My GS850G ongoing issues and maintenance.

[Grimly]

I realised that I don't have a seperate thread to document all the various things that have cropped up over the years, so this will do. I'll populate it with whatever photographic material I have from doing repair work in the past decade or so, and even before that, though pics from the 80s, 90s and even the 2000s are few and far between.

 

[hank2]

Looking forward to your future posts on this. I'm sure it will be enjoyed by many!

 

[Burque73]

Grimly,
To compile the innovative mods and repairs you've done to that 850 in one thread would be a great thing. I've enjoyed reading about your work and find it inspirational.

Seems like just going through the "what did you wrench on today" thread and transplanting some of your posts would be simple enough. That would be a start anyway.

 

[Grimly]

May as well kick off with a current mod - making adjustable preloaders for the forks.
I have a spare set of air-fork caps, and I found that 10mm threaded bar couplers fit perfectly inside them.
I picked up a couple of 10mm set-bolts, but they're actually a little bit short, so I'll cut some 10mm all-thread to the length I need and weld a nut on the top end.
My plan is to epoxy the bar couplers into the cavity of the caps, then cut off the air humps - there will still be 5mm thickness of alloy on the top after that, so strong enough, I feel. Getting a good bond between the aluminium, epoxy and steel will be crucial, as I don't want these things to work loose. They can't actually go anywhere, but the more secure, the better.

In use, they'll be quite simple, adjust the rod down until the pre-load is right, and nip the locknut up.

 

[Grimly]

Replaced the cheapanese relays in the fairing and the frame for some decent Bosch ones. I hadn't had any trouble with them, but they are a bit flimsy and I simply don't trust them, as the top pops off far too easily, which would leave them adrift and capable of causing some mayhem.









Also stripped a Telefix fork brace from a set of L forks that had been lying around for 20 years. Some monkey had attempted to strip them but all they'd done was round off all the cap bolts. It took some heat and the judicious application of a Torx 30 adjusted with a precision percussion instrument to achieve full undoing.

 

[GSXR7ED]

Good going!

Great to document your work! And with pics too!

Ed

****

 

[Steve]

... adjusted with a precision percussion instrument ...

I like that. :encouragement:

.

 

[Grimly]

Got the hokey-ass preload adjusters in place.
They seem to work.












There's about 12mm of basic preload in there because of the thickness of the washer and the protruding part of the threaded barrel, but that's fine as i had already tried a couple of 10mm spacers to see what difference they made, so knew I was on the right track.
The total available thread depth from zero adjustment to full (as seen in the pics) is 20mm, so plus the 12 gives me 32mm.
That works absolutely fine.

 

[Grimly]

Received another SU needle in the post, an AAA profile, and fitted it today.
The AAA is profiled to feed approximately 70 hungry horses on a tuned Mini 1000 (in the same ballpark for air demand), so I was fairly hopeful it would provide a reasonably close approximation to what I need here.
Instant difference on startup, almost immediately settled into a better idle than before. After some warm-up time, a bit of normal mixture and idle settings and the engine ticked over more steadily than it ever did before, so it's looking good. Flicking on the AFR gauge revealed the idle is a steady 12.6, so bang-on.
Wasn't able to do a test ride today as the wind was gusting up to 60+mph, so out on the road tomorrow with it.

In the same package was a hi-flow fuel inlet valve, normally fitted to fuel-guzzlers, but I suspect it's needed here to compensate for the gravity feed. I was never conscious of needing one before, but like a bolt from the blue it suddenly hit me - to rule it out, fit a bigger one.
I also suspect the petcock might not be flowing as much as it should, but will check that properly with a drain test both on the Prime and On setting. Last time I drained the tank on Prime there was no shortage of flow, but I've never checked it on the On position.

Once I get this carb sorted out properly, I can modify the spare carb for greater airflow and raise its capacity to almost match the next size up.
The carb in this case (currently fitted) is an HIF38 (1.5"), the next size up is the HIF44 (1.75").

 

[Grimly]

Got it out yesterday and moderately pleased with the results. AFR gauge (asssuming some measure of accuracy) tells me that hard acceleration is sitting at between 12 and 12.5, steady cruise is between 13.2 and 13.5 at 60 and 70mph. It peaks lean on decel to around 16, which is ok.
In all, the midrange isn't too far from what it was like with four carbs, according to the seat of the pants dyno, but the top end will not be there, of course.
I need to venture over to the motorway and put some top end time on it, just to see how it behaves. Previously, it was maxing out at 90, and I know that manifold will flow enough for 115, with the bigger carb.
Pre-AFR, I didn't know whether it was running out of fuel at 90 or airflow, or what.
Changed the oil today and put in some 5w50 just for a trial. The gearbox will shear that down in 2000 miles to a thin 40 at most, more like a 30. The crap that was in it turned out to be disappointing - Wave Power synth 10w40, which only lasted 800 miles before it went off. This gearbox is brutal on oils.

 

[zuluwiz]

Just how heavy is that "precision percussion instrument" ?

 

[Grimly]

Just how heavy is that "precision percussion instrument" ?

It was a one-pound ball-pein hammer.

 

[Grimly]

Today I made a better exhaust noise.

 

[Buffalo Bill]

Dude, you don have to post it 2ce…

 

[Grimly]

Dude, you don have to post it 2ce…

Two seperate threads in different places, though. Each with a different purpose.
Perhaps you're right - just here would be better, depending on what readers use to catch up on content with.
"New Posts" will throw this up anyway.

 

[Rich82GS750TZ]

Dave, please pardon my ignorance, but what is this?

sounds bada$$, by the way.

 

[Grimly]

That's the AFR oxygen sensor. Once I finish off sorting out the mixture and can be sure it's stable, I can remove that.

 

[Grimly]

Fitted a Telefix fork brace the other day and tried it out.
Not bad; can definitely feel a difference, just like every other time I've fitted a brace to the spindly forks of this era. In this case I was definitely feeling the front squrming a bit with all the extra weight of fairing, lights and everything else, so it's tightened things up just a touch.

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[Steve]

Not bad on the muffler sound. :encouragement:

I do have a question, though. What's the purpose of the shorter pipe? :-k

.

 

[Grimly]

The design evolved.
Originally, I'd intended for the cone-ended (actually just flattened) pipe to run the entire length and the incoming gases would be forced on all sides of it to eventually make their way through the perforations into the centre then outwards at the end. I'd intended to partially flatten the three surrounding pipes to provide a gas passage and also a central locator within the outer shell to keep the main pipe in the middle.
After I'd welded on the central pipe to the exit flange, I realised it was a bit skewed, but that immediately threw up another idea - keep the skew , make sure it went well away from the AFR bung and simply use just one short piece as a packing piece and gas flow channel. All the gas has no lack of expansion and flow spaces down past the main pipe, and as it hits the scrubbers some of it will percolate through them to freedom, but most will likely just find its way through the front half perforations. The scrubbers are mainly there to damp down any tendency for a hard reflection from the end wall, at which they seem to be working well.