm not so sure, if the crows foot has an offset of one inch then it's going to add one inch to the length of your wrench if it stuck strait out the front. It would add one inch pound to every foot pound you torqued the bolt too do to the added length.  Now if you 180 the crows foot it would subtract one inch pound per foot pound. Now maybe if it was 90 degrees to the wrench head the torque would be correct because you wouldn't be adding or subtracting any length to the wrench. Now you have to figure out how much torque you are losing to jaw spread if you are using an open end style crows foot. If you are using a boxed end style crows foot the torque loss would be a lot less do to the fact you have no jaw spread. Now if you are using an extension it's going to flex and subtract torque, so maybe if you had the crows foot sticking strait out the front and using an extension,the flex of the extension would make up for the added length of of the crows foot and you would wind up back at the proper torque value. I don't think you would though do to the fact that there are still more variables to consider. For example: Are You torqueing your base nuts on wet or dry???

--- End quote ---
I was trying to be funny with my post but I do think it is a good topic. Properly torquing things is very important. I do think things can be properly torqued by hand. I have known a few people in my time that think tighter is better and have no concept of what is tight enough. You can cost yourself more money and heart ache by over tightening things. I think it becomes more important to use a tool for torquing the smaller the torque figure. For example if you are torquing a cam cap on a thumper to 7.2 foot pounds you should use a good tool, that's why I own a digital snap-on 3/8" torque wrench but my 1/2" drive is a craftsman old school clicker. I just don't need the accuracy when I tighten the lug nuts on my truck. Some people have a good sense of what torqued right feels like and some people don't. I think that's what it really comes down to when you ask if you should use a torque wrench on your base nuts. I torqued my base nuts and even head nuts by feel (when I was young and tool impaired) for years without ever having a problem but I have a sickness called perfectionism and I also have the means to torque with a digital wrench so I do. I do not think it's a must for everyone.

jfabmotorsports.com:
In most cases getting the fastener tight enough is not the issue. It is stripping the nut or the hole that is the problem. I wish I had a neckle for every hole that I had to weld of helicoil for someone over the years. Oh wait...I got $20.00- $50.00 for those jobs! :-D

barryadam:

--- Quote from: TheGDog on March 12, 2009, 06:48:03 AM ---
And some definition to what the term "lapping" refers too?

From the context clues of the sentence it was used in... it sounds like some method/procedure for making sure the head-to-cylinder surface junctures are as planar/flat as possible so that the gasket seals proper... am I understanding it right?

--- End quote ---

The goal is to provide the best suface for a good reliable seal.  That usually means a flat surface.  There is a difference between "sufacing" the gasket area and "lapping".  Surfacing can be accomplished by cutting or using an abrasive attached to a stationary flat surface and moving the head or cylinder around on that surface to remove any high spots in the aluminum gasket surface.  You can do this to the head, top of the cylinder, base gasket area (although it's a bit harder), carb bowl, flywheel cover, side cover, KIPS cover, case halves, etc.  You get the idea.  I have a surface plate that gets a lot of use.  Some people use glass, although the tolerances for flatness of glass depend on a lot of factors.
Lapping is actually rubbing two mating parts together with a small amount of abrasive paste (grease with abrasive particles) to make the two surfaces match.  They may not be flat.  This is useful for things like conditioning the flywheel to crankshaft tapers so that they fit precisely.

As far as your cylinder and head goes, once you measure the bore, you can measure to make sure the head/gasket surface is perpendicular to the bore, the top and bottom decks are parallel, then surface the top of the cylinder and bottom of the head.  If you want to go the extra step and lap the two together, well, that's up to you.

Once the cylinder studs have been installed and head nuts torqued, as stated above, the material does get deformed a bit around the threads.

Regarding torque, don't forget, specs are given based on dry (friction) threads.  I use Anti-sieze in a lot of locations, so I have to be careful not to overtorque if I am using the specs.

KXcam22:
Lapping a head to a cylinder can be extremely effective.  I did my watercooled 2t 2-cyl roadrace bike, lapped each cyl to the milled head. I was skeptical but it ran with NO headgasket and only some kawibond as a sealer.  It never did leak. The silly bike had over .100" squish clearance stock. Cam.

BDI whats the range on that snap-on. I've been thinking about getting one.

Hillclimb#42:
 I had no idea that there was so many things to consider in torqueing nuts and bolts. Mainly because I don't torque too many. I do by feel with a wrench with dry threads and studs. I don't have one little spec of anti-seize, unless you call the grease in the axels and bearrings anti-seize. My 500 tends to lose bolts that are not tight enough, so I would think that anti-sieze would add to the bolt replacements. I don't lose head or base nuts or anything, but I think its important to re-torque, or in my case re-tighten after a few heat cycles to be sure it all good and the expansion/contraction has already done its thing.
  BDI, do you do any bolt or nut prep to clean the threads and overall appearance of the nuts and bolts. It always is a bum deal to have a brand new part bolted on with grimy bolts. They stand out big time on clean parts.

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