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- This topic has 23 replies, 2 voices, and was last updated 1 week ago by
Heather.
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Oct 2, 2026 at 8:56 PM #23603
HeatherParticipant- Hey everyone!
Not sure, but I think I introduced myself last year but it’s been a minute so….my name is Heather and I live in Florence, Alabama. Rawhide to be exact.
My question is, I was given a 2006 gt250r with a locked up motor not long ago. And we’ll, I’ve done all the work on it myself. Honed cylinders, got valves unseized, timed both front and rear. Basically have had both the front and rear cylinders tore down completely to the piston, cleaned and reassembled. And it’s been BEAR to say the least, but so much fun at the same time.
Current situation: I can turn the motor by hand everything turns over just fine. However, I am unsure how to tighten the can chain that attaches to the shaft and turns both cylinders. If I tighten the cam chain adjuster too tight, the starter only clicks at the solenoid/relay and does nothing. If I unscrew it too loose it won’t turn it at all.
Again, both turn fine manually by hand.
I’ve youtubed all I can and haven’t found anything on how to adjust the cam chain adjuster.
The service manual says to turn it by hand but there isn’t a way to do that.
Help! Lol
Thanks Guys and Gals
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Oct 2, 2026 at 9:16 PM #23604
♠️ M77KeymasterDo you have a picture of this tensioner if possible ? so you can show us here.
I would not recommend using a manual tensioner whatsoever, the OEM tensioner is best as it is automatic.
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Oct 2, 2026 at 9:30 PM #23607
HeatherParticipantDo you have a picture of this tensioner if possible ? so you can show us here. I would not recommend using a manual tensioner whatsoever, the OEM tensioner is best as it is automatic.
yes I will go get it
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Oct 2, 2026 at 9:51 PM #23609
HeatherParticipant
Now I will take it off if need be but those Allen head screws are a pain….and will take me a minute.
The two screws on the sides loosen and come off and so does the bolt in the middle. When off, there is a piece that proudest about two inches but seems fixed and won’t move. And I’ve tried ever which way to make the part tun bu hand clockwise and counter clockwise but no deal.
All I can do is screw it in flush with cylinder and loosen it.
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Oct 2, 2026 at 10:09 PM #23610
HeatherParticipantCorrection, cam chain TENSIONER, not adjuster.
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Oct 2, 2026 at 10:11 PM #23612
HeatherParticipant
mine is identical to this one -
Oct 3, 2026 at 10:45 AM #23613
♠️ M77KeymasterThat’s the automatic tensioner , as long as it has a curved tip , that’s the updated one  (old ones with a flat tip were not good on the 250cc so much so Hyosung had to recall them) , that’s just a sidebar.
If you unwind it , it retracts back , keep unwinding to a full stop, it should stay there (any shake or rattle will make it go forward again) – Pulling back the tip allows easier insertion to the engine.
Once inside the engine, rotate the middle screw again towards the right (i believe clockwise?) so it comes out of its park position and shots forward to touch the chain guides , spin the crank a few times (10x) to confirm all is well and no valve has hit a piston (timings)
If not, you will have to replace those specific tensioners,  new is always better
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Oct 3, 2026 at 6:09 PM #23617
HeatherParticipantThat’s the automatic tensioner , as long as it has a curved tip , that’s the updated one (old ones with a flat tip were not good on the 250cc so much so Hyosung had to recall them) , that’s just a sidebar. If you unwind it , it retracts back , keep unwinding to a full stop, it should stay there (any shake or rattle will make it go forward again) – Pulling back the tip allows easier insertion to the engine. Once inside the engine, rotate the middle screw again towards the right (i believe clockwise?) so it comes out of its park position and shots forward to touch the chain guides , spin the crank a few times (10x) to confirm all is well and no valve has hit a piston (timings) If not, you will have to replace those specific tensioners, new is always better
Okay, let me go check them out and I’ll report back.
