Topic: Chain and sprockets woes

[Raul CB750K1]

Well, the story goes like this: when I bought my CB350 twin it had a plastic rear sprocket! I imagined there was nothing better available sometime in its past and the same mechanic that covered the engine cover with gasket cement put that sprocket that was even cracked. So big deal, I'll cross that bridge when I get to it.


And I got. CMM quoted 82euro for the rear sprocket, 170 euro!!! for the chain and 30 euro for the front sprocket, shipping not included. No way. Local Honda dealer could only supply the chain.

I asked a local bearing and seals shop. You know, they deal more with industrial supplies but they deal occasionaly with chain kits. Obviously, there was no CB350 kit but I took the old ones, they contacted Tsubaki and quoted 130 euro for the full kit, that included a 530 o-ring Tsubaki chain and a "raw" rear sprocket. As he told me, they carry "raw" sprockets in all sizes so the customer can machine it to specs. He told me he could recommend a good machinist so I ordered it.

The parts arrived and everything was as expected. The problem came when I went to the machinist: he quoted 78 euro to do the job!! I don't discuss wether the job is worth it or not -surely it is-, but it would mean the chain kit will cost about 200 euro!. Well, I was in a catch-22 situation, so I told the man to go ahead.

But what was lingering in my mind was the fact that the sprocket is made of aluminium. Of course the machine work wouldn't include those holes that iron sprockets have in order to reduce weight and material. I was concerned about that fact and asked the guy in the bearing shop. He told me that he ordered everything to the Tsubaki motorcycle division, so he have it as good for a bike. My concern is if I'm going to spend 78 euro in a machine job, and because of the sprocket being made out of aluminium it would last just a few thousand miles. According to Murphy's law, I found yesterday in eBay the same sprocket, though not make by Honda, for 15 euro plus shipping from UK. Of course I bought it and called the machinist to hold the job until I make up my mind.

So, the question is: Have anybody ever seen an aluminium sprocket? If so, would it be durable -I guess it will be more than the plastic sprocket but that's not the point-. The durability is the only question, because if it is, the lesser weight will be a clear advantage, as it will also reduce the gyroscopic effect without the need to drill holes. Actually, if holes are drill it can even get weaker.


Here I post a picture of the "raw" sprocket and the plastic sprocket. Also, a picture of the old and new chain. I was surprised it is much wider. Having the same roller width, the wider links and the o-rings make it a much wider chain and I'm concerned wether it will rub the chainguard or not.

Also, the master link is the rivet type and I don't have the special tool. I've been told it is a matter of gently tapping the pin heads until it widens, but not smashing it to the point of bending the pin that would stop it from rolling.


Man, I couldn't imagine a drivechain kit would get so troublesome.

Raul

[TomC]

Hi Raul CB750K1
     I have never used an aluminium sprocket. But they seem to be common.
     O-ring chains: Having used an o-ring chain on my daily rider for the last 20 thousand miles I never want to go back to a non o-ring chain. But o-ring chains are wider than non o-ring chains. Today I measured four 530 non o-ring chains. They were .800" or 20.32mm wide. I checked Did chain's web site. They say that there 530 o-ring chain is 0.980" or 24.892mm wide. A difference of 0.180" or 4.572mm. One half on each side.
     On a 550 four there is no clearance with a non o-ring chain in the area of the case behind the front sprocket. So an o-ring chain will eat the case and the seal at the end of the transmission main shaft. I say no clearance because there is evidence that the non o-ring chain has been rubbing the case is this area. The answer to this problem on my 550 will probably to have sprockets modified to run a 520 chain. Current 520 o-rings chains are usually rated for use on modern 750 fours.
     On your CB350 you need to look for anywere that there is less that 2.5mm of clearance on both side of your current chain.
            TomC

[ofreen]

I had a Sprocket Specialists aluminum rear sprocket on a CB900F a few years ago.  The sprocket had 9000 miles on it when I sold the bike and was still OK.  I put it on there because I got a good deal on it, but I wouldn't seek one out for a street bike if I could get a quality steel one.  Aluminum may hold up on a 350 twin just fine, though.  Better than plastic, I'd expect.

