On my Krieger manual unit, I find that when the bike is cold, I have a ticking...but, it goes away when it warms up. I can adjust it TIGHTER an extra 1/8 turn so that it doesn't tick at all when cold, but, I figure as long as it quietens down when it's warm, that's tight enough...and the ticking is just something that lets me know it's not too tight.

My big question is...what is the cold ticking caused by? I'm going to guess it's about 3-4 ticks per second at about 2500 rpms....I could go crank it up and get an exact tick/per second at X rpms if that would help diagnose it.

FWIW, I can't tell that the bike runs or sounds any differently whether it's tight enough to eliminate the cold ticking, or loose enough to have it tick when cold.

 

Same here. I have that tiny ticking when cold on start up, but it goes away pretty fast. I like the fact that the cam chain has the proper clearance when warmed up to stop any wear issues and not too much to put stress on the cam/head interface. I've always been curious as to the exact function of that spring loaded plunger down lower and how effective it is on cam chain tension.

 

I think, for piece of mind, that I will order the manual one. The craptastic factory one has me a bit unnerved.

I'm assuming you take orders over the phone, KLX678? Do you take paypal, plastic, or MO?

 

More than likely it's the differential in thermal growth of the aluminum cases, cylinder, and head compared to the steel chain. Aluminum expands more than steel for any given delta-T.

 

If you think the little KLX 250 head is noisy, you ought to hear the racket coming from my '72 BMW 75/5 flat twin! Sometimes I swear there is a hand full of gravel thrown in under each cylinder head cover!

 

That's good enough for me!

 

Sure seems reasonable......

 

shim your rocker shafts. Its sideways play the rockers on the shaft.

I read all this stuff about tensioners. I could hear the rattle pretty good, so I took the adjuster bolt out and pushed the adjuster in with the end of a long alan wrench. It went "Click". It DID NOT FEEL RIGHT. Like the adjuster was stuck until I gave it a push. I think it was. After that I could hear the chain around 5,000 to 5500 RPM. At all other engine speeds the noise was gone. I rode it that way for a short while then put in the big bore kit. I had the tensioner out and checked it out really close. I assembled everything like it should be. Cranked the engine until I had oil in the top end and fired it up. This was at 4,000 miles on the bike. Every thing was quiet and has been for the last 3,000 miles. I have not touched the engine except change the oil frequently.

I truly think I had a problem with the tensioner when it was new. I also think its fine since I had it out. The spring is good sized and I should NOT have had to push the thing in the first time, so I think it WAS stuck.

I also think un bolting the tensioner and moving it back for one click is the wrong way to manually adjust the automatic unit. The person doing it has no way of knowing if its too much and tightening the bolts back up could put a whole bunch of unwanted tension on the chain. This could make things go to hell in a handbasket in a hurry.

Only my opinion from 30 years of wrenching.

David

 

Dave, the spring is only there to put enough pressure on the tensioner plunger to click it over when there's enough movement. Problem is if there is not enough movement and the ratchet pawl just barely goes over top of the rack tooth, it can and will kick back over top of the tooth and will continue to do that every time when there is any back pressure in the drive under deceleration. After tens of thousands of reversals as you accelerate and decelerate as you ride it will start gaining enough roundness on that tooth to make it easier and easier, gaining momentum until it skips a second tooth and then a third. Thus it will plunge in and out making all that racket. I know about this because on the second tensioner I noticed three or four teeth were polished on top. Being a quality engineer and knowing something had to be wrong, I looked at the parts under magnification and could see the rounding of the tooth edges, much like how shifter dogs round off and allow a transmission to kick out of gear when damaged by poor or rough shifting. The tensioner looks fine, but the function isn't there. This was the kind of trouble shooting I did when working at a cutting tool company and again at a heavy equipment manufacturer, dealing with root cause analysis. What appeared to be fine when just looking at the part proved to be damaged under critcal analysis.

Now as a mechanic you should realize that the cam chain only needs the play taken out, no extra tension is of any value and any binding just causes drag and takes up a bit of power. If there is tension on the system it actually is pulling the cams against the bearings, squeezing the oil film in there, risking the possibility of ending up with metal against metal and we know what happens then. It is also accelerating wear on the parts.

In my experience to date (about 11 years since the first manual tensioner for me and the second year for making and selling them with exellent results when the directions are followed and giving ready communications with me by phone or email) I find the adjusting of the manual adjuster to be very simple. The average rider who has the ability to follow directions and understand how to use a wrench on fasteners can easily do better adjustment than any automatic tensioner can. We're talking being able to fine tune the adjustment within less than .025 quite easily. This minimizes wear on the sliders and the cam chain as well as allowing the cams to turn quite freely as designed.

It's all about mechanicallyfunctioning as intended. It was never intended to have the cam tensioner plunger forced over the ratchet teeth and can leave potential for malfunction and possible wear if done so. Still the best design is manual, it's just that manufacturers are always looking to try to compensate for owners ignoring maintenance. We saw owners ignore the simple semi-automatic tensioner maintenance on the Honda ATC/XR/XL 185/200 singles. When the cam drive rattled there was a 15 or 17mm lock nut that was loosened allowing the spring loaded slider to take up the cam chain play while the engine idles. So many riders didn't bother. I've actually seen a cylinder where the cam chain slapped around so much that it cut through the cylinder in the cam drive tunnel. It actual cut through the aluminum! Yet the ones that were maintained would run almost for ever without cam chain replacement and that was with a roller chain, which isn't as durable as the HyVo chains now favored.

The problem with the automatic tensioner is if you simply take out the failed tensioner and put in a new one it is entirely possible the new tensioner will not go far enough to seat the pawl in and the same thing will happen again, it's about machining and tolerance stacking. It's also about spending over $70 for an OEM unit when a $33 part can do the job pretty much permanently. I have no idea how many other manual tensioners have been sold by other companies, but I do know I've sold about 300 in two years and have only had one guy who didn't like the fact that there was light ticking when at cold start up (some play is allowed at cold start up to compensate for thermal expansion of the cylinder, head and other parts much like setting up gear lash in a differential and other places where clearance is to allow for part growth as it gets hot) so I refunded his money and took back the part. All the rest ususually don't contact me, but some do and thank me for making a quality part at a good price that takes care of the cam chain play properly. Key word - properly, not jamming the tensioner in further than it should go.

But it's up to the owner.

 

Hey TNC, the candyass camper... don't know if I noticed that before. I'm a credit card camper myself. You know, throw the credit card down on the motel counter...

'Course there aren't too many motels in the Moab now, are there...

I'm thinking part of the function of that spring is to put help enough pressure on the slider to help the plunger to click over when there's play at idle. The other thing is the center of the slider will flex in and out a bit as a sort of shock absorber (think of it as a cam drive "cush hub") when the cam drive is under hard deceleration. That is what makes mechanical sense. That is a long slider and it's not fixed at the top, allowing a slight sliding action as it flexes. I'm going to have to look to see if it's used in the ZX/ZL/ZG cam drives sometime, but I'm thinking they use a really thick beefy slider that operates without that spring.