What to Use on Throttle Sleeve to Keep it Free?

I cant believe no one has replied yet.
Presumably you've tried WD40?

Maybe smear the slide with engineers blue and look for any high spots, take 'em down very gently with some very fine wet & dry paper wetted with parafin or similar, and thoroughly rinsed off. (or crocus paper)

Some one will shoot me down for suggesting that, but if you take it easy and keep checking. Maybe have to check in case the high spot is on the body...but I'd think it safer to work on the slide. then maybe a grraphite lubricant.

Dunno if that helps...but I couldn't leave you with no replies .

Del

Just a note. "Parafin", in the US, is kerosine.

As Dell has suggested there are plenty of lubricant available, but if it was OK and now is not (especially after only 1mile) then "What's changed?"

Suggestion from me is to do a little diagnostic on the sticky cable. Even disconnect one end and check that the cable still moves freely inside its own sleeve.

Until you know the "root cause" you might treat the symptoms and think the problem has gone away, but in reality all you will achieve is to disguise (cover-up) it with a band aid.

If it was OK when originally fitted, then what happens in the 1 mile of travel? Has it got hot against the engine and fused onto the cable? Has a loose item shaken and moved into a jam point? Does it feed through an area that is compressed while the bike is operating (like under a seat or through suspension points)? Has it been kinked by some movement during that 1 mile of travel? What contaminant could cause this tightness after only 1 mile of travel? (All rhetorical questions, just wanting you to think beyond the scope of "more lube".)

My brothers used to ride bike through the dusty portions of central Queensland mustering and so on. Riding in the dust zone behind a mob of sheep with visibility less than 50 yards and the throttle and brake cables never needed lube more than once per year. If there was enough contaminant to tighten the sleeve/cable in 1 mile, you would remember the event that splashed it onto the bike.

btw, WD40 was their lube of choice, just fit the can nozzle to one ond of the cable and spray.

Hi Just an Engineer,

It's the carburetor sleeve, not the cable. On my original carburetor, I never lubed it even once. This one I lubed with WD-40 when I installed it. I have now removed the sleeve, and found yellow deposits (Varnish) which are the problem. The WD-40 may have made it worse. I am convinced that I now must clean out or replace the gas tank (I only pored out the original gas, and put 1 gallon of new in). I checked the screen of the petcock and found yellow sludge (I cleaned it thoroughly before before the carb was installed). What do you suggest for cleaning the gas tank? A colleague suggested MEK, with acetone or lacquer thinner as substitutes. He also suggested silicon spray for lube. Is there any kind of filter that would not pass the varnish that I could install between the petcock and the carb?

Regards,

S

Maybe the WD40 has weakened the surface finish material, Use WD as a cleaner, not as a lubricant, the sleeves are usually made from something like cintered Bronze (however thats spelt) its self lubricating, the WD could have leached the lubrication out of it and dried it out as it evaporates, WD is a loosening/thinning agent.

I have found vaseline works best on my shafts

Isn't there a micro-screen filter at the bottom of the petcock?

When you say, "sleeve," do you mean the carburetor piston that the jet needle is attached to?

Suggest just removing the tank and sloshing the fuel around a bit, then dump it and fill with fresh. Do you mix the fuel with oil, or this an oil injection model?

"Isn't there a micro-screen filter at the bottom of the petcock?"

Yes, as I said, it had yellow sludge. I'm not sure it's stopping everything (certainly not dissolved), that's why I want to put an additional in-line filter.

"When you say, "sleeve," do you mean the carburetor piston that the jet needle is attached to?"

Yes. I have oil injection, but it makes too much smoke, so I may change to mixing in the tank. Will that help or hinder the problem?

I have a makeshift air cleaner element (described in my previous thread), and it has clamps, so I don't think it's a dust problem.

S

You should treat the gas tank with Creem; http://www.jpcycles.com/groups.aspx?LID=50503969-170f-44b6-9375-e53644d41603&DID=db9160df-7dc9-4c87-8d37-98c0ff0188f6

You should be able to find it at many motocycle shops.