Bless your heart, are you the only one replying back to all these posts? If so, my hats off to you. That’s a whole lot of volunteered hours on your part you certainly didn’t have to do. Especially, to help a bunch of strangers. At least, I sure appreciate it anyhow. After having spent hours upon hours, countless hours really and coming up to a stopping place because you’re just stumped. Sure is nice to have someone out there who can offer up suggestions!
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Oct 3, 2026 at 11:51 PM #23622
HeatherParticipantThat’s the automatic tensioner , as long as it has a curved tip , that’s the updated one (old ones with a flat tip were not good on the 250cc so much so Hyosung had to recall them) , that’s just a sidebar. If you unwind it , it retracts back , keep unwinding to a full stop, it should stay there (any shake or rattle will make it go forward again) – Pulling back the tip allows easier insertion to the engine. Once inside the engine, rotate the middle screw again towards the right (i believe clockwise?) so it comes out of its park position and shots forward to touch the chain guides , spin the crank a few times (10x) to confirm all is well and no valve has hit a piston (timings) If not, you will have to replace those specific tensioners, new is always better
I’ve got both tensioners back on, both retracted back. Taking a small intermission before going any further.
I find it helps keep the cuss words ans flying tools across the shop to a minimum. Lol
ETA: ya know, they sure screw on there a whole lot easier when it’s retracted back and I’m not fighting against the chain to screw it down. Fingers crossed I didn’t screw anything up in the process
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Oct 4, 2026 at 4:06 AM #23624
HeatherParticipantM77, your instructions were perfect, thank you. Got both tensioners in and seated correctly i do believe.
Problem is now, I am about 99.9% certain I did not hone the rear cylinder no where near as long as it should have. It didn’t have as must rust on the walls so I didn’t have to use it as much as the front cylinder. Now, when the rear piston comes up and goes to drop back down, that whole rotation is dragging really bad. It then frees up and spins perfect when it is time for the front piston to come up. So….looks like I will be taking the rear apart again.
At least this time I don’t have to take the valves, springs and darn keepers back out again!!!!
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Oct 4, 2026 at 9:22 PM #23632
♠️ M77KeymasterHmm, double check the plastic guides are not worn badly inside the metal tray that’s between the two camshaft and the plastic guides going down to the crank , the annoying part of rebuilding the twins is making sure the timing is spot on and there is a correct number of chain links between the centers of the cam shafts at the top , when you spin the engine 10x , look at the edges of your cam shafts, you will see a deep dash ______ , it must be the same level as the cylinder head lever where the rubber gasket sits
or the front lobes will be facing away from each other at almost 100% horizontal  and the rear lobes will try to form a triangle shape // \\  ,  it’s anotherway to check the cam shafts are spinning correctly so they are not hitting the tappets too soon or too late.  Though the cartoon diagram of the manual does make it easy to follow.
Better to spin manually a few times than 1 single press on a starter motor = bent valve or hole’d in piston.
As for the rear cylinder, sometimes i use my fingers to feel how smooth it is compared to the old one (it is stupid as a jagged edge somewhere has cut me before) , then i know if it needs rehoning or not , sometimes i dress the wall in oil and see how much the piston moves before connecting to the crank , very odd way of doing things that i personally would not recommend, it’s trail and error that got me there.
Though i would say check your piston rings,  incase each ring needs a gap away from the other
===_===
===_===
[oil control rings below]Instead of
==_==== [ring 1]
==== _ ==== [ring 2]
[oil control rings below]& You’re welcome , good to hear the tensioner trick worked! – one less for the swear jar!
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Oct 5, 2026 at 8:21 AM #23635
HeatherParticipantHmm, double check the plastic guides are not worn badly inside the metal tray that’s between the two camshaft and the plastic guides going down to the crank , the annoying part of rebuilding the twins is making sure the timing is spot on and there is a correct number of chain links between the centers of the cam shafts at the top , when you spin the engine 10x , look at the edges of your cam shafts, you will see a deep dash ______ , it must be the same level as the cylinder head lever where the rubber gasket sits or the front lobes will be facing away from each other at almost 100% horizontal and the rear lobes will try to form a triangle shape // \\ , it’s anotherway to check the cam shafts are spinning correctly so they are not hitting the tappets too soon or too late. Though the cartoon diagram of the manual does make it easy to follow. Better to spin manually a few times than 1 single press on a starter motor = bent valve or hole’d in piston. As for the rear cylinder, sometimes i use my fingers to feel how smooth it is compared to the old one (it is stupid as a jagged edge somewhere has cut me before) , then i know if it needs rehoning or not , sometimes i dress the wall in oil and see how much the piston moves before connecting to the crank , very odd way of doing things that i personally would not recommend, it’s trail and error that got me there. Though i would say check your piston rings, incase each ring needs a gap away from the other ===_=== ===_=== [oil control rings below] Instead of ==_==== [ring 1] ==== _ ==== [ring 2] [oil control rings below] & You’re welcome , good to hear the tensioner trick worked! – one less for the swear jar!
wait, waait, wait. The rings on the rear piston, they move around all over the place. Unlike the front. At least I think they do. I am unsure now…..I broke the rear back down again this evening. And thought about when I honed the rear cylinders walls. There was only a maybe quarter inch ring of rust up at the top of the cylinder compared to the almost inch of rust that was on the front. It took a while lot of, as you mentioned….oil then honing some then stopping to feel then back to oiling then honing some more. So I was tickled to only see a small amount on the rear and if I remember right I only went halfway down the cylinder wall with my hone. Since there wasn’t any at the bottom. Not taking into consideration that I was removing material thus leaving the walls uneven. On top of the fact that I didn’t hone it as long as the front. Lessons learned for sure. It was my first time doing it, but I’d rather learn the hard way so I don’t forget. I also didn’t get the walls spotless like I read about too. But they were free of dirt and grim and such and I oiled them prior to putting it back together.
I sure wish I had those timing instructions beforehand. I’m pretty sure I did it correct tho the placement of the lobes the way you mentioned above has me second guessing myself. I remember thinking they looked strange but I’m pretty sure that was before I figured everything out. Well, best as I could. I know I line up the front cams with the “F” haskmark on the magneto, i then put the exhaust shaft on the left side with the markings at the end of the shaft….we’ll one line was at 8 o’clock on the clock face and the other facing upwards at 12 o’clock. The intake side was at 12 o’clock and then 3 o’clock which was facing to the right. I started counting chain links at 12 o’clock on exhaust side. Counted 16 links to intake side. Did the same on rear except lined the rear chain up at the “R” hashmark in the little circle window.
I stopped soon as I got it broke down and will hone it then put it all back together in the morning. I’m gonna double check my marks too on my cam shafts.
Fingers crossed my friend!
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Oct 5, 2026 at 8:22 AM #23636
HeatherParticipantWhen i say the rings are all over the place I just mean they don’t seem to be seated in the groove on the piston like the front one. Plus, I had no idea the gaps were supposed to be in a particular order. Glad you mentioned it
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Oct 6, 2026 at 4:47 AM #23641
HeatherParticipantCleaned the cylinder walls with warm soapy water, oiled and honed then checked oiled and honed then checked……oiled and honed then checked. Washed again with warm soapy water. Oiled the cylinder walls……then realized I dropped part of the gasket inside the block.
Not where the chain goes…but down inside the abyss. Yup, sure did.
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Oct 6, 2026 at 6:46 PM #23642
♠️ M77KeymasterCleaned the cylinder walls with warm soapy water, oiled and honed then checked oiled and honed then checked……oiled and honed then checked. Washed again with warm soapy water. Oiled the cylinder walls……then realized I dropped part of the gasket inside the block. Not where the chain goes…but down inside the abyss. Yup, sure did.
Captain hook on your arm and hopefully the other hand has “crab arms” to pick and claw it out ? without having to split the whole thing apart! –  Tweezers might be too small for that job but i have a feeling you will get creative!
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Oct 6, 2026 at 7:36 PM #23643
HeatherParticipantCleaned the cylinder walls with warm soapy water, oiled and honed then checked oiled and honed then checked……oiled and honed then checked. Washed again with warm soapy water. Oiled the cylinder walls……then realized I dropped part of the gasket inside the block. Not where the chain goes…but down inside the abyss. Yup, sure did.
Captain hook on your arm and hopefully the other hand has “crab arms” to pick and claw it out ? without having to split the whole thing apart! – Tweezers might be too small for that job but i have a feeling you will get creative!
How did you know?! 🤣
Working on a modified pair of kitchen tongs now. Maybe we won’t need them anytime soon…..I hope anyhow lol.
And it’s way on down in there too. Heck no, it’s about 2 inches long and wedged up and underneath gear shift spindle.
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Oct 7, 2026 at 12:47 AM #23645
HeatherParticipantStill no luck….
Last ditch effort is a piece of small plastic hose on the end of my air hose nozzle to see if I can blow it up from the bottom of the block.
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Oct 7, 2026 at 2:02 AM #23647
HeatherParticipant
I bet i try my best to NEVER do that again.For future reference there is a hole at the bottom of the block, to the right of the clutch plates. Saw it peeking out of the hole, grabbed a pair of Tweezers and here we are. Not sure if you have to remove clutch plates or not to access it but I had already taken mine off earlier.
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Oct 7, 2026 at 11:50 AM #23648
♠️ M77Keymasterthat would be enough to get caught between the crank bearings as it disintegrates around the motor or blocking oil jets around the engine, nice work.  If it was sitting directly above the oil mesh (oil strainer under the drain cap) , 2 screws out and tweezers would have taken it away , which likely will remind you to remove the oil strainer mesh under the oil drain cap to see if anything else falls out (you might need a torch)
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Oct 8, 2026 at 5:47 AM #23656
HeatherParticipantthat would be enough to get caught between the crank bearings as it disintegrates around the motor or blocking oil jets around the engine, nice work. If it was sitting directly above the oil mesh (oil strainer under the drain cap) , 2 screws out and tweezers would have taken it away , which likely will remind you to remove the oil strainer mesh under the oil drain cap to see if anything else falls out (you might need a torch)
Thank you friend! I’m just thankful I didn’t have to tear down any further.
I got everything put back together and stopped tonight on what I believe is a good stopping point.
I thought I had the timing part down but I believe the rear is off. The lobes look too close together to be correct. I will sleep on it and attempt again in the morning. They are trying to make the triangle as you mentioned above.
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Oct 9, 2026 at 8:24 PM #23662
HeatherParticipantI forgot to install the 3 starter clutch plate bolts…….
Can you believe that? After all that, it came down to 3 darn little bolts I left off without knowing.
Lessons learned the hard way though you tend to never forget.
It turns over not at least lol
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Oct 9, 2026 at 11:18 PM #23663
HeatherParticipantFor anyone who is still following along….
I still have to double check my primary and secondary resistance values on my ignition coils.
As well as check my spark plugs. Other than that I’ve load tested my battery and it’s holding steady at 12.9. Throw in some good gas and oil and fingers crossed maybe the spark fairies will pay me a visit this evening.
I’ll update later.
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Oct 13, 2026 at 7:58 PM #23677
♠️ M77KeymasterYou got this!
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Oct 15, 2026 at 11:26 PM #23684
HeatherParticipantYou got this!
🙌🙌🙌🙌🙌
You know, this bike has been a bit of a learning experience for me. It was given to me as a project, thinking it would never run. And it did, for 10 years or so until I got it. So to see it turning over on it’s own is worth it’s weight to me! Makes me feel good giving even a small amount of life back to it.
Getting as far as seeing if I can get spark just blows my mind.
Just a few wires left so fingers crossed!
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