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Search Results (Searched for: stuck clutch plates)

  • 19stuberd
  • 19stuberd's Avatar
08 Feb 2024 16:04
Hello again everyone! You may remember some months ago helping me achieve my dream of fixing my 1973 DT3 when nobody else could and you may also remember that it was stolen from me in September of last year. I made it my sole goal to get a new one before the start of the 2024 semester, initially my goal was to buy a 1978 DT400 that was nine or so hours away. I managed to get very lucky though because it just so happened that my friend's dad was looking to sell his motorcycle and by some incredible odds it happened to be a vintage Yamaha as well! I talked to him and got a great price for it and now it's all mine! I put about 125 miles on it after owning it for a week or two, and the clutch blew. I'd never worked on a clutch but I bought the new parts and learned as I went along. The oil smelled like barbecue ribs and so did the clutch plates, the friction disks were nearly nonexistant. New ones went in and new oil added and everything's back to normal! 

Now comes the current issue. With 175 miles on the bike I rode it two days ago and put it away for the evening and then took it back out the next morning and it wouldn't start. I grounded the plug against the engine and kicked it and sure enough no spark. I took the bus to an autozone and bought two new BP7ES plugs for it (one for later) as the service manual says but I popped it in the boot and still no spark. Both times, though, I took one for the team and stuck my finger in the spark gap to see if it would shock me and sure enough in both cases I DID feel a weak shock, which probably means something.

I'm used to my DT3 with its caveman banging-rocks-together level ignition system and I believe this bike has a CDI which I am entirely unfamiliar with. I was wondering if any of you have any experience with working on this type of bike and how I might be able to troubleshoot this issue. I am looking in the service manual and online but you guys have been so helpful in the past I thought I would ask you as well. I'll keep you posted and look forward to talking to everyone again!

Thanks, 
Daniel

Pictures in case the attachments don't work:
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  • torqueflight
  • torqueflight's Avatar
18 Nov 2023 19:12 - 18 Nov 2023 19:15
Replied by torqueflight on topic 1974 DT125A Build/Restore
Well this is gonna sound insane. I took a plug from my 330i bmw, NGK R iridium. I have a 175 head still here, threaded it in the depth looked fine. Went to the plug resting of the head, tested fine, only problem was having to hold it in the boot since it has a push on end no threads and wouldnt hold in the boot.

Figured f it, threaded it in the head and it fired immediately. Test rode it and it ran amazing. The bottom and mid range was better than its ever been. It pulled very good. There was enough tension of the boot that it held just pressed up against the end of the plug. Go figure, if youre ever in a pinch a NGK R 12120037607 will work.

The only issue I noticed is it pulled really hard to the exact redline mark (8k) and theres a little bog/ slight break up. It def feels like it wants to pull hard past it but get stuck right there. If I modulate the throttle it I can feel it wants to go but something is happening. You think it has anything to do with the points or am I running out of fuel? I have a 140 main and the air screw is almost all the way in.

So overall solution, it was the spark plug that was the problem, theres something up with it to where it would work for a little bit then stop, making this all a very confusion puzzle.

PS, clutch is still slipping, prob gonna need to get new friction plates. 
  • MarkT
  • MarkT's Avatar
12 Nov 2023 14:56
It's not the oil.  Could be a lot of things. When bikes sit a long time, the clutch plates can get stuck.  Sounds like yours isn't completely stuck though.  Could be adjustment or something too.  You should be able to start and run in neutral, clutch won't affect that. 
  • Tinkicker
  • Tinkicker's Avatar
31 Oct 2023 15:12 - 31 Oct 2023 15:40
Replied by Tinkicker on topic And a New Candidate Enters The TK Household.
A puzzling one. I never saw the like before. Took the barrel to work and stuck it in the hot wash to degrease it prior to blasting it.

Took it out and gave it a look over to make sure all the oil and grease was gone.

In the upper fins at the rear was what looked like a honeycomb or wasps nest. Only instead of being made of paper, it appeared to have been constructed of a very hard clay like material.

The hot wash made no impression on it. A new one on me. Any ideas, it being a US bike?

Anyway, barrel was checked for taper and oval (fine), blasted and then given a quick hone for new rings. Just needs paint.

Clutch steel driven plates were stuck in the derust bath and then given a quick turn on the linishing belt. They are useable, but not great. Quite a bit of micro pitting on one of them, but still straight. I should replace it but nah, it will work ok. The rest were not as bad as they looked.  Basically after derust, they were just water marked and most of that came off after linishing.  I have had to refit worse in long out of production trannies.

New Vesrah frictions have been ordered.

New Koyo mains have been ordered.

Found a new genuine yamaha piston at a bargain price. Actually it was the only standard one I could find advertised in the country. It cost about the same as a chingaling cheapo piston.
I guess the bike shop thought it being std size, it would not be in demand.

Circlips and small end ordered. Already have genuine rings in stock as well as a full gasket kit.

Head is going into work tomorrow for a dunk in the paint remover bath and the clutch pressure plate is having a turn on my bench grinder wire wheel.

Apart from the oil pump seal kit and the airfilter, I think that is engine complete.

If everything turns up, I will build it and fit it on saturday morning. Might even have it started this weekend..
  • Tinkicker
  • Tinkicker's Avatar
28 Oct 2023 05:41 - 28 Oct 2023 05:49
Replied by Tinkicker on topic And a New Candidate Enters The TK Household.
Bugger.  I am going to have to pull down the motor.  I really, REALLY did not want to put so much effort into it.  I was looking at new rings, probably new clutch plates and new seals.

I set up the timing and put the rotor back on without incident and drained the tranny oil.  About 200cc came out, not the expected 600 or so, and that that did emerge was badly emulsified.  Aw crap, someone was careless with the hosepipe 40 years ago and the tranny has sat in water laden oil since it was put away.
Hey ho, the bearings still felt smooth.

Then I removed the clutch cover to change the crank seal and look at the stuck clutch plates.
My good god....

It was obvious where the missing 400cc of oil was.  It had turned to sludge and was stuck to everything.

Can anyone tell my why the plates had stuck?  What a mess.  1976 motor oil and water that came from the tap when flyaway collars, platform shoes and flared pants were the vogue.

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My troubles were just beginning.  I was not anticipating the next problem at all.  The cast iron barrel had rusted solid onto the studs and I do mean solid.  It did not move upon receiving the usual gentle tap with a rubber mallet.
Three hours it took to remove, involving heat, prying with tyre levers, using drifts, penetrating oil and more heat.  All the while, the water in the emusified oil was breaking down and oozing out over my 1ft x 2ft working space on the bench.
I used up about 5 j cloths just mopping up the mess from the worktop as it was breaking down.
Not a happy bunny.

Finally barrel was off, it had fought for every millimeter of stud length. 
So put barrel aside and gazed in horror at the rust and dirt particles absolutely covering the crank, covering the main bearing oil ducts, all over the big end and in the bottom of the case.
That put the lid on it. 
The prospect of rusty bearings in the tranny and dirt in the crankcase / down the bearing oil ducts made pulling it all apart a necessity.
Feck it all.

Time for a bath to stop the oil breaking down and continuing to make a mess.  Afterwards it was brought up to working temp with a heatgun to dry out the water left inside.  The thin film of oil spread throughout the internals should prevent any further rusting.

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Such are the slings and arrows of outrageous fortune.  Fear not, i tell thee, I will take up arms against this sea of pestilence and trouble.

Only progress made this week is the finished generator cover.

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  • Jogar
  • Jogar's Avatar
18 Oct 2023 13:54 - 18 Oct 2023 13:59
Clutch is doing weird stuff was created by Jogar
Okay, I’ve got a Yamaha 1969 AT1.  When I bought it, it wasn’t running. Had no shifter or clutch cover. I stole a shifter off another parts bike, bought a cover on fleabay.Ive got it running, when I went to shift, nada. No satisfying click of the gears to be heard. Everytime I’d pull the clutch lever in, it would detach from the claw inside the clutch cover (which made me want to snap my crayons). initially I chalked it up as the clutch plates being stuck. Long story boring, cleaned the plates off, still wasn’t doing anything different regarding shifting. Then I did what I should have done in the first place. I looked to see what was happening near and behind the clutch when I attempted to shift. The little clutch shifter arm is bent or something, and after moving it where it should be, it shifts for about 3 or 4 times. After that it gets off-kilter.

help? :) 
  • Tinkicker
  • Tinkicker's Avatar
15 Oct 2023 06:14 - 15 Oct 2023 06:18
Replied by Tinkicker on topic And a New Candidate Enters The TK Household.
Taking stock. The large pile of bits under the bench has dwindled to the rear fender and the motor.

