Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

big reeds in.

Seemed to make an improvement overall. OKO fits better too. No longer did the crazy hang/stutter/brick wall before the powerband with the DT80 pipe. Still completely gutless except for when it takes off 9-11k rpms. Didn't get to test it long before the coolant pipe sprung a leak, again. Going to try the stock pipe and the low mount rd80 gianelli I have to see how much of it is the pipes fault.

Ran the numbers on the port timings, they wouldn't be so crazy if that exhaust port notch wasn't there. ~182 exhaust, ~26.5 blowdown ignoring the notch. ~207 exhaust, ~39 blowdown counting the notch.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

207, holy shit.

you could get that notch welded up and renik the whole thing maybe. Tyler xmas had that done to a seized bidalot, I think it was under $200

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

GP porting!

i'm hoping that having the head cut correctly and the pro circuit torque pipe will make it more rideable.

what did you settle on for gears?

got one more bike on the bench before i can dig into this one, i'm itchin' to get at it!

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

which procircuit you going for? I did a lot of looking for small bore dirt bike pipes to try, most of em come out the wrong side.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

That dt80 pipe is garbage.

Put the stock pipe and tecno baffle back on, sealed up the dumb coolant elbow, and the bike rips now. 11k easy, no deadspots, no more super narrow powerband. Didn't touch the porting on the kit, just the dt100 reeds and spacer.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

i agree! much too large for the little 50 to fill, even with a kit.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

Dirty30 Dillon /

I've been pipe shopping for a dt50 pipe. I have a nice stock pipe but I want an underslung option.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

Dirty30 Dillon Wrote:

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> I've been pipe shopping for a dt50 pipe. I have a

> nice stock pipe but I want an underslung option.

This guy. I have one, it's nice unlike the dt80 one. I'm not into underslung. Bug DOS to find more or start googlin' rd80lc auspuff.

https://www.doscycles.com/collections/yamaha/products/yamaha-rd80lc-giannelli-exhaust?variant=16288673476

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

athena 38mm, stock head with o ring (had hella probs with water jacket seeping into cylinder, fixed with o ring)

Mik VM20, flange mount using matched YSR50 intake, stock 17W boost box

barnet clutch pack

hpi mini rotor, 2.5 btdc

NSR50 stock pipe

TCR oil injection delete

(had i known blake had the spigot intakes i would have went that route. the ysr intake and reed block were $13 shipped on eBay tho)

video: https://www.facebook.com/jeffwpayton/videos/10104899349611024/

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

the giannelli is gone btw, there was only one left after I bought mine

I've seen leo Vince pipes from Italy for the current dt50, they are super spendy but look so nice and I doubt they'd fit

The 17w is nearly identical to the TZ/TZR50 that other countries imported, sans internal gearing and carb as far as my research can tell (also as mentioned these came on RZ50). after talking with some South American folk apparently there was a plethora of kit parts (even race ratio gear kits) available down there, Daytona being a notable brand.

seeing as the frames are completely different I'd imagine it might take some work to make fit on the DT50 platform if it would work at all. occasionally TCR has 17w motors for sale, they call them liquid cooled YSR which makes sense because they are identical sans cooling system and internal gearing, so I keep my eye on their site for a custom flange mount pipe that they may have uncovered or come across.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

wow thats cool, so its a TZR or a YSR with the 17w swapped?

either way, neato.

my head gasket from athena sealed the chamber to water well, but it leaks externally like crazy, that sucks. i'll probably go with the o-ring when i re-do it and add a schmear of goo

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

it's an AR80 chassis, 17w motor transplant. the TZ/TZR (some TZR came with am6) had 17w motors and the 17w is basically a water cooled ysr, hope that makes sense haha

I love the boost box, it flexes with the throttle on mine so fun to watch

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

I had to yamabond my parmakit headgasket to get it to stop leaking water externally.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

mine was seeping into the cylinder from the water jacket, it's never really leaked outside, hard to tell too because it wasn't enough for the bike to not run and enough to make it run strangely. the coolant smoke blends well with 2smoke so it was always a crapshoot trying to decipher what color it was, smelling it would also lead to inconclusion because I love the smell of 2smoke and it also blended well.

now it's sealed up with the o ring and hondabond and plug looks as it should and smoke has decreased significantly. feeling confident, as it's been a 2 year debacle for me n the ktz

my conclusion is the stock cast iron cylinder likely has warped all the heads out there and putting it on a true flat cylinder yields shitty results. I decked the shit out of my head too and still had leaks. since owning the motor I've purchased 2 stock head gaskets and that's a small fortune itself. with the way it is now, I've got excellent squish (.6) for my application and the o ring is readily available from any Honda dealer

I wasn't impressed with the Athena head gasket that comes with the kit, but I was impressed at how many gaskets come with the kit

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

and thanks for the neato graham :)

that's actually the name of my 125 race bike, twoneat

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

Dirty30 Dillon /

river 2strokes Wrote:

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> NSR50 stock pipe

How did this mount up? Moreso talking about flange mounting changes. I know the NSR had a pretty big header

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

used the stock dt flange and adapted some pieces of the dt header to get the pipe to wrap around the downtube of the frame - from my measurements i think i added 1/2' of header, though i did my best to keep the nsr length.

i didn't write it down like a dummy, but i want to say header diameter was 22mm? it was close enough to the stock DT at least

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

have pics if interested, it was pretty straight forward, it has a nice shape that fits nicely under my frame, I'm really unsure what it would be like on the dt frame

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

Dirty30 Dillon /

river 2strokes Wrote:

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> used the stock dt flange and adapted some pieces

> of the dt header to get the pipe to wrap around

> the downtube of the frame - from my measurements i

> think i added 1/2' of header, though i did my best

> to keep the nsr length.