Lining the tank will keep the crud out of the carb.

This is a very common problem with old bikes.

I would not change from oil injection to mixing. I've heard that it can be done, but I'm not convinced that the lower part of the engine receives enough lubrication (crank, rod bearings, etc.), if you eliminate the oil injection.

If you are worried about too much smoke, just don't put any oil in it... it won't not smoke for long. Just kidding, of course. If the engine was designed to use an injection system, I'd just stick with that, smoke or no. At least smoke tells you that the piston is being lubed (I hope!).

Hi Skeeter,

"I would not change from oil injection to mixing. I've heard that it can be done, but I'm not convinced that the lower part of the engine receives enough lubrication (crank, rod bearings, etc.), if you eliminate the oil injection"

That has entered my mind, but when I changed the ebay carburetor back to my original (the sleeve finally came loose), I had to remove the muffler. When I went to put the muffler back on, I discovered that a puddle of oil had run out of it. Sounds like too much oil, wouldn't you say? What if I leave the oil injection there, but with the cable off, and mix oil with the gas too?

The reason I changed out the carb was because it wouldn't idle unless the choke was on. I had to start out with choke, then turn it off after half a block, and keep the throttle open about a third, or the engine would die. It's no better, and I think worse with my original. Maybe something else besides carb to cause this?

I have put in an in-line fuel filter, but still have the same gas. When I pulled out the carb, it had the gunk, and would have been sticking soon ( I rode it about another mile). Sure, the gas in the tank probably has more varnish, but all gas has some. Is the same problem that causes the idle problem also contributing the the sticking problem?

S

What color is the plug? http://www.yamaha2stroke.com/node/15

Probably try a NGK bp6es, you could try a 7[1 step hotter] until you get the jetting & oil injector sorted out.

Is the oil injector adjusted properly? It doesn't matter where the oil & gas get mixed If the ratio is correct the lower end will be fine. You should use premix until you get everything set up properly. The injector/pump set up is much more convenient than premix, once you get it pumping the right ratio

Here's some pics and a source of parts. http://www.bikebandit.com/houseofmotorcycles/yamaha-motorcycle-dt1c-mx-1970/o/m7088 using the wrong or no air cleaner will throw off your jetting.

You need to take another crack at cleaning the carb, sounds like the pilot jet is plugged or fouled plug.

Hi Garthh,

Your link does not have the air cleaner, nobody does it seems. My replacement could be part of the lean mixture, but not very much I think. I have gone over both carbs with a "fine tooth comb", using the third carb (from ebay) to familiarize myself with all the little holes. Both are doing exactly the same thing. One has a needle with a bigger taper, which helps some, but not at idle. Thanks for trying.

S

"Probably try a NGK bp6es, you could try a 7[1 step hotter]"

B7ES is the normal plug. I will probably get a B8ES next time, as it has always been a little black, but has never stranded me.

"You need to take another crack at cleaning the carb, sounds like the pilot jet is plugged or fouled plug."

You were right. I found 2 plugged holes on 1 carb. Now it idles too fast! Haven't tried the other one yet. I give you a good answer for this one too. Fouled plugs usually affect high RPM. I don't expect one to affect idle speed. I did file and gap it at the beginning.

S

Hi Ken,

"Sounds as if the crankshaft seals are shot. If they have not been replaced, then they are almost certainly done for, if the bike was sitting for 19 years"

I think you're on the right track. The seals have never been changed. Is it hard? Doing the pressure test won't be easy.

"Bad crank seals can, on many bikes, suck oil out of the primary drive, giving the impression of over-lubrication."

This fits the symptoms.

"Be sure the ignition timing is spot on."

Good suggestion. Also, I am suspicious that I don't have enough spark.

"Did you check the end gap of the new rings?"

