Riders Of Vision

Hello,

After searching through the forum I had gathered that Clevite bearings fit for a 1988 Mazda 323 would be a suitable substitute for the stock Yamaha big end bearings. I got the bearings, the OD, ID, and thickness all seem to be about identical to my old bearings (I have not yet checked oil clearance). All that seems great, but my concern comes from the fact that the stock bearings are 1.8mm wider than the new ones. This not only reduces surface area, but also causes the bearings to be positioned off-center & off-set to one another. The Mazda bearing's retaining tab is also slightly wider than the stock bearing's so it must be filed down to fit. Finally, the Mazda bearings are not drilled to allow oil to exit through the passage in the connecting rod.

Is there anything to be concerned about here? Did I end up with the wrong bearings? Should I drill an oil hole to mach the one on the con-rod? What negative affects (if any) will narrower bearings create? Can I go ahead and file down the width of the retaining tab (filed surface will not be a bearing surface)? I apologize if I could not find a previous post asking the same question, please post a link if such a thread exists! Pictures can be added if my description does not suffice.

Thanks in advance,

Rory

Don Minor has used them and is the person who told me about it. I don't believe this will cause a problem . How ever I'll try calling Don and ask him. I'll report back on what he tells me.
I called Don and he  told me a bit about the Mazda bearings. They are 4 layers as opposed to the Visions one .  They work fine !!
The reason the  Vision blows rod bearings is that the clutch debris builds up and plugs the pickup screen! If your oil light pulses at idle , the screen is plugged , CLEAN IT NOW!Clean it anyway!!
Don laps the oil pump to remove all the wear marks  and tighten it up. He packs the oil relief plunger as well.
His email is minordon@yahoo.com

Thanks for the help! I didn't think it would be an issue, but I want to be sure I do all of this right the first time. I did clean out my oil pump screen, and I was amazed at all the metal chips, bugs, and strings of yamabond #4 came out of it. Are you saying he packs the oil relief with grease? All I have done with mine so far is inspecting it, cleaning it, and replacing the o-ring & cotter pin.

Thanks again,

Rory

Don  disassembles the pressure relief valve and puts a small washer in it, to increase spring pressure. I did it many years ago on my '54 ford six, by stretching the spring, or adding a washer.

Okay thanks for the clarification, I'll be sure to give it a try on my vision!

rm97, thanks for posting your observations. I don't think I've seen such detailed comments regarding the Mazda bearings replacements. Unless there was and I missed it... :-[  Good stuff anyways!  :)

Are the Mazda bearings you sourced standard or oversize?  I can understand your concern over the size/offset issue as it relates to loading and area but the oiling hole seems just as important, no? Are there any other oil distribution features - grooves or channels for instance?  Rick gave some goods tips on oiling too BTW to ensure good pump pressure.

So if I'm understanding you, due to the smaller size and offset, the two bearing shells only provide a small band of contiguously supported contact around the journal? I can't help but wonder if it will be as long lived as the originals.

Quote from: Rick G on September 01, 2012, 04:45:05 PM
Don  disassembles the pressure relief valve and puts a small washer in it, to increase spring pressure. I did it many years ago on my '54 ford six, by stretching the spring, or adding a washer.

I will explain the relief valve in the side case...It is to leak oil back to the crankcase when pressure exceeds 70 psi Prior to reaching any moving parts. You want this to work @70psi...not higher. Reason being if pressure is too high in the oil gallery, there is a relief built into the OIL FILTER. And should this relief "pop" ...you will be sending UNFILTERED oil into the crankshaft and rod bearings. This could include metal bits and such. And this WILL cause a bearing failure.  People need to understand this design... I cannot comment much on the Mazda bearings..except to say , if does not have the same phyisical make up...oil holes, etc.... positive results are not likely to last long.

Yikes  :o  I don't like the sounds of that one bit :-\ :'(  Unfiltered oil you say!?

My bearings are standard. The front rod bearing was severely worn, and the rear bearing seemed to be bent, causing the rod to stick instead of spinning freely around the journal. Luckily I caught the problem quickly and my crank journal received no significant damage.

