cam chain slippage

[prometheus578]

"I was just gonna suggest that..."

Taking the plug out and manually pushing the plunger forward.
Our tensioners are held in position by the locking bolt, but I've done similar on the ratcheting types. Pull the end plug, push the rod forward so it ratchets to the next tooth, and then putting the spring back in and replacing the end cap.
90,000... I'd say replace the chain.
I don't recall for sure just how much travel the plunger has... I mean... how long it is and how far it should move, but I would think that having only a 1/4 or 1/2 inch of travel left in it... it's pretty much extended and the chain should be replaced.

[skids]

Re: "I was just gonna suggest that..."

Again, maybe my bikes have excessive wear, but I didn't get 1/2 inch travel in my tensioners after replacing the chains and I have done 3 of them. About 1/4 inch was all I could muster. (Rather disappointing)

Originally posted by prometheus578

I don't recall for sure just how much travel the plunger has... I mean... how long it is and how far it should move, but I would think that having only a 1/4 or 1/2 inch of travel left in it... it's pretty much extended and the chain should be replaced.

[TomB]

Our tensioners are held in position by the locking bolt

LOL

I kinda assumed folk would have figured that and undone the pinch bolt before pushing on the plunger and then nipping it up.

Maybe I expected too much.

[Stralya]

I have another cam chain tensioner here which I will compare with the original. It seems very springy.

We'll keep you posted.

Dan.

[79XS11F]

Any time I have done top end work on my engines I have had no problem getting the bridge into position between the cam sprockets. It's a tight fit but not a battle. I have rebuilt the top end on all three of my engines and all I can say is ...
If the the bob weight set up is correct and not out by 180 degrees...
The timing plate is on correctly...
The timing set to "T" ...
The dots on the cams are at the arrows ...
you should be good to go UNLESS ..
you are installing the cam sprockets in the WRONG order and allowing the looseness in the chain to occur at the WRONG place where it is not removed by the cam chain tensioner when you rotate the engine to the timing plates "C" mark.
YOU MUST install the intake cam sprocket first and maintain tension on the cam chain between the crank and that sprocket and then remove all slack between the intake sprocket and exhaust sprocket while installing the exhaust sprocket. When done like this the slack in the cam chain is on the exhaust side of the engine where it can be removed by the cam chain tensioner. It a small but VERY important little detail. Do it any other way and when you rotate the engine there is a good chance that the chain will slip or jump a tooth. When the crank is turned it must PULL the cams with no slack between the crank and intake cam and no slack between the 2 cams. Also make sure the cams themselves are in the correct places ...
Rob

[Stralya]

Thanks Rob.

I'm sure that's the order we did it in but to be safe we'll do it all over again. I'm off work with a sprained ankle at the moment and the bike's at Pete's place about 10 miles away and he's working through the day so it may be a few days before we can pull it down again.

I'll let everyone know how we get on. It should be the fasted full dresser in Australia!

Not just because it's the only full dresser in Australia either

Dan.

[Stralya]

OK, I've been wondering what to tell you guys for a couple of days now. The short story is that my bike is running like the powerful megabeast I always wanted but what did Pete and I do?

Well, believe it or not, we just cleaned the spark plugs!

I know, dear reader, you are sitting there rolling your collective eyes mumbling something like, "Oh, you're kidding, what a pair of Wombats."

But we must have cleaned the plugs five or six times during this whole drama and it never made a difference.

I pulled off the cam cover again expecting, almost hoping to see the arrows and dots misaligned but they were both spot on. We did the cam chain adjustment again and it too looked perfect.

By this time I had a knot in my stomach the size of a small sedan and it seriously looked like my dear old machine was about to start a new life as an artificial reef somewhere off Sydney Head.

We put everything back together again and did all the checks we had done countless times before, fuel, spark etc but the bloody thing just wouldn't start although it did fart into life for about a second and a half then nothing.

