Author Topic: Engine FAQ  (Read 63813 times)

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x2qwk4ux

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Engine FAQ
« on: April 12, 2005, 12:57:23 AM »
Use this topic to post any frequently asked engine questions.
« Last Edit: May 04, 2005, 01:24:53 AM by SteveD CB500F »

x2qwk4ux

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Camshaft installation (T & F marks)
« Reply #1 on: April 12, 2005, 01:01:35 AM »
{T} means Timing Mark. {F} means Fire. Anything to do with electrics / ignition you'll use the {F} mark. For true Top Dead Center..or anything else mechanically related you'll need to use the {T}mark. The ignition {F}ires slightly before {T}DC, & that's why there's a convenient mark for both of them. Now for the cam alignment...I have only done this with a 750, so I'll just tell you how mine worked. Put the crank on the 1.4 {T} mark. Try to approximate where the cam will have to be before mounting the gear....the #1 cylinder cam-lobes should be pointing away from the rockers (rocker should be riding on the heel (lowest part)of the cam- lobe). The edge of my camshaft has a straight line machined through the middle of it...like a straight line drawn through a circle. Well, the line should be horizontal (parallel) in relation to the head (not the ground)or seams of the camshaft caps. If you think you've done it successfully, than install the gear & chain-tensioner and give it a couple of revolutions...make sure that when you return to 1.4 {T} that the cam's mark is still the same. The way you make adjustments is simple, but tedious. Unbolt the gear & walk the chain back the necessary amount of teeth, then line up the gear's mount- holes with the camshaft & repeat the spin procedure with tensioner installed. If you ever get to a point where the adjustment of 1 tooth forward or one tooth back does not correct the alignment, then you could have a stretched chain. Hope it helps.

Question:  There are 2 lines that look like inch marks on either side of the part that says "T F 1-4". what exactly am I lining up with the notch to set the timing correctly?

Answer:  There are other marks on the plate that look like " that are kinda off by themselves. those are "advance" marks & you don't need to worry about them right now....they are used while setting timing to see if the advancer is working properly at roughly 3000 rpm & up.  See the "Ignition / Timing" FAQ.

Josh 

Offline Harry

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Camchain adjustment
« Reply #2 on: April 18, 2005, 01:08:53 PM »
How do I adjust my camchain?

Each model engine has its best method. The 750 is the easiest. It is done without the engine running. Simply turn the crankshaft to TDCC #1, then turn it about 15 degrees farther (in the running direction). At this point, the mechanical advancer's spring retaining pin will be close to the crankcase mark. Loosen the cam chain tensioner locknut and bolt, then carefully retighten both. The 500/550 may be done either running or not running, but the best method is not running. Do the same thing at the crankshaft, but after loosening the cam chain tensioner locknut, turn the tensioner screw with a stubby screwdriver. The factory valve adjusting screwdriver works best, as it allows a lot of leverage to turn that stubborn screw. Do the 650 not running. Turn the crankshaft to the magic place, then loosen the cam chain tensioner locknut, and carefully apply slow, steady turning pressure on the crankshaft while retightening the locknut. Do not ease up on the crankshaft until the tensioner locknut is snug. Turn the crankshaft very slowly but steadily. This is the correct way for the 650, and is usually the only way to quiet a noisy cam chain. The 350/400 is done running, but usually requires a careful, gentle push through the plugged hole at the front lower part of the engine, While the engine is idling, loosen the tensioner locknut and bolt. Remove the special plug bolt and insert a Phillips screwdriver. Gently push upward against the tensioner mechanism while snugging the tensioner bolt, then the locknut. Be really careful. If you push on the screwdriver too hard, you can damage the tensioner. (thanks to Mike Nixon; http://www.motorcycleproject.com/motorcycle/text/headgask.html)



