XS850 Master Thread

Cool, thanks Franz.. the 850 is not 1:1, but definitely some good crossover with the xs1100 video.. should be helpful

I read somewhere the 850 must be pulled and split.. still need to do more research to be certain.

 

Let me know what you find, I am interested if it can be done. Good luck.

 

Ok, with 2nd gear gone, doing research and inspection on pulling gearbox assembly, engine, et al..

Phase I - Inspection:
Claimed XS1100 fix for "2nd gear pop-out" says this can be done with engine in frame (xs1100).. Multiple videos, blogs, forum posts to support... Cool!

Question... Can this be done, as equal, in-situ, on the xs850? Reports, perhaps spurious, suggest not. Let's see...

Phase I, Step 1:
Inspect underside/oil pan accessibility...

<Google Drive Video Link Here>

Appears, from the video, oil pan can be pulled without pulling the engine, and perhaps even wo pulling exhaust.

More to come, TBD, Etc., Et Al.

 

Found this little nugget on reddit.. sounds like 2nd and 5th gears on the xs750 (and likely 850) can com out wo pulling the engine or splitting cases..



Likewise, someone on xs650.com shared this video as well, where they pull the #2 gear wheel and perform the washer swap.



I'll be inspecting everything before I commit to anything. Stay tuned!

 

Ok, much to report on rectifying the xs850 2nd gear pop out affliction... (and more still to come...)

xs750 & 850 share nearly identical cases and transmissions, tho exploded diagrams call for some part numbers (supposedly) unique to each bike...

Attempting to determine if the 79xs750 2nd gear wheel (1J7-17221-03-00) is interchangeable with the 81xs850 2nd gear wheel counterpart (3J2-17221-00-00).

On the exploded diagrams for both bikes, the 2nd gear wheel interfaces with the identical 5th gear wheel (1J7-17251-03-00).

Based on what we know from this post (Yamaha Part Numbers Explained), its clear that the 2nd gear wheels in question share identical primary part numbers "17221" and the 3 digit prefix (1J7, & 3J2) should simply align to the model code for when this run of parts was produced. 1J7 = xs750, 3J2=xs850.

Given this information, I posit that Yamaha part# 1J7-17251-03-00 and 3J2-17221-00-0 are completely, drop-in, interchangeable.

So... Based on the above, I acquired a NOS/NIB 1J7-17251-03-00 gearwheel in the hopes of matching it to my xs850.

I "think" this xs750 2nd gearwheel is going to be a direct drop in replacement for my worn out (xs850) 2nd gear.... Starting teardown of my bike tonight.

The 2nd gear wheel in question mates to the 5th gear wheel and I have NOS examples of that on order as well.

For posterity, below I've outlined the dimensions of this NIB/NOS xs750 2nd gear wheel...

Follow-up drawing of the xs850 2nd gear wheel counterpart, 3J2-17221-00-00, pending disassembly of my 850.



This lil fellar spent the last 45 yrs waiting patiently, on a dealer shelf in central Louisiana. Thanks Natchitoches PowerSports!


Edit/Followup.. A FB user posted this excellent photo and I added some details that clearly identify the issue these bikes face with 2nd gear pop-out. (Pictured below is the 5th gear wheel that interfaces with the 2nd gear wheel pictured above)

 

Ok, here is the 850 2nd gear wheel (3J2-17221-00-00).

My suspicion from the previous post, that the 750 2nd gear wheel could be dropped in, was partially incorrect. the 850 2nd gear wheel has a smaller ID and includes a press-fit bronze bushing.

The 750 wheel (above) is also a hair thicker & is offset to the outside, with a relief pocket on the inside side face to accommodate the washer that people usually swap to the outside in the "washer swap" mod.

On the 850 the washer is already on the outside and the gear has zero offset.




Given the 750 gear has a larger ID, a bronze bush could be turned and press fitted into the gear so it will work on the 850 shaft. The 750 gear is still slightly ticker than the 850 and so on assembly we could either omit the outside washer, or use a surface grinder to take down the offset boss that is slightly proud on the 750 wheel.



