Re: 1989 Yamaha DT50 build thread

This week I Kreem'd my tank cause I had a couple of pin holes. Overall I wouldn't recommend Kreem, like many others on the internet have already said. I feel like it isn't going to hold for that long, the coating came out really thin no matter what I did. I think this will especially be a problem with the pitting present in the tank. I only used Kreem because a buddy got a random package delivered to his house (addressed to him) with all sorts of dirtbike shit and Kreem that he didn't want.

I also got an RD80LC exhaust from eBay, there's a couple German sellers on there with them. All in all it was like $180 shipped from Germany and took a week to get here. Seems like the power band hits a little lower now, closer to 7500 RPM (thank God), and the red line is like 13-13.5k rpm. It's definitely got some more torque now as well.

As you can see in the picture my dumb ass zip-tied the exhaust to the swingarm which resulted in several snapped zip ties until I realized why it wouldn't work. I have it zip tied to the frame now until I make a bracket. The zip ties work pretty well though.

I have a cylinder coming in that I haven't seen anyone talk about anywhere except Portuguese forums. No idea when it's gonna be here, but it's an Athena 80 kit, listed on the Athena site as fitting a DT50/YSR so it should work. Worst case scenario it's a DT80 stroke kit and I have to swap cranks. But I did the math and with the stock DT50 stroke it's like 77cc, so I have high hopes it'll fit.

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Re: 1989 Yamaha DT50 build thread

Here's it's big brother ::

My 1989 Yamaha XT350 .

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Re: 1989 Yamaha DT50 build thread

> P D Wrote:

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

> Here's it's big brother ::

>

> My 1989 Yamaha XT350 .

Nice! My first bike over 50cc was a 1982 Yamaha XT250. I loved that thing, been trying to find an XT again but no such luck so far

Re: 1989 Yamaha DT50 build thread

> Nick Haber Wrote:

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

> > P D Wrote:

>

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

>

> > Here's it's big brother ::

>

> >

>

> > My 1989 Yamaha XT350 .

>

> Nice! My first bike over 50cc was a 1982 Yamaha XT250. I loved that

> thing, been trying to find an XT again but no such luck so far

Thanks .

At the time , I couldn't find a bike I wanted .

So , I built that^ one from parts I bought from all across the country . Started with a frame , a pair of rims and a transmission , all of which were questionably serviceable . The frame had never been even registered , forcing me to jump through the hoops in order to get it titled and road legal . That was a fun project . ;)

Re: 1989 Yamaha DT50 build thread

Athena 80 kit won’t work on a 50 without some finesse. You have to bore the cases and fit the long stroke crank to get it to work. Rd80 pipe honestly kinda sucks. Just get a stock over bore go back to the stock pipe and enjoy it being slow. It’s never gonna rip.

Re: 1989 Yamaha DT50 build thread

> Daniel '' Wrote:

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

> Athena 80 kit won’t work on a 50 without some finesse. You have to bore

> the cases and fit the long stroke crank to get it to work. Rd80 pipe

> honestly kinda sucks. Just get a stock over bore go back to the stock

> pipe and enjoy it being slow. It’s never gonna rip.

I kinda figured I'd have to bore the cases. Disappointing to hear I gotta swap the crank but I'm gonna do it. So far I like the pipe. As for ripping, I kinda had given up on building this bike up but I binge-watched every video on YouTube of the Portuguese fucking blasting their DT50's and I got inspired. I'm just gonna keep throwing time and money at it for the foreseeable future

Re: 1989 Yamaha DT50 build thread

The Portuguese rippers are all on the 100cc kits. It looks like fun, but honestly with how much work and money it is to get there it’s not worth it. Get a yz80 if you wanna go too fast on a dt50 or go for a derbi senda engine if you want to have something more reliable.

Re: 1989 Yamaha DT50 build thread

Good on you for all your efforts to keep it going, that’s a lot of work just getting it to a usable state

The battle will continue when that athena cylinder arrives though. notorious mating surface issues, I eventually had my stock head cut for oring head gasket, remedied all leaking but took several methods before success.

