Timing chain break in, and...

I searched the database for an answer to my question, learned a lot of stuff, and found a lot of information to think about, but I couldn't find a direct answer to a question I have so I am just going to ask....

I have the early timing chain metal tensioner and have purchased a rubberized replacement and also a big pin chain from Jason. I'm not worried about installing either initially, but I think that the chain straps grind into the rubber until the rollers engage so there's some "break in" for the tensioner. What is the procedure to account for the break in? Do I set the tension like normal, then ride the bike for some amount of mileage then pull the cover again to readjust the tensioner? What would that mileage be? 1 ride? 500 miles? 1000 miles?

Ultimately, I think the rubber tensioner might make the timing chain quieter, so that's a good thing. I'm interested in opinions on this. Thanks in advance

Unlike the original chain the big pin is already worn in so you are left with the rubber wear only. So in theory only one ride is needed but I would give it 500 miles.

I didn't receive the shipment with my big pin chain yet, but I did get my timing cover off. I used a good sealant last time I inspected the chain, so the cover was stuck on there good even after I removed the screws. For a minute, I wasn't sure how to get it off, but I just split the gasket with a razor blade by giving a single tap with the hammer and the timing cover was free. The current chain has 30,000 miles on it and has almost 1/4" up/down play, so it was due for an adjustment. It feels very flimsy to me. I'm kind of surprised at how light duty the chain is, how it lasted this long without blowing apart, and how it will compare to the big pin chain that I have coming. From the looks of it, I wouldn't think it was stout enough to be up to the job, but it lasted 30,000 miles...

Can't wait to read how much quieter you think the timing side is with the rubberized chain tensioner. Not being a wiseass. I am interested since I also happed to drink the cool aid and ordered the rubberized tensioner for my Pre-Commando to see if it makes any noticeable difference.

Schwany said:

Can't wait to read how much quieter you think the timing side is with the rubberized chain tensioner. Not being a wiseass. I am interested since I also happed to drink the cool aid and ordered the rubberized tensioner for my Pre-Commando to see if it makes any noticeable difference.

Click to expand...

I'm having an engine "noise" at idle that I don't like and I have been inspecting everything, hoping that it's not the cam lobes/followers or the connecting rods. I tried the inspection camera up the drain hole and it took an hour to get it in position to see 1 cam lobe. I'm going to try inserting it through the timing chest breather hole today since I have the timing cover off now...

Sorry I digress,.... but I thought my noise might be the timing chain, but the original chain seems "OK", but could have used a slight adjustment, which after 30,000 miles isn't a surprise. The current timing chain feels like a noodle and I'm surprised that it seems like such a light duty item. It looks like a bicycle chain to me, not a timing chain for a 50 hp motorcycle. I have the big pin chain coming from Jason to compare it to when it arrives. Maybe I'll be surprised that the big pin chain seems light duty as well.. I don't know yet...

I bought the rubber foot tensioner thinking that it must be an improvement or AN wouldn't have superseded the old metal type with it... That, and the fact that no one here is complaining about the rubber foot one. It should be quieter because of the rubber, and the fact that the chain is new and tight, not all sloppy and rattling like a bag of bones like the current chain

Being a wiseass is welcome. Being a transplant from NYC, I miss the more "direct" kind of communication of the east coast.

the verdict is in, the mystery is solved..... The owner and one cam lobe are blue today..... shit is coming apart...



Grindings noises have causes...

BTW, I used a $20. endoscope camera that shoots straight ahead or at a right angle to the wand to view my cam lobes. I shoved it into the "crankcase to timing case" hole right behind the timing chain to inspect each cam lobe. It didn't take much wiggling to view each lobe as I pushed it along. I don't think it can see how good your lobes are, but definitely showed me that my furthest lobe looks cooked.... My premature diagnosis is that the follower was either oil starved or just didn't fit the barrel well enough so it was hanging up making it grind on the cam....

