Hi All
i picked up this (turns out its a 74 DT360) earlier this year, and finally got around to getting it going, as my girlfriend wants to take it on a vintage offroad ride next month.
I got it running, and it runs ok, but not perfect. 
I think the exhaust baffle could be clogged with carbon. When running, almost nothing comes out the end and it seems like it's choking a bit.
I see no way to remove the baffle, and as I'm not a 2 stroke guy (altho I have alot of old 4 stroke bikes) 
Ive heard of heating these pipes up to clean them out, is that what I need to do?
Also, when i cleaned the carb, the jet sizes seem wrong compared to what I have read on here, 180 main, 50 pilot. I was thinking of ordering that keyster rebuild kit off ebay for 50.00, as it has the correct jet sizes (220 and 80) as well as all gaskets, etc. Is that a decent kit?
Last thing for now, it has a plastic Malcolm Smith tank on it, and I'd like to find an original, going by the oil tank, i need the green one.

Thanks for any tips!

Doug

I tried to upload pics, but they don't seem to be working?

 from near Salisbury, UK.

Look up your bike on the VIN table in the Tech Library here (see top toolbar) to id exactly which model you have.

Avoid the Keyster kits - genuine Mikuni jets are still available new. If you haven't done so already, check out the o ring on the jet setter in the carb. Again, new ones are still available from Yamaha.

Chucking the exhaust on a fire is a good way of cleaning it out.

If the bike was stood for years, replace front and rear brake shoes.

Post photos via a third party host, such as Imgur.

Thanks, it's a 1974 model. I did replace the setter oring, the old one was bad. New one has a little resistance when I slide it in the hole.

If it's a 1974 model, then it is a DT360A. 

Does it still have the original cdi fitted? The pulser can go iffy on those and some folks replaced the whole cdi set up with the points system from the same year DT250A - that's what a previous owner had done to my own DT360A. 

I have no clue about the cdi

Welcome. If it's a "74 the end muffler will come out of the main chamber as a complete unit. If you think it's blocked then it probably is-- deep in that end part is a fixed spark arrestor that gets blocked up. Put it in your log fire. But first the very end portion should come out although in the fire it'll likely loosen to remove after the burn. Look down in there when end is out & should be a spiral vsne thingy that clogs up. Also look in where the tail muffler engages into the chamber as grows where that pipe stops. If you can fitted a garden hose in there it'll be OK. Ideally the complete chamber & all should have a burn. But tail muffler sounds like the main cause as of 'now'. One more thought while 'I'm at it' which is if the main jet is way undersized & performance is down then possibly the jet has been reduced to try ,& get it to rev out as blocked exhaust give a rich main jet sniffling effect . So that's just my random thoughts which could be wrong without hearing it. Videos are easy to load onto YouTube then link to here. Pics I put on Google photos then link. Imgur seems the popular one here but I'm old & hard to change my thinking once I get a handle on something & it works. Cheers. Ps not sure how you came up with RT1 if it's a "74 but does it have original reservoir rear shocks & exhaust ending on the left after crossing through the frame.

Burning the end pipe now. Water wouldn't even flow thru it. I replaced the 180 main with a 230 i had. Hopefully it's just the blocked exhaust causing most of the problems. Thanks for the tips!

I would have left the 180 in there and tested. The stock jetting is 180/50. No air flow due to stopped up muffler = no suction to draw fuel. Now that you have BBQ'd the muffler, your fuel flow will increase also.

What i read on here was that stock jets were 220 & 80?
I can put the 180 back in easy enough.