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Hi Dave,

Nice work on removing those ribs!

Yes, Yamaha's parts diagrams and service manuals are notoriously bad and full or errors. And they were probably able to save a nickel by not machining the end of that shaft.

I would not worry too much about not having an oil feed to that idler gear. It is only lightly loaded for about 1/4 of a revolution when you kick it, and after that it is just freewheeling for the rest of the time. That idler gear also has a self-lubricating oilite sleeve which probably gets a good bit of splash lubrication and oil mist from the spinning clutch pack.

However, if this issue will keep you up at night, here is another option. Since you will already be cutting a C-clip groove into the end of that shaft, you could use a cutting wheel to carefully cut into the shaft where the hole should be. Go just deep enough to break through to the inner diameter of the shaft so that the pressurized oil has a path to reach the idler gear.

On the bright side, your crankcase is already machined so your kickstarter will slip right in!

Brian
 

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I agree with Brian, the idler gear has that sleeve with spiraled holes that allow splash-oil to reach the contact surfaces fine. My advice is to put the groove as far out as you can, then work with shim washers (very thin washers) on both the inside and the outside of the idler gear to get the right spacing so the idler gear's teeth perfectly match up to the one on the clutch and the kicker. Probably not a necessity, but I'm anal about those sorts of things. Besides, it doesn't take much to have that gear have rub interference if it's not centered.
Don't worry too much about the inner shim/washers as spacers, it's mainly there to keep any incidental wear on the aluminum crankcase from the gear. Just make sure they are stainless steel. Also, don't worry about grinding the flat on the shaft for the D washer. The design was to keep that suface to the gear from spinning, but for the life of me, I don't know why. I suppose the thought might be it doesn't wear on the E-clip, but that e-clip is hard steel, not likely to wear from a washer, spinning with the 1/4 crank turn of the gear when under load, or not.
When you bolt the cover on, first just do it so the bolts are seated. Then test the kick starter for interference. Mostly that the lever returns freely under it's spring return. Then finish tightening in two or three rounds of the fasteners, checking the kicker each time. I had a problem with mine where the very final tightening caused the kicker to not return. It turned out the gasket set used a thinner gasket than the OEM. I sanded down the crank case surface that the kick mechanism rested on. I'm attaching your photo with my highlight showing the area in question.
One last thing; I would not use heavy grease on the idler gear. I think it would actually block the holes in the bronze sleeve incorporated into the gear and prevent splash oil from doing it's job. It has to be a maelstrom of oil inside that side cover when the motor is running and hard to believe that area would ever lack for lubricating oil. I'm attaching a photo of the idler gear with the oiling holes. As you can see, they overlap the edge, catching oil and slinging it into the contact surface. It's brass and would wear faster than the shaft so a bit sacrificial in that respect but it could be it also is a fit design when things warm up so it doesn't seize on that shaft. I don't know.

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Discussion Starter · #63 ·
Thank you so much for your incredibly helpful insight, Brian and Gerry! I would never tackle a project like this without knowing that this Forum has such knowledgable members like you (and MANY others). You have both relieved my concerns with the idle gear! So today, a friend gave me a hand grinding the shaft for the idle gear C-clip. The job went extremely easily with a second set of hands. I used an old T-shirt to line the crankcase while placing a few refrigerator magnets strategically to help hold the up the cloth and also catch the material removed from grinding. My buddy spun the shaft for me while I handled the grinding - once again utilizing the Dremel's Flex-shaft attachment. I'm finding that thing very handy!


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I'm still waiting for some parts to arrive in order to properly located the idle gear on the shaft as Ski Pro 3 suggested. However, in the meantime I figured I would mock up the clutch pack and check for clearance with the modified 1987 TW200 ride-side crankcase cover. I did my best to line up the bolts with the shallowest part of the crankcase cover and was able to fully seat it against the crankcase (no gasket) without trouble. I rotated the clutch boss slightly left and right multiple times to make sure the bolts where closest to any point of contact and everything seemed to clear. It appears that taking the inner reinforcement ribs all the way down flush to the inside face of the cover eliminated all clearance concerns. I had to back the bolts out 1.5-2 millimeters before I detected any issues. Still, I decided to play it safe and also smooth down the face of the clutch spring bolts as TW-Brian did. I also have about 1mm of back and forth movement of the kickstart shaft with no gasket between the cover and the case. I'm fairly confident that I should not have any binding issues.