Motor needs new seals and gaskets throughout and I already bought new, genuine piston rings for it. I need to rebuild the oil pump and plumb it in.
Since the clutch plates are stuck, probably new frictions too.

Of course I will have to blast the cylinder and paint, dip the head and covers in the stripping bath and paint those also. Probably fit new JIS crosshead stainless case screws while they are off.

The points and condenser will be cleaned and refitted unless they are badly pitted, the cap blown ( unlikely since it ran) or the spring is rusty.
New Daichi contact sets are around £15 in the UK. A large section of budget that should not be spent unless absolutely necessary.

As I keep mentioning, the bike is just not desireable enough to make replacing things as a matter of course viable. Safety related parts yes, others no.
The 175 yes, very desireable. The 100 no.

I will not be splitting the cases.

That just leaves the air filter. - £30, the exhaust end cap ( new for £75 or complete used rear box for £50 on fleabay) and the rear fender needs attention and the bike is as complete as it arrived.

Needs headlamp unit. There is a kit available that replaces the 6v sealed beam with a replacement reflector and a 6v led headlight bulb. Probably go down this route.

I take it the original sealed beam unit is 5.75"?

Need a new chain. The old one is still OK, but false economy refitting it at this juncture. The engine sprocket looks new and is a genuine yamaha one. I already replaced the worn out, shark toothed rear one.

Then I need 4x indicators and as far as I can see the bike is pretty much complete.  I will have to make new rear indicator stays, they have have proved to be unobtainable so far.  No biggie making some up one lunchtime.

If the missus had not placed an embargo on the debit card, I reckon she would be about finished now.

I think I am looking at another £200 - £250 which will bring the bike in slightly under budget. I hope..

Large pile of bits under bench reduced to two items on bench.

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  • Schu
  • Schu's Avatar
06 Oct 2023 18:20
I will be doing both crank seals. When my other 360 blew the seal thru the retainer it was from a backfire while trying to start it. I resolved the backfire issue by changing it over to points and condenser. 

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But this seal popped out while riding the bike. It was running fine and just fell flat on it’s face in a cloud of white smoke. I had to go in inside anyhow to free up my stuck clutch plates.
  • RT325
  • RT325's Avatar
12 Jul 2023 04:42 - 12 Jul 2023 04:44
Replied by RT325 on topic Inherited Enduro 1975 DT125B
You mention 'afraid to back out the mixture screw any further' with a high idle.
I suggest screw the mixture 'in' to 1.25 turns out & back out the speed screw to slow it down, which is different to the mixture screw. Mixture is on a steep angle. Speed screw goes straight in to the slide--under the slide kind of,--without seeing it & guessing a bit.
Be sure you have cable clearance at the carb top when trying to slow the idle down.
Sorry, just wondering if you have the two screws confused, that's all.
Re the stuck clutch. If ya lucky--very lucky after 20 years--you could paddle it along with motor running then drop it into gear & get into second.
After that then go rapidly on & off the throttle & 'might' free up.
Remember to hold the clutch back to the bar while riding.
If it does free it'll be instant so don't get a fright.
So if it does, then give it a good work out & tie the lever back overnight--maybe every night to be doubly sure until you go in there sometime to clean the plates up & steels of rust etc. I had luck doing that with an HT1 90cc that'd been parked for a similar time outside corroded alloy & rust everywhere.
  • Tom P
  • Tom P's Avatar
11 Jul 2023 19:20 - 11 Jul 2023 19:25
Replied by Tom P on topic Inherited Enduro 1975 DT125B
Stuck clutch is common, and it happened to mine as well. Many here suggest zip-tying the clutch lever to the handlebar overnight, and sometimes the plates loosen. Don't do what I did, before asking here... holding the brakes, clutch lever in, revving and punching it into first. I did work, but then slipped badly, so I replaced the friction plates. I could have done other damage as well, but 2K miles later, no issues. Are you sure it's in neutral? Bulb may have blown as well?
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