I'm new here and am sure this has been covered before, but I wasn't able to find a specific thread... I have two bikes, 1975 DT 125 and 1969 CT 175. I also have a 1971 TMX100 Bridgestone... I have a general question about restoring these old bikes. I am not necessarily looking to make my bikes showroom quality, just want them to look and function well because we do ride them. My question is on finding replacement parts. I see some bikes online that seem to be in perfect condition, with every detail restored down to the correct hose clamps. I'm guessing that the large parts (fuel tanks, seats, headlights, engine parts, etc. are either in good condition to start with or are pulled from other bikes and made like new again. However, what about the small parts like grommets, hose clamps, wire harness clips, JIS screws and other misc hardware, grips, foot pegs, rubber parts for shifters, spokes, wiring bullet connectors, rubber pads for mounting the fuel tank, etc. I'm guessing there isn't a one stop shop for everything, but I wondered if you may have some sources of where you go for certain parts. Here is my short list to contribute - hoping to add to it:

Clauss Studios  - They have quite a few parts (not everything, though) that are replicated from originals using cast urethane. I got two rubber boot parts for my Bridgestone air system there.

Venhill - I ordered a clutch cable repair kit and built a new clutch cable for my Bridgestone using soldered fittings.

Ebay - I got a used carb for my 125 and a NOS (new old stock) main switch for my Bridgestone.

Amazon - I was able to get batteries for my Bridgestone and CT1 here.

Napa Auto Parts - I was able to get a battery for my 125 here.

Local cycle shop - air filter for my 125. They had to special order it from somewhere.

 

Where are you? Parts for older Yams seem quite common in the US, but if you are anywhere else in the world, the shipping and import duty charges are quite high. CSMNL are worth a try if you are in UK, and dont mind paying for new parts.

I live in southern Idaho, United States.

I should also add to the list a part that I'm struggling to find, not a resto part but a functional part is a jet kit for my 1975 DT125. I can find a rebuild kit that has the gasket and jets (though I ended up buying all these parts individually the first time). I have replaced both the main jet and pilot jet, but I still end up running it with the choke on (won't idle otherwise), then I foul out the plugs. I've taken it apart and cleaned it all several times. I was going to try re-jetting but I can only find the original jet sizes for replacements, not different sizes. This probably should be under a different topic heading... 

Welcome from OC CA. I learned a ton over the years from the experts on this site, so youve come to the right place.
I've had great luck with Claus studios for hard to find parts
Also Yamabits (great prices) and CMSNL in EU, both have had many hard to find parts and ship faster to CA USA than Partzilla, which is also a good outfit. Also, I use eBay a lot with almost no issue (use partzilla or CMSNL to look up part numbers) so long as you know what your buying and the seller has a great rating....I've bought parts from Canada, Germany, Thailand, Indonesia etc. on eBay from good sellers with zero issues.

Lastly, before you wirebrush or sand or try to get rust off mechanically, do yourself a huge favor and buy a gallon of Evaporust. this stuff is amazing....wash your rusty parts with soap to get off dirt and grease and put them into evaporust overnight and you will be amazed. You can plunk them in without washing, but then the stuff doesnt last as long or work as well. This stuff is a game changer

Don't forget Yamaha as many parts are still available new.

Mikuni jets are readily available in many sizes from distributors like Niche Cycle.  "Kit jets" are to be avoided.  Use genuine Mikuni.

Sounds like carb isn't clean yet as not idling without choke is a common symptom of that.  Many of us have experienced having to clean carb multiple times and especially depending on what method you're using. 

Could also be an air leak but hard to say. 

"Also Yamabits"

Sorry to be a pedantic arse  , but the company in the UK is Yambits. 

+1 to everything else recommended.

I use images on CMSNL, fleabay and the internet in general to educate myself on what a part I need actually looks like. Do this and have quite a wide search criteria - many parts are incorrectly listed, although is usually done accidently because of lack of knowledge on the part of the seller.

CMSNL and Partzilla usually list which other models used a particular part, so search under these models as well. Finally, I have had a lot of success buying job lots that included the part(s) I was after - what isn't needed can be sold on.

Something that is now quite common when ethanol type fuels have been used, is for tiny drill ways in a carb to become blocked.

Whatever it is causing these blockages seems in some cases to be either difficult or impossible to remove? It's worth trying ultrasonic cleaning, but in some cases the only viable option is a new carb.

Easy enough to check if drillings are clear, using an aerosol can of carb cleaner, with the supplied very thin tube on the nozzle. If a drilling wont let carb cleaner through, its not going to flow either fuel or air.

Before checking the carb body is free from blockages, best to avoid spending money on jets or rebuild kits, as they wont help with a blocked carb body.

Are your new jets genuine mikuni? KDI sells great repo parts and is a site sponsor also Motodad24 ( enduring cycles) on eBay. Rocky Mountain M/C. 

Fitting new parts will not help with a blocked carb body. Always check drill ways are clear, with aerosol carb cleaner, before even thinking of new parts.

Main wear parts in a carb are needle/needle jet, float needle/needle seat. Main and pilot jets, don't wear appreciably, and it's only worth changing them if there is a need to adjust mixture for ethanol type fuels.