Cam Chain Tensioner bolt

[koolio]

I'm missing the two bolts that hold the push bar cam tensioner on my Cb500T.

Can any old hex bolts be used to replace them? Also how does the bolt work? Does it simply put pressure on the push bar & is this enough to stop it slipping?

 

[turtledragon]

two bolts? besides the 4 bolts that hold the tensioner body to the cylinder body, there's only 1 tensioning bolt that i know of. you may need to post a picture to clarify this question.

as for how the bolt works...
the bar inside the tensioner housing is spring loaded and presses against a roller which in turn presses against the cam chain to take the slack out. loosening the bolt, takes the resistance off of the rod allowing the spring to do its work, pressing the rod against the roller as far as the cam chain slack will allow. then tightening the bolt back down along with its lock nut holds the rod firmly in its new position until wear and stretching (or slipping) requires a new adjustment.

 

[koolio]

two bolts? besides the 4 bolts that hold the tensioner body to the cylinder body, there's only 1 tensioning bolt that i know of. you may need to post a picture to clarify this question.

as for how the bolt works...
the bar inside the tensioner housing is spring loaded and presses against a roller which in turn presses against the cam chain to take the slack out. loosening the bolt, takes the resistance off of the rod allowing the spring to do its work, pressing the rod against the roller as far as the cam chain slack will allow. then tightening the bolt back down along with its lock nut holds the rod firmly in its new position until wear and stretching (or slipping) requires a new adjustment.

Thanks. It is indeed 1 bolt apologies I thought one went in the end but it doesn't. Thanks for the explanation is that bolt enough to stop the rod moving? Can I use any old bolt and nut? Or does it have to be some special honda one.

 

[turtledragon]

Thanks. It is indeed 1 bolt apologies I thought one went in the end but it doesn't. Thanks for the explanation is that bolt enough to stop the rod moving? Can I use any old bolt and nut? Or does it have to be some special honda one.

yeah, that one bolt is all that holds the tensioning rod in place. as long as it's tight (no need to really muscle it though) and the lock nut is snug, it holds just fine. as for replacing it, finding an original bolt is certainly never a bad idea. but it's just a bolt. so as long as you're able to match the size and thread pitch, you're fine. or if need be, you can even drill the original hole out to a larger diameter and tap it for whatever bolt you plan on putting in. the engineering here isn't particularly sensitive. as long as you're able to get a bolt in there and keep it in place, you're fine. assuming of course the rod and all the other roller bits inside the engine are in working order.

 

[koolio]

assuming of course the rod and all the other roller bits inside the engine are in working order.

Indeed they are, thank you for you help will let you know how I get on!

 

[Scruffy]

Take the housing to the hardware store with you, get a stainless steel replacement bolt and jamb nut. You don't want that fitting getting stuck... Brass hardware works well also.

 

[koolio]

Take the housing to the hardware store with you, get a stainless steel replacement bolt and jamb nut. You don't want that fitting getting stuck... Brass hardware works well also.

I've got plenty of bolts and bolts, and I won't use stainless because I don't want it to get stuck! (Galvanic corrosion)

 

[Scruffy]

Never had a problem using stainless, but, I do spend the extra on marine grade whenever possible. Same with brass/bronze hardware.

Now, cadmium plated or galvanized? Nothing but headaches.

 

[koolio]

Never had a problem using stainless, but, I do spend the extra on marine grade whenever possible. Same with brass/bronze hardware.

Now, cadmium plated or galvanized? Nothing but headaches.

Off topic can I ask what kind of problems? Surely you get bi-metal corrosion issues with alu engines?

 

[Scruffy]

You have to use the right alloys of fasteners. Some stainless will react to aluminum, some won't. I get most of my hardware from marine or aviation sources. Purpose designed to be inert, where cadmium and zinc plating, especially in high humidity or on the coasts, tends to attract corrosion... That's why good 4 stroke marine outboards have stainless or bronze fittings, and sacrificial zinc anodes.

Costs 3 or 4 times as much to use marine grade hardware, but I only plan to replace the stuff once... The kicker outboard for our daysailer has marine grade stainless bolts, was only used in saltwater, and has been left to rot since at least 1999... hardware is perfect. Aluminum lower unit that sacrificial anodes were never installed on.

 

[koolio]

Interesting, I was under the impression all stainless will eat aluminium due to the nobility difference and the better the stainless the less its durability, tensile strength, fatigue resistance, and machinability but much improved corrosion resistance, compared to mild steel.

I'm not so sure you are correct about the cadmium, where I understand it is the standard choice for marine and aviation, zinc is too reactive of course unless as an anode, it will too eventually give way though.

I can understand where you are coming from though if you only want to replace the stuff once and next time I buy bolts for my engine will be SS with a thick coat of copper grease on the thread and below the head.