It is basically zero where they enter the cylinder, however it could be greater up higher, and I suspect it is. This could contribute to the problem, but I know how it ran before, and it isn't doing it now.

I have given you a good answer. Regards,

S

Another great answer from Ken...

Changing the seals will be a big job involving taking the crank out I'd expect but on the plus side, I would bother with pressure testing! Just change the seals, making sure that the shaft they seal against is ok...if that is pitted through 19 years of sitting still with condensation on it you are stuffed.

I remember my old Lambretta had a crank seal go...it sucked in oil which whiskered the plug every 20 miles, so it was stop and clean...stop and clean, but it got me home.

Del

yEAH

Ken's got it.

The seals lasted just long enough to make a short ride.

The clutch side won't be that bad.

The flywheel/magneto probably needs a special puller.

You need a proper seal driver to install.

To do a pressure test put freeze plugs in the intake & exaust.

Knock the ceramic out of an old plug & glue or braze in a shrader valve [stem from a tire] so you can use a bicycle pump to put in 1 or 2 pounds of pressure. spray the seals & base gaskets with soapy water, leaks will bubble.

If you used something like this for a filter http://www.bikebandit.com/search-products?q=pod+air+filter&ch=2&sc=10 you will probably need to richen it up a bit since the stocker is fairly restrictive

I just posted the link for bike bandit for the pics. You can probably just measure the seals to buy replacements from a local bearing supplier.

You need a proper seal driver to install.

Whatever happened to the good old days when we could do this stuff with little more than a wooden drift and a mallet?
As long as you drift it in square and keep everything clear of the lip it's not rocket science. Or is kitty going to get thrown outside again?
I'm with you on the puller tho' ...no way you'll break a taper fit without the right tool.

Del

I would call a piece of wood that is nice & square with the correct sized hole a "proper tool"

An example of an improper tool would be a screw driver, extention, steel punch....

You don't have to buy one.....

I have a nice fork seal driver, made out of PVC pipe & a pipe union for a slide hammer, duct taped inside for "proper" alighnment.

Wrapping a piece of vellum around the shaft can keep the lip from turning inside out, make sure to lube the seal face & maybe a thin layer of gasket sealant where it fits in the case.

Sometimes you can make your own flywheel puller, many yams the factory puller is a large metric bolt that has been drilled & tapped down the center for drive screw.

the trick is figuring out the pitch of the threads in the flywheel.

Others have a few holes tapped close to the shaft, you may be able to use a steering wheel puller.

So Del,

since you had a scooter did that make you a mod? [listening to Quadrophenia yesterday]

I have a nice fork seal driver, made out of PVC pipe & a pipe union for a slide hammer, duct taped inside for "proper" alighnment.

Ah, excellent, I love 'home made' tools and jigs .

Nah I wasn't a mod...but it was fun tagging onto the end of a line of scooters as we all leant through an S bend on the way down to the beach (of course it was always sunny in those days and England always won the Word Cup...)

Del

Hi Garthh,

I have the flyweel puller, and have already used it to replace the points. Will I need to pull the engine to replace the seals? This may be more work than I am willing to put.

"Knock the ceramic out of an old plug & glue or braze in a shrader valve [stem from a tire] so you can use a bicycle pump to put in 1 or 2 pounds of pressure."

I like this kind of thinking. The link says 6 pounds, but less is good if the guage can read it. You get a good answer too.

S

I would certainly give it a shot, before I cracked the case(s). Taking a chance with $20 worth of seals, is much different than fooling around with the crank & tranny.

The last pressure test I did was to find porosity in a case, so I didn't worry too much about the actual pressure. On the carb side use a solid plug drill & tap for a small gauge, use an expandable [rubber freeze plug] on the exaust side.

I even seen guys run 2 stroke oil in the tranny & a hotter plug, to avoid dealing with leaky main seals. Drive it till it drops.

Regarding cleaning the fuel tank, I'd suggest "Don't put anything into it that you wouldn't normally put into a fuel tank."

