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

yeah i'm getting the same thing, no bottom or midrange whatsoever. I think i might still be leaking some tranny oil through the clutch side crank seal because the inner bushing was chewed up, and i'm smoking like crazy, oil injector not hooked up... but shouldnt be enough to cause the total shit boggyness in the midrange.

that airbox you sent me with the holes in it probably isn't helping things. I might try to tape over them and see if it clears things up.

I don't know how the silencer can goes together but the guy i bought the bike from said he had spent several hours getting it apart and de-coking it.

the exhaust in the fire thing, hmm, i usually leave it until it stops smoking like crazy; 1-2 hours, then knock it out and all the crud will crumble out.

i had to mess with the needle height a bit, raised it way up (to cope with the drilled out airbox) and i'm also going to get some different main jets to play with.

I'm somewhat concerned about compression, my piston and cylinder looked good, but it seems low, the athena head gasket seemed really thick compared to stock, so i might order an OEM MLS head gasket and deck the head a bit to get some more low end.. i'm not expecting much, though, given how rediculous the porting is...

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

Mine feels boggy overall until revved super high. Doing a hill climb is tough since the bike only works at half throttle and above. It also doesn't hit the revs fast enough to hop out of ruts. I really wanna try the HPI treats has, but I don't know if ill ever justify spending bills on this thing. Still want to hack a pipe, flat slide and throw my Boyesen Rad Valve on at some point.

Anyways, I finally fitted the Showa shock I have. It bolts on great! Just need some shims to get it centered. Stock shock is longer off the bike, but the Showa has a taller stance with me on the bike! Showa, also feels stiffer in comparison to the soggy stock shock that's probably meant for a 100lb teen.

Removal and installation was also super easy. Remove side covers, seat and tank. The bolts are held on with a washer and cotter pin. Remove top pin first for ease. Super pumped to get proper shims and jump this thing already.

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

Showa shock from a GPR or Senda? / stock dt50

Tops

Bottoms

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

Showa measurements:

12mm bolt hole

30.3mm bolt hole width

13.25" eye to eye

Stock DT50 measurement:

12mm bolt hole

40mm bolt hole width

13.5" eye to eye

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

† CH∆D † /

Funny we are all bogging at low rpm. I may try to just take the spark arrestor off & see if that's part of it.

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

I'm pretty sure that's just how it is. Gotta get the HPI!

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

yeah i noticed some improvement by going richer on my needle. The airbox was drilled out so i went 2 clicks rich, then i taped over the drill holes (massive improvement) but i'm still running 2 clicks rich. I have some four stroking in the midrange, might go back one click leaner... either way i'm pretty sure the needle was lean from the factory.

I haven't checked timing yet and I think i have a B8ES plug which i could probably go to a 7 or 6 for better snap.

Given the way these things are ported its not really surprising, and i'm sure the thick athena head gasket isn't helping. Going to a thin copper gasket, or stock MLS with some headwork might help a bit.

I'm just getting used to shifting every 10 seconds and cruising around at 8000 rpm.

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

ha ha

rode to work today, truck was dead this morning and i didn't have much of a choice.

ran about 30 minutes straight WOT, keeping up just fine with cars on a 65 mph road. Probably 55-60 mph as advertised.

puking a ton of smoke... like serious bug fogger smoke screen action.. thinking it has something to do with that fucky crank seal.

maybe just keep adding oil and not worry about it until it fouls plugs? Its hard to tell if the level has actually gone down, probably ought to change the oil and measure how much i put in, then drain it out again and 2x check.

either way, i'm pretty impressed. still thinking i might sell it because its not faster than a moped (by much) and it cant carry a passenger (no pegs) and it just doesn't fill a hole in my stable.

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

Sooo, 1 month ride report, rode to work every day except for 2 days i was down with a flat tire... not too shabby.

She's been holding up really well. The flat tire thing, duh. I replaced the tube in the 19 inch front, then i put a Gazelle 17x3 that i happend to have laying around on the rear. She gets loose in grass and gravel but handles on the road much better. Plus its a Gazelle, so like, invincible for running over shit. Kinda goofy with the mismatch IRC GP1 trials front, maybe i'll switch the front to Gazelle (do they make 19"?) and go full road-style on it.

Spokes have been an issue, the spoke nuts are all rusted.. probably had 2 flat tires with water sitting in them because all the rusty spokes are on one side of each tire... bummer... broke one, rear is a bit out of true, but not too bad.