We have a product here called Startyabastard, no kidding, that's it's name. On the strength of the second and a half fart, I took off to the local Auto parts store and picked up a can. You just spray some into the airbox and Bob's your uncle apparently.

Well, on my return I see Pete standing there with his chest pushed forward with an ear to ear grin and giving me the old double thumbs up signal.

I got out of the car and heard what I hadn't heard for almost a month...my bike purring away as if to say, "Well come on, jump on and where have you been anyway?"

Gobsmacked, we scratched head and scrotum, said some rude words and I took off back to the Auto parts store for four new spark plugs.

Safely installed, Pete took it for a test blat after once more synchronising the carbies and declared that it now pulled better than his bike.

So there you have it Guru's and others. So endeth the lesson.

We both know the spark plugs were not the problem. I put in a brand new set just before I rode the bike over to Pete's place so it just couldn't be the plugs. However, after following the advice,the manual, the yellow brick road and a mongrel dog that wandered past, the final analysis shows that the plugs I bought before I rode the bike to Pet'e must have been faulty.

My thanks goes out to all who've contributed to this thread, heaps of vital information now exists for future numbnuts to read and avoid having to type an explanation like this and feeling foolish.

Thank you all once again.

(Name withheld)

[petejw]

well we got it going... finally,

it seemed to b a cpl of different things that contributed
to the bike failing to run.

firstly we took the rocker cover off and rechecked
the cam chain timing, not a problem, it was still
all lined up tho we
did retension the chain by removing the plug
and pushing harder on the tensioner.

The bikes battery had now been on charge for a cpl
of days, and a new set of spark plugs did wonders,
tho the old ones werent really that old,
the bike was also running lean causing the coughing
and spluttering on start up.

The bike now starts and runs well.

A BIG thanx for all the offers of advice.

[prometheus578]

That's why I always put in new sparkplugs whether the customer thinks he needed them or not.
Saves a lot of aggravation.

[Stralya]

Yeah, those day old plugs will get you every time

[prometheus578]

we must have cleaned the plugs five or six times during this whole drama and it never made a difference

That's why I don't do that, either.
It won't remove all the carbon tracking further down the insulator and the juice would still rather run down the cone than spark across the gap.
Plus, the crushed walnut shells or what ever, if you use one of those compressed air spark plug cleaners, can get lodged down deep, get hot, glow, and cause pre-ignition.

[Stralya]

I suppose the frustration is akin to that golfers suffer. It's maddening but don't you just love it?

I guess we just love tinkering as well as really quick bikes. Everyone needs a hobby I guess.

Sometimes you feel the whole bike will disintegrate if you don't hold your tongue just right

Looking forward to heaps more fun, I bought a Wiseco big bore kit in May and Pete bought one last night. I have a couple of good cylinder blocks spare so the next step is reboring followed by installation which should only take a day but I'll just bet Murphy's Law will prevail once again.

After that we're looking at Webcamshaft cams and then doing something like Maximan did with his exhaust system but that's way into the future.

In the meantime, I have a set of '78 cams that we will put in Pete's '81 Special and see if that makes a difference.

Will keep you posted.

Dan.

[Dragon Tamer]

I have had brand new spark plugs that caused the bike to miss badly, at least until I had hooked up all four plug wires. I attributed the problem to someone in Scotland (on the Isle of Islay) who had obviously sent out a defective bottle of their fine product and it had caused a small foggy spot in my vision the next day which apparently made me think that a four cylinder engine would run with three plug wires. My wife thought it might be caused by something else but as she knows nothing about motorcycles she could not possibly be correct and I won't bring it up here.
To my credit, it was harder to find than the miss in my lawnmower engine, I fixed that one in almost nothing flat by removing my finger from the spark plug and it straightened right up.

[AlanB]

Islay is a wonderful place......I guess; I have been there, but I don't really remember......

AlanB



It is not that far from here, and has several Malt Whiskey Distilleries...........