MEK might be a wonderful solvent, but if ANY of it gets onto seals, plastic parts or anything else, you have a catastrophe. Petrol is also a wonderful solvent, is far less expensive than MEK, far less dangerous and far easier to handle and everything in the fuel system is designed to cope with that solvent.

As someone else suggested, slosh, drain, dry it out, maybe add some fresh petrol to "rinse", slosh, drain and dry properly.

I've once seen "yellow" in petrol way back when we used to receive fuel on the farm in 50 gallon drums. When we'd syphon the last drops out, if the drum was old and rusty AND there was a little water in the bottom, then the water looked like yellow petrol.

We would decant the good fuel off the top and use the yellow stuff as week killer.

Yeah, this is good advice. How long had the gas sat in that tank? '70 Yamaha, hope it wasn't anywhere near 38 years! Sounds like some of it turned to "varnish" though. Would certainly cause problems, and plug up any filter you could use. Get it out of there.

You are on the right track. The slide in a motorcycle carburetor should not be lubricated. In a premix two stroke it operates in an environment of atomized fuel and oil, and on a four stroke (or oil-injected two-stroke) it operates in a mist of fuel. Either way, and added lubricant gets washed off and is unnecessary.

Is there any kind of filter that would not pass the varnish that I could install between the petcock and the carb? add the product "stabile" in the gas so the varnish will not form when the bike isn't in use for long periods of time. MEK or lacquer thinner should remove the deposits but the sleeve doesn't need a lube

any kind of filter that would not pass the varnish that I could install between the petcock and the carb

No. The varnish forms weeks or months later in the carburator as the fuel becomes stale. When the gas originally passed through the filter it was still good. But now it is sitting downstream of the filter in a bowl. Drain the carburator before layup. Stabile can be used as an alternative. But if you read the manual, or had it professionally winterized by the dealer, they would drain the carb according to the manufacturer's service procedure.

The OP stated that the varnish formed in an hour of driving. How can the varnish form that quickly from the gasoline?

He used old gas. Buy some new gas. Use it within 2 months now with the 10% ethanol. A filter can't make old gas new.

The only intent of the filter is to catch the solids that are in the tank.

Does this bike have an air cleaner and a non-leaking connection to the air inlet on the carburetor? If dust is getting into the fuel chamber, it can cause the piston and needle to stick. Recently experienced this problem with one of my bikes. I thought a pressure fit of the inlet hose to the air box was good enough, but it wasn't, so I found a clamp to remedy. Now, the engine runs like it should.

This is probably not the problem but I have seen it happen so it may bear checking.

The bore of the carburetor BODY as well as the slide can wear. This will cause the slide to cock in the bore enough to stick. When the bike is not running everything slides smoothly (although there may be a little to much clearance). But when you start the bike the high level of vacuum on the engine side of the slide will pull the slide sideways a little. Now the slide to bore is point loading and the surface tension of the lubricant (like Ken says its gasoline) is exceeded and the slide sticks, until you turn off the motor and the vacuum goes away! Putting in a new slide may get the clearance low enough even if the problem is bore wear.

I had an open class KTM that was doing this and it was TO exciting.

heat up auto grease until it's liquid enough to shoot it into the cable sleeve with a hypodermic needle. this works in most cases

kenn

It could be that the cable itself has somehow got frayed, in which case no amount of lubricants will do any good, you will just have to replace the cable.

It's great to hear you got some use from the bike, and are close to getting some more. As expected, you have gotten some good sounding advice already. Let me try to add my two cents worth.

For the unwanted collection of stuff in the tank. Try this. Make sure there is no filtering device in the tank or the fitting attached to the tank. Then run a loop of fuel hose with an inline fuel filter designed for an automobile. I don't usually like the clear plastic ones, but if you are just running it in your yard it would allow you to watch it catch the debris. Otherwise use a steel filter, and rout the extra line clear of the exhaust. This is the easiest way to remove the trash safely. Check the filter every hour or two and replace when you find it starts to become restrictive. These filters should cost under three dollars.

