sachs performance tuning;

alright, here's the set up.

sachs balboa 505c

70cc reedvalve athena (boyesen reeds!)

casematched (with help from jeremy sullivan long ago)

21 mm 'racing edition' phbg dellorto

12 tooth front sprocket

heavily modified tomos estoril (thank you naz)

gas mixture of 40:1 using motul 800.

today was the first time i've started it and ridden it, so obviously i am in the tuning and break-in phase. it has a few low spots and a few batshitcrazy spots (yay adrenaline!). definitely not jetted right; super rich right now at an 88 main and the stock idle jet for that carb. smokey as hell.

so, has anyone run a similar setup or have any advice, words of caution, magical wisdom, recommendations?

Re: sachs performance tuning;

loctite everything.

make sure your exhaust has some flex built into it.

Re: sachs performance tuning;

exhaust was modified in such a way that it is now rubber mounted to the frame and flange mounted to the kit instead of the traditional sachs spigot mount.

Re: sachs performance tuning;

let us know! I have the same engine and just wondering how the Athena 70cc performs.

Re: sachs performance tuning;


Re: sachs performance tuning;

Where did you get the 70cc from. I want one.

Re: sachs performance tuning;

Hopefully I can come and take a looky this weekend.. that's my plan anyways. Oh and I used a rubber bushing mount slightly separated from the exhaust to hang the pipe on, so the whole pipe swings with the motor. This would be the second pipe I have mounted on Sachs engine and so far so good.


Re: sachs performance tuning;

triple check for airleaks

love lots of smoke

Re: sachs performance tuning;

lots of smoke. currently running an 88 and plug choppin' looks good.

there is a slight leak at the exhaust header and a pinhole leak where the exhaust was sliced in half to twist it to fit better. this should be fixed as soon as naz has time. :)

Re: sachs performance tuning;

Yeah, very curious how this one runs, it's the same set up I'm planning on my other ped. Did you get the kit from treats? I was planning on buying his, but now it's gone!

Re: sachs performance tuning;

no, i got this kit from last winter.

the 80cc reedvalve athena i bought from treats is on a different sachs project which i will post about in a few weeks probably.

Re: sachs performance tuning;

still running the 88 jet. bogs in some spots, rips in others. still rich. smokey for sure. very, very loud.

engine shakes like a motherfscker; one of my crankarm pins fell out on one of my test runs which meant no rear break for a second. thrills.

any ideas on clutch adjustment? it was suggested the clutch may be too tight. hm.

and something that was brought up in another thread... thoughts on clutch replacements that would be higher quality? it seems possible but the question is how and what.

Re: sachs performance tuning;

I haven't seen any clutch replacements- I know the multi speed "outer" clutch plates are different, being a composite of metal and fiber, but I don't know if they last any better.

What combination of sizes do you you use on the metal "inner" plates?

I've been running 3 thick metal plates and a really really thin spacer on the end, but today I noticed that 3 thin and 1 thick measure out the same, so I tried it in this order, going away from the crank: thin metal, fiber, 2 thin metal, fiber, thick metal. It had good enough take off, without the hard snap that sometimes can happen. Really, I haven't noticed a difference yet, but I just did it today.

Re: sachs performance tuning;

The best thing I've found you can do for your clutch is change the ATF all the damn time. Like once a month. I used to run the 70cc piston port kit at 45mph and I never had any serious clutch problems.

Re: sachs performance tuning;

thanks brendan. i will definitely keep that in mind.

Re: sachs performance tuning;

get ready to need a new clutch.

Re: sachs performance tuning;

^ sorry, didnt read taht everyone else wrote about clutch problems before me :)

Re: sachs performance tuning;

:) s'alright, i've been aware of the clutch problems for quite a while, now i just get to deal with them as they come up. yargh.

exhaust leaks should be fixed this weekend, then more tuning and breaking in for a few weeks, then maybe we'll get the gps out.

