Yesterday I got the carb on, the rear boot in place that connects the carb to the air box, got the throttle cable in place, routing it where it best fit, and thought I better check the clearance of the cable to the expansion chamber, since this cable did not allow me to use the elbow on the cable that was on the original cable. Set the pipe in place and the throttle cable hits the pipe. I could bend it out of the way and strap it down, but that is what I found out the hard way that is what the elbow was for on the other cable…. Bummer. I looked a lot closer to the original cable, and it is in a lot better shape than originally thought. I will use that one  Today I had visions of getting the gas tank cleaned, and derusted. Got it all flushed out with water had the ExoRust on hand to clean out the rust and a small mix of oil and gas to toss in and swish around when the tank got all dried out. After I flushed it out, I thought, using my air compressor might work to get the mild dent in the tank pushed back out. No crease, just a mild push on the side. So, I screw in the gas cap, take my compressor with an air nozzle with the rubber end on it and held it to the opening for the petcock to go into. Blocked the air coming out of the gas cap vent and noticed a little bit of the crease coming out. Good, one more try ought to do it. So, I did. Looking over the tank I seen some things that didn't look quite right. The area around the rear mounting hole was "different". Things looked like they moved, things look like they might have a crack in them. I started freaking out. Ran to the faucet to add water to the tank and it happened..... the rear of the tank had a crack in it. After a few words I will not repeat, I took the tank back into my shop and that's when I noticed the real problem... I winged my tank as I call it. I don't know what else to call it because the tank now looks like it could fly.

 

After a brief bit of time passes by, I still wanted to continue with the bike, getting it ready to start for the first time in 30 plus years, maybe 40. After all, there are tanks out there still to replace the one I ruined. Besides the bike can be run with a jury-rigged tank, if need be, just to see if everything is proper. So, I figure I better check the spark, even though I knew it would be fine, after all when I rode it last time 40 years or so ago it had spark then. I take out the plug that I held onto for all those years, stuck it in the connector and kicked the motor over with my hand on the kick starter.....no spark. Turned off the lights in my shop, tried it again to see if it was a faint spark, still no spark. Broke out the shop manual and checked what tests can be done on my end. Resistance testing is it. The ignition coil passed on the primary test, 1 ohm, but failed on the secondary. At the stator wiring harness the one 2 prong connector passed with close numbers, and on the other connector, 2 of the 3 wires passed with slightly low numbers but another OL on the wire that are supposed to have 790 ohms (the black and brown leads) It appears I need to figure out what parts, if not all are bad with the CDI ignition in this rig. Oh, the Clymer manual says if there is any more testing needed, take it to a shop that has a CDI tester. About the gas tank, I was thinking about the Yamaha parts place that I used to get my repair parts from back in the day on the east coast. They have been around long enough that they may have parts for my bike still. When looking for other parts I went to their website and they supposedly have parts that other places don’t have. I am all to aware that they may not have their website updated to reflect what they really have, but they have prices, So I got a tank and decals for the sides ordered. I will call tomorrow to see if they really have a tank in stock or anything in the way of the ignition parts I may need. One thing I did that may be good, I got the new cable from DC Plastics off that does not fit, and the original back on all lubed up and ready to go when I get spark and gas to the carb. I will need to remove the carb one more time to check that the throttle is opening and closing properly since the twist grip doesn’t seem to be giving a full turn. That will be later.

   Until next time…. Boy I hope it gets better…..

Please pardon the novel, I see my adventures get wordy.

Nice update...  sorry for your troubles...  if it makes you feel any better you aren't the first one to spread a tank like that while trying to use pressure to remove a dent. 

Tank might be repairable...  try wrapping some ratcheting tie downs around it with the ratchet over the gap at the bottom.  Then slowly tighten straps...  resetting as needed...  cardboard over the tank helps...  crack can be welded/brazed....

I feel your pain. I did that to an AJS or Matchless tank in the "60's. Was welding it up where leaking along the seam by memory, underneath anyway. Filled with water testing after each fail as leak kept creeping along. So i left the water in for one last try & flipped it up on something soft & welded away-- then it went OOMPH & spread its wings. Customer & the boss not happy haha--& me too. So yep--feel ya pain.

Yup that blows. We’ve all had mid restoration tragedies but once you hear it start up for the first time it’s damn rewarding. Glad I didn’t let the body shop try to fix my tank with compressed air. I opened up the tank from the bottom and pushed out the dents from the inside and used an inner tube on the dents nearest the fill hole. Check that your carb slide is dropping all the way down and sliding up with no resistance. Not saying it’s not the cable action but good to rule out those challenges. I have a dent free, rust treated 72 175 tank with some pin holes. I opted to repaint a spare mx125 tank instead of repairing it. If you strike out getting a replacement tank you’re welcome to it. Not sure if it’s shorter that the 250 but it may be. 

@ MarkT, I will do the strap thing and hopefully find someone that can weld it for me. Thanks for the advice. I was hoping that the dealer that I used to go to perhaps had a NOS tank on their shelf since they have been around forever, AND their website parts inventory shown they had a tank in stock. I called today to confirm, and just like Partzilla, they show stuff online that they really don't have.

I was searching the posts about my CDI problem and found a post about Deet refurbishing CDI component(s). I emailed him, he replied that he had to deny the job. I guess he no longer does that. so I still need to address that as well.

@RT325, Did the pressure from the water steaming up from the heat of the welding do that to the tank???

@ Adguy2112, after the tank went back on I was ready to fire it up, so I hoped. Then I checked for spark, and well you know....

