Suzuki TU250 - anyone seen/ride one?

Discussion in 'Thumpers' started by anomad, Dec 10, 2008.

  1. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Thanks Brett. I read with great interest many of your posts in this thread, particularly those where you took your engine apart for fun and replaced parts trying to track down your rattle noise. I'm not so concerned about the noises now, particularly as they do quiet down when the engine gets hot. My other bike is a Ducati Scrambler which is also a noisy-as-heck aircooled design. Even when running right they tend to sound like a box of rocks.

    As for PO maintenance, there wasn't any except for him installing a brand new battery for me, and I did pull the side cover to double check his work which looks fine. I was the first one to do anything to bike, and I definitely drained the oil from the right bolt.

    I haven't had a chance to try and restart the bike since my last ride to see if I'm still having starting problems, but I think I'll put some fuel system cleaner in the tank too and some more fresh gas. Will report back on how it starts.
  2. LuciferMutt

    LuciferMutt Rides slow bike slow

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    I did not, since it was running fine on my first ride. I didn't experience the hard start until my second ride, and have yet to do a third ride on it, so it may start up just peachy next time. I'll put some more fresh gas in it along with some seafoam or something. It's got about 180 miles on it now.
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  3. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Rats. The TU was nearly impossible to start today. I wanted to go out and put some more fresh fuel in it with some seafoam, so I hopped on it after getting home from work.

    Fuel pump primes, FI light goes out, hold clutch, press starter. Just cranks and cranks and cranks and cranks. Took me about 10 tries of cranking for 5-7 seconds each to get it started, and I was getting close to giving up. Once finally started, it settled into a fine idle, and ran fine. No smoke, no nothing. I rode it 3 miles to gas station, shut it off, filled it up, added 2oz seafoam/gallon, then it started up perfectly at the gas station. Rode another 10 miles around town.

    Seems cold starts after any length of sitting are very difficult for some reason. Any guesses what's going on? I'll have to see if the seafoam does anything, but I doubt a really dirty fuel system since once it starts it runs fine? With so few miles (~200 now) on the bike, I wonder what could be going on.

    I noticed on the throttle body, there is a stepper motor that turns a cam that moves the throttle stop when you turn the key to on and fuel pump is priming. It makes a pretty gnarly sound, if you listen to it closely -- possible it has stripped teeth or something?
  4. LuciferMutt

    LuciferMutt Rides slow bike slow

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    As long as I'm spamming this thread, I'll post another update.

    Checked the battery today. It's brand new, but who knows. All fine there anyway: 12.8v at rest, 13.6v at idle and jumps to 14.5v with some revs.

    Checked the airbox next -- all good there, no nests, bugs, or obstructions.

    Checked the spark plug -- all good.

    Put my hands on as many electrical connects as I could see and made sure everything was tight, and found no abnormalities.

    Decided to try my luck and the dang bike started right up instantly like it's supposed to! Went for a nice 50 mile ride. I'm quite pleased with the way the engine seems to be breaking in, now at 240 miles on the odometer, the bike is holding speed against our incessant southwest winds better than just 100 miles ago.

    Hopefully all that SeaFoam I put in the gas along with more fresh gas has gotten a handle on the problem.

    I'm starting to strongly suspect there was water in the old fuel (seller said he put some fresh fuel in it, but who knows from where or how much or what it was poured on top of -- the bike had been sitting for years), or that it had phase separated. Any time the bike sat still overnight, the water or heavier liquid settled at the bottom of the tank -- and what does the fuel pump prime itself with the next morning when I try to start it? Something that won't combust -- so I crank and crank and crank until the fuel pickup gets something that will burn.

    So why did the bike start fine when I got it off the delivery trailer? Perhaps because the fuel had been jostled/mixed enough during the journey to keep the water from settling at the fuel pickup. Grasping at straws here, but it wouldn't be the first time bad gas has ruined somebody's day.

    Hopefully the issue is gone for good now and I can get enough miles done to hit the fuel light and then fill up, but if it crops again I guess I'm going to need to completely manually drain the tank and start from square one.
  5. MYUMPH

    MYUMPH 'Ol Timer Supporter

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    Your theory sounds reasonable to me. One thing for sure, if you can burn all that gas outta there, you can eliminate that possibility if the no start returns.
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  6. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Dang it! The No-Start came back. Bike has been starting and running perfectly since Wednesday. Ran nearly a whole tank of gas plus seafoam through it, and was at 178 miles on the trip odometer and didn't have a fuel light yet. Was showing the bike to my mom, and then the darn thing decides to be temperamental and not start again. Had been sitting for maybe 20 minutes this time and was hot.