The oiling passage is an oil relief passage, not an oil supply passage. As I see it, rendering such a passage useless would increase the oil pressure in that area and allow the rod bearing to float on the layer of oil, instead of rubbing on the crank. I'm not sure what negative affects removing that passage has on the system... someone more knowledgeable would have to answer that question. There are no oil distribution passages on the bearing.

The small size and off-set is what had me worried the most, and is what led me to post this thread. Unfortunately, since I can't find stock bearings these seem to be the best known option aside from custom built ones. I hope that the increase in bearing quality, and possible increase in oil pressure will lead to success.

I guess I will scratch the oil relief modification idea. Maybe the relief valve spring becomes less stiff over the years and needs a bit of help?

Don relates that he has 40,000 miles on his Mazda rod bearings, He has used this option more than once. He (like  me) is very hard on his bikes, expecting maximum performance and running the shite out of them.
The reason for the shim on the oil plunger is to restore a 30 year old  spring to something near new specs. As I said its an old trick , which was old when I was young.
There was a post years back , from a Visionary in one of the Scandinavian countries , who used Mazda rod bearings , to rebuild his XZ.  I believe he reported success.
As to the quality of the stock bearings, as far a I'm concerned , there junk, anything would be an improvement.

Here is a correction for Don Minors email address minordon@yahoo,com

Thanks for the input everyone! I'll be checking oil clearance on the new bearings as soon as I can get my hands on some moly grease.  I will also look through my shop manual to see if they give any specs on the kg/mm rating of the oil valve spring.

I finally got some moly-grease so I was able to put the rods back on the crank. I greased up the bolts, tightened the rods with the plasti-guage in place, removed the rods, and saw that the clearance was well within spec. I then removed the plasti-guage, re-greased the bolts, oiled up the crank and bearings, and torqued the rods back on 9ft-lbs at a time until I reached 27. I was happy to see that everything was going smoothly, but when I went to see how smoothly the rods spun on the crank I was very disappointed. The rods were almost stuck, I could get both rods to spin, but not easily. Thinking that this didn't seem right, I redid the entire procedure and ended up with the same results. Is it okay for the rods to not spin easily like this? Will this no longer be an issue once pressurized oil is running through the system? If not, does anyone have any ideas as to what is wrong, and how I can fix it? The crank was in good shape (and within spec), but I did replace the connecting rods. Considering clearance is within spec I wouldn't think this is my problem.

Thanks,

Rory

Are the rod journals round? Did you measure them? Do the rods have enough side clearance with the offset Mazda bearings.

Try one rod at a time on the crank.  Don't stretch the rod bolts too many times, they can break in use.

I will measure the rod journal, but I do know that the crank journal is round. The rods have plenty of side clearance, the new bearings don't affect this. I double and triple checked that the rod caps were on the right rods/not turned 180*.

Just checked, con-rod journals are indeed round. I also re-checked the crank, which is still round :D

According to Craig at Hanson Racing Technology in Chico, CA the crank journal needs to be ground about .001".  Since you checked with plastigauge and your clearances are within spec I don't know what else to suggest.  If you have clearance you have clearance. 

Sometimes the big ends of the rods become slightly egg shaped and need to be re-sized.  Precision grinding of the mating surfaces of the rod caps to close up the hole, and then precision reaming of the big end of the rod to make the hole round again.  I read about this on the Clevite website some time ago, hope I got it right.

I think I will measure bearing clearance again with the plastiguage. I have a feeling I might be better off getting the crank ground, and purchasing oversize bearings. At the very least I will probably have a machinist measure all the parts using some real precision tools. Any other suggestions are welcome.

QuoteI think I will measure bearing clearance again with the plastiguage.

that sounds like a good first step. try and measure 90 degrees to where you measured it last and see where it is.

I've never had one of these apart so bear with me....  Did you say there was a hole in the rod that was covered by the Mazda shell? Did you end up drilling a matching hole in the bearing shell? Does that hole direct oil to the wrist pin?

Yes there is a hole in the rod that is covered by the new bearings. I did not drill a new hole through the bearings. The hole does not lead to the wrist pin, it just squirts out of the side of the rod. Now that you mention it, I might go try to see what that hole could be lubricating, if anything. At first I thought it was just an oil relief, but maybe it sprays oil on the cylinder walls.

