Questions timming chain and rear differential

[erod1]

I have two queations. My timming chain is making noise. I was surprised when the mechanic pointed it out to me. I thought is was the valves making noise. My bike has 14,000 miles. Is it normal for the chain or the tensioner to go so quickly ? Also what will it cost to repair this.

Question two is my rear differential is leaking from the fill plug. I replaced the plug with a new one. But it still seeps out. What could be causing this.

[Matt Chapter]

Question two is my rear differential is leaking from the fill plug. I replaced the plug with a new one. But it still seeps out. What could be causing this.

Second part first, as the saying goes.  Did you replace the crush washer, or just the bolt itself?  If so, someone else will be along shortly to talk about volumes of gear oil and what not.  I can't remember if it's the overfull transmission that will sling the oil to the final drive, or vice versa, or if it's the differential and final drive.


As for your first question.. sheesh, I hope I'm hearing valve noise and not the timing chain on my bike!

[erod1]

Thanks for the reply. I reused the old washer. When the part came in from the dealer I was surprised it did not have the washer.

[Bob_Roller]

I'm quite surprised that the timing chain is making enough noise to hear it over the normal valve 'ticking' that is common with these bikes .

There are two rubber coated parts that come into physical contact to tension the chain .

But it's not very common to hear of this at this low of mileage .

Cost to replace the chain, one item that may cause issues, is the exhaust header pipes, if they have not been off since the bike was built, it's not uncommon the have the aluminum nuts seized on the threads of the head .

If that is not a problem, about 5 hours of labor to replace the chain and the tensioners, if the nuts are seized, it can get costly .

A lot of owners, resort to cutting the nuts off and not even trying to remove them, cleaning up the threads on the head and install new exhaust nuts, they are not that costly and are a lot less costly than having the threads repaired on the head .

Is the mechanic you are dealing with, well versed on BMW airhead bikes, if he's not, I'd want a second opinion on your bike .

The leakage from the fill port on your final drive, is this the one at the top of the final drive ?

My first question would be, how much oil is in the final drive ?

The 10mm plug at the back of the final drive, is the fill to level, remove it and see if any appreciable amount of oil drains out .

Do this on a 'cold' final drive, bike hasn't been ridden today kind of cold .

[erod1]

Thanks for your reply Bob. The noise can be heard at idle. I do not hear it when I give it throttle. I was quoted $1000 for the job. So I decided to put it off.

As far as the rear drive. I filled it from the top. I did not check the side level. I will look at it on the weekend.

 It was a liitle cold this morning riding to work. It will be colder with no sun going home. But I enjoy riding this bike. The bike was sitting for about 10 -15 years. So I am slowly bring it up to date.

[montmil]

Don't now where you hail from, Ed Rod, but get with a forum administrator, aka: Justin, and get him to "approve you" to get into our photo gallery. A hassle, yes, but spammers are the root evil...

Anyway, check out my photo / essay DIY timing chain replacement. If it is the chain and/or tensioner or guide, the job is not difficult. I bought a complete timing chain replacement kit from Motobins that had everything for the job -including the stuff I didn't know I needed.

$1000.00? I'd "put off" that mechanic... IMO. 14K miles is too soon for the chain unless the bike has been an in-town poke along ride. The chainis lubricated by a crude method where engine oil is spit thru a copper tube onto the chain. Higher revs generate higher OP and the oil can drench the chain "more gooder".

You also did not mention the model year of your bike. Helpful info for those peeps responding with answers.

[Bob_Roller]

The next time you ride the bike, pull the clutch lever in with the engine running and the transmission in neutral and see if it makes any difference with the noise you have .

You may have to do this without sitting on the seat to get a better hearing angle .

The transmission makes a lot of unusual noises when in neutral with the engine at idle .

[erod1]

Thanks Monte. I am from Long Island NY. My bike is a 1986. I recently had the carbs rebuilt and changed all the cables. The mechanic said it is the timming chain or the tentioner. I told him the same thing , that how is it possible that a bike with only 14k could have a chain problem. The noise does come from the front of the engine. So I do agree it is the chain or tensioner. Could it be that the bike has 114,000k ?

[erod1]

Bob. I'll try that next. But I do hear it from the front engine case.

[montmil]

Bob. I'll try that next. But I do hear it from the front engine case.

Does the sound change or come n' go with throttle on, then off/coasting?

A l-o-n-g shank screwdriver makes a fine stethoscope to close in on pesky noises.

[jg928s4]

worn cam gear could get sloppy on the cam making hard to time and extra noise.  I am currently dealing with that...

You can change chain and add new  tensioner spring following the mentioned instructions, I seem to have had success in getting that far done.

[erod1]

The sound is only at idle. The trimming holds good.

[erod1]

I noticed today that the sound goes away when I am in gear. I notice it right away when it is in neutural.

[Bob_Roller]

I'm sure now, that it is not the timing chain !!!!!!

Just saved yourself $1000 !!!!!

[erod1]

Bob. But noise is coming from the front engine cover. So what could it be ?