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

fuckin rad!

I wouldn't sweat running 110 width tires on those rims, I run 110 bt45s on 1.6" xr100 rims, granted they have a weird profile, but they handle well enough to blow through my knee sliders pretty quick. The 130 widths are overkill on small bikes, I cant even get close to the edge of my profile on my rieju. (edited)

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

Sick. 110 is what I'm after. The TDR rear fender situation is so wide it could use a little more tire width to balance it out.

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

stock cyl bored to 46mm rules. Threw in a 43mm stroke crank too. Bike finally feels right. I just threw it on, porting would probably be even better. who wants to buy a parmakit?

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

Bump!! Trying to figure out if i should go crazy on my new dt50lc or keep it bone stock. Wish it would rev out quicker mostly. It’s so slow to rev out. what can i do to make that a lil better? Ditch the spark arrester?

Also, picked up a parmakit on the cheap, but not sure if i should even bother with it after reading about Daniel’s issues. What’s the consensus on the Parma? Not worth the trouble?

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

Dirty30 Dillon /

It's really hard to beat a stock DT50LC. They are so predictable and reliable.

I think with something that size the benefits of the kit don't really outweigh the complications involved.

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

Parma is not worth it. It can probably maybe shred with it modified to take an o ring and the right pipe. But the exhaust port is so high on that kit, the blow down is 32 iirc and the exhaust duration with the notch is over 200*. I was never able to get it to be "fast", went with the Athena 50 and it was ok. Stock rocks. The portugal dudes put the 44mm stroke crank in and run the 100cc kits to go super fast. The guy is pulling wheelies in 3rd gear and getting over 70 mph.

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

spend the money on a ttr front end and a gpr shock. Worst part about dts is the crappy suspension and brakes.

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

ehhhh parma no good? thats a bummer. i got everything for a full rebuild just waiting for it to come to the top of the project list. if i can figure out the head thing i'll see about offering them but i'd need to build up at least 5 cores so i'm not machining them 1 at a time

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

I was always bummed my kitted dt50 wasnt even close to as fast my stock ns50. I reluctantly got rid of it, but only because I knew I was going to spend way too much money to get somewhere near this level, then promptly break everything.

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

Definitely gonna do the ttr fork tube front wheel swap. Stock gpr shock is a direct swap?

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

> Get Blatzed Wrote:

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

> Definitely gonna do the ttr fork tube front wheel swap. Stock gpr shock

> is a direct swap?

yuh, it's a little on the stiff side for lil dudes but you're a big boy so it'll prob be good for you. Rani swapped his, he might have good input.

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

the steering bearings are the same with the TTR, whole forks, handlebars and everything drops right on.

i put a 'small wheel' 17 on my TSM (not even close to a direct swap) and got the 19 disc for my DT50.

i'm hoping running that KX65 pipe on there will help it out. i'm not trying to build a racer but holding 65 up hill would be nice.

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

Wanna buy the parmakit from me on the cheap? I’m gonna stick with stock top end.

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

already got one, ha, i was stoked when they came out but i'm seeing a lot of them lightly used coming up for sale now, bummer.

i have had super good luck from everything i've ever bought from parma, the hobbit kit, the puch kit, and the tomos kit all are total blasters, just gotta figure out how to make this bad boy sing.

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

Do a port map, it's way too crazy exhaust duration. The powerband is paper thin. I have not liked any parma anything I've had, but I have heard the hobbit kit is pretty fast.

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

eh bummer, maybe its time to finally figure out how to DIY a power valve? do you think its made to be used with a long stroke crank and a spacer, is the port map all weird or just set up for hi hi rpm?

yeah the stock cylinder couldn't afford to be ported .5 mm higher it was already marginal.

their tomos kit is probably my favorite puch -compatble kit out there period, IMO better than a polini (gasp!)

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

Yeah, I bet it is made for the 44mm stroke dt80 crank. I dunno how you cram a powervalve into that tiny cylinder, and would be very hard to seal. This weird fantic engine I ended up with it had a cable controlled power chamber(what I call for lack of knowledge of what it actually is), that opened up a chamber in the head that was placed after the exhaust port and before the exhaust that essentially was a jbot boner. That could be doable? Wish I would have taken pictures, Snordley has it now. I just wanted the Ducati ignition off of it for my Peugeot.

I've heard the gt80 crankshaft is the same as the dt80 so if you could find one around for cheap you could plop it right in your dt50. But I would probably opt for overbored stock with a spacer for the most torque you would get from the long stroke. Naz was working on doing it to a ysr, I dunno if he ever finished it though.

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

woahhhhh that is a hot tip right there

im going to be pulling the cases apart, all new bearings, etc. so i might as well drop in the DT80 crank while i'm at it, that is, if i can find one...

alibaba maybe?

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

There's usually a few on eBay for less than $100. Or if you were trying to buy new theres this site with a lot of cool stuff for dt50.