So my commute is about 5-6 miles of stop-and-go city traffic, then 15 or so miles of wide open with occasional stop light. She doesn't mind the wide open on the way into work, but when she has to do stop-and-go after being held WOT for 20 minutes, the clutch gets a bit cranky.

I switched over to 20w50 - castrol semi-synthetic with the cruiser picture on the bottle- and that has improved clutching significantly. My clutch pressure plate is also warped ever so slightly, so it drags and shifting is a bit notchy once she gets hot. I might move up to a gear oil, because clutch slip hasn't been an issue at all, or maybe try a full-syn 20w-50... the scratch on the crank seal bushing has resulted in it eating about 400ml of oil over the last month (not a big amount, but scary when you only have 750 ml total in the 'case) and i got a wierd grinding bearing noise when it got too low to lube the trans shaft. Put in more oil and the noise has completely gone away, i think it was just a free-running gear on the shaft that was rattling rather than a spun bearing... Took the case apart and no shine in the oil.

Anyhow... running wot at 55 mph, she seems ok but the top end just isn't there. I found an old post of Roald's where he says the pipe and silencer is restricted. The pipe chokes pretty abruptly right at 10,5k rpm, and there isn't much power over 9,5 (and no power under 7k) so I'm thinking about adding a pipe. The DT pipes are all for either the older engine (screw flange) or the newer AM6 motor, so i'm thinking about one of the cheap <150$ NSR pipes, since all the GPR/AM6 pipes are 200++

Anyhow, the longer i ride it the more i'm liking it. Once you get used to riding the clutch and stomp shifting, its not bad... Kinda like... learn to love the bomb ya know. She smooths out beautifully at 11k rpm, which i hit going downhill a couple times into work, so i think bigger carb, bigger reeds and the pipe would let me stay in the porting better. With 180+ exhaust duration, you can just feel the engine wanting to pull, but getting shut down because the pipe is too long and restrictive for the cylinder.

I could probably get a cheap boost just by bending out the reed stops, but they are steel and i really really don't want to shred them.

Its always like, get a bike, its stock, get it running good... buuuut... its just not quite fast enough... so you start adding shit, pretty soon you've got an time bomb screamer that shreds parts constantly ends up breaking something major, and you park it... damn... already going down the rabbit hole! Seriously though, this cylinder is ported to rev 12, 14k all day long and the trans, bearings, and everything else are set to handle it, but they have this shitty pipe that chokes it at 10,5... having no power on the bottom end, it just makes the power band too narrow. I don't think it can get any worse bottom end by adding a pipe... maybe i'll build one of j-bot's boners and use one of those trick magura choke sliders with the NSR pipe...

fun fun fun...

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

So rad! Bummed ya didn't make it to Denver for us to ride DT's 2gether. I feel the same way about the carb and pipe situation. I know Curbcast has fitted some kind of pipe on one of his DT's. Holla at ya boy!

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

† CH∆D † /

I haven't got that one running yet though. FMF fatty from a KTM50 on that. Still rippin the stock bike with its 1st gear fog show & shuddering clutch. Perhaps tomorrow I'll take off the silvencer to see if even just that helps low end

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

† CH∆D † /

Did I correctly read somewhere the 50 motor fits in late 70s dt100 mounts & frames?

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

Um.. really? Sounds awesome! Much more of a technologically developed motor than a 70's 100cc.

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

† CH∆D † /

The 100 frame is cool looking with a single rail backbone. Shits born to be a choppa'

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

LL danktip Wrote:

-------------------------------------------------------

> https://www.mopedarmy.com/forums/file.php/7/118905/

> image.jpg

> Showa shock from a GPR or Senda? / stock dt50

>

> https://www.mopedarmy.com/forums/file.php/7/118906/

> image.jpg

> Tops

>

> https://www.mopedarmy.com/forums/file.php/7/118907/

> image.jpg

> Bottoms

Only took a year or so, but I finally put the Showa shock on. I don't bottom out anymore!

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

Meanwhile, in California, a 1988 DT50 with 6 years of back reg fees from the DMV is going for $1,500

FML

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

🇮🇹💦 Of the Loin /

I want one so bad

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

sick! I love mine to death

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

Team Ratchet Boyd Wrote:

-------------------------------------------------------

> Meanwhile, in California, a 1988 DT50 with 6 years

> of back reg fees from the DMV is going for $1,500

>

> FML

there are a few 100cc enduros for around $500 right now.