Also, on the topic of the pressure relief valve... Looking through my Yamaha shop manual, it says that the oil relief valve opens at about 57psi, while the oil filter bypass valve opens at about 14psi. In other words there is really no point in increasing the relief valve's spring pressure, as the oil filter bypass will open up long before the relief valve does.

EDIT: After doing some more measuring and making some careful observations, it seems that the new bearings have a slightly larger OD than the rod ends. This causes the the bearings to pinch the crank journal right where the con-rod and con-rod cap meet. I think I will just take the crank and rods to the local engine machinist and see what kind of advice I get. I could try modifying the bearings a bit, but I don't think that is worth the risk.

Quote from: rm97 on September 30, 2012, 03:14:16 PM
Now that you mention it, I might go try to see what that hole could be lubricating, if anything. At first I thought it was just an oil relief, but maybe it sprays oil on the cylinder walls.

I wondered if it was angled to shoot oil towards the underside of the piston. Are there small oiling holes through the piston skirt in the oil control ring lands?

Yes there are, the more I look into this the more I think I will be drilling a hole in the bearings/getting new bearings with a hole. I wonder how much a custom set of bearings would cost... I'm hoping I can get away with new (maybe) custom bearings rather than having the crank and/or rod machined.

When measuring for oil clearance clamp the rod, wrist pin end in a vice, with bearing in place set the C/S in the rod journal add the plasti gauge then torque the rod cap, remove rod cap carefully and measure.

Like I said, don't titen/stretch the rod bolts too many times, they will break.

Quote from: motoracer8 on September 30, 2012, 10:39:33 PM
When measuring for oil clearance clamp the rod, wrist pin end in a vice, with bearing in place set the C/S in the rod journal add the plasti gauge then torque the rod cap, remove rod cap carefully and measure.

Like I said, don't tighten/stretch the rod bolts too many times, they will break.

That is exactly what I did when I measured the clearance, with the addition of molybdenum disulfide grease on the bolt threads (As suggested in the manual). Bolts were torqued 9flt/lbs at a time, alternating between bolts until each was at 27ft/lbs. Bearings, and crank journal were thoroughly cleaned before I started assembling parts. Since I started messing with them, the bolts have been tightened three times.

A mechanic friend of mine never used full torque value (maybe half?) when using plasti gage. He claimed any more than that was just stretching the bolt - not changing the clearance any. Often in getting up to the final torque you inadvertently move something and smear the gage strip giving bad results. That was his theory anyway and I never heard a knock from any of his rebuilds.

Most engines do have a squirt hole to cool the under side of the piston crown. It is technique from pre WWII air craft engines. You should read Kevin Cameron's column in CW , he is the heir apparent  of Gordon Jennings.
If you don't know who he was , you should !  Ask me if you need to.

Hello again,

I took a little break from this project to keep up with school/sports, but I'm back at it. I talked to Don, and the following is our conversation copied from my e-mail.

Quote
Rory Malloy
Oct 14

Hello,

    I have been working on rebuilding my 1983 Yamaha Vision, and I have discovered that new rod bearings are in order. While I was looking through the ROV forum I saw it mentioned several times that you had successfully used connecting rod bearings made for a 1988 Mazda 323. Since this was my best lead for getting rod bearings for the Vision, I went ahead and purchased a set of bearings from summitracing.com, advertised to fit the Mazda. Unfortunately when they arrived they did not fit, the locating tab was too wide, the bearings were too narrow, they did not have the oiling holes, and the bearings were made for a con-rod with a slightly larger bore, causing them to pinch the crank when bolted down. I then got myself a service manual for a 1988 Mazda 323, I looked up the specs for crank OD, con-rod ID, and oil clearances. Everything matched the measurements of my Vision's crank and connecting rod.
    At this point I thought that maybe I had received the wrong bearings, I found another supplier on e-bay that had listed their bearings with a picture identical to what I was looking for. I ordered those and soon found out that they were identical to the ones I already had, and not identical to the picture (I should have known not to trust the picture...). I have returned the bearings, but I still don't have bearings that fit correctly. Am I missing something? Where did you get your bearings from? Did you need to modify some of your parts for the Mazda bearings to fit? Do you have any clue why all the bearings I'm getting are nowhere near the dimensions the Mazda service manual states they should be? I hate to be bothersome, but I feel I have hit a dead end, and I'm really not interested in either having custom bearings made, or taking parts to a machine shop.