I have been mixing STP with my motor oil since 1982 after rebuilding my Norton motor for the Featherbed frame, my Norton was an everyday rider for most of its life with me and has clocked up a lot of miles, about 15+ years ago I had to replace the crank cases and a full tear down of my motor but to my surprise the cam lobes where still in great shape, my original cam was built up and had a 2S cam grind when I built the motor for the Featherbed frame over 42+ years, as well very little wear on the conrod bearings and the main bearings had no wear at all (all bearing replace of course with the rebuild), call STP snake oil but it has proven to me that it works, I mix 500ml of STP to 2ltrs of motor oil.
My round alloy oil tank is only 3ltr, I run an Lochart oil cooler all year round since 1978 and the STP from 1982 when the conversion was done, as for my timing chain it was replace 15+ years ago but I run an auto timing chain adjuster which was also installed back in 82, when a timing chain gets loose it does make a rattle noise when idling.

Ashley

I don't know how many people have had a timing chain break. My P11 maintenance manual says the timing chain is of short length and is not unduly affected by stretching.

There is an old post on this site about the RMA automatic timing chain tensioner. Of course, it is non-conclusive other than there might have been a design change at some point that made the auto tensioner not the best idea. The early ones supposedly worked.

STP is slippery stuff. Hard to hold onto the parts with numb fingers when tearing and engine apart that has been running with STP in it. Takes a while to clean it of too. I use a small amount of it in my oil.

My rattling dry clutch and FCR slide rollers will probably drown out the improvement in the timing chain rattle with the rubberized standard adjuster. Just kidding. If it works at all I'll notice it.

The good thing about the STP is if you let the bike sit for some time the STP sticks to everything and when you do start the bike the cam and everything is protected and lubed, I also use a STP/oil mixture when assembling my motor.
My old auto timing chain adjuster pushes down on the timing chain, not pushing up on the chain like the stock set up, very rare I open up my timing case, well after running the auto chain adjuster my motor runs a lot quieter and not having to go inside the timing cover every 10k miles to check on the timing chain/adjustment.

Schwany said:

My rattling dry clutch and FCR slide rollers will probably drown out the improvement in the timing chain rattle with the rubberized standard adjuster. Just kidding. If it works at all I'll notice it.

Click to expand...

You saw my post in another thread about FCR vacuum release plates failing?
Caused by the seal wearing from rattling slides.

o0norton0o said:

I searched the database for an answer to my question, learned a lot of stuff, and found a lot of information to think about, but I couldn't find a direct answer to a question I have so I am just going to ask....

I have the early timing chain metal tensioner and have purchased a rubberized replacement and also a big pin chain from Jason. I'm not worried about installing either initially, but I think that the chain straps grind into the rubber until the rollers engage so there's some "break in" for the tensioner. What is the procedure to account for the break in? Do I set the tension like normal, then ride the bike for some amount of mileage then pull the cover again to readjust the tensioner? What would that mileage be? 1 ride? 500 miles? 1000 miles?

Ultimately, I think the rubber tensioner might make the timing chain quieter, so that's a good thing. I'm interested in opinions on this. Thanks in advanceWhen I fitted an IWIS chain from the chain man it was actually I little on the tight side even in its most slack state. But with it also having a new rubber tensions I thought that it would quickly ‘wear in’. I don’t know how long it took, but it did just that.

Click to expand...

When I fitted a new IWIS chain and new rubber tensioner, I found the chain was on the tight side even with the tensioner backed off as far as it would go. I don’t know how long it took, but it did ‘wear in’ sufficiently to be about right when I took the cover off sometime later.

So, with a new chain and new rubber tensioner, I would personally set it a little on the tight side (don’t go crazy obviously) in the knowledge that it will wear into the rubber a little.

Well, I pulled it apart and the blue on the cam must be from a reflection from the LED lights. The cam is OK. 2 of my lifters have a few pock marks on them , so they are going to be reground to clean them up. It's barely noticeable, but I don't like it,....so it gets changed. I also have a an extra pair of lifters that I have to look at as possible donors. I can feel my wallet getting lighter already...

o0norton0o said:

Well, I pulled it apart and the blue on the cam must be from a reflection from the LED lights. The cam is OK. 2 of my lifters have a few pock marks on them , so they are going to be reground to clean them up. It's barely noticeable, but I don't like it,....so it gets changed. I also have a an extra pair of lifters that I have to look at as possible donors. I can feel my wallet getting lighter already...