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

the one i've seen is the DT80 AC motor like same as the GT80, etc. but road legal. Is it the same? What years would i be looking for.

yeah i'd totally go used if i could, just didn't think they were ever sold in USA.

this bike is like the hammer that the head has been replaced twice and the handle 3 times, engine is bad, paint is bad, bushings and suspension all shot.... i dunno how deep down this hole i want to go.

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

gt80 crankMy eyecrometer says they're the same for the primary shaft. The ignition taper is most likely wrong though. Could ask the seller for sone measurements? I dunno if you would have to trench the cases to run that crank either. The more I think about the time to make the ngine faster, the more I think you should just shove a dt125 engine in it and call it a day.

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

at my day job we call this 'scope creep' ha ha.

yeah the YZ80 would be the one to get, they haven't changed it for about 20 years and they are dirt cheap and pretty overbuilt in the bottom end.

so then i'd have YZ80 forks, YZ80 wheels, YZ80 shock, YZ80 engine.... basically just a tube frame with a VIN on it left from the DT50?

like i said about the hammer...

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

> Daniel '' Wrote:

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

> I dunno how you

> cram a powervalve into that tiny cylinder, and would be very hard to

> seal.

like this

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

haha holy shit yeah exactly like this....

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

Chöschi21 C.K. /

When i was in France about a Year ago we got overtaken on the Autoroute by a 50cc Derbi Supermoto, we don't know what it's setup was, but i believe to have seen a Full MSX Kit, that thing had to have gone about 90mph.

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

> Chöschi21 C.K. Wrote:

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

> When i was in France about a Year ago we got overtaken on the Autoroute

> by a 50cc Derbi Supermoto, we don't know what it's setup was, but i

> believe to have seen a Full MSX Kit, that thing had to have gone about

> 90mph.

I've lived in France for nearly 3 years now. Outside our house is a nice long stretch of road leading from the town out to the countryside. There are a few 50cc bikes like DT50R, Derbi Senda, Rieju that go past every now and again. Some of them are flying past at 125cc speeds. I had a DT125R in the UK and some of the 50cc here look on par speed wise. The French seem to be born with 2 stroke tuning in their blood.

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

> Graham Motzing Wrote:

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

> woahhhhh that is a hot tip right there

>

> im going to be pulling the cases apart, all new bearings, etc. so i

> might as well drop in the DT80 crank while i'm at it, that is, if i can

> find one...

>

> alibaba maybe?

Parmakit is garbage. Isn't worth it's weight in scrap. My personal hunch is that they're mis-cast, based on how off the internals of the water pipe on the side look. Like everything internal is a few mm off.

DT80LC is 42mm stroke. I have an aftermarket 43mm stroke crank in my dt50, with the stock cyl bored to 46mm, hpi and firebox pipe. It rips. Now the clutch can't hold it. Portugal dudes machine them to fit an extra disc but i'm not that smart. AC DT80 cranks look really similar but I've never committed to getting one to compare. I actually have a DT80LC2 crank kicking around, has some play in the conrod. ProX makes a dt50/80 rod but i can't find one for sale in the states.

If i had a stock DT50, I'd just put an hpi on it and rip. Maybe bore the cyl up if it could use a refresh. I have a strong hunch they're like mb5's where an hpi makes more difference than cylinders and pipes and shit. Trying to build and kit one is an expensive rabbit hole of importing a bunch of parts from other countries.

Tangent, a DT80LC2 has found it's way into my garage. Engines rebuilt with a 44.5mm DT50 crank, hpi mini, malossi 110cc cast iron kit. Waiting on clutch parts from germany to fix the rigged up one that's in it, and some other parts to refresh the rest of the bike. (edited)

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

> Lee Hoffguy Wrote:

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

> I have an aftermarket 43mm stroke crank in my

> dt50, with the stock cyl bored to 46mm, hpi and firebox pipe. It rips.

> Now the clutch can't hold it.

Have you ever tried shimming the springs ?

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

> P D Wrote:

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

> > Lee Hoffguy Wrote:

>

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

>

> > I have an aftermarket 43mm stroke crank in my

>

> > dt50, with the stock cyl bored to 46mm, hpi and firebox pipe. It rips.

>

> > Now the clutch can't hold it.

>

> Have you ever tried shimming the springs ?

it's probably more of an issue of clutch surface area and less of an issue with spring tension.

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

pretty common in the moto world to go to higher pressure springs or shim springs, the ones in the DT50 are super duper light. 2nd and 3rd gear even stock you can make that clutch slip.

moto clutch springs are basically just die springs that come in just about every shape size and spring rate imaginable. I was able to find stiffer replacements for my bridgestone at True Value right off the shelf. They are probably a good bit stiffer than they need to be but they work.

i'm rolling this build around in my head, one idea i thought of was to un-counter-sink the head, like, cut the chamber into the head deeper, then go to a thinner base gasket or even turn down the base gasket face on the cylinder. That would push all the ports back down... you could go as far as the top ring on the piston so maybe 1-2 mm which could be pretty significant.

i dunno, the more i think about crank swapping that just sounds like a whole can of beans... if i get it apart and my crank is schlotto, then maybe i'll consider it, but as it sits i don't think the crank is schmoked.

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account