sachs 504 performance

stephen haverty /

so I rebuilt the sachs 504 with new seals and gaskets. I was thinking of getting the Athena 70cc kit. but I was kind of convinced that it wasn't best. so my plan now is to put in a new piston set, a dellorto sha 15mm carb and a tomos nitro bullet exhaust. along with new chains and maybe front and rear sprockets. for anyone that has worked with the 504 d engine I was wondering if this is the best plan? or if there is any other small thing I can do to get optimal performance. thanks for all the help guy.

Re: sachs 504 performance

stephen haverty /

oand I have an internal ignition on the way as well. would a new cylinder head make a huge difference?

Re: sachs 504 performance

You have to replace the cyl and the head as one unit on a Sachs, so that's out. Do you have issues with your current piston? If your compression is good I'd just keep it.

I'd avoid making your gearing too much taller because the sachs clutch grabs low low and that engine doesn't make much low-end power.

Honestly if you get your carb and pipe tuned you'd be in pretty good shape already...if you can't stop there, port your stock cyl

Re: sachs 504 performance

As a base for you... my old 504 ran an avg of 30 with the A jug (no porting), 14.5mm intake (angle chopped off), SHA 14.14, SHA metal mesh insert, Gianelli circuit (folks hitch and moan about the pipe but I like it), and the stock 11x46 gearing. 17x2.25 rubber and my 6'2"/210+lbs. You'll need the larger Sachs intake if you're running the 15mm sha...I got a few I can send ya one for a few bucks. Otherwise that setup sounds good for at least $30 if done right. I would keep the gearing near stock...especially if you have any hills. At the tallest id say 11x40 but no taller.

Re: sachs 504 performance

On my 504 I have a cut/turned/welded intake, 15mm bing, 32mm header left pretty long with the black treats clamp on chamber and it does 34 all day. 36 sometimes. Stock gearing and the motor has never been opened up.

Re: sachs 504 performance

Also... only replace the piston & rings if absolutely needed. If compression is low but piston is good try just rings. And if you replace the piston try to use one that matches the jug otherwise it may need modified some to match the porting. Second... not sure if it was a typo but are you running as D or A crank? Lastly... don't change up gearing too much or it'll be useless.

Re: sachs 504 performance

you can modify the D jugs to work pretty well even with the shorter stroke cranks. athena 70 is fine, kindof underwhelming but with some taller gears it can move pretty well. probably can get away with leaving the clutches untouched until they do break loose.

Re: sachs 504 performance

Will, how do you modify the D jug to work better with the A? I got one I've been waiting to put on.

Re: sachs 504 performance

id say your better off porting the exhaust on your a cylinder as your crank is probably 42mm not 44mm so you wouldn't see much more out of the d cylinder. the porting on the a is adequate in most ways as the intake port can handle up to a 19mm carb just need to raise the exhaust port roughly 2mm and grind away the extra meat around it to help get thos gasses moving faster i have had good results with a little porting and a bored out square bing with the gianelli pipe with my gearing at 11x38 didnt suffer to much on the low end with decent top speed but 11x40 had wicked low end just topped out much to fast for my taste im in the prairies so i have time to get up to speed even in the city of winnipeg

Re: sachs 504 performance

Would milling a bit off the base of the D cylinder be worth it? To kind of make up for the shorter stroke.

Re: sachs 504 performance

OP pmed me... hes running an A not a D crank.

Re: sachs 504 performance

had a feeling as i dont think the 504 came with a d crank

Re: sachs 504 performance

Jeremy Gentry Wrote:

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> had a feeling as i dont think the 504 came with a

> d crank

Yep no d. However there was the limited run 2-gang 504s that came out of Switzerland. (edited)

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