Primary Chain

[DEmily]

Hey everyone,

A short time ago I submitted a post about bottom end noise. As many of you may remember, I worked on restoring the BIGDOG for over a year and finally got him on the road. He runs like a champ, however, after getting the valves all adjusted in to specs, I could hear a rolling / lapping type sound from the bottom end. I traced it down with a stethascope to the housing just in front of the starter. Descided it was the primary chain so I pulled the engine just this evening. By the way, you should never pull the motor from the frame whole if you are a small guy and by your self. My back will be pitching me a major bitch in the morning.

Anyway, I will be breaking it open tomorrow. I have one to replace it with, however, there is no real way to tell if it is stretch or not until I get the old one out. The question I have is: how much slack or slop should the primary chain have. I noticed while removing the clutch that the crank will turn a between 1/4 and 1/2 inch before it engages the primary chain. Seems like an awefull lot of slack to me. Any thought ?

[DEmily]

help!

I got the primary chain out and matched it up to the one I purchased. They are almost exactly the same. I put the purchased chain in and it seems to have a bit less slack but not much difference. Where as the first chain allowed the crank to turn say 3/8 inch before the chain goews tight the second one
allows the crank to turn about 1/4. The difference in small when lifting the chain to test slack. I found no visible spots anywhere form chain slap. I will say the back of the original chain is shiny, but the second one is black like the rest of the chain. Can anyone tell me if there should be slack in this chain?

[Bubba1954]

If the outside of the old chain is shiny and the new one is not, it was most likely rubbing some where. Even though you may not have spotted where. The 1/8" added chain slack of the old chain might have just been enough to allow it to rub.

[randy]

Couldn't the chain be shiny from rubbing against it's guide? Looking in the fiche, there is a primary chain guide that performs somewhat simiilar function as the cam chain guide. I would think that it contacts the chain in normal operation, no?

HTH

Randy

[DEmily]

Yes Randy, I do believe you are correct. This is why I beleive that.

After pulling the bottom of the engine, I noticed a layer of what looked like rubber particles on the oil screen. In a panic I pulled the crank and inspected the crank bearings. Two of the bearings are shiny, kind of looks like an old chevy I worked on years ago, when oil supply was reduced by blockage and the mains got hot. Of courses this is not good, and even after deciding about this chain I have to determine what to do about these two crank bearings. I will plastigauge them tonight to check for tolerence, but I have a bad feeling I could be done driving her until I can come up with a bearing solution. I know these bearings are not available, nor is the primary chain. I kind of got this feeling I may be done with it completely as the parts are so hard to come by.

I guess I'll know more tonight, but this has got to be the biggest disapointment I have ever experienced with this bike. To have a custom hi-vo chain and bearings made for this bike would probably cost a pretty pennie. I'm just not sure I can sink anymore big bucks in to it.

[randy]

Dan,

The bearings ARE available from Yamaha. The chain is not, though. There is a chain from a (reported) low mileage engine on Ebay right now.

Good luck

Randy

[DEmily]

Randy, Last I check I could not find them. I will have to get with some dealers to see what they have available, that is if the existing bearings are gone.

[randy]

Dan, Primary chain on Ebay is item#2485666980. Reportedly 22,000 miles on it.


Bearings are available through Bikebandit. They get them direct from Yamaha, so your dealer should be able to get them for you.

Also try Zanotti's

randy

[DEmily]

Thanks Randy,

Zanottis is where I got all my bearings, rings, and valves from. About 6 months ago he told me he could nolonger get them, but maybe he has a new source or something. I'll drop John an email.

[DEmily]

Just check all the bearings and they all are well within specs. I'm not sure about the chain. If you put them both on a pipe and hold them up there is about an 1/8 of an inch difference. I don't know if that is enough.

I did check with Zanottis and John told me he can now get all con and main bearing including the thrust for all colors except yellow. And even more surprising, he has a line on primary chains. I'll get prices from him soon hopefully.

[TopCatGr58]

Musings on Primary Chains

Hey there DEmily, and others,

While I was perusing the Yamaha parts catalog, I remembered this thread about not being able to find the Primary chains from Yamaha. I remembered about the parts numbering system, how the 1st three are the specific bike designation, and the rest is the actual part number, so if you can find the same part from a different model, then it will cross match!

Well, I looked up the # for the Chain 1st on the 750 triples, it is:
1J7-16139-04-00 with a note about it being 72 links long.

Then checked the XS11 it's # is:
2H7-16139-02-00(Changed from -01-00 in 78 to this in 81)
and a note about it being 54links long IIRC.

Then I did a search for other bikes, amazing how Yamaha got away from using primary chains and went to direct drive sprockets/gears!!!

But, I found a much newer bike, the XJ600J Seca, 92-98 and it's #:
4BR-16139-00-00 with no notation as to length!? But you can see a trend here can't you!?

I then went to Cycle-Parts.com and did searches for all three, and they all came back with being available, but the prices went like so:
XS750/72links=$184.00
XS11/54links=$170.00
XJ600/?links=$120.00

This kinda tells me that the XJ chain is even shorter, but it is available, not sure how hard or expensive it would be to purchase 2 of them and have them spliced together to the proper length!?

But, at least the XS chain showed as still being available from this source. Just wanted to post as an FYI, as well as something to ponder!?

DEmily, perhaps your local shop could either order the XJ chain, or get their technical catalog to look it up to see what it's dimensions are, might be a possible fit, might not!?
T.C.

[DEmily]

Thanks Tcat. Zanotti motors now has them and they also have all the mains and con bearings. Not sure if they are coming from Yamaha or not, but it looks like someone is making them.

I did get the used one put in and it did stop slapping the case, however , it is still kind of noisy down there. I asked my brother the PO, and he said it has always had that kind of rolling, raddling sound. He said his 83 750 midnight Virago sounds the same way. I hope that is the case. Anyone else experience the sounds I am discribing?

[Upright]

DEmily,

How's your noise doing? Any change? I saw no one else has chimed in yet. Mine makes a clattering noise. (I think we discussed this in another thread, too!) Bob at Merriam Cycle listened to it and wasn't concerned. He said "these things make noise." He said it sounded like the primary chain.

-Craig

[DEmily]

Sounds the same. I believe it is the primary chain. Can't be sure, but it seems to run great and have not had any problems with it.
Does the sound you hear come from the starter area behind the jugs?

[pratel]

If I remember correctly, the sound you hear is like a metalic chuck chuck chuck sound at idle? This is not an uncommon sound, and I dont think it is anything to be concerned with. Visitation has been doing this for 10+ years. If I remember, Ken Talbot, and Rick Jameson, or maybe JP Honeywell recommended to leave it alone, due to the immense strength of this chain design. Of course it is your decison!, YMMV