Suzuki x4 gt 125 tuning with a cdi and no points.
I finally got around to making my own electronic ignition to get rid of contact breaker points.
1982 x4 125 twin, dead breed.
This was the last of the twin cylinder 125's of the 1980's and comes in at 1982.
The reed valves have been replaced, the metal one's binned and a set of Yamaha yz 250 one's fitted after I cut them down to size.
The exhausts I made myself from original downpipes that I cut off the original pipes. The expansion chambers are sized for performance, based on old tuning diagrams from my racing days.
I finished it off with some porting to the cylinder barrels and some high flow filters.
I managed to get it from 16 bhp to 25 bhp tested on a rolling road last year. The weakest link on this bike was contact breaker points, so now they are GONE.
Rotor pick ups now look like this. (apologies for photo quality)
I tried using 1 pick up and 1 cdi, and it did not run correctly, so I fitted two, and 2 separate cdi units, that now have advance and retard curves, making the bike now rev well past the 10,000 rpm it was before, the rev counter goes to 12 rpm, it goes cleanly well past that, so I hazard a guess at around 14 - 16,000 rpm - that will safely destruct this engine in minutes if maintained, so I need to fit another rev counter and limit the engine to 13.000 rpm. 36 bhp? who knows.
Another shot from the other side, again a mobile phone photo and not very clear.
Just for the blockchain as motorbikes do not seem very popular on here.
Tomorrow it gets a full road test, have a fantastic week.
I have not seen 1 of those in ages, I used to own 1 when I was a teenager. Awesome bike you have done it up nicely.
I collect old 2 strokes, and use this one daily every spring - autumn, thanks for the compliment.
nice bike
Thanks, I like it now, it was pretty horrible when it arrived though.
My first road bike, back in the mid 80's, a suzi gp100
One of those came up for sale the other day here, I am still undecided if I am buying it or not, it is cheap at £125.00 and running order, my first road bike was the Yamaha rd 250 lc.
@deliberator I guess you are trying to tuning this motor bike.. I was surprised to know that this bike has two cylinders. After tuning if the volumetric efficiency of this engine will improve it will produce more power from the same displacement, i think.
Yes I have tuned it now, been tuning it for 3 years and 6 months, it started off at 16 bhp and is now well over 30, due to modern components, it just goes to show how efficient air cooled twins "can be" and I use it daily, as it is cheap to run.
Great job!
There are people on Steemit interested in motorbikes, but they don't usually have any money...
I used to be into them and still find it all facinating - this is a photo of me when I was at school in the 80's
What a fantastic photo, guessing you are around 5 years younger than me then. Was that a 78 gt 185?.
It was a 125 like yours - I think it was indeed a 78 one.
I'm no spring chicken - I think that photo is from 84 and I would have been 17.
I saw this bike parked over the road recently - ever seen one of these?
(Avenger 350)
Oh so you are 1 year younger than me then, and no, never seen that one before, very rare indeed.
I really like ur bike, I also have a suzuki 125. And I wanted to make an electronic ignition, but it doesn't work like I want it to do. Is it possible that you can send me the circuit diagram?