Here are a few closeups of the wear on my xs850 2nd gear wheel dog faces.

 

Jesus clip never heard that name for the circlip.

 

My best guess is he thinks they look like prayer hands... ¯\_(ツ)_/¯

 

More to share..

This is the 5th gearwheel (1J7-17251-09-00) that mates with the 2nd gear wheels from the previous posts.

This specific example is revision 09 of gearwheel 1J7-17251. None of the partzilla or other North American parts diagrams for the xs750/850 call for this specific revision.

All the North American diagrams call for Revision 03, (1J7-17251-03-00), & probability is high that revs 09 and 03 are interchangeable.

I could be wrong & we'll know soon enough.. Enjoy!

 

So you should be able to use these parts with no machining?

 

Ok.. Good question, Franz.. Thanks..

Short Answer:
For the 5th gear wheel (1J7-17251-03-00, 1J7-17251-09-00)... Yes, I suspect no machining will be required, and this component --may--be-- drop-in compatible for any xs750-850 bike (TBD, pending further research).

Concerning xs750/850 "2nd" Gear Wheels, 1J7-17221-03-00/3J2-17221-00-00:
As detailed in above posts, the 79 xs750 2nd gearwheel (1J7-17221-03-00) (as confirmed) is NOT directly "drop-in" compatible with the 850 bikes. The 850 calls for the 2nd gearwheel "3J2-17221-00-00" and ID on this 850 gear is smaller than the counterpart 750 gear (as well as other differences, as outlined above, see above).

In regard to the xs750 2nd gearwheel (1J7-17221-03-00), as proposed, a bronze bushing can be turned and pressed into the 750 2nd gear wheel (1J7-17221-03-00) to attain compatibility with the 850 transmission, & matching ID of the 850 2nd gear wheel (3J2-17221-00-00) (this is what I will attempt to do, bronze bearing stock on order from mcmaster -- other variables at play, as well -- stay tuned).

Concerning xs750/850 "5th" Gear wheels, 1J7-17251-03-00, 1J7-17251-09-00:
The most recent post, above this one, is about the 5th gear wheel on the xs750/850 (which mates to the 2nd gear wheel (also detailed above))... dimensions and details for this NOS example of the "09" revision 5th gear wheel are detailed above. In theory, this "09" rev should be drop-in compatible on any xs750/850 bike. (TBD, watch for follow-up posts below for confirmation)

Thoughts:
Each year/model example of these bikes (at least in north America) calls for the gearwheel "1J7-17251-03-00"... (Thats Revision 03 of gearwheel 1J7-17221 (installed in my bike, pending de-install)). I suspect the "09" revision may have been specific to EU or A/PAC skus (for some reason, still not clear at this time).. I suspect gearwheels "1J7-17251-03-00" and "1J7-17251-09-00" should be completely drop-in interchangeable.. TBD

Stay tuned.

 

Just be aware that "revisions" could be due to any number of issues, a change in the supplier, some change in the physical casting, a change in machining/metallurgy/coating/finish, etc. It may be a "change" that is neither visible nor testable w/o laboratory-grade equipment.

Or it could be immediately obvious.

In my experience, Yamaha is pretty good at ensuring backward-compatability in revisions of major parts.

 

I always thought it was called that because of what is said when it flies off the pliers and into the far distant corner of the shop under things. As in "Jesus, where did that thing fly to?"

@slackard, delightful, Kevin Cameron style write up on your exploration of the XS850 transmission. Did you consider having the worn lugs on the old gear wheels welded and re-machining them?

 

Makes sense.

 

Welding and re-machining is likely ill advised since these gearwheels are induction hardened. Any welding would take the temper/hardness out of the HAZ and could lead to an unstable, soft or brittle part. To do this properly, one would need to re-harden and re-temper after welding/machining. Few shops are setup for or have the necessary experience to do heat treatment correctly, and in a 1-off custom job like this..it would be astoundingly expensive to have it done right.