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Great job! And thanks for the recognition. I was amazed at the versatility of the Demel tool to tackle the job of cutting the groove for the clip.
Now, if only Fred reads this and sees that indeed this is repeatable and he gets around to installing his kick start on his TTR225 motor.
Come on down Fred! I have all the tools and experience, but you better hurry, my memory after COVID, well, she ain't so good as she used to be. I might just forget I even know what your talking about. Ha!
 

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Discussion Starter · #66 ·
Thank you for the compliments, Brothers! Today I finished assembling the engine. Because the inner C-clip for the kickstart idle gear assembly could not be utilized, I used two of the proper OEM washers to ensure that the idle gear could not contact the crankcase. The first washer fit almost perfectly into a recess in the crankcase and I could feel a little contact while turning the gear if I applied slight forward pressure on it. The gear turned smoothly with two washers stacked. I also used two washers on the outside face of the gear instead of rounding out the OEM washer that has a flat area to match the TW200's notched output shaft. This left what I felt to be an acceptable amount of surface area and play on the shaft to be well lubed with oil.

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After popping in the kickstart assembly, I moved on to the clutch assembly. There was some slight rust marks on a few of the clutch plates. Using a brass brush, I cleaned them up a bit. Here's a "before" pic.

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Here is a shot of the engine all back together with the modified 1987 cover and Kickstarter. Everything went together just as it should with no trouble and perfect function! I also decided to throw the TTR's stainless pipe back on the engine. When I performed the stainless header pipe mod on my TW, I was able to detect a noticeable reduction in engine noise. I figured that it might help me hear any odd sounds a little better?


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Discussion Starter · #68 ·
Not yet, Brian. I had some errands that had to be taken care of and - to be honest, I'm a little nervous about firing it up! I was ok with holding off the initial start-up until tomorrow after I re-mentally-assemble the engine in my head a few more times. Plus, I just received notice that a last-minute model rocket launch is taking place tomorrow. This means I've got to change out the Duro Power Grip wheel for the factory TW34. The TW is outstanding for rocket recovery and the TW34 leaves very little mark on the land.
 

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Congratulations
I look forward to the video of that big bore T-dub purring like a kitten 😀
One day I hope to join the big bore club myself ......
mike from NC
 
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Discussion Starter · #70 · (Edited)
Okay! So here's the update... I had a bit of a scare yesterday! I filled the crankcase up with oil and fired up the engine. Everything was fine for a few minutes and then... SMOKE! And quite a bit of white-colored smoke actually.


I immediately freaked out and searched the Forum for answers as to what I screwed up. I read that oil in the exhaust could be the culprit, and this bike's muffler was definitely loaded with oil. Still, it seemed like too much smoke for me to not feel like I did not make a mistake somewhere during assembly. I read about possibly having a piston ring installed up-side-down - did I pay attention when I assembled the piston??? I was unable to mentally confirm or deny whether I did or not. After a restless night of very little sleep, I called my very good friend back East who has been a professional mechanic for his entire life. His first job was at his Father's auto shop when he was 13. I should have just called him yesterday! He tells me that I don't have to worry about it. If a ring was installed improperly then the bike would smoke almost immediately on startup. He told me to run it for 10 mins, let it cool, and run it for 10 minutes again. He said the rings just need to settle in and I'll be fine. Just to be sure, I removed the muffler from the bike and torched the shit out of it with a propane weed burner until the smoke subsided significantly. Well, turns out my buddy was right - AGAIN!!! Damn, I miss you, Nick! After re-installing the muffler and running the engine once again, the smoking subsided! Save a very slight haze likely caused by a little oil still in the muffler. At this point, I am happy to report that I believe this engine is ready to enter the TW transplant phase!

 

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Oil burning could be from a couple things. So here's what I suggest:
After riding it for a while, say 1/2 a tank of gas where you get it good and warmed up for a nice long ride or two, check your engine compression using a compression gauge. Warm engine. Throttle held open as you crank the motor. Use the starter motor, not the kick starter. If the compression is above minimum spec, then it's likely the valve stem seals. Did you change them out? Easy enough to do but does involve pulling the head off the motor.
Some folks don't care if the motor smokes from stem seal leak, but I'm not one of them. In my opinion, there's a bit of unburned oil along with the burned oil. and it will accumulate on the head and valves.

If it is the valve stem seals, the smoke is usually heaviest when you first fire up the bike from sitting for a while, like overnight. The oil has the chance to run down the valve stem and into the motor, hence the smoke during the first few minutes. Usually it will clear up and while it's still burning what's running down the valve stem, it's not an accumlation and most times you won't even smell it, let alone see the blue haze. Rings, on the other hand, will smoke any time the motor is running.

Another reason a motor might smoke right after a rebuild is the accumulation of assembly lube. I use that stuff religiously and heavily. My motors smoke like a locomotive climbing a mountain pass. Ha! But it burns off after a good long run and things return to normal.
 

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Discussion Starter · #73 ·
then it's likely the valve stem seals. Did you change them out?
Yes, Sir! The valve seals were replaced as well as a 6005 cam bearing was installed while I had the engine apart. I wanted to perform what preventative maintenance I could while I had the opportunity of the head being removed. A compression tester isn't something I own but, I know I can borrow one from the local O'Reilly's parts store. I certainly am curious as to what the compression actually is! Judging from the Kickstarter, this engine certainly feels just a bit harder to kick over compared to the TW200.
 
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Yes, Sir! The valve seals were replaced as well as a 6005 cam bearing was installed while I had the engine apart. I wanted to perform what preventative maintenance I could while I had the opportunity of the head being removed. A compression tester isn't something I own but, I know I can borrow one from the local O'Reilly's parts store. I certainly am curious as to what the compression actually is! Judging from the Kickstarter, this engine certainly feels just a bit harder to kick over compared to the TW200.
Do a search for 'compression gauge' on Amazon. There are lots for under $20 and that'll do just fine for the home mechanic. Sort by highest rating to help decide which will be best. I check my compression every oil change at least. Mostly because I check my spark plug for jetting reads, so as long as I have the plug out, might as well do a compression check. The important thing is to do it on a warm motor.

EDIT
After careful review, this one is as good as any, will arrive overnight (for my address anyway) and extremely affordable at $16.88. Besides, Amazon has a great return policy if you find it less than you expected.
 
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Discussion Starter · #75 ·
Thanks, Gerry, it's on the way! I performed the first oil change on the rebuilt engine today. I can't say I was surprised at what I saw. Some dark-colored oil with a little bit of some "sparkle" to it. The magnetic oil plug caught a bit of ferrous material and there was also a fair bit of debris in the oil filter, as well. Here's hoping the next batch comes out better.

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Then I discovered a small problem! I had failed to re-install the right-side footpeg which acts as a stop for the Kickstarter preventing it from over rotating. I thought kicking this thing over felt odd... Well - I must have kicked it too far because the corner of the Kickstarter mounting bolt rotated far enough around to make contact with the side-cover. Enough contact that is actually punctured the side cover, although just barely. After a few minutes of running the engine, I confirmed a small oil weep coming from the damage. DAMN!!! I then remembered that I had a bit of two-part epoxy clay used for high-thrust model rocket construction. After confirming that the product was fuel safe and had a pressure rating of 90PSI, I mixed up a small ball of it and forced it into the damaged area of the cover. Then I smoothed it over nice, called it a day, and cracked open a Coors.

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I look forward to the video of that big bore T-dub purring like a kitten 😀
Here you go, Mike!

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