That seems like a lot of money for a sprocket.  Over here, you can get rear sprockets for CB350 twins for less than 30 bucks from places like J.C. Whitney or other mail order houses.

edit for typo

[hcritz]

Hey Raul:
Funny about the plastic sprockets...
I raced Moto-cross for 6 years...most of what we raced in was very sandy.
I was eating up chains and sprockets BIG TIME!
One of the local gurus said try the nylon sprocket on the rear...It outlasted the steel sprockets by a HUGE margin.
Plus the chain lasted a lot longer. I would have never believed it...but the nylon is much more abrasion resistant.
I ran a Suzuki TM 250...and the drive train took a Serious beating...full throttle landings...never used a clutch except at the starting line!<G>

[eldar]

Dont a lot of bikes not use aluminum sprockets anyways? If they can do it now, why cant a 30 year old bike do it that has much less power? If it is made right, it should not be a problem as long as prpoper lube is maintained

[Terry in Australia]

Some of those old nylon sprockets were good, they were especially useful on dirt bikes to to their abrasive resistance and weren't affected by lack of lube.

The alloy sprockets are ok-ish, it really depends on what grade of alloy is used, so the blanket statement that "they'll all good" doesn't really apply. Still Tsubaki is about as good as you'll get Raul.

Most of the bike shops around here sell aftermarket sprockets that seem to last ok, and like offy says, they're very cheap. Watch those modern O and X ring chains though, they're no good if they're too wide.

I can buy quality japanese industrial non O ring chain for $50.00 AUD (about $40.00 US) for a 10 foot length, and they're just as good as any modern O ring or X ring chain, what many people don't understand is that a well maintained non O or X ring chain will actually last longer than a sealed chain. Cheers, Terry. 

[ofreen]

I can buy quality japanese industrial non O ring chain for $50.00 AUD (about $40.00 US) for a 10 foot length, and they're just as good as any modern O ring or X ring chain, what many people don't understand is that a well maintained non O or X ring chain will actually last longer than a sealed chain. Cheers, Terry. 

Looks like I am going to follow Terry around here tonight and agree with him.  Non o-ring chain will be fine for the use you are likely to put a CB350 twin to.  Non o-ring chain can be made to last a long time, but the maintenance becomes a chore if you commute or tour on a bike and you run in the rain.

[tsp37]

Several years ago Chevy started using timing gears with plastic teeth.  The shadetree mechanics that I knew automatically replaced those gears with all steel sprockets at the first opportunity, probably because they were prejudiced against the plastic.  I never knew of the nylon teeth actually failing.  I'm sure other manufacturers, when using timing chains, use the same sort of sprockets.  I personally never changed a timing gear, although I just finished changing the timing belt in my better-half's Accord.

What was the condition of the plastic sprockets?

[Terry in Australia]

What was the condition of the plastic sprockets?

Have a look at the pic mate, it looks ok to me. cheers, Terry.

[tsp37]

What I see looks good.  But having a picture is not quite the same as having the part in hand to inspect up close.  So how's the riding weather in the DEEP south?

Terry, too

[ofreen]

Several years ago Chevy started using timing gears with plastic teeth.  The shadetree mechanics that I knew automatically replaced those gears with all steel sprockets at the first opportunity, probably because they were prejudiced against the plastic.  I never knew of the nylon teeth actually failing. 

AMC used them in their V8's.  I replaced several in Jeep 304s years ago.  They crapped out at 60,000 miles like clockwork.

[mrbreeze]

I bought a used 68 Pontiac Le Mans in 1977. About a month after I bought it,the oil pump seized up. On teardown,I find bits of nylon gear teeth in my sump screen. It locked my pump and twisted the pump drive shaft at the pump.So when I started it up....I hear clang,clang,clang and the idiot light is on. The cam is still turning the distributor and the distributor is still turning the shaft up top but not at the bottom(oil pump). The po of this vehicle had replaced nylon to steel timing gears but never cleaned the oil pan out so all the broken bits finally worked into the sump and locked my oil pump. What an experience!

[Raul CB750K1]

What was the condition of the plastic sprockets?

Have a look at the pic mate, it looks ok to me. cheers, Terry.

Have a better look Terry. It's cracked and the mounting holes have been enlarged with the use.

I'm a little pissed off with this deal. If I end up not being able to use that new chain it's going to be an expensive lesson. I have to check it out soon because I indeed took the old chain to the shop to order a replacement. I really didn't care about o-rings because I knew a well-lubed regular chain could outlast the CB350 engine -almost-, but they brought this chain without asking me wether there was any clearance issue or not. But I feel in case I can't use the chain I will have to struggle to get a refund. Live and learn...

