Yamaha SR250TH Exciter - Newbie Resto- (Mod?)

I just bought this bike this past weekend, it's a Yamaha 81' SR250TH. Everything I have read says it will be a great starter bike, both for wrenching (which it will need) and riding. It's my bucket list project. I'm gonna restore as much as possible, but I don't think it will be a complete restore.



Since I'm brand new, I'm kind of unsure exactly where to start to take inventory, and I've got some challenges to face before I can even start.

I am missing any and all keys for the bike, so removing the seat, unlocking the gas cap and the steering column switch will have to be done and replaced or re-keyed (which might be cheaper) but I would love to hear thoughts. I think I can change out the locks on the trunk without too much hassle.

My plan of attack is kind of like so.. again, I'm such a newbie, and advice would be great.

- Replace battery
- Check electrical systems (as much as possible)
- Check fuel system for leaks
- Check compression

Then: clean and disassemble and clean/ reseal as much as possible to get bike to run, then take stock of everything to see what other work needs to be done.

I will definitely be keeping this thread updated with progress, as I'm sure I'll be searching for a lot of advice.

Here goes nothing! Thank you in advance for any tips/tricks/advice/opinions!

Re: Yamaha SR250TH Exciter - Newbie Resto

The ignition can easily be replaced. They are a dime a dozen on ebay. The gas cap could be a different story. If you want to keep everything keyed the same, then yes, have it re-keyed.

If you are having electrical issues, make sure you use a multi-meter, it will save you a lot of guess work.
If the bike has not run for a long time, change the oil and filter
Drain the gas and check the tank for rust and particles. start fresh.
Check and change the spark plug/ wire if needed.
Inspect the chain
Check your fuel lines
Do a compression test if you can.
Check your brakes
Check your clutch cable.
Try charging your battery before you spend the money for a new one, or have it tested at your local auto parts store.

These bikes are surprisingly resilient, and unless it was abused, you will probably be focused mostly on overdue maintenance. You can accomplish most of these things with or without the keys. You have joined the best site on the web for information of these little bikes, and everyone here is usually helpful and willing to help.

Good luck, and keep the updates coming!

Knuckles

Re: Yamaha SR250TH Exciter - Newbie Resto

Thanks Knuckles!

Just your list is extremely helpful! I need to give you guys a major update, as I have already done some of work, and I want to show off my progress! I have spend so much time reading and was even able to find a new(used) tank thanks to hdscarbro , as mine was uber-rusted.

I am going to try and take some pictures and update tonight!

Re: Yamaha SR250TH Exciter - Newbie Resto

Knuckles is spot on, but if I may... A few modifications to his list.

In that condition you WILL have electrical issues. Buy a multi meter asap.
Always change the oil and filter befpre attempting to start a new to you bike. Never rely on the POs ability or desire to maintain the bike.
If the spark plug lead is in ok shape, pull the boot off of the end and cut 1/4" off, then reinstall the boot. Do the same at the coil end if possible. Just make sure it'll still reach. You don't need to remove much, but due to the way the lead fits the coil and boot the ends get chewed up and can cause issues.
Replace the chain. Again, don't rely on the PO to have taken care of critical items. Only way to be sure is to do ityourself. A new chain is cheap insurance. While youre at it, replace the sprockets too. Worn sprockets will destroy a chain in no time and for a bike like yours they can usually be had for the price of a case of good beer.
Replace all fuel lines. $5 at the parts store is way cheaper than catching rhe bike on fire when a dry rotted lines cracks on you.
Compression test is a must. If you have no or poor compression, it has to be fixed before going any further.
Definitely check brakes. Your manual (get one if you haven't yet) will detail how to correctly adjust them. Lube (or replace) the brake cable. Clean and verify that the brake hamd control is working. Inspect rear brake components for worn spring, overly rusted actuator rods, bent/damaged brake pedal.
Lube the clutch cable immediately. If the rest of the bike is that rusty, the cables will be too. Best bet is replacement. Motion Pro likely has them cheap.
For testing/tinkering, the old battery is fine (if it's functional) but when it's time for regular riding, go new. Modern batteries (Shorai for example) and mantinence free and ultra reliable.


Remember that above all, it's your ass on the line. Avoiding injury or being stranded all comes down to you. It's not necessary to spend a pile of money, but don't skimp on the important things.

Good luck and keep at it.