Warlock's view on best method for 500/550
The camchain tensioners on the 500/550's are designed to be self tensioning. What this means is that the slotted screw is actually the visible part of an internal half moon gear which mates with a spring loaded rack gear inside the tensioner assembly. Ideally, when the lock nut is loosened, the spring will pull the tensioner, pushing the slipper against the chain, and rotating the adjusting screw automatically, as needed, in the process. The adjusting screw is then held stationary while the lock nut is tightened. All this is done with the engine set at #1 cylinder at 15 degress ATDC on compression(the position at which the chain slack is designed to be on the tensioner side). Over time, the rack and half moon gears may become gummed up and not operate freely. Thus, the spring may not be able to move the tensioner attached to the rack gear. It has been suggested that a small amount of torque be applied to the adjusting screw while tightening the lock nut. This is to overcome any resistance which has manifested itself in the adjusting mechanism. Loosening the lock nut and exercising the adjusting screw has also been an option. Be careful not to apply too much force to the adjuster screw, as the slotted ends  have been known to break under excessive force...and THAT would be a problem...
« Last Edit: August 26, 2005, 04:26:33 AM by Harry »
Harry Teicher, member #3,  Denmark....no, NOT the capital of Sweden.

Offline SteveD CB500F

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Changing Head Gasket - Easy Peasy...
« Reply #3 on: August 25, 2005, 12:05:00 PM »
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Offline SteveD CB500F

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Smoking on Startup
« Reply #4 on: September 08, 2005, 05:23:14 AM »
by TwoTired:

One of the by products of combustion is water.  Also, any humidity in the surrounding atmosphere will condense on surfaces that have a temperature differential from side to side. Your cold drink glass is a common example.  When the muffler cools down the water condenses inside the pipe.  The heat of the next run cycle vaporizes this water and it exits as white vapor.  Also, choke operation causes the engine to run so rich that the combustion is not complete.  The incomplete burn residue exits the muffler as black soot suspended in a gaseous medium.  Mixing this with a white vapor cloud will give you grey smoke.

Something to note is that the muffler heats from the exhaust valve to the pipe exit.  If the run cycles are short and the flow is small (idling), the entire muffler may not reach a temperature high enough to convert all the water into vapor and dry out the muffler internals.  Repeated short run cycles can build up more water in the muffler than can be exhausted.  This is a major contributor of exhaust systems rusting out from the inside.

Lastly, the severity of the condensation is proportional to the magnitude of the temperature extremes.  Or, you'll see more vapor in cold weather than in hot weather.

The only thing to be alarmed at is if the exhaust vapor has a bluish tint, as this would indicate oil in the combustion chambers.  If this only happens during start up, then valve guides/ or guide seals are suspect.
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Offline SteveD CB500F

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Why won't my bike idle at 1000 rpm ??
« Reply #5 on: September 12, 2005, 02:09:46 AM »
More from TwoTired:

I find that carb sync can have a dramatic effect on idle smoothness and speed.  But, it is only one factor.  Compression check? Cylinder pressures (equal compression across all cylinders) and precise timing also play a part.  Worn carburetors won't idle as well as new, tight fitting ones either.  The slides wear with time and vibration.

Check your points cam for smoothness.  Ideally it would be as flat and smooth as a mirror, and certainly well greased.  I had one that got grooves in it from lack of lube.   The points would open eraticly depending on whether it followed the grooves or the ridges.  I was able to buy a new replacement from Honda that solved the problem.

 The emulsion tubes downstream from both the main and slow jets have cross drilled holes in them.  These add air to the fuel before it is delivered to the carb throats.  These holes are quite small and easily plugged up with varnish. 

Other things to check would be the spark plug cap resistance and equal plug gap settings.  I would like to know what spark plugs you are using if they are not NGK D7EA.  Did all your spark plugs appear to have the same color and quantity of deposits?
Compare them to the pics at:
www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

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Offline SteveD CB500F

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Lets clear up early/late K heads with late F cylinders...
« Reply #6 on: November 09, 2005, 03:50:41 AM »
Dr Rieck says the following:

...once and for all.