Yup I am gonna pop the carb one more time to check since the twist grip does not feel like it gets a full turn. Weird though, this is the original cable I put back on If anything it should have some slack it anything for the years of use it had before it was put away for decades.

Very nice offer on the tank, I looked up the tank for a CT2 and I see that it has a flip top gas cap, mine is an MX with a screw top cap. If it was an MX175, boy I might would have to snag it up. You mentioned this is the one with pinholes?

175 tanks are definitely smaller...  not sure it would fit very well on a 250

Apart from the tank cap isn't the tank shape the same as DT360A--DT250A. Re-my tank winging, I thought it was residual petrol fumes igniting. Just a subtle OOMPH--@##$$k what was that lol, lifts welding goggles--oh hell, i'm fired haha. Wasn't hot enough to heat the water. bloody stupid things i do & have done!!. Maybe i left the fuel tap open, i don't know, but was inverted with the cap on. To de-gas them we just used to drain then stick over the car exhaust for a bit to neutralise or something & always worked till then. We'd flast the gas over the lid which might give a small woosh & thought ok she's safe now--& alway was--till then, but never tried welding full of water again haha.

@ MarkT, Since the 175 is smaller I will not go for it. I did look it up on Partzilla to see if it was the same number, and when I seen it wasn't, I knew something had to be different.

Got an update... I put some other posts on the General Questions part of the forum so I would not clutter up this string with the peripheral things needed to keep my rebuild going, and maybe more exposure too?

I found a new CDI from HPI through DC Plastics, should be coming in 2 weeks. I am glad it is all new parts. What I am not glad about is this one has its own kill switch. BUT I ALREADY HAVE A BRAND NEW KILL SWTCH!!!! It is gorgeous, it is the exact same as the original!!! The trick is the original is a single wire, the new one is 2 wires, one is ground, but the same bullet connector as my nice one. I am still going to do what I can to use the one I got from rsteve56.

About the tank.... the tank..... well I did the strap thing, and it was actually drawing the sides back in, very easily. What I wasn't watching for was for how bad the sides were spread. It made the rear tank mount stretch in a way that the metal it was welded to inside the saddle portion of the tank bulge out, since the rear mount was on a shorter radius than the tank itself. With that bulge in place, when I started drawing the sides in, the bulge just bulged out more, since it was already headed that way. So in 15 minutes I thoroughly trashed the tank the rest of the way. It turned the rear mount up at a 45 degree angle compared to where it was. I had been looking for a replacement tank on Ebay, beside here, and seen a few possibilities. On Thursday evening I trashed the tank, because if I could get it back in shape I could have dropped it off to the guy who bored my jug, he said he could weld the leaks.  Then I would would not need to pursue a different tank.
There was a tank up for bid that was in really good shape but a yellow "74 tank with a starting bid of $159 and a "Buy it now" price of $253 with no watchers. Ending on Friday. There were others, but this was the nicest one, with a few very minor dings. I waited for the last day to bid, now that my tank was trash, and since in my experience, if anyone was going to bid, it would be on the last day. Well someone did bid on it, so there goes my chance of a cheap tank. When I shown the tank to my wife 3 days before, she said "just do the buy it now price". I didn't want to then since I am a tightwad and wanted to go for the cheapest route. Well I wasn't going to get into a bidding pissing match so s soon as I seen the bid, I hit the buy it now button and got the tank. It will be in next week.

Well that's the long and short of it. I still need to check how the original throttle cable is acting. Need to pull out all the CDI stuff which is no hurry since it will be a while before they show up, but I might anyway. It has been my weekend thing lately.

I am so close, then again....

Until next time....

Last weekend I got the carb back off to check how the original cable was working with the slide. It appears it is not letting the slide go down as far as the new one that did not work because of the exhaust pipe. That one, let the slide almost bottom out all the way. The original one looks like the motor will run 1/3 throttle if I leave it the way it is. I check all adjustments all along the cable, there are 2 of them, one at the top of the carb, the other along the length of the cable. That one, the latter one is bottomed out as far as I can go by hand, there are a few threads showing, but not enough to fix the whole problem I see. I did not want to chance cranking it in all the way with pliers or something of tat sort for fear of screwing up yet another item on my ride. I also checked the placement of the soldered end in the slide, to make sure it is not hung up on something. It is good. I have not double checked the twist grip yet, but it works well, so I really think it could not be that since, if it was it would be bound up inside, but I will check anyway. 



The “new to me” tank came in mid-week, it looks promising, debating whether to paint it now or later like I planned. I hope the new CDI comes in sometime next week from DC Plastics, that will be the last piece of the puzzle to put together as long as I don’t need to get another proper throttle cable to replace what seems to be an original throttle cable that now appears to be too short somehow….


 

3-27-22 update
I did get the throttle cable working better. I took it apart, checked everything carefully, made sure all the adjustments were drawn in as far as possible, which tey all were. With the carb still off and had checked everything out, I ws goint to pu the throttle handle back together when I noticed when the bottom half was not on the throttle handle that held it onto the handlebar, the throttle closed all the way. Plaing with it a bit more I seen where the inside of the throttle handle stopped, a part that could be reduced in size so the throttle grip rotated back more to close the throttle. I got out my trusty sharp wood chisel and carved away the extra plastic that stopped the carb slide from closing. Problem solved. There is now just a slight bit of play now that is detectable in the grip.
 
 

I like the patina on that tank, so I'd say paint it later!