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AU
Webby130
9/12/2018 2:28pm
9/12/2018 2:28pm
Hi all I’m looking to build a power house cr125 engine.
But I’m unsure we’re to start with what year engine
Or what year bottomend to topend I have been told a couple different ways to go.
First idea is
1996 cr125 bottomend with the 1996 cylinder
But usinging the 1998 cr125 power valves
Second idea
98 motor with Six speed box wider transfer ports standard than the earlier models and tune cylinder send it to Steve clithero
With an hpi ignition 37mm carb
Any comment I will read and take not of what the best idea is to get the most power out of a cr125 engine
But I’m unsure we’re to start with what year engine
Or what year bottomend to topend I have been told a couple different ways to go.
First idea is
1996 cr125 bottomend with the 1996 cylinder
But usinging the 1998 cr125 power valves
Second idea
98 motor with Six speed box wider transfer ports standard than the earlier models and tune cylinder send it to Steve clithero
With an hpi ignition 37mm carb
Any comment I will read and take not of what the best idea is to get the most power out of a cr125 engine
We are working on a full works build 97 - custom mapped hpi to suit
But the base cylinder and engine in all stock, rebuilt form - only produced 30 hp on my dyno, it was quite sad vs modern engines
If you already have an 05-07 - it may perform better than you'd expect vs transplanting a mid 90's engine and building that.
but - if you have a mid 90's engine - it CAN perform well too
The Shop
This is too hard to accurately describe in a short time - and as Ive seen on a T shirt that sums up my experience in (not) understanding this - I can (try) to explain it for you, but I cant understand it for you
2 strokes are insanely complex despite their mechanical simplicity - with enough time and effort most engines can produce good power - but some of that time and effort may also include some welding/redesigning of a lot of variables - and sometimes its not worth the time or money to make one project good
The hpp powervalve sucks
Rod length is similar to yz - usable, angled intake isnt ideal but can work ok for mx application.
Im working on one fairly heavily soon - with a goal around 40hp. All new stock with 4 different pipes tested it was 30... will be some hmwk to make it happen.
If I figure it all out - ill post some details
How much do TM144's Dyno at stock?
We recently had the full PC team spec motor here at 33.5 or so on a 1991 If I remember right
It wouldn't be hard to be 35-36 - that's easy.
And the pipe thing - isn't too hard either - but to be where a modern ktm is at - would be nearly impossible
Keen to follow your results with the modified CR project you're doing. Sounds like a lot of welding and devcon.
https://thumpertalk.com/forums/topic/1176376-the-ultimate-cr-125-af/
Just my thoughts.
Pit Row
build a longer pipe for the 150 - and you will shift the rpm range the same way
What is the best mods to to this engine ....?
In your neck of the woods:
https://twostrokeperformance.com.au/
does great work
But didn't comment on the power curve getting there which I still haven't seen a chart on.
The yamaha's 96 and on were clearly strong engines in SX and outdoors - which leads me to believe they had more from 9k-11k than the hondas
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