Hi everyone, just looking for a little advice. (posting this on a few websites so I'm guessing some of you might be seeing this in other vintage bike forums too)

So, I recently bought a '73 RT3 360 Enduro. Bought it because my Dad used to own this exact bike, and my goal has been to find one and surprise him the next time he comes to town. The bike I bought appeared to be in great shape, and ran well when it arrived. I took it out for about an hour long ride on day one and was so stoked, memories flooding back, etc etc.

Day two didn’t go so well…. As I remembered, this bike had the vicious kickback that they seem to be legendary for. My solution to this when I was a kid riding Dad’s was commit to a good hard kick and don’t give it the opportunity to bite back. I applied the same technique here, except I guess I’m stronger now and gave a real solid kick that it tried to kick me back with, but I went right through it….. which…. went horribly wrong, and seems to have wrecked a lot of the engine internals…

I was going to pull it apart but decided that since I’m not the best vintage bike mechanic (yet), I might want to have more of an expert look at the damage, so I trucked it down to the local Yamaha dealer who is a great older fellow with experience on these bikes from back in the day.

He just phoned with some pretty devastating news… he confirmed my suspicion that I broke the kickstart shaft gear (which I’ve already been searching for on eBay), however he said that damage was much more extensive, including idle gear and transmission shaft, and that the whole bottom end would need to be pulled apart and it was going to be a huge job to get it going again, if I can even find the parts, He suggested that maybe looking of a complete bottom end might be a better solution.

So here I sit, bummed out as all hell. Not sure what I’m even asking for here (other than sympathy), but anyone with any suggestions on where I might be best to start next would be greatly appreciated.

If I can figure out how to post a picture of it I will do so.

Thanks in advance for any helpful pointers.

Sorry to hear your trouble. I have 2 just like yours and they will let you know who's boss when you are starting them. The good news though is that the parts broke and not your ankle, I had a 1983 Honda XL600 that kicked back on me, the parts did not break, the kick starter bent my foot straight up so my toes touched my shin, pulled my Achilles tendon from my calf muscle which rolled up behind my knee. Took 11 months to recover physically and 3 years to recover mentally to where I could kick start a bike again.

So enough about me. I see most of the engine parts on eBay, Speedandsportinc.com, NWVCP.com and other places. I have bought whole engines and bikes on eBay just for parts, they were fairly inexpensive because of the condition. The engine is not that difficult to remove and disassemble. Copies of the service manual and parts manual are available. You may be able to rebuild this with a combination of new and used parts plus your original parts. This would also be a good opportunity to make sure the piston and clutch are in good shape. You could also do a nice polish job on all the external parts much easier plus repaint the cylinder. Sounds like you are in good hands with the dealer's mechanic.

The 360's can do some damage . . . .

On a lighter note, unless you damaged the case itself, the rest of the parts are replaceable and available. Buying a used motor can be good or bad, unless you know it has good parts in it.

You can download a PDF of the service manual from the Workshop section up top which I HIGHLY recommend. You will need it no matter what. Now that you have to go inside, it is a good time to learn about what's in there! Here are a couple of good videos from member Joe Gresh on what you will be running into:



And part deux:


Welcome to the Forum!

These old bikes will break your heart sometimes. But they pay ya back! My Evil RT has been a year long struggle, but I find an excuse to ride it just about every day now.

Which reminds me, I have a spare mainshaft or two if ya want one. PM me.

Thanks everyone so cool to get expert advice (and sympathetic shoulders).

Got a few more specifics, which also leads to a few more questions...

Broken:
- Kick Gear
- Transmission main shaft (snapped the end right off)
- Kick Idle Gear
- Kick Pinion Gear

It appears they are mostly available on the internet, but here’s where things get confusing to me:

The dealer, said that the serial number said that it was an RT1, and not RT3. I also do recall recall an RT1 stamp on the left side of the engine case that I noticed earlier and had wondered about. But this bike is obviously the ’73 model, (Baja Brown) and as far as I thought, the 73 bike’s were the RT3?

From some more internet research, the VIN number on the frame appears to indicate it’s an RT3 so I’m not sure what “serial number” the dealer was referencing (he’s closed now). Wondering if maybe at some point the engine was replaced with an RT1 engine, don't know how I could find that out.

The yamaha parts catalog lists different part numbers depending on whether you search under RT1 (which only comes up as a ’71 bike), or RT3, so I just want to make sure I don’t order the wrong parts. To really make things a pain, the “Kick pinion gear” is only listed with a part number on the RT1 Yamaha parts list (214-15631-00-00). When I check the RT3 parts list, that same gear in the diagram says “Unavailable in Price Book, Alternate parts28T not available, and doesn’t list a part number for it…

At first it looked like the diagrams for both RT1 and RT3 transmissions were identical, but on closer inspection there are a couple of differences, so I’m guessing I really need to know which one I’m dealing with in order to try and find the correct part. Unless any of the experts here know whether or not any of those broken parts that I’ve listed are compatible for both models?

