DT125R ARCHIVE

NORFE · DTR Trusted Engine Builder

magnito weight removal/reduction

Seanyftw · Guru

Maybe give us a picture tutorial or something mate? lol. Difficulty rating?

NORFE · DTR Trusted Engine Builder

will do im just puttin some picsa on nah smile

NORFE · DTR Trusted Engine Builder

heres a before and after picture

remove magnito fasten it to the bench with a long wood screw and a washer fru the middle

then get the 1mm cutting disc on a hand held grinder

draw around the rivets with a marker pen in a hexagon shape

then take your time and cut away the sides

when your done you will have it looking the same as this below

NORFE · DTR Trusted Engine Builder

it now revs like a mx bike no weight on the crank so it spins up loads quicker

front ends been floating every time i rolled on the go go grip

biggrin

well happy

going to get a morning at the dyno soon as i can

see some figures

mr karnage · Guru

would that not throw the balance off?

NORFE · DTR Trusted Engine Builder

if it was a bodge job mate might do , but you can visually see if its ok

iv no extra vibration at all feels fine & runs loads better for me any way biggrin

Calum122 · Guru

Inner rotor kit?

NORFE · DTR Trusted Engine Builder

yeah be better pal smile

Calum122 · Guru

Alright NORFE (or anyone else) Explain.

You know what i'm like.

What have you done?

Why was it built like it has and not like your mod.

Why isn't this a formal 'deristriction'?

What are the disadvantages?

Is it safe?

Is it worth buying a spare magnito off you (lol) to do this with.

Surely this has got to be hazadous to the engine?

Wouldn't an inner rotor kit be a better solution?

Calum122 · Guru

Do Inner rotor kits generate less electricity and hense why they don't install them from factory?

NORFE · DTR Trusted Engine Builder

ha right here goes

iv cut off the gret titanic weight off the front of the mag as u can see in the pics

the magnito comes made with an added weight to slow the recipiocating mass down to make it abit dopey if you like, makes the 2 stroke engine less responsive with the weight that the crank has to move

it causes no harm or damage to the engine and is perfectly safe, iv normally had to add weights to other bikes like 500cc 2 strokes to make them less aggressive to ride

but seen as this is a low power engine it will make the engine rev faster anf less load on the engine

i went out for an hour earlier and covered about 30 mile and it was a difrent bike! r8 gud fun, revs like a mx bike now

inner rotors produce the same as other stiles all the big bikes now have inner rotor setups or most iv seen any way biggrin

Calum122 · Guru

I've done a little research!

The Magnito weight acts like a damper for resonance (that is a dramtic increase in amplitude when a driving frequency, i.e. the engine, equals the natrual frequency, i.e. any part on the bike, of an oscillating system. And no I didn't look that up that's from memory ). So by altering that weight you change the natrual frequency of the bike. Reducing the weight increases it's natrual frequency (I think). This means that your bike now needs a higher frequency in orfer to resonate. Which isn't hard since there are so many mechanical parts moving a different frequencies. If you encounter such dramatic 'vibrations' then you've reached resonance.

That's one problem that you face by reducing the weight. I don't think you'll meet it due to the small reduction in weight. However that added weight is also to reduce wear on the engine. Parts like the small end bearings, big end bearings, conrod etc.

More importantly (I think this is factor of the inner rotor kit) is that you will unbalance the clutch. With such a light weight on one side and a heavy weight on the other you unbalance the clutch and effectively ruin it. I really think that's for the inner rotor kit. They say that if you do do a inner rotor kit then you need to have the whole engine rebalanced.

For you NORFE I think you'll be alright. I'm not sure how you ride your bike but I use mine as my sole transport. If you just ride it for fun then I don't think it will make much difference to the reliability.

What would be interesting is to see the performance gain. Is the performance well worth the loss in reliabilty. Hey NORFE if it breaks let us know lol.

the only way is YAMAHA DTR · Guru

Calum122 wrote:
Alright NORFE (or anyone else) Explain.

You know what i'm like.

What have you done?

Why was it built like it has and not like your mod.

Why isn't this a formal 'deristriction'?

What are the disadvantages?

Is it safe?

Is it worth buying a spare magnito off you (lol) to do this with.

Surely this has got to be hazadous to the engine?