First, the 77/78F2/3 heads shared a common head drain back hole which early K,F and late K heads did not.
This eliminated the middle drain back holes in the F2/3 heads.
The 4 studs next to the eliminated drain back holes require cap nuts and copper sealing washers on the F2/3 head only.

The late F2/3, 77/78 cylinders CAN accomodate the knock pins(or dowels) and the rubber gaskets which allows you to run these early/late K and earlyF/F1(75/76) heads.

The later F2/3 castings are good as they are more stout but this does add weight.

Trying to run a Wiseco 836 kit with an F2/3 head will result in low compression secondary to the increased volume of the F2/3 chamber.

Bottom line....early/late K and early F1(75/76) heads will work on late (F2/F3) cylinders and early/late K and F1 upper cases with mild opening (joining) of the F2/F3 two inner drain back holes at the base of the cylinder.
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Offline SteveD CB500F

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Installing camshaft, chain and sprocket (CB550 but pretty generic)
« Reply #7 on: January 10, 2006, 01:45:47 PM »
Submitted by Gordon

For some reason, every time I'm putting one of these engines back together I can never seem to remember how to get the damn cam chain, sprocket, and cam back together.  Since I've seen this problem posted here at least a couple of times, this time, after I finally figured it out again (for the fourth time) I took pictures, as much for my sake as anybody elses.  Because I know I'll forget again by the next time.  ::)

The problem I always run into when doing this is that I put the sprocket on the camshaft first, and then the chain.  Doing it this way, there isn't enough room in the cam chain slot for everything to fit, and you end up scratching up the head and possibly breaking the chain by trying to force it on the sprocket.

The chain has to go on the camshaft first, and then the sprocket.  This way you can lay the chain over the part of the camshaft that the sprocket bolts on to, leaving plenty of room to drop the camshaft into its bearings and resting the sprocket in its lowered position.  If done correctly and with the tensioner completely backed off, the chain easily slides right over the sprocket
« Last Edit: March 24, 2009, 05:41:55 AM by SteveD CB500F »
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Offline SteveD CB500F

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Engine Oil Change Procedure CB750 - Dry Sump
« Reply #8 on: March 28, 2006, 01:20:43 AM »
Excellent set of instructions posted by Jonesy:

Here's how I do it (FWIW...)

  • Start up bike and let it run for about 10 minutes. This warms up the oil and gets things roiled up inside, but not so hot you'll burn yourself. This helps lets the oil pick up crud and let it drain away with the oil, rather than having it settled out and stay in the engine.
  • After the bike is warmed up a bit, shut it off and put it on the center stand.
  • I start with the oil tank first. I remove the sidecover and temporarily undo the rear brake light switch to get it out of the way. I also crack the filler cap. Have a drain pan ready and remove the plug. I have a piece of aluminum that I bent into a small trough to keep the oil from running all over the frame.
  • After the tank is drained, replace and tighten the plug. Proceed on to the oil pan plug and drain the oil from there. Again, replace and tighten the plug.
  • With the oil pan plug out, kick the engine over a few times to pump out the remaining oil
  • Lastly, remove the oil filter housing. If all the parts are in the housing, there is a thin washer between the oil filter element and the spring. This likes to stick to the filter and before you know it, you've thrown it away. (This is probably why 90% of them are missing)
  • In other words, when you remove the innards, don't lose it!.
  • Wash out any sludge or particulates that have collected in the oil filter housing. Take a good look at what's in there, as any sizable bits of metal might be a warning that something's on it's way out. In some cases it's worthwhile to drop the oil pan to give it a good cleaning and look for any signs of trouble.
  • If you bought an oil filter kit that includes new O-rings, fit the small O-ring on the oil filter bolt and seat the big O-ring in the groove of the filter housing. Apply a bit of clean oil to the oil filter bolt O-ring to make it easier to reinsert into the housing.
  • With the bolt back in place, reassemble the oil filter housing with the spring first, then the washer and finally the new filter. Reinstall the filter on the engine, being careful not to overtighten the bolt.
  • Reinstall the sidecover over the oil tank and put the brake switch back in place.
  • Fill the oil tank with 3 quarts of oil. According to the owner's manual, the oil level will settle into the correct range when the engine is started. So far, I've found this to be true.
  • I like to hit the starter a few times with the emergency stop switch off to circulate the oil into the empty filter housing before running the engine. After doing this, fire up the bike and make sure the oil light goes out in a few seconds.