Click to expand...

Any signs of what your unusual noise could be ?

Do you know what cam you have? If it’s unmarked at 30k miles it must be a good un. It also suggested you’re using a good oil etc.

Remember the golden rule… “never put an engine back together as it was”.

It’s wallet busting upgrade time

Fast Eddie said:

Any signs of what your unusual noise could be ?

Do you know what cam you have? If it’s unmarked at 30k miles it must be a good un. It also suggested you’re using a good oil etc.

Remember the golden rule… “never put an engine back together as it was”.

It’s wallet busting upgrade time

Click to expand...

I only got it apart a few hours ago. I still have the timing chain on, so I haven't wiped down the cam to get a better look at it. It's such a pain the hang on to the pistons and rotate the whole mess while eyeballing the cam. I need a good night's sleep so I can wake up with some fresh energy to see where I'm going with this. Two of my followers were polished and shiny, and two of them had some pitting starting. I can only assume that I have to look at those cam lobes very carefully......

My cam is the stock 1970 commando cam. I don't follow the terminology much so I don't know what it's called.

I have a wish list that makes my wallet cry, but don't we all... In my case since it's all apart the temptation is that much greater...

Could the noise you heard be the timing chain going tought then slack? The lobe of the cam pushing against the lifter, then the lifter pushing against the lobe, will bunch up the chain as it is being pulled forward, then tighten it up again as it starts to hold the cam back.

I found the issue on a top end noisy B40, the crank pinion's keyway had widened and the pinion was sliding back and forth as the valve spring tension varied.

So, I haven't even started my examination yet today, but I thought the noise was near the cam when it was running at idle. I thought that maybe the followers were a bad fit in the bores and were grinding away, but they seemed as smooth as butter when I looked last night. I had no metallic appearance in my oil, nor any metal on my drain plug magnet. My oil filter has a big magnet inside it and I disassembled the filter and it had no metallic particles either, which is a good sign.

I have many things to check... Things like keyways, sloppy bushings, and contact surfaces are all on the list. As Nigel said, I know for sure that I have a "busted wallet"...

robs ss said:

You saw my post in another thread about FCR vacuum release plates failing?
Caused by the seal wearing from rattling slides.

Click to expand...

Yes I read your comments.

o0norton0o said:

I didn't receive the shipment with my big pin chain yet, but I did get my timing cover off. I used a good sealant last time I inspected the chain, so the cover was stuck on there good even after I removed the screws. For a minute, I wasn't sure how to get it off, but I just split the gasket with a razor blade by giving a single tap with the hammer and the timing cover was free. The current chain has 30,000 miles on it and has almost 1/4" up/down play, so it was due for an adjustment. It feels very flimsy to me. I'm kind of surprised at how light duty the chain is, how it lasted this long without blowing apart, and how it will compare to the big pin chain that I have coming. From the looks of it, I wouldn't think it was stout enough to be up to the job, but it lasted 30,000 miles...

Click to expand...

Try just using grease on your timing cover gasket unless you have some big gouges it'll seal fine and come off easy
Works for me

In my race engine, I tried an IWIS HD chain when I tried fitting a Jim Comstock hydraulic tensioner.

I recall something like Fast Eddie said, the IWIS chain came up tight with the hydraulic and a standard tensioner. The HD chain went back to Andy the chain man, replaced by a standard dimension IWIS one.

I have since used standard IWIS, Renold and Regina chains and AN tensioners.

Sorry, I can't remember which, but when I was doing cam timing one time I found one of the chains was quite worn with tight spots that made accurate tension setting difficult.

But I just reached into the spares box for another one and included one in my next AN order. I guess the one in the spares box now is AN supplied Renold.

I am happy with standard dimension chains for this application. But I don't leave it for 30,000 miles to look at it.

Sometimes there are no short-cuts. If I had rattles, I would have the motor out of the frame and apart. You might find there are flats on the cam lobes. Fixing the chain issues might only have a cosmetic effect.