If you are concerned about the condition of the crankshaft due to pitting or other scoring at the seal area, try a bearing wholesaler. Most common shaft sizes used by machinery that damages shafts have had very thin sleeves made available by the bearing manufacturers. You will not find these at the factory dealerships. An aftermarket repair facility that is familiar with the bike might know of the sleeve if they have ever needed one. I would suggest you look for them yourself at a bearing distributer if you feel the shaft is in poor condition. They are dirt cheep, and work as promised.

If you are not able to stop the smoking with the oil injection system, there is a smokeless oil made for 2 strokes by Texas Oil Refinery. It might make things more bearable till you get it nailed right. Good luck. Bob C. ( I'm on another computer, and can't log on)

Hi Bob C,

I have already put a see-through filter after the petcock. It is ty-rapped away from the muffler. I did not plug up after the 8 miles, but the micro-screen for the reserve tank pretty much did. The petcock has another micro-screen at the bottom. It only plugged up the once so far. After the 8 miles, I let the bike stand awhile, then later I could not turn the throttle. the sleeve/slide/piston was varnished stuck again. I pulled the carb, and found the spacer to the engine contained a thickness of varnish all the way around that I estimate was 1/32" thick. At that point I dumped the gas, and attempted to clean the tank with some fresh gas and solvent. That has been dumped too. Tomorrow I will see what goes.

I have adjusted the points. The instructions in my Climer book do not work. It says the points should open when the piston is 1/2 inch before TDC. When I get close to that setting, the points never close. It was set about 1/4" BTC. I was getting misfire at about 6,000 RPM. Now I have them set to about 1/8" BTC, and tonights small ride got me up to over 7,000 RPM.

After adjusting the points I put the head back on. It was torqued to about 20 ft.-pounds, now I have it to 30. I think I have gained a little in the idle problem from those 2 things.

S

Is it possible to remove the microscreens, and just let the junk collect in the add on filter? As long as it is getting cought in the factory micro screens, it will not get to the add on filter.

As I understand the points setting, it should go like this. Slowly rotate the engine in the correct rotation, till the piston is 1/2" from TDC. At that piont adjust the pionts so they are JUST opening. What I do not know is if there are two adjustments here. On an automobile you can adjust how far the points open ( .016), (.020) ect. as well as when the points open relitive to the crankshaft py rotating the distributer. Do you have both adjustments? If so, first adjust the maximum distance the points open according to the climer book. Rotate the engine back and forth till you find out how far the points will separate. After that is set, then do the 1/2" thing. If you are not confused enough, recite the firing order for a 14 cylinder radial airplane engine.

Can you remove the new varnish by spraying carberator cleaner in the carb, or do you need to dismantle it? I am at a loss as to why the varnish would build up that fast and then dry up. Is the varnish wet and sticky, or dry?

"Is it possible to remove the microscreens, and just let the junk collect in the add on filter?"

I could remove the one on the petcock bowl, but I wouldn't want to.

"Do you have both adjustments?"

No, the only way I could advance the timing now would be to remove the magneto and drill more holes for the 3 screws, or make slots.

"Can you remove the new varnish by spraying carburetor cleaner in the carb, or do you need to dismantle it?"

I could spray it on the slide, after removing it, not sure how I would do the carb throat. I have been using steel wool.

Is the varnish wet and sticky, or dry?

It is sticky at first, then when it dries, the slide is stuck. I drove the motorcycle to work today, 3 miles each way. When I came home, it took some torque on the throttle to free it, but it didn't stick on. I noticed that my original carb had a stronger spring than either of the ebay units. I am using it now, which will make it much less likely to stick on (a dangerous situation). After dinner I took another short ride (~1 mile). I had no problem with the slide then. Have you ever used silicon spray on a motorcycle carburetor slide?

Have you ever used silicon spray on a motorcycle carburetor slide?

