3xv: Project Phoenix

[Steveog]

I found washers that fit perfectly around the bushing (Arrow #1). They are not shown in this picture, but are the same ID as the bushing and OD as the dog-bone inner surface. These washers took up the slack between the dog-bone and the inside of the mounting point at the swing-arm. This may not be what Yamaha intended, but it certainly makes sense, as there is no gap between the bushing and mounting points. I can't imagine the dog-bone being designed to float on the bushings, side-to-side. There is no room at arrow #2 for any washers inside the mount, even though the parts diagram show that such washers exist (parts numbered as 11). Another great case for even more care taking photos and notes when disassembly occurs months before reassembly.

Finally, I've got the swinger mounted to the chassis. It was a tight fit, as the powder-coating added a slight bit of dimension that wasn't there originally. No force (beyond my lame-ass muscles) was needed to get the swing into position. It moves beautifully smooth now with new pivot bearings, end caps and SP thrust bearings.

Steve

   

[Warwick]

Part No. 11 is just the bearing seals Steve.

I noted the float at 1 too when reassembling. I just left mine as it was though as it had always been like that and worked fine before disassembly.

Feels good to have a two piece chassis, huh?

[ybk]

Yep the float is normal, the linkages only have washers on the outsides. That diagram is deceptive, they make the seals look like washers..  Just take note of which way round each bolt goes in and the torque associated with each.

[Steveog]

Thanks boys. Glad to know I didn?t lose or misplace parts. The first picture shows what I?ve done at the dog-bone pivot in question. Should I take it apart? The washers I've installed allow a bit of free play and everything lines up. All new parts.

I'm a bit embarrassed, as I could have checked those ?washer-looking? seals on a site such as MegaZip. All descriptions of the parts there are in English.

Warwick - Yes. It?s been two months battling this swing-arm. Very good to get it together and feel how well it all works with the best pieces in place. Thanks for the tip on those pattern seals, bearings and running tests on those SP thrust bearings. Invaluable for this old, 3xv rookies.

Karel - Glad you jumped in on my behalf. Yes. I have two torque wrenches on loan to button things up. No sense in going this far to simply trust experience. I'm tempted to safety wire the linkage nuts in place.

Since my last post, I've mounted the shock. Everything is still finger tight. ?Looks like I need a bigger bench.?

Steve

[Warwick]

So long as there is still a bit of float I'd imagine it'll be OK, Steve. Not sure why there is so much float built into that particular joint though? It did cross my mind to look at taking up some of the float on mine to see how it felt, but I decided against it in the end on the assumption that as the others are a tighter fit the float might be there for a reason  .

I wonder if lateral movement along that bearing sleeve is the source of the knock that is sometimes heard when lifting the bike by the rear subframe?     

[Steveog]

I just took a look at the configuration of the rear suspension on a 4DP2. It has collars with flanges which slide into the bearings and seem to meet, creating the surface on which the bearing rides.

It's not clear if the TZ has any float built into its system...at the point we?re discussing.

The 3xv rear suspension moves in only one perceptible direction. Up and down. There seems to be no reason for the dog-bone to float on its collar/bushing.

I'm going to leave things as they are on my bike for now. Well, I may try to source a higher quality (stainless) set of washers. The current set up on my bike emulates the way the swinger thrust bearing ride on the pivot bushing.

That said, probably better to move on, building the engine.

Thanks for your thinking on this, Warwick. Yamaha must have had a good reason for delivering the bike in this configuration, but we, as a group, seem to keep searching for ways, attempting to improve them.

[Steveog]

No. I did not blast and coat the shock spring. Dreaming of an Ohlin's, Nitron or K-Tech.

Had too much business today. No shop time. Thought this might be a good time to better show how I modded the typical 3xv, soft stock spring with a simple trick, picked up from US/NASCAR. Its called a "wedge". Its a piece of industrial rubber. By isolating the upper coils, the spring it is stiffened. This is not the same as cranking up the preload. The spring's active length is essentially shortened, thus making it stiffer. So, a very small bit of travel is sacrificed for an inexpensive way to a noticeably tighter suspension.

I did this quickly, as an experiment, the week before I lost the crank on 9/11/18. It worked, even on a swing-arm pivot that was just the bushing grinding into what was left of the swingers pivot bearings, lubed by mud and water.

It will be mounted with hex-head bolt, using PVC as a guard, rolling on the shock. It was originally mounted with a big cable tie. That seems a bit half-assed and a red flag for sharp tech inspector. Because the bike is now in this state of re-assembly, I'm also considering rounding off the square edges, making it a bit more "finished".

I weigh 180 lbs. A bit over 12 Stone. This mod made an obvious improvement in an afflicted bike's handling. Looking forward to how it will feel with proper suspension action and lubrication.

Steve

[thump566]

So long as there is still a bit of float I'd imagine it'll be OK, Steve. Not sure why there is so much float built into that particular joint though? It did cross my mind to look at taking up some of the float on mine to see how it felt, but I decided against it in the end on the assumption that as the others are a tighter fit the float might be there for a reason  .

I wonder if lateral movement along that bearing sleeve is the source of the knock that is sometimes heard when lifting the bike by the rear subframe? 

I also acquired the knock following my refurb but decided I may have got something slightly wrong so stripped, rechecked and re-assembled the shock linkeage whereby it disappeared. Possibly I was just lucky or was a numpty.

[Steveog]

Thanks, Thump. I haven't even lifted the frame and swinger searching for this "knock". It would seem that now would be a good time to look for it, as I only have the bare frame, swinger, linkage and shock in place.

