Difference tzr125 and dt125
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@irongamer727 Higher compression, more aggressive port timings, bigger transfer ports, cleaner transfers, bigger boost ports. Auxilary boost ports. More spark advance. Increased squish clearance. Better designed crank journal spaced for increased fuel atomisation. Smoother inlet tracts. No emission laws to adhere to. Smaller piston to wall tolerances. Less blow by, single rings... The list goes on.
If you're really interested then I'd recommend reading a book on a the subject as it's not something I am going to describe in a sentence or two...
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@irongamer727 I'd recommend Tuning For Speed By Phil Irving PDF available online
http://tuningforspeed.com/files/Tuning_for_Speed.pdf
As a start
Then have a read of Graham Bell's Two Stroke Performance Tuning
Then Graham Bells Engine Performance TuningYou always want to read in Chronological order. Phil's book was written several decades ago, Grahams during the late 80's.
Irvin was way ahead of the curve and received the highest engineering award they have in Australia. Named after him called the Irving award. The guy is a genius.
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@calum I have Graham 2 stroke at home. First time I read it I didn't understand much. Perhaps time to do it again.
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@irongamer727 I refer you to my previous statement.
Start in chronological order. Ready Phil Irvins book first. As this will introduce to the concepts at the time, which are assumed or taken for granted in later books.
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@declan The barrels are cast with only so much metal in them. It's not a case of inside liner. The walls are only so thick and can only be ported so much.
You could spend thousands and thousands porting the barrel, and the result is ultimately worse than a £60 RS barrel. It's cost vs Reward.
If I was going to spend X amount of money for maximum bang for buck, do an engine swap. It'll be cheaper and better.
So I'd rather swap the DTR engine out for a 2RK engine out of the UK spec TZR. Or better still Rotax 122 engine, or a YZ engine or anything else.
By all means, mildly port and tune the DTR engine, but accept that there are limitations. Ensure that what you spend, is less than what it would have to have simply swapped the engine.
That accounts for time as well as money. An engine may cost less than a decent port, but if it takes a year to fit then it's cost you time.
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The DT is still pleanty fast for what it is, a road going bike developed for teens on L plates, it's a damn site quicker than any of the 4t 125 bikes around, and they get incredible reliability when right. I plan on doing a lot of miles with long runs this year, so simply a road going mx would not work.
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@oldman I mean you're right, however, when push came to shove, I couldn't afford a bigger bike so it was easier to just chip away at tuning the DT.
You 100%, but sometimes a bigger bike isn't always an option. Having done my test several years ago, I have never owned another bike. The Aprilia that I am building is the only bike I've bought since doing my bike license, and I could have had that on L plates lol.
I think it's come to a point now where I could go out and buy an R1 or something, but then I know it wouldn't satisfy me.
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Like many people my age have done the big bike thing up to several zx9r's and an rf 900. They were unbelievably fast but the current crop of litre bikes makes them look like mopeds in comparison. They were beyond my ability in all honesty and the temptation to use the power was always there. I was lucky never to come a cropper on one of them and the 650 I have now is more than adequate and would be my first choice for a continental tour (I wish). For a few hours out in the countryside down a few lanes content on the 125s and not as demanding mentally either as a big bike. The temptations not there to wind on the throttle or chase someone that passes. Happy to add a bit of "pep" to the 125s but no more than that, but it's a personal decision and each person's passion is different. Just find it hard to justify spending hundreds of pounds chasing a few bhp when alternative bikes are about to give that extra kick. Does not mean I will never try it though, change is good! Bike I regret selling the most is a zx9r b4 in green with a stage 1 tune (if I remember correctly), absolutely brutal and mint condition, upgraded to newer model but not the same terror when riding
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@oldman Yeah, but you can say the same about anything in life. You wanna see the amount people spend on Starlets, when you could say go buy an Evo, or a GTR. Then they tune an Evo/GTR and you say go buy an Audi RS6 and it goes on and on.
The lads over at Skellerns are mental. Tuning their Air Cooled RD's to like 50+ bhp. There is something about the powercurve of a tuned bike. Or the sense of accomplishment when you hit that goal. It's something to while away the hours thinking over, rather than realising it's all pointless and everything means nothing. I think there is something to be said about chasing a power curve. If you can stand back and say you've built something special, that out classes the competition, that's an achievement in its own right.