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

DT50 is cooler than the 100cc models! (see what I did there)

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

Carlos Rosario /

LL danktip Wrote:

-------------------------------------------------------

> ...re arranged the pump

> tubes to no longer go in the carb. No noticeable

> difference...

Honestly I never understood why people in general mess their bikes, spend money and a lot of work hours to makes things worse. You just made your bike worse during cold running and will also take longer to get into the correct temp. No performance gains, only less efficient, less gas mileage and more pollution in the tip of the exhaust and carbon in the engine...For sure something to think about. ;-)

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

Dirty30 Dillon /

I've been stripping my DT50 for a the last few days. The bike was hacked up by the PO and I'm doing as lite-handed a hardware as I can manage, Tank was shot, seat pretty rough, carb was in pieces, and all the controls/gauges were chopped and cut off.

20161114_230925.jpg

I'm hoping to get it throwing spark, than go the route of OKO and maybe rework a Doppler pipe to fit. Or, I'd also use an NSR/NS/MB5/GPR pipe if I could find one. I'd prefer the low pipe over the tucked stock one

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

Dirty30 Dillon Wrote:

-------------------------------------------------------

> I've been stripping my DT50 for a the last few

> days. The bike was hacked up by the PO and I'm

> doing as lite-handed a hardware as I can manage,

> Tank was shot, seat pretty rough, carb was in

> pieces, and all the controls/gauges were chopped

> and cut off.

>

>

>

>

>

> I'm hoping to get it throwing spark, than go the

> route of OKO and maybe rework a Doppler pipe to

> fit. Or, I'd also use an NSR/NS/MB5/GPR pipe if I

> could find one. I'd prefer the low pipe over the

> tucked stock one

I've got one of these that I'll never use. High pipe for life. Interested?

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

I've got a DT80LC Gianelli high pipe on its way that I'm almost positive should fit right up: http://www.ebay.com/itm/191950358917

(edited)

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

Carlos Rosario Wrote:

-------------------------------------------------------

> LL danktip Wrote:

> --------------------------------------------------

> -----

> > ...re arranged the pump

> > tubes to no longer go in the carb. No

> noticeable

> > difference...

>

> Honestly I never understood why people in general

> mess their bikes, spend money and a lot of work

> hours to makes things worse. You just made your

> bike worse during cold running and will also take

> longer to get into the correct temp. No

> performance gains, only less efficient, less gas

> mileage and more pollution in the tip of the

> exhaust and carbon in the engine...For sure

> something to think about. ;-)

any effect of closing off that coolant circuit is so negligible it isn't even worth mentioning.

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

Dirty30 Dillon /

Dave & Bummerzz Wrote:

-------------------------------------------------------

> any effect of closing off that coolant circuit is

> so negligible it isn't even worth mentioning.

Yeah, it's certainly not a new bike anyways. I doubt anyone buying a Yamaha DT50 is too concerned with the minor amount of pollution between a water-warmed carb and not.

That said, I am curious if anyone has deleted the Boost Bottle/Chamber off theres. I'm looking to go OKO with a DT100 intake, which doesn't have the opportunity for the boost chamber. I'm wondering if I should replace it or just not even worry about it.

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

I'm using a pwk on a rt 100 intake, the carb has to sit a little crooked as the bowl rests on the engine otherwise, you can leave it and get your bonus carb warming powers back. Also just ordered one of those gianelli pipes too, I'm curious to see what it does. Currently running the stock exhaust and the parma 70.

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

LSLB LOSE LOSE LOSE NO MATTER WHAT

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

I have some rubber intake setups for these. I believe they're good up to 24mm. I can get bigger ones though. I've only mocked one up on a loose cylinder but they are sold for dt50 so should work just fine.

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

RB you should have done some embedding action. ;)

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

Carlos Rosario Wrote:

-------------------------------------------------------

> Honestly I never understood why people in general

> mess their bikes, spend money and a lot of work

> hours to makes things worse. You just made your

> bike worse during cold running and will also take

> longer to get into the correct temp. No

> performance gains, only less efficient, less gas

> mileage and more pollution in the tip of the

> exhaust and carbon in the engine...For sure

> something to think about. ;-)

lolz

Not everyone that modifies their bikes has these issues. ;)

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