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The 2-Stroke Garage => Turning Wrenches => Topic started by: Perattzi on August 08, 2021, 11:04:54 PM

Title: 76 Suzuki A100 rotary valve
Post by: Perattzi on August 08, 2021, 11:04:54 PM
Howdy! (Not sure if this belongs here on in the projects section. It's not a resto or anything...)So glad the forum is back! Spent many many hours on here about 10 years ago. Never would have built my RD without everyone's help. RD is about to get a refresh, but in the meantime my coworker enlisted me to get a 76 Suzuki A100 'Go-Fer' back on the road. His grandfather bought it new and has been hiding in a garage corner since my buddy was a kid. Here it is fresh from the shadows:
(https://i.imgur.com/FHXdXBO.jpg)
Has since cleaned up pretty nicely.

Checking out the motor, so far top end looks good, has about 6k on clock.the bottom end is directly oiled by the pump. Only big issue I have encountered is the rotary valve is sucking a ton of gearbox oil in somehow. At first I thought my buddy had overfilled the gearbox and one of the outer o rings could be bad, but upon further inspection seems I should just replace all seals/o-rings/and gaskets associated with the rotary intake. This is my first time working on a rotary. Mostly I tinker w/ Yamahas. Surprisingly I was able to find most of the stuff still available from Suzuki and is on the way. 

(https://i.imgur.com/Of9Wz9B.jpg)
(https://i.imgur.com/GBV26d8.jpg)

Only part I haven't ordered is the rotary disc itself. Visually it has some wear, it doesn't 'feel' too bad to the touch. Anyone with experience feel I should replace it? The part is only available overseas and may take many weeks to arrive. Was hoping to button it up fairly quickly but also want to do the job right.
Will update some other progress.
Thanks!
Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on August 08, 2021, 11:11:19 PM
This thing is damn near a moped  :vroom:
(https://i.imgur.com/wUQXfET.jpg)

(https://i.imgur.com/ThiD3Mz.jpg)

As you can see tons of gear oil where it ought to not be!
Title: Re: 76 Suzuki A100 rotary valve
Post by: rodneya on August 09, 2021, 12:36:29 AM
Quote from: Perattzi on August 08, 2021, 11:11:19 PM
This thing is damn near a moped  :vroom:
(https://i.imgur.com/wUQXfET.jpg)


Whats the deal with the pressure plate bolts?
Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on August 09, 2021, 12:57:09 AM


Whats the deal with the pressure plate bolts?
[/quote]

Oh, those are definitely whacky! The springs kind of screw in from the back of the pressure plate and have a loop on the outside end, you just pull them out-stretched and slip the retaining pins in. Why that seemed like a good idea to the engineers is beyond me! I will say they are in there pretty snug.
Title: Re: 76 Suzuki A100 rotary valve
Post by: sav0r on August 09, 2021, 07:48:40 AM
Since you aren't racing that disc looks fine to me. I'd run it.
Title: Re: 76 Suzuki A100 rotary valve
Post by: 85RZwade on August 09, 2021, 09:03:47 AM
Neat bike, and looks like it cleaned up nicely.
Title: Re: 76 Suzuki A100 rotary valve
Post by: m in sc on August 09, 2021, 10:08:10 AM
neat!

my 67 kaw 120 has the same setup on the pressure plate.  spring tool and you pull the spring out, pull the pin to remove. to reinstall, pull spring back out and slide pin back in. pretty ingenious actually.
that things way cool.  :clint:
Title: Re: 76 Suzuki A100 rotary valve
Post by: SoCal250 on August 09, 2021, 12:32:32 PM
Cool little bike  :thumbs:

Does it stilll have the Go-fer logo on the left side? If not, repros are available: https://www.diablocycle.com/A100-GO-FER-Side-Cover-Decals.html
The Gopher is one of those cool '70s graphics that just has to be on the bike. It's classic!

The "CCI" decal for the right is still available from Suzuki
Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on August 09, 2021, 01:17:44 PM
Oh dang! Nope the Go-Fer decal is gone(his dad probably thought it was dorky in 1983 or something lol)Definitely am going to order those decals and surprise him! So cool 😎.

Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on August 09, 2021, 05:28:34 PM
(https://i.imgur.com/RO78vow.jpg)
Fit some new tires/tubes/strips. Hard to find rubber bands for this bike. Went with some Shinko pseudo trials type. Surely will be a bit squirmy on twisties but he's likely just going to putt around a campground on it. I think the big excitement is just to have it functional again for his dad and grandad to see.
Pulled the rotor off to fit some new points. AlwYs amazed at how many bikes my one and only puller fits!
Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on August 28, 2021, 10:46:16 PM
(https://imgur.com/a/CtVM6ev)
Well, after jacking my back helping a friend move a giant bandsaw up some sketchy stairs, took some time off. Feeling good now and Been making progress the past week. Got the carb sorted, rotary valve seals/o rings/ gaskets all replaced. No longer sucking gear oil.  :whoop: replaced the points, set the gap best I could.. what a hassle that is on this setup! Installed new oil feed line and new oil pump crush washers at all the Union bolts. New head gasket, fuel line, spark plug etc. put oils and fuel in, started right up! Then quickly realized I need a new exhaust gasket lol. Idles and revs well. Not ready to test ride it yet but happy with results.
Only thing bugging me is the damn oil pump. There definitely a bit of a leak somewhere bc I can see the new green Motul seeping down the side of the pump body. At first I didn't see any oil moving through line but bike is smoking. I was being mindful of shitting it down if I saw the smoke decrees drastically. Then I saw some of the new oil slowly move through the line but appeared there's a large air bubble. I cracked the bleed screw on the side and oil ran out but it seems like not much if any oil is actually pumping out. Really not sure how to proceed. A new old stock pump is pricey and likely has old dried seals.
(https://i.imgur.com/aJo8kUJ.jpg)
(https://i.imgur.com/gSCHtpr.jpg)
(https://i.imgur.com/vZhEexI.jpg)
(https://i.imgur.com/yNkW1Xv.jpg)
Title: Re: 76 Suzuki A100 rotary valve
Post by: Striker1423 on August 30, 2021, 07:56:47 AM
on my old kawi 90 the oil line looked similar, but was elevated above the pump not under it. As far as the air bubble is concerned, crack the banjo bolt at the oil line and jiggle the line carefully. once the air comes up, retighten the banjo and crack the bleeder on the pump again. Don't crack he hard plastic line or you'll be replacing it.
Title: Re: 76 Suzuki A100 rotary valve
Post by: m in sc on August 30, 2021, 10:14:55 AM
also..make sure the check valve is working in the banjo. side note: ... those aluminum crush washers are dismal at best, i like to swap them with m6 stat o seals if you can, easier on the threads. .02

Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on September 03, 2021, 01:03:56 PM
Thanks for the tips! I knew the pump would be a little thorn in my side. Yes the crush washers are disappointing. I'll pick up some of the other you suggested Mark. I'll just get new banjo bolts too if that's another problem area. Also ordered a new o ring/seal kit for the pump. Once I get this sorted it will be to ride it!  :thumbs:
Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on September 03, 2021, 01:47:42 PM
So looking at the parts fiche looks like only the rotary intake side has a check valve, and not the magneto side... seem cirrect?  What's a good way to check the valve, just compressed air to see if it flows one way and the other? Thx
Title: Re: 76 Suzuki A100 rotary valve
Post by: Striker1423 on September 03, 2021, 02:00:59 PM
On rotary motors the oil injection occurs to lube the rotary plate. However, the pumps typically have check valves on any outlet. One they might have deemed serviceable and one they might not have. Would be weird to allow oil to seep at all times.
Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on September 03, 2021, 03:20:12 PM
Thx. Yea on this setup the line from the pump splits with one line going to left side of the crank and the other goes to the rotary intake. That side indicates a check valve. The banjo is quite large. Guess I'll just pull the magneto and points plate to see.
Title: Re: 76 Suzuki A100 rotary valve
Post by: m in sc on September 03, 2021, 03:22:24 PM
i know on mine the check is at the fitting on the motor, but, again, its a kawasaki.
Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on January 04, 2022, 02:40:00 AM
Forgot to post up the progress! Bike is all done now. Ended up rebuilding the oil pump(took a month and a half to get correct parts after being sent the wrong kit from Asia). No more leaking or air bubbles, run like a top!   :cheerleader: Fixed all of the little electrical and minor mechanical eccentricities. Pic of my buddy grinning after his first little ride around on it. Cool this bike is on its 3rd generation in the family. Well now onto someday buttoning up my RD project and maybe fixing that damn Puch Moped in the shed...  :rolleyes:

(https://i.imgur.com/qhNUGMA.jpg)
Title: Re: 76 Suzuki A100 rotary valve
Post by: pidjones on January 04, 2022, 07:05:15 AM
Always gratifying to make a friend happy with one's efforts. Well done!
Title: Re: 76 Suzuki A100 rotary valve
Post by: Striker1423 on January 04, 2022, 09:41:58 AM
Sweet!
Title: Re: 76 Suzuki A100 rotary valve
Post by: pdxjim on January 04, 2022, 10:54:28 AM
Looks great Joe!
Title: Re: 76 Suzuki A100 rotary valve
Post by: SoCal250 on January 04, 2022, 01:02:35 PM
Nice work :clap: congrats!
Title: Re: 76 Suzuki A100 rotary valve
Post by: Perattzi on January 04, 2022, 03:33:15 PM
Thanks guys! 🙏
...also forgot about my Yamaha DT100 resto collecting dust 🤦‍♂️  Just so cold in the garage right now now! 🥶
Title: Re: 76 Suzuki A100 rotary valve
Post by: m in sc on January 04, 2022, 03:45:32 PM
yeah man, nice job on that one.  :olaf: