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Old 09-04-2013, 01:57 PM   #46
Sting32
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Joined: Oct 2009
Location: Minneapolis, Ks
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Quote:
Originally Posted by Twin-shocker View Post
Flat slide Dell Ortos seem very difficult (and expensive!) to set up properly, but once they are set up, work much better than round slide types.

A very good upgrade for any bike fitted with round slide carb, is a flat slide OKO, which are very easy and cheap to set up, and can be found on Ebay for $49!

The 30mm version tends to provide a bit of extra power at the very top of the rev range, and the 24mm seems to do a good job of softening the power of a bike, if its a bit much for the rider.
This has to do with crankcase stuff how exactly?

Changing the carb completely out, is easier than swapping jets, and moving needle clip. No wonder the Honda Reflex is the "best ever" trials bike made, in your mind...
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Old 09-04-2013, 03:01 PM   #47
jonnyc21
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Wonder where this will go...

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Old 09-04-2013, 03:20 PM   #48
thegraydog
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C'mon, Sting, it's a carb thread too. See posts #38 - 40...
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Old 09-04-2013, 04:34 PM   #49
laser17
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Originally Posted by thegraydog View Post
C'mon, Sting, it's a carb thread too. See posts #38 - 40...
My story is that I was trying to fix a engine rattle with a different carb - and im sticking to it...
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Old 09-04-2013, 05:20 PM   #50
lineaway
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I fixed an engine noise this week in two minutes. Poor guy drove almost 100 miles round trip. I guess I could have sold him something cheap on Ebay. Damn kickstand spring was rubbing on his new tire!
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Old 09-05-2013, 01:06 AM   #51
Twin-shocker
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Quote:
Originally Posted by Sting32 View Post
This has to do with crankcase stuff how exactly?

Changing the carb completely out, is easier than swapping jets, and moving needle clip. No wonder the Honda Reflex is the "best ever" trials bike made, in your mind...
Anyone who chooses to fit a Dell Orto flat slide carb, will almost certainly regret it, as they are very difficult to tune, and seem to be greatly affected by atmospheric changes! An OKO at $49 seems to be a bit of a no brainer here.

The TLR in modified form is a reasonably capable bike, and the bike built by B&J Racing and ridden by Bobs son, is very often used to beat riders on the very latest machinery.

In stock form its a perfect beginner bike, and maybe the dwindling sales of new trials machines would be reduced somewhat if a basic modern day beginner bike was currently available?
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Old 09-05-2013, 06:02 AM   #52
motobene OP
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Quote:
Originally Posted by Twin-shocker View Post
Flat slide Dell Ortos seem very difficult (and expensive!) to set up properly, but once they are set up, work much better than round slide types.

A very good upgrade for any bike fitted with round slide carb, is a flat slide OKO, which are very easy and cheap to set up, and can be found on Ebay for $49!

The 30mm version tends to provide a bit of extra power at the very top of the rev range, and the 24mm seems to do a good job of softening the power of a bike, if its a bit much for the rider.
A techie expert friend says the new carb was buggy when it first came out, but they sorted that out. I'm glad to have the Keihin on the Raga, so no need for anything else. I had the Dell'Orto PHBL on the Econo. It worked great. Very smooth.

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Old 09-05-2013, 06:13 AM   #53
motobene OP
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Checked into my main bearings on the Raga. They are going to get replaced, but I really don't know if they are truly bad or not. I made some assumptions about the right main bearing, then received a new one. When I measure the two old ones and the new one more carefully - with no seals - in the milling machine I found the lateral place to be very close to the same, as in normal. This is apparently 0.012". with no seals. I could push the inner races sideways on the new and left one ~0.012" and the assume bad right one more like 0.013". Lateral play doesn't mean much. It's radial play that counts. I can't measure that accurately, however. I kept getting none to maximum 0.0003", but that's not assembled in cases and with the crank.

Under the microscope I found wear, but don't know if it is normal or excessive. Without a control like one of the Econo's for-sure great bearings, I have no way to know what is unusual wear. Both bearings roll well, especially the left one, rolls super smooth feeling and tight.

The following three pix are through the microscope lens. I shot the worst looking surfaces on the inner and outer races of the right main bearing:







The depth of wear is very shallow. Note the manufacturing grinding marks extending through the region of maximum wear. The total depth of a grinding mark is micro puny, measured in microns or millionths of an inch.

My only option at this point is to replace the bearings and do a test ride, as I've done everything I can think of to do. I could be wrong, but this level of wear is not true smoking gun. And since I'm an idiot who assumed stuff and ordered only one main bearing, I'll have to wait another week to put the motor back together.

motobene screwed with this post 09-05-2013 at 06:22 AM
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Old 09-05-2013, 09:20 AM   #54
Twin-shocker
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I get the feeling that any 2T bike with main bearings lubricated by gear-box oil, is probably going to need bearings changes more often than those lubed with pre-mix? Reason for that is metallic debris in the gear oil, which may be at quite high levels unless oil is changed quite often.
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Old 09-05-2013, 09:49 AM   #55
laser17
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Quote:
Originally Posted by Twin-shocker View Post
I get the feeling that any 2T bike with main bearings lubricated by gear-box oil, is probably going to need bearings changes more often than those lubed with pre-mix? Reason for that is metallic debris in the gear oil, which may be at quite high levels unless oil is changed quite often.
I think the real life numbers are the other way around. I see alot more "other" brand crank bearings being replaced than GG. As easy as tranny fluid is to change, there is no excuse for not keeping it clean. My dad was a GG dealer for years (sold alot of bikes - 2nd largest GG dealer in states) and never replaced any crank bearings on a pro!
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Old 09-06-2013, 07:34 AM   #56
motobene OP
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Quote:
Originally Posted by Twin-shocker View Post
I get the feeling that any 2T bike with main bearings lubricated by gear-box oil, is probably going to need bearings changes more often than those lubed with pre-mix? Reason for that is metallic debris in the gear oil, which may be at quite high levels unless oil is changed quite often.
It's the other way around as Laser17 says. The reason is the better film strength of ATF versus oil mist. It doesn't take much to lube a main bearing, but an abundance of ATF versus an oil film is better, not worse.

Consider also the greater chance of injecting grit through the air filter, especially with dry or under oiled (or wrong oil) on the filter. All it takes is one stream dunking to carry lots of grit into pre mix lubed main bearings.
Transmission-lubed main bearings are likely more protected, not less.

Yes, you could trash some bearings if you got metal chunks from the tranny into the bearings. I think that may have happened on my bike, as it is obvious someone split the cases in the past. I'll call the former owner and get the story of what failed, and how many times he went in there. Maybe it'll explain why the bearings under the microscope show some surface indentations from eating some kind of grit.
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Old 09-07-2013, 01:59 AM   #57
Twin-shocker
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Interesting.................Fantic TS has drive side main lubed with trans oil, and like GG has issues with metallic particles in the oil, but come to think of it no major problems with drive side main failure.

Here in the UK main bearing failure on trials bikes does seem quite common though, but I guess that might have something to do with corrosion, which is maybe worsened by the fact that most people seem to use very thin autolube oils, which doesnt provide as good corrosion protection as the thicker pre-mix only types?
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Old 09-07-2013, 06:30 AM   #58
motobene OP
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Quote:
Originally Posted by Twin-shocker View Post
Interesting.................Fantic TS has drive side main lubed with trans oil, and like GG has issues with metallic particles in the oil, but come to think of it no major problems with drive side main failure.

Here in the UK main bearing failure on trials bikes does seem quite common though, but I guess that might have something to do with corrosion, which is maybe worsened by the fact that most people seem to use very thin autolube oils, which doesnt provide as good corrosion protection as the thicker pre-mix only types?
I have a Fantic. I remember something like that.

My theory on the high UK main bearings failure rate: Most bikes have bearings lubricated by oil mist. Thus the main bearings are directly exposed to what ever sneaks through the air filter. Your environment is generally quite wet and muddy, and I see lots of stream crossings in videos, particular in Scotland. Does the same hold true for the midlands and south?

Combine this environment with the possibility of an air filter 'culture' (by culture, I mean what is assumed to be good and right) assumes light oiling or even no oiling is 'the tits', this would account for your higher incidence of main bearing failures.

What is your general culture? Your assumptions?

Rx for your environment would be full-on soaking of cleaned, dried filters with Maxima FFT and squeezing out the excess. Your filters should be blue and very sticky to shed water around the filter, and to keep particulates stuck to the oil during a major dunking. The tits, as they say.
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Old 09-07-2013, 08:03 AM   #59
motobene OP
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Quote:
Originally Posted by laser17 View Post
Ive been hearing about more and more tight clutches. Seems like a trend - glad you found the smoking gun in your case.

Did you ever sort out the loose fit on the crank bearing? Was the case machined on the large side of spec? Im very curious about this. I 1st hear that the reason they stopped using the Mg cases was due to some spun bearings and then I hear the factory Editions had some bearing failures. (not by a great source - just an online thread) I wonder if something else is going on. Some Gorilla damaging the mating surfaces during assembly? Bad CNC work? Nothing?
Sorry, I missed this reply. I think maybe the bearings just have a tad bit of wear and will be replaced. Can't confirm this yet.

On the Mg cases, there no issue I know of with manufacturing, as the two materials machine close to the same. Could ther have been some missed bore diameters? Always possible. You'd have to have a sloppy fit inded to 'spin' a bearing race that has a sealing o-ring on it. I think to Mg or not will come down to material properties, as in thermal transmittance and expansion, modulus of elasticity, and strength.
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Old 09-13-2013, 03:03 AM   #60
motobene OP
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Last night the magnesium-cased 2011 Raga 300 Engine was reassembled with new main bearings, and the crank, flywheel, and clutch assembly out of the 2010 TXT motor. Learned the vibration and noise was not a crank/flywheel balance problem, nor a clutch & primary gear problem, because the Raga's guts went back into the Econo 280, and that bike ran just as smooth as it did before. I expect the Raga, with new main bearings, will run smooth and quieter like the Econo. In other words, that I found the problem and it was micro wear in the main bearings. That would be astounding if true. What it says is it doesn't take much wear to raggedy up a main bearing. Stay turned for the test ride, after the left-side brake welding and frame painting is done.

Reassembly of the Raga was harder than the Econo because I had to replace the main bearings. As a precaution to a tight bearing press, I froze the bearings and heated the cases. Still very tight! Lots of taps on bearing to drive it home with an outer race from of the previous bearing as a tool. Very easy to tilt the bearings and get them stuck, so I took repeated measurements of depth progress with calipers.



The main seals were pressed in next. I started by hand pressure and finished using an old seal as a tool. They press in seal lip side out (facing you). The amount of lip expansion over the inner bearing race surprised me. Those lips are really stretched!



I've taken again lately to greasing instead of sealing gaskets so if I have to work on it later I don't tear gaskets up as much. The case halves assembly was fairly easy except for balky kick start pawl stop that sticks out of the left case and inserts into the right case to slip behind the pawl. It'd made of aluminum, not plastic, on this model. The tapered part wanted to push the cases apart. You have to turn the kick starter gear to all the stop to go behind the gear, but the taper imparts a little spreading force when the tip is just sliding behind the pawl.

Case bolts in and torqued, I cut off the excess gasket. Then on went the piston and cylinder and head.

I checked the squish with solder. I had an 0,32mm new base gasket. It came with an 0,35mm gasket. The squished ended up a bit shy of the theoretically ideal 1mm at 0,92mm. A more ideal gasket would have been 0,40mm, but it's close enough.

I fitted a low-compression head this time. I've tried the other two. Runs potent with the high compression head, but I'm investigating more smoothness this time. What differs in the head is the profile and depth of the dome cut where it starts at the squish and end up at the plug. Obviously the low compression head has the most volume. Note the small radius in the standard head dome-squish intersection.



Anyway, it's all back together to await the revelation the test ride. Will Mr. Raga be sweet like Little Miss Econo? We shall find out.


motobene screwed with this post 09-13-2013 at 03:19 AM
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