Thanks in advance,

Rory Malloy

____________________________________________________________________

Don Minor
Nov 5

I took the rods, crank and bearings to a machine shop.They made them all work for under $30. My crank was really a mess, it had to be welded and reground.

____________________________________________________________________

Rory Malloy
Nov 9

Don,

That's interesting, did you end up making the crank larger than it was from the factory? Also, the bearings you got, were they narrow like the bearings I have received, or were they about as wide as the original bearings? Do you happen to remember where you bought your bearings from?

Thanks, Rory

____________________________________________________________________

Don Minor
Nov 11

Yes the bearings were not as wide as the stock ones. The machine shop made the rods fit the crank after the regrind. 40K miles,they are still working. I got them at auto zone.

____________________________________________________________________

Rory Malloy
Nov 11

Don,

Okay, thanks for the info! I'm assuming you don't mind, so I will be posting this conversation on the riders of vision forum to benefit others who may have the same question.

Thanks again, Rory

So it seems as though he had to pretty drastically modify his parts to accommodate the new bearings, meaning that this is not the bolt-on (or at least close to) fix I was hoping for. At this point I would move to custom bearings, but the 1988 Mazda 323 shop manual I have been using gives dimensions for bearings that should fit the Vision perfectly. With that in mind, I'm now wondering if the manual is wrong, or if have I have been getting the wrong parts, and if the latter, where can I get the right parts? I have made a thread on a Mazda enthusiasts' forum, so I hope to get an answer soon. I will keep this thread updated with new information if/when I get it.

Thanks, Rory

Rory, thanks for the update. I appreciate the research you're putting into this and look forward to hearing any helpfull info that may come from the Mazda forum. Keep us updated.  :)

Thanks! I'm still looking, and I have found something that is somewhat promising... I will throw another post up here if it works out. In the meantime, does anyone have stock crankshaft and/or connecting rod dimensions (journal OD, big-end bore, etc)? I couldn't find any in my manual aside from the oil clearance. I might e-mail Yamaha, although I'm doubtful that I will get anything useful out of that.

I'm not familiar with all the terms you are using but I do have a crankshaft and connecting rods lying here before me. Tell me where to measure and in metric or inches.    BDC

Are they brand new? My crankpin (part of crankshaft that rods bolt over) has about a 44.94mm OD, which I believe is stock, or just slightly below. My connecting rods are just about at 48mm ID for the larger of the two holes, and it is about 19mm from the outside of one bearing retainer indent, to the other. With that information, I think I may have found something to fit my parts, but I'm not sure if they would fit others' without machining.

My crankpin measures 45.00, 48.00, 18.90, and 1.50mm thickness.    BDC

Thanks for the info Re-vision!

Okay so my new bearings have finally arrived! Before I get into talking about those, I think I have disproved my theory as to why the other bearings didn't fit. I had been thinking that said bearings were too large for the rods, causing them to curl inward at each end of the bearing when bolted together. I had then speculated that the bearings were the right thickness, which is why I was still getting the proper oil clearance measurement. After looking at all the parts, and the MFG's measurements, I have debunked that theory. I now believe that the bearings were simply made for a smaller OD crank pin, meaning that had I got my crank ground down, the Mazda bearings would have likely fit nicely. Unfortunately, the bearings were still rather thin at roughly 17mm.

Now, on to the new bearings. As I believe I have already mentioned, around two weeks ago I found a Clevite/Mahle bearing catalog, showing measurements for engine bearings, organized by make, model, and year. I then spent many grueling hours looking through a long list of cars, and comparing the measurements to my own. Eventually I found some bearings that had dimensions close enough to be worth further investigation. Those bearings were made for a 2002-2011+ Nissan Altima 2.5L, and have the Clevite part number CB-1858AL. These bearings are also available in .25mm, and .50mm undersized versions.