    Usual scenario -- cranks and cranks and won't fire. It's not even sputtering. Finally after about 10 attempts again, it does sputter a bit and I can finally get it going. What the hell. Is it possible I have a bad coil pack or sensor somewhere? As soon as it was running, I went right to the gas station and filled it up again, and it started fine there too. The fact that it doesn't even TRY to start when it's cranking -- the engine just cranks and cranks and there's no fire at all has me worried that I have some kind of electrical problem in the FI or ignition system :/
  7. PreChewCharlie

    PreChewCharlie proto-n00b

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    Do you know how to do the old shade tree check for spark by sticking a screwdriver in your plug wire then holding it near the plug post and watching for it to jump the gap? I'd give that a shot immediately the next time it won't start. But even before then I'd probably pull the plug to check for fouling and to check the gap. It's possible that there's a hairline fracture in the porcelain that is causing a partial short giving you weak spark — the only way I know to figure that one out is to replace the plug. It's a cheap way to eliminate one possible point of failure before moving on to more complex and expensive possibilities.
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  8. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Yeah, I better do a real check for good spark, and I think I'll just put a new, properly gapped plug in right away.

    Bike started and ran fine this morning though -- I added more seafoam and also some Heet water remover to the fuel.
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  9. Nifty250cc

    Nifty250cc Adventurer

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    Haven't seen any issues with the frame yet, but I'm running a 19" front wheel, about double the suspension travel in front, 5.25" of travel in the back, and tip the scales pretty light at 150lbs. Curious to see how it holds up over time.
  10. Smaug1

    Smaug1 '19 Kawasaki Versys 1000, '15 SMax

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    250 Or 350 maybe, but not 150.
  11. Nifty250cc

    Nifty250cc Adventurer

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    On a separate note I've finally found my way to ADV Rider!
    Sorry, to clarify I meant I'm 150lbs, not the bike :lol3
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  12. Scoozi

    Scoozi Been here awhile

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    Sorry for taking so long to answer this, I don't visit this section often. Here's a write up of the build:- http://www.bikeexif.com/suzuki-tu250-custom
    and a picture of the other side :-)

    [​IMG]
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  13. Scoozi

    Scoozi Been here awhile

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  14. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Passed 500 miles on my bike on Thursday but I was out of town all weekend so no riding.

    Looks like I'll be doing the 600 mile service over the holiday weekend. :ricky

    I rode it to the Suzuki dealer to pick up an oil filter and replacement o-rings and a new spark plug just in case and some guy in the parking lot saw me leaving on it and yelled "NICE TU!" I have everything I need now to do the full 600 mile service -- had to buy yet another spark plug socket since I didn't have an 18mm yet...

    The engine has been starting fine lately thankfully, but I'm still running this second tank down.
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  15. MYUMPH

    MYUMPH 'Ol Timer Supporter

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    Some friendly advice if you happen to remove the 3 bolt plate that holds your drain plug in to clean the screen. Be sure to use a JIS bit and not a regular Phillips, as it will strip the heads very easily. They are very tight from the factory.
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  16. LuciferMutt

    LuciferMutt Rides slow bike slow

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    I bought JIS screwdrivers years ago when I had a Kawasaki with carbs. The only screwdrivers that could get those darn Keihin carb screws out without damaging them.
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  17. Bar None

    Bar None Long timer Supporter

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    ^^^^^
    Still having issue with starting your TU?
    Could the fuel cap vent hole clogged? Fuel filter in tank clogged?

    You know about http://tu250riders.com?
  18. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Yep, been over at that website multiple times. The bike has been starting OK since last week. Waiting to see if the problem resurfaces -- I think there was some truly nasty fuel hiding in the bottom of the tank after sitting that was (and may still be) causing some problems.

    How can I test if the cap vent is clogged? There was some aluminum corrosion on the inside of the cap.
  19. Bar None

    Bar None Long timer Supporter

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    Blow air thru it with a air compressor nozzle. download.jpeg
    Also you might want to take the tank off and remove the fuel pump to check the filter plus that would be a good time to make sure all the old fuel is out and the tank is clean.
  20. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Well I gotta take the tank off for the break-in service this weekend, but I don't have the O-ring for resealing the fuel pump if i take it out. I should probably call the dealer and see if they have one. I've been kinda avoiding wanting to take the fuel pump out. I might wait and see if the problem comes back or not.