Lets say we ignore material hardness/temper... We could build up some weld and would need to machine/grind it back to original dimensions & original tolerances... Work holding then becomes the next big concern.. perhaps with proper-sized mandrels, in a 3jaw chuck, on a rotary table, on a knee mill, one could attempt this type of machining with some degree of precision/repeatability.. In theory all the dogs should engage at the same time... and all these angles, radii and undercuts would make it a very difficult job to do correctly. If done poorly & out of tolerance, you risk loading up a single dog and snapping it off because the others are making zero contact and doing zero work (or worse).

Sourcing original (not worn) parts is the ideal path forward.. With luck the 750 specific 2nd gear wheels can be adapted to the 850. Will report back when I have more info to share!

 

Delightful explanation of why not weld and re-machine. A plain and yet technical reasoning. Thank you.

 

Getting late and didnt want to get into a whole thing here.... Just wanted to share this little nugget..

Manual states, "use deep 32mm socket to remove the clutch boss nut". No mention of just how deep...



Lots more photos to post, coming soon!

 

Details below on the very important XS750/850 "Clutch Holding Tool".

 

What's the part number for it .

 

Is that mig welding, it looks neat.

 

Where can I get some of that stock material? Grainger?

 

Thanks! It's TIG welded.

I get most of my mild steel and aluminum from the local steel distributor. They have drop-cut / hobbyist section, & I head over there every other week or so to pick things over.. usually $0.50/lb. (except when I bring donuts!)
Bronze or other exotic stuff i'll go through McMaster-Carr (not cheap, immediate shipping)
CoreMark metals will do small online sales, have good variety and will ship.. not cheap tho
OnlineMetals is another option.. even less cheap, depending on what you need.

Most mid sized cities will have some kind of local distributor serving local shops... If you call around locally (fab shops, steel distro house, etc..) just ask if they sell small drop quantity, or have a hobbyist/drop section you can pick.

A local fab shop sold me this steel pipe drop for a box of donuts... Never hurts to ask!

 

Do you do all your own welding and machining?

 

My family recently experienced a (profoundly understated) --*"MAJOR"*-- loss.

My uncle, Terry (see above), passed in a *GOD DAMNED TRAGIC* .... "FARM ACCIDENT", Oof, Age 84.
At age 84, Terry was going on 30!....Healthy *AF* & had *MANY* years to go.

(GENUINE TEARS AND SADNESS, PEOPLE!)

Terry was a skilled & storied "Tool & Die Maker".

The "Chat-Bot" says, "A good Tool & Die Maker was often considered the most technically skilled hand on the shop floor".

---THAT'S TERRY---

Terry gave a KIDNEY to my own father (his brother), and he was my machine shop mentor, FULL STOP.

I have leaned on & learned from Terry many, many, many times.

I know a number of other "Shop" folk, who I also lean on from time to time... Good people!

So, to answer you question, Franz....

Yes, for the time being, I do all my own shop/fab/etc work.... Old school and manual, to the extent possible.

I have a "day-job" / "co-worker" who is also a major contributor to my personal shop efforts (Joel, Clockwork Bikes).

Terry's loss will be omni-present in EVERYTHING I do, from here forward.

-- SHOP -- SAFETY -- IS -- NO -- JOKE -- FULL -- STOP --

 

@slackard sorry for you losing your uncle Terry in such tragic circumstances.

 

Interesting and startling discovery after getting the clutch basket off..

Pictured below is the bolt that holds the "middle gear drive" to the "axle drive" shaft.

On its own, this bolt backed itself out, bumping up against the shift shaft assembly.. Only 1 or 2 threads still engaged.. would have been a bad day if this bolt walked its way into a spinning clutch basket..

I am certain the basket has never been off. since the lock washer was as-new... Not good that this bolt backed itself out, it will def be getting some lock-tite when it goes back in!


Still working on getting the shifter fork shaft out in order to release the 5th gear wheel for inspection/replacement...

Big engine internals photo dump coming soon..

 

Starter clutch bolts have been known to back out too on the odd XJ.