After I double checked measurements a few times, I ordered two sets of bearing halves from ebay. A little over a week later, they arrived and I was finally able to see if they had a chance of fitting. As I put the parts together, I was pleasantly surprised to see just how well everything fit. The bearings were pushed into the rod and rod cap without too much effort, while still making for a snug fit, and the retaining tabs were in the right spot. On top of that, at 19.1mm, the bearings were almost the exact same width as the OEM Yamaha bearings. Unfortunately the bearings were not perfect. First the oiling holes in the bearings must be elongated a few mm to align with those in the connecting rod. Secondly, the Vision crank pin is bigger than that of the Nissan. This means that the crank pin must be ground down, even if you aren't getting undersized bearings.

I hope to get a ride over to the machine shop after school someday this week. I will give the shop the crank, and the measurements, hopefully they can get that part of the process taken care of without charging me too much. For those interested, bearing dimensions can be found at the following address, http://catalog.mahleclevite.com/lv/display_partdetail.php?cram=CB1858AL&cm=1542 (http://catalog.mahleclevite.com/lv/display_partdetail.php?cram=CB1858AL&cm=1542). It is worth mentioning that before having the crank ground, you should factor in the fact that the Nissan's minimum oil clearance is lower than that of the Vision. I purchased both set of bearings from the following ebay link, a little expensive, but the places with better prices were back-ordered at the time. This seller also has undersized bearings available, http://www.ebay.com/itm/Clevite-CB1858AL-Rod-Bearing-/350659542565?pt=Motors_Car_Truck_Parts_Accessories&hash=item51a4effe25&vxp=mtr (http://www.ebay.com/itm/Clevite-CB1858AL-Rod-Bearing-/350659542565?pt=Motors_Car_Truck_Parts_Accessories&hash=item51a4effe25&vxp=mtr). I'll let everyone know how this turns out, hopefully I can finally get the engine back together.

By "under size" I think they mean for smaller, worn crank journal, so the shells would be thicker than "standard".  Just a guess on my part.

There not for a worn crank , but for a crank ground under size to return the bearing surface to a uniform size and finish. The usually come in 10 , 20, 30 and 40 th. thicker for under sized journals.

I'm just lazy, I should have put . . "worn AND REGROUND . . ." 

All too often I assume other people understand what is in my head, because it's really obvious to me. ;)

rm97    Great Post!  Thanks for putting in the hours. I didn't think there would be a great "bolt in" solution but it sounds like you're getting really close. The added width is going in the right direction too. Given the choice, I'd take a little material removed for the oil holes rather than settle for skinny shells.  :D

Having a good machine shop look is the right thing to do and hopefully they'll come back with good news.  :D At a reasonable price.  ;)

Can you elaborate on:

Quoteyou should factor in the fact that the Nissan's minimum oil clearance is lower than that of the Vision

Looking forward to the next report!

Yes, I believe that "undersize" rod bearings, means that the bearings are made for a crank that has been ground down, meaning that the bearings are actually larger than standard. I agree, that seems like a very odd way of referring to the bearings, but from what I have seen that is the way most people refer to those types of bearings. If these bearings are actually called oversize bearings, I would certainly appreciate someone correcting me.

Quote from: Rikugun on December 09, 2012, 08:57:57 PM
rm97    Great Post!  Thanks for putting in the hours. I didn't think there would be a great "bolt in" solution but it sounds like you're getting really close. The added width is going in the right direction too. Given the choice, I'd take a little material removed for the oil holes rather than settle for skinny shells.  :D

Having a good machine shop look is the right thing to do and hopefully they'll come back with good news.  :D At a reasonable price.  ;)

Can you elaborate on:

Quoteyou should factor in the fact that the Nissan's minimum oil clearance is lower than that of the Vision

Looking forward to the next report!

