Hi All

I hope you don't mind me posting this on here, for my son really.

So, he has a Suzuki 125GN which he wants to cut down into a bobber/scrambler type thing, he knows what he wants to do and how he's going to go about it but he's come to a point now when he needs to start making sure everything runs before he starts spending (MY) money on it.

It has been stood for at least 7 years outside, we picked it up (free) and he has stripped it down completely, the engine is sat on a bench in the shed at the moment and he is prepping the frame ready for cutting down, hoop attachment and then powder coating.

However, he wants to test the engine to see if he needs to strip it down, it turns by hand so is not seized, the carb is a right off so will need a new on and obviously there are no keys, (we didn't steel it!).

So my question is this, how can he bench test the engine? Are there any things he should look out for on such a project? And has anyone done anything like the 125gn before?

He's just turned 19 so can't get on the K's yet!!

I know it's not K related but he posted on another forum and didn't get much support (not very welcoming some people) but I said I would ask on here as I'm sure someone in K land has done all this before!

Hope you don't mind me posting this on here.

Thanks in advance 

Dave (& Gabe)

Put everything back together, try the engine, and strip it again.
I know, it's some work, but then you know everything fits and works.

Edit; did your son took it apart?

One thing to consider when stripping an engine enthusiastically is that, despite the satisfaction and fun, it can cost quite a bit to buy the necessary gaskets etc. to put it back together. If the engine was cost-free, then, so long as it turns over okay and compresses with plugs in, and there's no nasties in the oil, I myself wouldn't do much more than clean it up and have the rocker cover off to check the cams for signs of wear and set the clearances.

I think the GN/GS 125 Soozooks were the run-forever commuter bikes? so they should be tough enough?

Good solid advice from everyone,so put the engine back in get it running and go from there.Good luck with the project.

There's a guy in our office that abuses the crap out of a Honda CG125 (fair play: he's good with the maintenance too. I know - I get my ear constantly bent with him wanting to know how to do things properly ). The point of this statement is that I have been really surprised at how cheap spares are (£70 for an OEM barrel & piston and gaskets to fit?). I doubt the Suzuki spares can be that much more expensive than Honda ones in general?

Thanks for the advice guys. I think you're right, clean it up and put it back.

Yes Arlina, he has done it all himself, I am trying to keep back from it so he not only learns what to do but will also have the satisfaction when done. 

Dai, yes I've had a look through the usual places and could get everything you need to completely rebuild one for very little money, a carb is about £20 for instance. In fact, as usual, the most expensive parts are the plastics, but as he wants to cut it down that doesn't matter.
  
I will pop up a few pictures when he's done.

Thank you all for the advice and support with this.

Dave (& Gabe)

It;s always wise to test the engine IN the bike, the frame is made for that.
Unless you have an engine stand that looks like a frame....

Guys will learn

Davep wrote:So, he has a Suzuki 125GN which he wants to cut down into a bobber/scrambler type thing . . .

You've got a bonanza there.

Arlina wrote:It;s always wise to test the engine IN the bike, the frame is made for that.
Unless you have an engine stand that looks like a frame....

Guys will learn

Amen sister.
So much easier to sort it out stock before making modifications but, you may learn more doing it the hard way.
Good luck with the build!

I'd go ahead and build the bike and try out the engine the way it is first as long as it turns over freely and the valves move up and down. It may surprise you and be a good runner or not but either way you need to run it to know and if it's toast used motors are pretty cheap and easy to swap out.