No but that does not mean that it will not work. Another thing you might try is dry teflon spray. Either one of them that keeps the slide from sticking will be an improvement.

If you can't remove the microscreen while cleaning out the debris in the fuel tank, the majority of the debris will be in the microscreen, not the add on filter. There is nothing wrong with catching the debris in the microscreen, it is just so small compared to the add on filter, that you will need to check it much more often.

Is there a color that your 2 cycle oil has been tinted to? Is the varnish that you are finding in the slide the same color? I am thinking that the post that mentioned the leaking crank seals may be correct. Is it possible that there is too much crankcase pressure building up causing some of the oil mixture to be blowing back out of the carb during power stroke? In 40 years of automotive repair work, I have never seen varnish build up this quickly. I will gladly tell all that motorcycle repairs are not my daily work, but still this varnish has me concerned.

The varnish from the tank is going into solution in the gas & hardens up when the volitiles evaporate.

Clean & seal the tank as I suggested earlier.

Hi Dell,

I must be awfully close to the 3.2mm, and am convinced the points are set close enough. They don't give it as an angle, but cars at this altitude idle their fastest at about 10 deg. BTDC. The stroke on this engine is 2.52 inches (64mm).

Looking more in the book, I found that GYT stands for Genuine Yamaha Tuning. As I suspected, they are racing conversion parts, and don't apply to my bike.

Third day of riding to work, and the slide is still working. I think the sticking problems are behind me as long as I use up the gas in a reasonable amount of time. Now I need to do the pressure test, or change out the oil seals. The transmission oil has not gone down noticeably, but that doesn't mean air can't be getting in above the oil level.

Another thing I want to do is get the headlight working. It looks like I will have to convert it to 12V, as 6V lights are impossible to find, other than used, which would be stupid. I have taken out the center of the sealed beam headlight, now to find a lamp that can go in there to replace the old one. It was a 35W/35W.

S

Actually bike bandit carries the headlight for $7

Jc whitney has a halogen replacement the shell is $24, the bulb $10 (6volt)

http://www.jcwhitney.com/Yamaha-DT-Models-Motorcycle-Lighting/200004537-600014762.jcw

I installed a similar set up on an old xs yam [triumph knock off], made a world of difference.

You can probably install a later model magneto & go 12 volt

Sounds like you ran enough gas through it to melt all the varnish.

Thanks Garth,

I spoke too soon on the slide. I took another ride around the neighborhood, and after I stopped, I opened up the throttle, and it stuck open! Have you ever used the Creem?

I have another sad tale to tell. My taillight which was good was loose in the socket. I didn't get around to gluing it, and now it vibrated to pieces. I was looking in my car parts box for a 12V replacement, but didn't find one, but found a 6V that looked new! I rode around the neighborhood with it on. When I came back, I revved up the engine, and the wire came off the battery. Both filaments blew out, and it blew a hole in the glass. In getting it out of the socket, it shattered, and about cut my thumb off. Dell, could you lick it?

I am thinking that it would charge 12V with the magneto I have, but would the horn take 12V?

S

I have used creem on 4 different tanks, Including an old BSA that was very rusty.

I even used it on a brand new tank, to avoid future problems. The cleaner that goes in 1st is sort of nasty. You end up with a nice plastic liner.

Looks like the battery is the regulator!

http://www.yamaha2stroke.com/images_other/wiring-diagram-1974-dt250-a.jpg

The ignition coil may melt, not sure about long term effect on the magneto.

"The cleaner that goes in 1st is sort of nasty. You end up with a nice plastic liner."

I was skeptical of it, but you must like it. Does the tank have to be totally dry?

"The ignition coil may melt, not sure about long term effect on the magneto"

Mine had 3 magnetos, one for the ignition, so the battery isn't involved. The diagram I have shows 1½ charging the battery in the "day" position, and 2 charging it in the "night" position. I am thinking of replacing the battery with a regulator as an acquaintance of mine did. I don't need lights or horn when the engine is off.