Thanks, it's nice to see that others are benefiting from what I'm finding. The added width is certainly a good thing, and the Mazda bearing would have also required drilling an oil hole. The Mazda bearing's retaining tabs were also a little too wide to fit the con-rods properly. A bolt on mod would be nice, but these bearings are amazingly close considering how different the two vehicles are. Grinding down the crank a bit to fit the Nissan bearing may even be enough to avoid moving to the .25mm versions, letting you have three chances to destroy your crank instead of just two ;D.

As for that quote. The Nissan bearings are made to have a minimum oil clearance of 0.0178mm, while Yamaha specifies a minimum of 0.028mm for the Vision's oil clearance. It may be worth your while to have the crank machined down an extra 0.01mm or so from the maximum crank pin OD specification of 44.9740mm. If you didn't there is a chance you could end up with too little clearance, meaning more time and money would need to be thrown at the machine shop to get the clearance within spec. Just me "thinking out loud". I'll try to get the machine shop to write down the final measurements so I can pass on the information. Out of curiosity, who else done the Mazda bearing modification other than Don, and I think someone in... Iceland? Have people been able to get OEM bearings before?

Thanks!

I could only go to the local machine shop one day last week, unfortunately when I got there the machinist said that I should try going somewhere else... I finally got someone to drive me to the second machine shop today, the machinist said that the crank is close enough already that it only needs a good polish, no grinding required. Unfortunately the shop has a few projects ahead of mine, and they are closed next week. That means that I will be waiting until the first week of the new year to have it done. I was looking forward to working on the engine over my Christmas vacation, but that obviously isn't going to happen. On the bright side I got full tour of their nice, clean shop! I also got a nice new avatar picture of yet another bike I want, I'll see if anyone can identify it.

Happy holidays!

The term "undersized bearings" is an industry standard . They are intended for a crank with reground under sized journals.

Kind of hard to see such a small pic but looks like a little Honda 250 V twin.  I don't remember the specific model but is similar to the "Barbie bike" .

So guess I was right before, thanks Rick! The bike is a little Honda 250 twin, a new VTR. I think that it looks very nice, kind of like a Ducati monster, but the small size would make it a perfect bike for me right now. Plus its a Honda! Unfortunately they only sell it in Japan...  :'(

Quote from: fret nut on December 20, 2012, 01:46:38 AM
Kind of hard to see such a small pic but looks like a little Honda 250 V twin. 

VTR250 perhaps.

edit: oops! missed it by 2 minutes  :P

Hello again,

Great news! The machinist was nice enough to find time to finish my project for me before they closed for Christmas. Hans from Advanced Engine Rebuilding, Inc (http://"http://enginesbyadvanced.com/") did an excellent job, I highly suggest this place to anyone nearby. I'm trying to get a little more information, but so far I know that they drilled oil holes in the bearings, polished the connecting rod journal, and they bored out the connecting rod's big-end bore because they were slightly out of round. I measured the vertical oil clearance of the rod bearings and got around .046mm, which is right near the middle of the range suggested by Yamaha. I also had my last day of school today for the next week or two. With that in mind, and the fact that the apocalypse isn't ending up very apocalyptic, I might even have a chance of getting the engine back together before 2013 (I will likely still need to switch out some valve shims, but that is no big deal). Hopefully anyone else with rod bearing problems will be able to use this thread to help them figure things out. Basically, if you need to have this done, get your crank, both con-rods, and the proper bearings (see page 2), and the oil clearance spec, then take it to a good machine shop at let them take it from there. I ended up paying a little over a hundred dollars for everything, but if the con-rods' bores weren't out of-round it would have been more like forty five dollars.

thanks, Rory

That sounds pretty reasonable money for close tolerance and critical work. Thanks again for documenting your journey into the realm of rod bearings too. That's good info someone very well may need to access again. Good luck with the assembly and hopefully 2013 will see you riding your Vision again!  :)

Thanks! I agree, they didn't overcharge at all, I was pretty happy to have everything done for $100. I will also mention that I made a few mistakes. The Yamaha manual actually specs 0.035 to 0.054mm of oil clearance for the connecting rod journal, I had accidentally been looking at the main bearing oil clearance which was a few lines below and labeled "journal clearance"... Also, the machinist said that he removed metal to get 0.0015" of oil clearance, not that he removed 0.0015" of metal to get the proper oil clearance.