Wouldn't an inner rotor kit be a better solution?

like ftting a lighter flywheel, faster to speed up fast to slow down, why is this bad? for going up hills it would stop easyer but like norfe says, it will rev like fook biggrin on the flat

NORFE · DTR Trusted Engine Builder

never had a problem with any engine mode iv done really only thing ever hapen is oil pump fail

i only ride it the odd few hour a week, if you worry about doing things an never do it u never learn ,,,thats way i think any way smile

but if it was my only transport id be leaving the bike how it was made, as any thing you mod will higher the risk of failure simple as smile

i dont care what i do or try if it goes bang i no its sumet not to do lol

trial and error is the best way to learn things me thinks any way pal

Calum122 · Guru

Yeah that's true. I suppose in life you never get something for nothing lol.

Not going to get lots more power without a risk!

But I am interested in this mod. But I favour reliability. After all it's my only mode of transport. Also IT'S a 125! It's only going to reach a certain power anyway lol.

I want my DT to look amazing and sound amazing. Bout it lol. Still interesting...

NORFE · DTR Trusted Engine Builder

well im 19 stone and the 1-60 thrash seem to be over in a few seconds today loads quicker than befor the mod

so imo its made a big difrence, fun wise and **** like traffic light starts i dont think its a big power mod just a mod for power delivery of the engine

its off like a rocket running r8 well today

Calum122 · Guru

Can I have a go on yours before doing it to mine?

Jokes

NORFE · DTR Trusted Engine Builder

ha corse u can biggrin

the only way is YAMAHA DTR · Guru

Calum122 wrote:
Can I have a go on yours before doing it to mine?

Jokes

bet norfe go a spare one some wheres to modify, hes got everything for parts

NORFE · DTR Trusted Engine Builder

i think so if any one wants 1

mr karnage · Guru

id have one off you

if you havent ive got a spare one i could send you

NORFE · DTR Trusted Engine Builder

yes wel i was going to say id do an exchange service

send one and ill send a modded one, then al always have one in if u get my drift

plus a small fee to cover the work and postage smile

eG x LoGiKzZ · Guru

so whats it like up hills NORFE? i want to try this but if it makes the bike **** up hills i doubt i will

NORFE · DTR Trusted Engine Builder

its fine all round mate,been up a big hill today got stuck behind a car, dropped it down a gear and flew past it,plus better coz it revs quicker

good mod mate get it done smile

Calum122 · Guru

That's what I'd do. Have two! I would feel bad though cause I'd have to ask NORFE To mod it lol. But now I know it's just a small fee to do the work and postage it's almost tempting. Haha. Like I said though speed isn't an issue for me ATM. Just trying to get the bike looking CRISP!

NORFE · DTR Trusted Engine Builder

any time smile

MDK · DTR Legend

sounds fun but can see this takeing years of the engine . if I want better speed I would just buy a rd legal yz or a larger cc bike . pushing such small engines to there limit overall will just have a bad outcome .

think we will see need a new engine thread from norfe within 6 mth lol

NORFE · DTR Trusted Engine Builder

mx bikes have a smaller magnito than a this modded one,mx bikes arnt faster really just geared different to road bikes, iv had 2 cr 125 supermotos on the road and my dtr is just about faster top end, mx bikes are geared for accseleration and bottom end, and are horrible to ride on the road lol good fun tho but not practicle

theres no reason to say this modd will cause any engine damage , but i **** give a fook if it does or dont, it works well at the moment lol and feels a whole lot better to me so thats all that matters

biggrin

the only way is YAMAHA DTR · Guru

Calum122 wrote:
I've done a little research!

The Magnito weight acts like a damper for resonance (that is a dramtic increase in amplitude when a driving frequency, i.e. the engine, equals the natrual frequency, i.e. any part on the bike, of an oscillating system. And no I didn't look that up that's from memory ). So by altering that weight you change the natrual frequency of the bike. Reducing the weight increases it's natrual frequency (I think). This means that your bike now needs a higher frequency in orfer to resonate. Which isn't hard since there are so many mechanical parts moving a different frequencies. If you encounter such dramatic 'vibrations' then you've reached resonance.

That's one problem that you face by reducing the weight. I don't think you'll meet it due to the small reduction in weight. However that added weight is also to reduce wear on the engine. Parts like the small end bearings, big end bearings, conrod etc.

More importantly (I think this is factor of the inner rotor kit) is that you will unbalance the clutch. With such a light weight on one side and a heavy weight on the other you unbalance the clutch and effectively ruin it. I really think that's for the inner rotor kit. They say that if you do do a inner rotor kit then you need to have the whole engine rebalanced.

For you NORFE I think you'll be alright. I'm not sure how you ride your bike but I use mine as my sole transport. If you just ride it for fun then I don't think it will make much difference to the reliability.

What would be interesting is to see the performance gain. Is the performance well worth the loss in reliabilty. Hey NORFE if it breaks let us know lol.

won't unbalance the clutch because the clutch is on a separate shaft and not the crank shaft