[Terry in Australia]

Fair enough Raul, in the enlarged pic the crack and elongated hoie is very obvious, and sadly I'd suggest that this had nothing to do with normal wear, but poor installation procedure. If you get stuck mate, send me your old sprockets and I'll find you a couple of new aftermarket ones and some good non-O ring chain. Cheers, Terry.

[JohnG]

I have used an aftermarket aluminum sprocket on a CB750 with good results (probably got 15K hard miles out of it) and also on a CB350  (eventually sold...no problems with sprocket).

Nice thing about a MC is you can monitor the chain and sprocket condition, unlike the timing chain area of a car. 

The fact the CB350 has a cushioned rear sprocket assembly and modest horsepower makes for a good environment for the components.

As someone said, JC Whitney has pretty good stuff at good prices. you can order on-line.

       Good luck!
        John

[Raul CB750K1]

Fair enough Raul, in the enlarged pic the crack and elongated hoie is very obvious, and sadly I'd suggest that this had nothing to do with normal wear, but poor installation procedure. If you get stuck mate, send me your old sprockets and I'll find you a couple of new aftermarket ones and some good non-O ring chain. Cheers, Terry.

Thanks for the offer Terry

[puppytrax]

I ran an oversized aluminum rear sprocket on a Triumph Bonneville for 12 years; no problems, no excessive wear...but I'm pretty anal about maintenance; I cleaned & re-oiled the chain every weekend...   

[Terry in Australia]

I ran an oversized aluminum rear sprocket on a Triumph Bonneville for 12 years; no problems, no excessive wear...but I'm pretty anal about maintenance; I cleaned & re-oiled the chain every weekend...   

Ha ha, well if you managed to keep a Trumpy on the road for 12 years Rich, it goes without saying that you're a maintenance freak, ha ha!

[Raul CB750K1]

Bump! I just won an auction -via Buy it now- the other day of a rear sprocket. It said "48 states only" but I thought that with paypal and more than 500 feedback it would be enough for the seller to complete the transaction. I suggested USPS international flat rate box ($15) and he quoted "Standard international" $20. For some reason I thought he was going to send it surface mail and I can't afford to wait three months. I asked him if the shipping quote was for airmail and this is his response (cut&paste)...


IT SAYS 48 STATES I DON'T MESS WITH ALL THE OTHER STUFF,WHEN ARE PEOPLE GONNA LISTEN. 30.00 TO YOU,IF YOU WANT IT PAY IT.


No comment


BTW I contacted Tsubaki Spain and they are trying to find me a genuine Tsubaki machined rear sprocket -actually the have one in the catalog- and change it for my "raw" sprocket -I guess there would be some money going either way but I didn't ask about it, enough with getting the right one-. The chain is wider but I checked in the engine and there is no clearance issues to my understanding.

[Terry in Australia]

I asked him if the shipping quote was for airmail and this is his response (cut&paste)...

IT SAYS 48 STATES I DON'T MESS WITH ALL THE OTHER STUFF,WHEN ARE PEOPLE GONNA LISTEN. 30.00 TO YOU,IF YOU WANT IT PAY IT.

Don't you just love sellers like that Raul? They really raise the profile of Ebay, don't you think? (Jesus.................) 

[hymodyne]

I have a new rear sprocket and HD530 chain coming from JC whitney.

It'll be going on once we get out of the single digits here in NE.

hym

[Raul CB750K1]

I managed to buy a sprocket in UK. Arrived yesterday and seems good enough. Thanks to my politeness I overcame the US seller's reluctancy and he finally sent me the sprocket airmail, though I doesn't have it, so I will have a spare one for when the time comes to replace the original one -maybe I never see that day... -

The Tsubaki representative here has been very helpful too. She called me yesterday telling me she found the sprocket in Italy and would be ordering it along with some other stuff. I asked her about how long would it take, so when she told me "a minimum of four weeks" I simply told her I could buy the sprocket on my own and how about a refund for the raw sprocket. She told me no problem, I will be taking the sprocket to the shop I bought it, and I thanked her for their great customer support.


I hope this is the end of my chain and sprocket woes.... Don't you have to love and cherish your bike when you have struggled for every single part of it?

[Terry in Australia]

I hope this is the end of my chain and sprocket woes.... Don't you have to love and cherish your bike when you have struggled for every single part of it?

Don't get too carried away Raul, it's still only an old boat anchor, ha ha!