Thanks to all for any help and advice.

So first off, check on the top of the transmission case (left side right brhind the cylinder (the rectangle right by the stator wire in this overexposed photo)



There should be a number there. If it is different than the frame, then your motor is not original. Not anissue. The RT1 prefix was used for all the 360s up through 1973.

So take the MOTOR number and go to our vin charts (under Workshop link up top) and find out what MOTOR you have. Once you have that, go to the specifications section and you will be able to compare the different year transmission ratios.

You might send a PM to DEET or Enduronut who should be able to tell you which years parts will easily interchange for whatever MOTOR you have. Then, your best bet may be to just find a correct year full motor and get the whole shebang. Probably cheaper that way.

That would be my suggestion.


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Sorry to hear about the bike damage. I am probably the same age as your Dad and did a number on my foot last year right after I got my replacement 1973 RT3. I say replacement because I owned a brand new one in 1973. My very favorite bike. Because of the knowledge I gained on this forum, I learned that there are two very important things to help prevent (notice I did not say cure) kickback:
1. Set the timing perfectly using the "Deet" method. Send me a PM if you have a hard time locating the write-up.
2. Recondition your decompression valve and make sure it is working and adjusted right. The manual you can download on this site should give you all the information you need.
Also, you may want to search craigs list for a parts bike. I have one and it is always coming in handy. Unfortunately, I cannot provide the parts you need as they may be needed for my repairs in the future. Use www.searchtempest.com to search multiple craigs list sites at a time.
Good luck.
PS, Makotosun is exactly right about the RT3 engine and frame ID starting with RT1.

After having 4 different transmissions in my RT1 I have a little experience in this area.

You can make a RT2/3 trans work in an RT1. Not sure about the other way, but the primary difference is the RT2/3 uses a conventional 2 rail system for the shift forks to travel on. The RT1 is unusual in that it has the 4-5 fork on a cylinder that runs back and forth across the shift drum. The rail for the 1-2-3 forks is in the same place on both bikes tho, so to use an RT2/3 trans I just used the RT1 4-5 fork on the RT1 shift drum.

The only other difference I ran into was the diameter of the grooves that the 1-2-3 forks ride in got bigger on the RT2/3. So you need to use the matching forks for whichever trans.

I don't want to make it sound too easy. At one point every time I put the cases together it magically transformed itself into a 3 speed! That turned out to be a clearance issue with the RT1 4-5 fork. The big drum mounted one. On the 4th gear shift It was running into the RT2/3 fork which I had to use because the larger dia slots. Some sanding and grinding fixed it.

That was a CR trans BTW. And I loved it. Unfortunately it was jumping out of 3rd 4th AND 5th! I think I'm all standard RT1 now.

Once again thanks to everyone for all the help! Latest update is as follows... Picked up the bike from the dealer and confirmed the VIN on motor matches the VIN on the frame, and according to the number it is indeed an RT3 so at least that confusion is sorted out. As for the "Gear, Kick Pinion" that was in question, the dealer helped me do some research and confirmed that the part number from the Yamaha RT1 transmission schematic (214-15631-00-00) will indeed work for an RT3 transmission. So that combined with some super helpful offers from people on here has me feeling pretty good about getting all the parts that I need.... Except.... now that I've got the bike back home and start looking inside, I do see a bit more damage, and it's the inside of the engine case (yikes). I'm crossing my fingers that it might be minor enough to not cause a huge problem, but of course I'm far from certain. There's a little black cover piece (part # 214-15492-00-00) that sits above the main shaft and kick shaft. The engine case is broken where that cover screws into it. Probably easier to just show a picture or two.....




So yeah... the little cover piece is also bent but I'm sure it could be replaced or bent back into shape without much drama. but its the damage to the inside of the case that is more of a concern, because I don't have a "before" picture, I can't actually tell how much of the little lip might have broken off (other than the little bit you can see on the end of the screw in the photo. Here's hoping it's not too major.... any ideas? Either way, I'm going to take the motor off the bike tomorrow.

Sad story.
I had a critical failure myself with a 250 2 stroke when one of the bolts holding the clutch plate broke off while the bike was running.
The cause of the problem was the previous owner.
He welded the bolt because he broke it off himself when he tried to get the inner clutch hub off.

In this video i explain the critical failure i had.


I started to rebuild the engine but some thiefs stole the engine along with a lot of tools in my garage.

In your case, it might be repairable if you know a good welder, but if the weld breaks like it did in my engine, it might cause another critical failure and wreck even more parts.
If you are lucky you will find another right side crank case to replace this one.

Good luck

---Ben