I'm going to buy a small bag of "bearing quality" stainless washers for the dog-bone mount at the swing-arm. If anyone wants a couple, PM me. I'll have many more than I'll need.

Steve   

[Steveog]

Thump - My suspension linkage and shock mount is still just "finger tight". When lifting the frame today I heard THE "clunk.?" With nothing else on the bike, there was clearly a slop-factor at all linkage mounting points. I had just replaced all bearings, seals and washers.

My guess is that the "clunk", reported by many, has more to do with suspension linkage tolerances than anything else. Validating Thump?s experience. I'll have more data after I cinch up all the bolts/nuts to torque specs.

New question. In the attached picture, there appears to be two (2) possible mounting points for "L" shaped linkage attaching to the frame. I used the standard mount.

Is the alternate mount there to modify suspension action? If not, what purpose does it serve. The parts diagrams and maintenance manuals don?t seem to address this phantom mount.

I could be a numpty and missed something obvious. Any help appreciated.

Thanks

Steve

[Steveog]

All - My real job was postponed to the end of the month. Good shop time. Cleaned the cases with kerosene, rinsed with water. Ready for assembly.

While I was in there I discovered a tiny hole in the clutch cover at the kick-start seal. Looks as if it had worn through over many years of use. Used JB Weld epoxy to fix. Wondering if I shouldn't build up the spot with more epoxy to avoid any potential re-breaking on the spot.

I?ve seen a product that uses soft aluminum rod to weld aluminum with only the heat from a propane torch. The demo shows the sealing of a hole in an aluminum can. Could this work on my clutch cover? That fix would eliminate any chance of the epoxy breaking loose.

I also discovered a mystery inside the Left Hand Carburetor. There is an "R" cast under the body of the carb where it joins the float bowl. A similar casting mark can also be found in the float bowl.

I know the carb is correct for the cylinder. Can someone clue me in as to the R on a Left Hand carb. Does it stand for R-Model, as all the Sp's and SpR's have different carbs? Not a big deal. Just curious.

Thanks

Steve

[ybk]

That lower shock mount supposedly drops the rear so not much use. Haven't tried it myself though.

No sure about the carbs..maybe some meaning relevant to another bike - the TM28 and variants were used on many yamaha's..

All my bikes have had the clunk in the suspension if I recall correctly. I'll check the SPR once I start stripping it but I'm pretty sure it's normal..

Can you see daylight through that clutch cover hole?

[James P]

No sure about the carbs..maybe some meaning relevant to another bike - the TM28 and variants were used on many yamaha's..

Yes - I think it must be some Mikuni reference identity for the carb body casting style. I have checked three different versions of the TM28SS (TZR 1KT, TZR 3XV and DT200R 2YY) - all have the "R". I also checked a straight-bore TM28 (i.e. not angled-bore like the TM28SS) from an RG250 - it had a "K" cast in the same spot. I further checked a TM28 from an RM80 (basically a mirror image version of the RG250 carb) - it had an "R", but it was cast in a different spot to that of the TM28SS. If anyone knows the significance of these markings, please let us know!

Regards,
James

[Steveog]

Thanks for the feedback, gentlemen.

ybk - I would be interested in to hear from anyone who has used the alternate shock mount. The mounting plates are not the same as the SP model, but both R and SP have two linkage mounting options.

The "thunk" is still a mystery. thump566 seems to have solved it.   

Yes, you can see daylight through the hole in the clutch cover at the kick-start seal, but the seal had kept it covered. Most of the external engine seals were a bit worn and weeping slightly. They will all be replaced. That tiny hole is definitely due to wear. Its not a crack. Here's a video that explains welding aluminum with only a propane torch. https://youtu.be/yqkceLrH9Ao Tempting. But, I can't afford to F-Up the clutch cover.

James - Good details on carb comparisons. The (R) probably means nothing to the performance of the bike, but after 28 years, most of the 3xv history and iterations seem to have been discovered. We now have one more mystery. As you say, If anyone knows the significance of these markings, please let us know!

Back to the shop. Weather here is perfect for riding (cough...testing). But, can't take the bait and get into a hurry, now.

Thanks, Again.

Steve

[Steveog]

Finishing up the carbs. Dunk bath in potent carb cleaner for 4-6 hours, rinsed in fresh water, careful reassembly using spray cleaner and compressed air. No. I didn't have them soda blasted or US cleaned, so some embedded grime remains on the exterior. The carbs worked OK before the crank ate itself, but after examining the needle valve and pulling the rubber o-ring gasket, I noticed a bit of corrosion and decided to clean the jet and replace the o-ring. Unfortunately, you can't merely order up the o-ring. Its part of the needle valve kit. I went to my local fastener experts and they had o-rings of proper ID, but was almost twice the thickness as the stock piece. (see pic. Stock o-ring at the top).

When I attempted to add a bit of pressure to fit the new o-ring on the jet...no joy. I turned down the o-ring in my handheld drill, added penetrating oil and it all went together without further fusssing. Set the float bowl to 15mm. Moving on to replace needle/jet o-ring in RH carb today.

Anticipating running in a brand new engine, I bumped the LH carb main to 200 (190 Stock) and the pilot jet to 20 (Stock 15). I'm planning to use the stock -00 box for run-in, but am also anticipating bumping to a Zeel ignition (on-hand) and have seen many advise to jet up, based on the hotter spark.

Comments welcome.

Steve