The OE head gaskets are not cheap, the head gasket that comes with the athena put in the trash

I can wholeheartedly confirm the best DT is completely stock - wheelies and I topped out at 62 on mine when I had it - had a used YSR piston and rings and low comp too

Shout at me if there’s anything I can help with

Re: 1989 Yamaha DT50 build thread

Well the Kreem lasted a whopping 2 months. Went riding today and smelled gas the whole time. One of the pinholes is leaking again, womp womp. Also, the kit I ordered on Amazon isn't coming so that's sick. Not sure what the next move is gonna be, I have a YSR I bought in parts I gotta assemble so for now I guess the DT stays stock except for the gearing/pipe

Re: 1989 Yamaha DT50 build thread

Brandon Weiss (Detective brandon to you) /

Fill that tank with paint stripper and drywall screws, clean the eff out of it. Then use caswell sealer.

Re: 1989 Yamaha DT50 build thread

anything with actual break-through pin holes, the easiest way to fix it is brazing it. sealers won't hold once its broke through no matter what

i dunno i avoid all that shit, i do a muriatic acid soak using a rubbermaid with like 1" in the bottom to really burn it all out good, then i strip the paint in the affected area, then a couple rinses, then braze it, coat the inside with half gas half oil mix, sand, bondo, sand, primer, paint.

i've saved some pretty gnarly shit. This ninja 250 had like 1/4" rust holes that i had to weld roofing nails to close up, someone had tried a bad JB weld and bondo job on it and it was all smashed up. When i was done you could definitely tell it had been patched, but it didn't leak and got the jerb done. More time with the bondo and i could have made it nice but it was a $200 commuter/beater bike so who cares.

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Re: 1989 Yamaha DT50 build thread

> Graham Motzing Wrote:

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

> anything with actual break-through pin holes, the easiest way to fix it

> is brazing it. sealers won't hold once its broke through no matter what

>

> i dunno i avoid all that shit, i do a muriatic acid soak using a

> rubbermaid with like 1" in the bottom to really burn it all out good,

> then i strip the paint in the affected area, then a couple rinses, then

> braze it, coat the inside with half gas half oil mix, sand, bondo, sand,

> primer, paint.

>

> i've saved some pretty gnarly shit. This ninja 250 had like 1/4" rust

> holes that i had to weld roofing nails to close up, someone had tried a

> bad JB weld and bondo job on it and it was all smashed up. When i was

> done you could definitely tell it had been patched, but it didn't leak

> and got the jerb done. More time with the bondo and i could have made

> it nice but it was a $200 commuter/beater bike so who cares.

> >

That's inspiring! The only reason I used the Kreem instead of brazing in the first place is that a friend got a random package with a bunch of motorcycle shit in it (clutch levers, motocross boots, Kreem, etc.) that he didn't order and so he gave it to me.

It's my understanding that the only good way to get gas resistance when repainting a tank is to powdercoat it; is that the case? I've never painted a tank before

Re: 1989 Yamaha DT50 build thread

yeah, when i first got into vintage moto stuff it was 2004 right after ethanol gas came out, kreem version 1.0 was not ethanol safe because the people that originally came up with it never anticipated anyone doing something so stupid as putting ethanol in gas.

well, for a few years there, motorcycle tanks that had been 'kreemed' 10,20 years ago were all turning into snot, people would go out to the garage to get their bike ready for summer and the carb would be disintegrating and the tank would be full of the nastiest shit you've ever seen, and i would buy CB350's, CB750's, etc. all day long for 100 or 200 bucks, you couldn't give the things away. my buddy was a tow truck driver and he was picking them up 3 or 4 at a time. If i had a dollar for every $400 mint condition RD350 or CB750 i passed up back then, i could almost afford one now.

so... ever since then i've just got a real bad taste in my mouth for any of the 'goop' type sealers.

I do most of my refinishing with catalyzed urethane single stage auto paint, its relatively cheap, it sprays on super nice, and its fuel resistant, basically fuel proof. You do need a good air compressor with filter, drier, and a HVLP type spray gun.

My buddy maize builds some of the nicest bikes around, he does a base coat using high end rattle can, then clears over it with spraymax 2k clear (which is a rattle-can catalyzed urethane clear) the finish is top notch pro auto body grade and it can all be done by an average guy in a garage with no tools.

Powder coat doesn't melt from gas exposure but it can get chalky or change the finish if its a matte finish. Personally, i don't like powdercoat because you have to strip down to bare metal and you cant bondo, but it is tough as nails. Its great for stuff where you just want it to look 'pretty good' and not get scratched... like mopeds... but its more cost/work and its something that you gotta send out

Re: 1989 Yamaha DT50 build thread

> Graham Motzing Wrote:

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

Good write-up on paint, bodywork isn't my strong suit. Thanks!

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