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Post Info TOPIC: 3MB00P


DTR Respected Member

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3MB00P
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Hi my friend just gave me a 3MB00P full top end and just wondering will it make any difference to my dt which has 3MB00 top end on at moment



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MDK


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question is what is your bike doing now with regards to speed and power ?

I think it all comes down to a combination of things to improve a bikes speed no point putting a good topend on if you have a restricted cdi or zaust .

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DTR125CO-1.jpg


de restrictions

good clean up of a old batterd  dtr  95

 



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iv put 3rm 20 cdi on me m8 said these barrels are ported better or sumet by Yamaha and cum of a tzr originally and with dep pipe on should be a good upgrade but I don't know if it be worth putting on so thought id ask

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Isn't the 3mb00P the tuned/ported topends?? :O

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Yamaha DT 125 RE -06



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check this out:
dt125r.activeboard.com/t54404549/4dl-tzr-engine-unmaintained/

the P stamped 3mb00 is a tuned/ported topend from Motori Minarelli in italy(..?) .

That should definitly give you alot more power if it's one of those topends
But bigger ports => you'll need a bigger carb, to get optimal gains

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Yamaha DT 125 RE -06



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I'm selling a 32mm dellorto carb from a tzr125 4dl which is what these barrels came from. They were made for 125cc race series in italy to compete with the Cagiva Mito and Aprillia RS125.

P does indeed stand for ported. the head is also slightly different. If you're interested in the carb im after £90 delivered.

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I've fitted the 3mbp on my standard dtr. I'm reverting back to the standard setup. Just doesn't run very well on the dtre.

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The Leviathan Project



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in what way mate-explain for others please?

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Well i was at a dinner table in a place with no signal.

When i get back i'll go into more detail. But bascially i've not benefitted from any of this porting. And i spoke to a specialist at Yamaha and he said the porting is identical bar the exhaust port being ever so slightly higher.

It's nothing special. It's the sp version that you really want.

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The Leviathan Project



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Basically the higher exhaust port means more power in higher revs. But at a certain rpm my ignition is retarded and therefore it's actually worse off. Better with the lower port because the ignition benefits there.

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So a CDI suited for those barrels would be needed then too to get any gains?

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Yamaha DT 125 RE -06



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The P ported barrel isnt just exhaust port height. its the transfer ports as well im pretty sure. I've got one at home so ill have a good old look and try and measure some bits and get some photos up. It wont run better without a large carb. The 32mm dellorto is a much bigger carb than the standard 28mm carb that the 3mb standard barrel runs. If i were running p barrel it would have to be running a dellorto. I'd also have the head from the 3mb p too and yes a differnt CDI. probably a 4DL. The gearbox in the tzr was also a different set up.

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Right. So my point still stands. A 3mbp on a dtr is crap. Unless you convert it to a tzr setup. Which i do have. I have tzr carb and cdi but haven't fitted it.

And Andy I argued that at Skellerns but the technician disagreed and said it was just the exhaust port that was raised.

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Blimey. like i say id be very suprised. with the powervalve system, raising the port doesnt seem to be acheiving very much.

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does anyone know the standard piston is on a 3mb00p as its off a tzr and some one say 56.40 but then they say its a dtr barrel which is 56mm ahhh it gets confussing all i want to do is a get the next o/s wosner piston kit for it

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there are 2 different sizes. the 56.00 standard had a longer stroke. the 56.4 a shorted. if youre getting rebored then you'll get it bored to the piston. If not then measure the bore accuratly.

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I just used a dtr piston mate.

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so class it as a 56mm coz it standard and get a 56.50 for rebore

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The 56.40 is for very old dt's. the 54.00 is for the current dt's and the 3mb's run those.


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If! The barrel is on the original bore then yes. Otherwise no

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Think some of the TZR's ran 56.4 too. never measured my 3mb p as I got a rebore.

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Yeah old tzr's and dtr's but the 3mbp is 56.00 I have done the tzr myself.

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The Leviathan Project



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Just get new sprocket's i'm running 13-57, top's out just over 60.

Lift's in third, pulls off in second nice

Could just as easy go up on gearing to achieve higher top speed i did 75mph(on the speedo on a flat surface) before on knobbly's with 16-57

So i bet with higher gearing and better tyre's i could get another 15mph

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