Re: Yamaha SR250TH Exciter - Newbie Resto

Couple more things -- adjust your valves before trying to start. And tires, man. check them thoroughly, and if they're at all questionable, replace.

I had a SR250 for a few years, fun little bikes.

Re: Yamaha SR250TH Exciter - Newbie Resto

I know a fair bit about these. I have one that I ride almost daily. There are lots of ways to go with the keys. Re-key, buy new ones, take everything off and have one key etc.

The options are endless. I have a build thread in my sig. If you have any questions, ask away.

Re: Yamaha SR250TH Exciter - Newbie Resto

Update Time!

So, I bought this beauty off of Craigslist for $100, with no idea of what I was getting myself into. My intention is just to get the bike running well first, then fix all the cosmetic stuff later. I first removed the headlight to in turn remove the ignition so that I could have a key made that would hopefully open up the tank, run the ignition and the seat lock. I broke the outer case of the ignition, and I wasn't paying attention when I took it apart, because now I can't get it back together, but I may just replace it anyway, save me some headache. The gas tank was in horrible shape, rusted through in a bunch of places, the petcock was eaten away which SUCKS. The cap was stuck seized... whatever, not worth dealing with. Since I have no tools or know how for metal working... time to find a new tank.


Top view, pitted and rusted


Underside, rusted through along both seams and in the back corners


corner rust, hard to tell, but there are a few layers of metal missing

Luckily I was reading through another SR250 build thread and was able to find a new stock tank in MUCH better condition thanks to hdscarbro! He even included the petcock and a key for the cap (score!) (I forgot to take pictures, but it's only got some surface rust, easy enough to deal with later).

I removed the trunk, and seat and stock airbox as well as the battery box, I want to leave the airbox off, but I may put the battery box back in, if I can't figure out a way to mount the battery back in. It's a traditional filled battery, so it's gotta stand up. Any suggestions are helpful. I am thinking a UNI foam filter (as I hear the paper/mesh pods are just more trouble than they are worth), and I think I am going to need a crankcase breather filter (any tips?) I'm going to keep everything else stock, engine wise at least (for now).


partially stripped, this was before I took out the battery box and changed the controls.

I stripped the handlebars and ordered new levers, controls, throttle body and grips, I'm pretty happy with the way it's turning out so far, but upon recommendations, I may replace the clutch, throttle and maybe brake cables? They don't seem to be in bad condition. I found out after I replaced the front brake lever, that I had accidentally eliminated the front brake light switch, and now am trying to figure out how to integrate a switch without having to replace the perch (again). I started another thread about that (http://www.dotheton.com/forum/index.php?topic=66561.msg763807#msg763807), but any and all advice is appreciated. Bought a mini speedo from DCC and I found a simple idiot light set up on the $50 mod thread that I want to use as a model to make my own. (http://www.dotheton.com/forum/index.php?topic=6496.msg85494#msg85494)


Diggin the new handlebar set up, eventually I want to get flatter bars, but stock will do for now.

Went to do an oil change last night, and when I opened the drain plug... this is what I got...


Those drops are from the little bit of oil I dropped through the spark plug hole... I don't think that's good

So... I poured a little more through the spark plug hole, just to make sure the internal parts are not bone dry. I'll drain it again tonight, and actually put oil and a new filter on.

I bought a new chain, I was going to leave the sprockets, but I have changed my mind, and am going to order a set , and change them all at once. I'm gonna replace the fuel line and any hoses leading to or from the carb, which I want to make sure is clean. I'm hoping the addition of the foam filter will not constitute having to re-jet the carb, since everything else will stay stock, but we'll see once I can get it started.

So far, so good, still seems like a lot of work needs to be done before I can even think about starting it up... but it will happen!

Just an FYI -- the airbox on these is very restrictive. Switching to a foam filter will require rejetting.

I run a velocity stack wide open and run a 127.5 jet

I'm at sea level

Figured as much, although, I think it will be a job to look at once I can get it running, I'm in MN, which looks to be approx 1,400 feet above sea level. So... I'm sure that re-jetting is now on the list, once the basics are covered.

My experience has been that the idle jet needs to get drilled out and adjust. somewhere between 2.5 and 3 turns out from seated.

It starts better this way.

Thanks Cosworth! It's a starting place anyway.

On a motor that sat dry fpr an extended period of time, a compression check is definitely in order. You may want to replace external seals as well (shift rod, crank, etc.).