Again, this is how I like to do it. It doesn't HAVE to be done this way, but I hope it's helpful.

From jaknight:

If you happen to want or need to drop your oil pan (I obviously don't know how familar you are with these bikes), just a heads up to keep track of what holes the different bolts come from; they do vary in their length.

    If you happen to need the torque specs for the different bolts:

    OIL TANK DRAIN PLUG - - - - - - 24 FT LBS  (ideal median)

    CRANKCASE DRAIN PLUG - - - - - - 24 FT LBS (ideal median)

    OIL FILTER HOUSING BOLT - - - - - - 20 FT LBS (ideal median)

    OIL PAN BOLTS - - - - - - - 7 to 10 FT LBS (pick your median)


From toycollector10:

On an older bike you will probably have a lot of gunk sitting in the bottom of the oil tank.

After you have drained the oil put a screwdriver down there and see what you bring up stuck to the tip, and use a flashlight to have a look inside the tank. If it is a mess down there I recommend you pull the tank off the bike and clean it out properly.

and Hondaman:

Although the torque on the oil bolt is listed at 20 ft-lbs: for many years, I've only tightened them to (snug + 1/8 turn). This works out around 7-8 ft-lbs on a T-wrench. I've always done this because the oil filter housing distorts and locks that $%#*! bolt in something awful, often causing its destruction the next time around.

...just some experience. It won't leak if your large o-ring is new...   
« Last Edit: March 24, 2008, 08:11:07 AM by SteveD CB500F »
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Offline Bob Wessner

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750 Engine Removal and Replacement Trick
« Reply #9 on: June 11, 2007, 01:05:17 PM »
Provided by Hondaman.

Quote
--------------------------------------------------------------------------------
Quote from: jdigga on June 08, 2007, 11:19:07 PM
So the weeping from my fins is at the point where stuffing half a Shop Towel in between isn't enough to stem the spray.  I'm a bit tired of having to wear a specific pair of oil-stained riding jeans, so it's time to make the necessary repairs.

I started the tear-down around 5:00pm.  Most everything came off without any problems.  I did have to use an impact driver on the front sprocket cover and found to my dismay that the sprocket bolt was loose!  Luckily it appears that the cover has a little shaft on the inside to keep the bolt in check.  I also discovered that the rear brake splined shaft is slightly bent, but it functions just fine.

I knew the actual removal of the engine would be challenging, but I had no idea what I was in for.  I tried putting the bike on its ride side but I could get the right angle to pull the frame off.  The engine was getting hung up everywhere, and as soon as I'd release one spot, it would hang up somewhere else.  I must have put the bike upright and back down again half a dozen times.

By now it's around 8:30.  Took a breather for dinner and browsing this forum for some tips.

Went back out for one last attempt before calling it a night.  The bike was on its side and while staring at it I realized the engine wasn't going to come out that way.

I put it back upright on the centerstand and broke out my set of lady fingers.  Shoved one in the lower right rear mount hole, one underneath the rear of the engine, and one in the upper right rear mount hole to act as a handle.  Pried the rear up to clear the lower mount.  Pulled up the front of the engine to move it towards the right a bit.  Basically I walked it out of the side, front-back-front-back. 

Turned off the garage lights and closed the door at 10:30pm.