>

> i didn't write it down like a dummy, but i want to

> say header diameter was 22mm? it was close enough

> to the stock DT at least

Yeah, that's perfect info. Not so worried about fitment on the frame, that'll be easy, Just curious about flange to motor.

Thanks man.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

Dumping some knowledge I've found in here. Portugal goes wild on DT50LCs, seems like they were sold for many years there. Even got a factory disk brake model later on. DT50 is 39mm stroke, DT80 is 42mm? stroke.

Jasil/Top Racing makes a 43mm stroke crank.

Enabling you to use big big DT80 cylinders like Athena 80cc, Gilardoni 100cc, Polini 100cc.

And then channel your inner Portugal and do wheelies through every gear.

From what I can dig up, a lot of people say the Jasil conrod sucks and they get a different one pressed in. You could probably run one of these big kits with a stock stroke and smaller CC if you are a wizard who could machine the base down or find a taller piston?

Also tangent, if you really want a disk brake front for whatever reason, TTR-125L fork tubes are the same diameter with a disc 19" wheel.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

stopping in to say that OKO's kinda suck, VM20's rule.

Raising the transfers on that Parmakit actually make it work properly.

Portugal firebox low pipe is fast fast but wicked loud.

If you want a HPI mini rotor order the DT50MX kit from HPI directly. The one on treats and the DT50LC one on HPI.be will not fit.

If you want 12v super easy on stock ignition: TTR125 electric start reg/rec plugs right in. TTR50 battery fits in the stock box, need to make little spade to bullet adapters for the battery. 12v 2 prong flasher relay also plugs right in. Change yr bulbs, and the stock horn sounds hilarious on 12v. Stock headlight is sealed beam and hard enough to find in 6v so either chop and glue in a H4 bulb or get crafty with a polisport or something.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

Lee Hoffguy Wrote:

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> stopping in to say that OKO's kinda suck, VM20's

> rule.

>

> Raising the transfers on that Parmakit actually

> make it work properly.

>

> Portugal firebox low pipe is fast fast but wicked

> loud.

>

> If you want a HPI mini rotor order the DT50MX kit

> from HPI directly. The one on treats and the

> DT50LC one on HPI.be will not fit.

>

> If you want 12v super easy on stock ignition:

> TTR125 electric start reg/rec plugs right in.

> TTR50 battery fits in the stock box, need to make

> little spade to bullet adapters for the battery.

> 12v 2 prong flasher relay also plugs right in.

> Change yr bulbs, and the stock horn sounds

> hilarious on 12v. Stock headlight is sealed beam

> and hard enough to find in 6v so either chop and

> glue in a H4 bulb or get crafty with a polisport

> or something.

Nice!! all good info! Do you have a link to the firebox pipe??

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

Dirty30 Dillon /

Daniel '' Wrote:

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> Nice!! all good info! Do you have a link to the

> firebox pipe??

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

Daniel '' Wrote:

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> Nice!! all good info! Do you have a link to the

> firebox pipe??

Firebox pipe: https://www.motoscoot.net/escapes/sport/escape-yamaha-rz50-dt-fire-box.html

Random portugal bike to show the fit. Looks a lot like an NS50 pipe HMM.

Shipping was a lil pricey but it came super fast from portugal.

Also also, stock cyl has enough meat on it to take it out to 46mm.

You can buy one pre-done but thats pricey: https://www.motoscoot.net/grupo-motor/cilindros/cilindro-kit-kaio-hierro-d-46-yamaha-dt50lc.html

but pistons in all sorts of sizes are available for getting crafty: https://www.motoscoot.net/grupo-motor/pistones/piston-de-recambio-rijomotor-yamaha-dt50-portugal-elige-diametro.html I haven't looked super hard but there might be a 45/46mm moped kit piston with the ring pins in the right places to jam.

do a youtube search for dt lc 46mm to see how it jams, planning on trying a bored cyl on this other DT I've got.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

my dt50lc hpi direct from hpi fits.. maybe I got lucky? how did yours not fit?

digging all the info here - thanks lee!! come up to columbus sometime

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

river 2strokes Wrote:

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> my dt50lc hpi direct from hpi fits.. maybe I got

> lucky? how did yours not fit?

>

> digging all the info here - thanks lee!! come up

> to columbus sometime

John(allredred) and I keep talking about coming up there, maybe one day.

Ordered Chappy HPI from treats, flywheel didn't fit the taper, couldn't get a nut on. Got a machine shop to cut taper deeper, they cut it too far. Ordered DT50LC flywheel from HPI.be, flywheel fit wayyy to deep. Hit the stator long before the taper.

Got talking to Willy @HPI and showing him some pictures, and he said I had the wrong flywheel and adaptor plate. Managed to return the plate and flywheel I had for the ones from the DT50MX kit. Fit perfect!

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

There just so much gnar going on in here.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

that's confusing lee, at least you got it sorted

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

ps TTR125 swingarm bolts right into DT. Needs a link mount and shock mount added. TTR125 brake plate fits stock wheel with a 12x15mm bushing tapped in. Could probably also skip the link and add a shock mount straight to the swingarm.

Anybody have any ideas on a radiator thats similarly sized to DT but thicker? Don't wanna go portugal double radiator but could use a little more cooling with a kit. Most dirt bike ones seem way too tall to keep the shroud.

Re: NOT-A-MOPED: 1988 Yamaha DT50... Thoughts?

hello i've added more parts that don't belong to my 2nd DT. Also you can lace a rear rim to a front hub using stock rear spokes. I broke one spoke though and can't find an individual one to buy, who's holding?

Kinda want a wider rear rim to run a gpr/rs50 size rear too. moneypit.

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