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modifications to the sachs 150KN

Discussion in 'Modifications and Projects' started by buzzawak, Mar 4, 2009.

  1. Hi all, If you are a 150KN owner the following link may be of interest. Iit describes a number of modifications to improve the handling and performance that can be done on the sachs 150KN. I found this while web surfing. I can not verify the information and as yet have not tried any of the modification.

    www.townsvillemcc.net/For Download/2008/RR Stuff/SACHS 150KN Modifications.pdf
  2. That's a great read mate, not just for the Sachs, but engine stuff in general

    Thanks! :grin:
  3. The engine mods seem like a lot of effort to go to for what would probably only be a minor power gain. Probably be cheaper and easier to just bolt in a 250cc Chinese engine.
  4. Yes very true, but then you will want to improve the 250cc engine, where will it end. The whole changed engine rego check thingy can be a pain aswell
  5. Agreed, but unless you were planning on racing in a >200cc class I don't see much point in that level of modification on an engine with such limited potential as an air-cooled, pushrod single.
    Buy something designed for performance, rather than economy, and most of the work is already done for you.
  6. AS a fellow Suchs, um I mean Sachs owner :p , I cannot justify spending the time and money on any upgrades ( unless you race it ), although I have thought about it - good read though.

    I am not willing to upgrade/modify as the KN does the job I need it for, and then get a bigger bike once off the P's
  7. Hey, don't knock the old pushrod :) When I was a teenager I stuck a hotdog pipe on the family lawnmower. The point is peoples like to tinker and at all levels. For some riding is only part of the fun of owning a bike.
  8. I think thats the point, cheap racing class & learn how to modify engines as you go.
  9. Very aware of that :grin:.
    Problem is that if you start out with what is basically a very agricultural engine then it's not going to take many mods before you end up subjecting the remaining original parts to loads they were never designed for and they break. Don't forget that this is a bike that has already been upgraded from a 125 (and only fairly recently too) - and that it's also the most powerful motorcycle that manufacturer has ever made.
    If you want to go to that much effort on a 125 you'd be better off restoring an old CG125 or GS125. At least then you'd have a nicely restored classic rather than just a modified Chinese copy. If you wanted to race then I suspect a CBR125 would probably be a better starting point.
  10. Jd, your 100% right, I posted the modification information mainly because I recently purchased a Sachs 150cc off eBay and found very little info about the bike, so figured it may be of interest to some.

    You may ask why did I buy the Sachs! Well I use to ride a CB750/4 back in 1980's (Yes I am a old bastard). The wife replaced the bikes with a family. All that being sensible and responsible stuff.

    Now the kids are older and don't need their dad as much the wife said its ok now if I want to kill myself on a bike (my life insurance is payed up).

    My MOST test is coming up end of this month and I didn't want to buy a bike that would have issues as soon I got it home plus my budget was $2500 including riding gear.

    As far as mods that I would consider while I have the Sachs will be to address obvious failings.

    1) Wider front tyre
    2) Stiffen up front forks
    3) Improve the breathing (port and polish)
    4) Smaller back sprocket
  11. lol JD you feel very strongly about not modifying this.... :shock:
  12. Not really, I was actually thinking of buying one myself until the importers went under. If I had I undoubtedly would have done something to improve the suspension and brakes so I'm certainly not denying the information you posted is useful.
    I just think things like fitting oversized pistons and machining out inlet manifolds are pointless on a cheap Chinese bike. Short of replacing the engine completely your almost certain to find that any potential gain is largely negated by existing original parts you can't easily change (like valve area).
  13. Improving the Express front end

    The forks on the Sachs Express are very sad. Very soft and bottom out to easy. On the weekend I stuck the bike up on the centre stand and undid the fork caps. The Express has a progressive spring with a 90mm spacer sitting on top of it. I replaced the original spacer with a 100mm piece of pipe with the correct diameter and replaced the fork oil with 210cc of 10 weight fork oil.

    The front rubber looks more like a bicycle tyre which I wouldn’t trust on a merry-go-round. I managed to get a wider second hand tyre from the wreckers with 80% tread Size 90/90 x 18". This was a great improvement. I had to raise the front guard 10mm to provide a bit more clearance but this was easy to do by elongating the mounting holes in the brace under the plastic guard.


    A vast improvement over the original setup. The bike rides much better, don't nose dive when uses the front breaks and feels secure in the corners

    Cost for the 90/90 x 18†was $30. ½ Lt of fork oil $9 and the piece of pipe I had spare in the tool shed
    Total cost not including the pipe was $39.00
  14. Please see:


    for another persons thoughts & plans re modifications

    Safe riding to all