In the process of putting the bike down so many times, my points cover took a beating (even though I put it down on those rubber puzzle mats).  The right bar on my clubmans is pointing slightly more downward than the left.  I forgot that I left my key in the seat lock and it broke off--I was able to retrieve the bit inside the lock, but I only have one key.

Honda made a huge access improvement in 1979 with the DOHC bikes.  The lower right frame rail is detachable and the engine pretty much falls right out.  I pulled my other engine the other week, and other than it being a heavy SOB it was hardly a challenge.

And to think I'm only 1/4 of the way there.  I still have to take the engine apart--I have no doubt I'll run into problems there.  Plus all the cleanup of old sludge buildup and repair the busted up bits.  Then put it all back together again.  Don't get me wrong--I love tinkering with my bikes and learning about them.  But sometime it's just frustrating as hell.  I'll feel better when I'm back on the road again.

Just had to get that off my chest...

Before you put it back in....there is a flange on the motor mount on the lower right side. Grind or file the top of the flange off to the height of the rest of the mount, then shoot a bit of paint on it. This makes the whole assemble-disassemble job MUCH easier. This little flange has probably left several notches in the rib on the bottom of the engine where the bolt goes thru, which can actually jam the engine so badly on the way out as to require a frame cutout to unjam the whole thing (don't ask me how I know that....). But, removing this tiny little flange top will prevent all of this... 
We'll all be someone else's PO some day.

Offline Bob Wessner

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Engine Weight
« Reply #10 on: August 21, 2007, 01:54:08 PM »
Engine Weights for those contemplating shipping.. or solo lifting. ;)

SOHC/4's

CB500: 152lb / 69 kg
CB550: 159lb / 72 kg
CB750: 176lb / 80 kg

Non-SOHC/4's

CB350 Twin: 108lb / 49 kg
« Last Edit: March 24, 2008, 08:10:25 AM by SteveD CB500F »
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Offline SteveD CB500F

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How to tension the camchain.
« Reply #11 on: February 09, 2008, 04:00:11 AM »
BryanJ's patented "many years in the trade" method for tensioning the camchain!

Follow the manual as far as positioning the engine with #1 cylinder 15 degrees before Top Dead Centre (TDC). Loosen the locknut and put pressure on the crank so that it's just about to turn, either with the kickstart OR with a big spanner on the big nut on the auto advance so that all the camchain "slack" is at the back and then, whilst holding the pressure get your mechanically trained spider to tighten the locknut.

Been doing that on ALL OHC Hondas for 30 years and as long as the tensioner moves and the chain isn't worn out its guaranteed to work.
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Offline Bob Wessner

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750 Head Bolt Sequence
« Reply #12 on: June 13, 2008, 07:43:00 PM »
Provided by Upperlake04
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Offline SteveD CB500F

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Compression test numbers, yours vs Honda book value.
« Reply #13 on: January 20, 2009, 06:41:43 AM »
From Two Tired:

So you did a compression check and the numbers were lower than book value.  Does it need an overhaul?
First question you should ask, is “Does my test equipment lie to me?”
Even if you assume the gauge is accurate (Hey, it’s brand new!), the means of connection can alter the readings.

We’ll make two examples A 350 Four and a 750 Four.
The 350 is actually 347cc displacement, making each piston move 86.75cc.  It has 9.3 compression ratio, making the combustion chamber volume 9.327cc.

My compression tester, purchased at the local auto parts store (see pic), has a long, fat hose on it.  The volume of this hose I measured as 11.5cc.  There is also the volume of the gauge itself.  But, I chickened out pouring alcohol in that for a volume measurement.  I also didn’t account for any rubber hose expansion incurred from higher pressures within the hose, increasing its volume capacity.

Anyway, the volume of test apparatus adds to the chamber volume during compression, because its volume has to be compressed to deflect the gauge needle.  So, instead of a 9.237cc combustion chamber, you’d have a 20.737cc total chamber with my compression tester, which effectively lowers the cylinder’s compression ratio from 9:1 to 4.1:1.