Re: sachs performance tuning;

oh the trials and tribulations of mopeds. fsck. oh sachs monsters, why do you misbehave so..

monday and i went on my first 'real ride' on this bike. georgetown to ballard, ballard to moped monday, moped monday to the west seattle bridge and then to home.

i got my first taste of sachs clutch problems. already i need to take my clutch apart and rebuild (my clutch grabs like crazy awesome but isn't really into letting it go, which occasionally means the death lurch at stops and fighting to get the clutch unstuck). 30 weight motor oil was suggested and is probably where i will be going with this.

exhaust problems which springs will fix quick. i knew this was going to be a problem. thankfully the spring mounting brackets had already been added to the exhaust when it was modified.

the coaster brake bar that goes from the crank to the rear wheel hub rattles against my exhaust and makes the bike sound like it's going to crumble. ha.

strange headlight problems resulting in surges of bright-dim-no light-bright-bright-dim (bad connection? where is it?). i'm thinking i'll do the battery thing instead of running the light off the bike for this one. one less electrical thing to worry about.

beginning of the day was fouling plugs dirty, dirty black. i should have kept with that. end of the day and my plug is grey. lean. too many different carb adjustments done in one day and not enough trial and test runs. changes that were made; needle was set to the lowest setting (per tim p's suggestion) and i had lowered the jet from an 88 to an 86 a few days prior. airfilter was changed. all at different times. tweaks here and there on the mixture and idle screws. brain on verge of exploding. i think i will raise the needle back up to where it was. rich.

i must admit though, this thing rips and accelerates fast once it gets off the line and is pretty damn fun. i zipped past quite a few people when i wasn't keeping in time with amy. i fear the vibrations though. it cracked a good portion of my sparkplug boot off. ha.

sadly, i don't really plan on touching this bike until the end of august when i have time and sanity again.

back to the drawing board.

Re: sachs performance tuning;

If I can get a access to a lathe, I'm going to make motor mounts out of derlin. I just hope they don't shatter.

the hard take off, like "reeee- slam" are the weights loosening up, or too much space, from what I've seen.

Re: sachs performance tuning;

take off is pretty easy, just kind of slow off the line but zips up pretty fast.

the death rattle of the stuck clutch when i come to a stop is what worries me. :( the death rattle seemed like it happened more often after long stretches of road with no stops/lights. grr.

also, rubber mounting = the suck. vibrates SO much. bleh.

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I found some lock washers that are the right size to take up the slack, but you would need a stack of them, and it wouldn't protect the case at all.

Heat and sometimes lack of fluid make it lock up. Sometimes revving before and while you stop can break it out, but not always, and if you gots more power- that's really not going to work.

The really frustrating part is that sachs still makes clutches for all kinds of cars, and motorcycles- who was asleep when they designed these things?

Re: sachs performance tuning;

i don't think it's a lack of fluid though the 30 weight motor oil that tim suggested may be a good idea as a replacement. i'm pretty sure it's the heat causing the clutch to lock up. revving the engine a little at lights and when i am slowing down to stop works well, but not always.

anyway, plan is to rebuild the clutch, figure out the headlight, and go from there. i definitely have some issues with this bike i need to work out before i get it back on the road again. trials and errors and all that. at least now i know about some of the clutch issues first hand instead of by word of mouth. ha.

Re: sachs performance tuning;

Wondering where you found the 12 tooth primary sprocket?

Thanks guys for the advice on the clutch. Mine is starting to let go off the line but once hooked/revved up seems fine.

FYI....Prima G3 with 80cc Athena.

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Its good to hear someone has a Athena sachs running. There are two here in Tempe with the 80cc kits that run great on the stand but not on the ground....upside down pistons??? Oh well, now you can play with the fast bikes cause I hear the sachs can rip. Small bore, I have a 11 or 12 that I accidently got for the v1, you can have it if you want.

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What gear are you running on your G3? I was winding out stock at 30mph. I just put a 31T on there and lost all my bottom but I think I could hit 40mph on a long stretch. This is a stock ported cylinder with a dellorto 16mm and exhaust. Anyone fix their clutch yet? Anyone have New pads? I need the thickness. I want to have some made.

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