Sins of the PO and reflections of a newb carb rebuilder of a BS32ss 1980 gs850gl

[Steve]

That's OK, I have fat fingers, too.

Then there's also that chance that the VIN tag says it was assembled in December, 1978, leading some to think that it's a '78 bike.

I have a copy of a magazine from 1979, don't remember which one it was, but they did a shaft-drive shootout. They gathered examples of all the shaft-driven bikes available at the time and did a comparison test. The test involved a ride from their offices in southern California to Daytona for the races. The races were in late February or early March that year, so the 850 that they had in that test obviously had to be assembled a bit before that, possibly in late '78.

That was an interesting test. The contenders were: Honda GL1000 Goldwing, Yamaha XS1100, BMW R100 (might have been R100T), Kawasaki KZ1000ST, Kawasaki KZ1300 and Suzuki GS850G. The overall winner was the GS850G.

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[Uncamitzi]

Cautious success.... went for a short ride and everything seems ok at first blush... a couple more shake down runs... but because there's some popping going downhill with no throttle.. sounds like both sides...so that's a plus... I'm guessing I'm still running a bit rich.. Might have to adjust the air screws a bit more...... thoughts?

[Steve]

Popping on deccel like that could be a perfect carb mix, but also include a leak in an exhaust gasket.

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[Steve]

Carbs back on.... temp gas fed ... cautiously optimistic I gapped the spark plugs... charged the battery, and primed the carbs watching for overflow or leaks... pulled the choke (enrichment) cable and cranked................ fired up.... ... No airbox yet... but even without the airbox it warmed up and settled into a nice steady idle adjusted to about 1100...

Yes, they will start and idle, even without anything on the intake side of the carb, but if you give it any thottle, it will fall flat on its face. When you have a helper available, hold a folded shop rag over the carb intakes and try it again. The idle will be a bit smoother, but when you apply some throttle, it will actually rev up like it should. If you could find a way to clamp the rag over the intakes, it will run well enough to ride around the block. It's just not a permanent condition that I would consider leaving in place.

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[Uncamitzi]

Popping on deccel like that could be a perfect carb mix, but also include a leak in an exhaust gasket.

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I'll pull the plugs when it stops raining... I went to Wright's to get a oil filter and on the way back the throttle cable broke.... Long story and a longer walk.... fixed now... left turn lights quit working.. I'd laugh if I wasn't so tired from the hikes today....

[Uncamitzi]

As I am making mixture adjustments there is popping like a backfire through the carbs. It's not rhythmic but rather intermittent. It seems I've been here before... trying to get the mixture right but I don't remember backfiring through the carbs... I'm going to clean the plugs and start again. willing to take suggestions. I'm working on the second method suggested in Bikecliffs website. http://members.dslextreme.com/users/...n_CV_Carbs.pdf

[Steve]

I have not taken the time to go back and read through all the posts, what are you using for your starting setting on the mixture screws?

I have always started a bit rich, with three full turns out from lightly seated. That is three full 360° turns, not three "flips" of 180° each. I have to specify that, because I helped on owner many years ago that insisted that his screws were out three turns. After I rode about two hours to get to him, I started turning the screws in to establish a base point and was surprised when they bottomed out at 1 1/2 turns. Yep, three "flips" of the screwdriver, which he called "turns".

Three turns out is more than is usually necessary. Because it is a bit rich, it will come off "choke" a bit quicker and is easier to work with.

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[Uncamitzi]

After my last test ride I found these things. Stuttering at cruise when maintaining steady input on throttle. Carbon fouled spark plugs. And the most worrying.. the airbox boots have moved and may not be making a seal... I started with 2 full turns (counter clockwise) off the lightly bottomed air screws. It was running really great as I left.. but got bad as I made the turn to come home (about 10 mile round trip in city driving) ... I'll fix the airbox issue and move back to where I was.

[Uncamitzi]

AIRBOX!!!!! grrr... IMG_20190505_151212353.jpg I hope this works... I would like to find the tiny fingered guy that designed this style of airbox attachment!!!!!

[Uncamitzi]

Good news, bad news... trial and error after error,... Test ride results. airbox stayed in place on bumpy Salt Lake streets... Bad news bike ran like crap and fouled the plugs again. In (clockwise) to lean and out (counter clockwise to) richen ...right?) Less than two turns out and the bike dies when the throttle is "bipped".... Going back to school on the slide needles I left at the #2 slot.

[Big T]

The mixture screw only affects the idle mixture
What throttle position is giving the problem?

[Steve]

In (clockwise) to lean and out (counter clockwise to) richen ...right?

That is correct.

Less than two turns out and the bike dies when the throttle is "bipped".

Have you tried the recommended THREE turns for a starting point?

Going back to school on the slide needles I left at the #2 slot.

Where did you find needles with more than one slot? Stock needles only had one slot.

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[Uncamitzi]

Yes 3 was way to rich....but more on that in a sec.

I had decided to leave the Dyna Jet Needles in but I miscounted..they were on the 3rd slot down.. not the second.. I am NOW putting in the stock needles... sigh

I haven't yet taken a shortcut that didn't end up biting me in the ass and being a pain in my back...... OH the lessons I'm learning.......

[Uncamitzi]

The mixture screw only affects the idle mixture
What throttle position is giving the problem?

Hard to tell until I can quit fouling the plugs on every test ride.... I was checking the gap in the sparkplugs after this last run and found that #1 was almost closed... that's got me worried..but I may have bashed it on the way back out to the bike.... (I hope)

[Uncamitzi]

Well............there's yer problem...................