What of the 750?  736cc/4 is 184 cc piston displacement per cylinder.  Many (not all) 750s are 9:1 compression ratio, leaving a combustion chamber volume of 20.44cc.  Adding a test apparatus volume of 11.5cc yields 31.95cc total volume, which changes the actual CR to 5.76:1. 

Astute readers will note that the larger the displacement of the engine, the less effect test equipment apparatus volume has on the compression ratio, and the measurement numbers.  If you bought your tester at an AUTO parts house, like I did.  They expect your 350 to be cubic INCHES not cc.  The 350 in the auto world, is 5700cc.  Or, 16 times larger in displacement.  (Only 7 times of you have 750.) …Now you know.

So, why are Honda published numbers so much higher?
Looking in the Honda 500/550 shop manual, there is picture of someone doing a compression test.  The apparatus has a very long, thin, rigid metal tube between the gauge head and the spark plug hole.  Clearly this small tube apparatus was used so as NOT to add very much volume to the combustion chamber, which will result in a much closer representation of actual chamber pressures.   I don’t have such a gauge.  Therefore, I don’t know what the actual volume is added by the Honda test apparatus.

So, unless you have a test gauge like Honda or one that adds little volume to the chambers, your test result numbers will be lower than book values.

The numbers can still be meaningful even if they are lower.  All cylinders should still be within 10% of each other.  And, not significantly higher after adding a few drops of oil to the cylinder for a wet/dry comparison.  Don’t add too much.  Oil is not compressible, you just want enough to wet the piston rings to aid their seal onto the cylinder walls.  Good rings won’t be affected by adding oil.  Leaky rings will be.   
Note, adding oil volume increases the compression ratio by removing compressible space.  A few drops is plenty for small displacement engines.  If your combustion chamber is 9cc, adding a teaspoon of oil, lowers the compressible volume 5cc!  So, be careful that your noted rise in measured pressure is not due to too much added oil volume, rather than sealing off leaky rings.
 

--------------------------------------------------------------------------------

 
 
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Offline SteveD CB500F

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Rings for Henry Abe 900 Piston Kits
« Reply #14 on: March 24, 2009, 01:25:12 PM »
From Jerry Griffin aka RXman:

Quite often the guys that have the 900 Henry Abe kits for the 750's are looking for ring sets. I just got off the phone with Ed at Total Seal (www.totalseal.com) I shipped my 4 NOS Henry Abe pistons to him to fit or cut & fit for 3 piece oil rings. The good news in that Total Seal can supply all 3 rings (top, 2nd, and 3 piece oil) without cutting the piston. Henry Abe made 2 different 900 pistons however and my qualifier here is that I have the smaller/lighter of the 2. Axel's site (www.satanicmechanic.org) lists my pistons as the slipper type.

Here are the Total Seal part numbers:

Top Ring           203778
2nd ring            201336
Oil Ring 3 piece  001549   

Hope this can help others.

Jerry
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Offline SteveD CB500F

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Make your own CB500 Clutch Pushrod / Push Rod
« Reply #15 on: February 23, 2011, 09:32:09 AM »
As of this writing, CB500 clutch push rods are pretty much impossible to find anywhere. They come up on Ebay every now and then but sell for $50+.  That's just stupid for something that may well break again...

So, between Shifter19 and Number13 (seeing a theme here?):

Measurements for a Honda OEM pushrod are:

10 1/8 inches or 257 mm long
3/8 inch in diameter or 9.5 mm

You can easily fashion a push rod from
3/8" steel rod found at any hardware store.
The shifter side end should be ground flat and square,
and the brake side end should be neatly rounded in a semi-sphere
to mate with the clutch basket. If you err, err on the side of a bit too
long since this will allow you to keep the lifter mechanism low and avoid cracking.
May also be a good idea to quench harden the ends.
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