Adding a SECA 650 back to my collection...

XJ Motor & SECA Experts,
Happy Thanksgiving to all!

I decided to use this rare opportunity with a couple days off to tear the motor apart and resolve the Starter Clutch problem. I've found the major issue.... Two of the bolts holding the clutch plate to the gear boss backed out and were impacting the driven gear (see pic). What a MESS! Fortunately, I purchased an entire used clutch assy. complete with shaft gears etc. So the damaged gear(s) aren't an issue.

HOWEVER, I also purchased an aftermarket clutch plate assy. which is very different in design to the OEM piece. Honestly, it looks pretty "cheesy" compared to OEM. I'm debating whether to install one of the OEM units which don't really show any signs of wear or go with the aftermarket unit? Seems the only real problems are: Damaged gears (I have replacements), Damaged Bolts (I have replacements).

Does anyone have any opinions on this clutch plate issue? OEM or Aftermarket? Any experience with the aftermarket unit....

Respectfully,
KURT

 

IMHO the oem unit with some new rollers and springs would be a better choice. And red locktite.

 

Wow, those bolts are supposed to be loctited in there, and from experience, they usually are (i.e. they are next to impossible to break free). Maybe someone had been in there before? Odd.

We've sold the aftermarket versions for a few years now and have had no complaints. For some extra durability you can substitute the XJ700/900 roller springs into it.

 

Thanks for the replies.....

It's obvious someone had been inside this motor before. The clutch springs were marked like aftermarket and some of the residual of old gaskets not properly cleaned off was evident on the side cases. But there wasn't anything that made me believe they had been all the way down to cracking the cases open to get to the starter clutch. However, there was absolutely NO evidence of ANY lock-tite on the starter clutch bolts. I suppose it's possible someone was in here before since I can't believe this was skipped at the factory?

After sitting and staring at it for a while, I decided to just toss the new unit in there. Len hadn't seen any problems with these and it was "New" even if it did appear inferior in design. The disassembly was a good bit more demanding than my XS1100s as this little SECA 650 is MUCH more complicated. Getting it back together while I still remembered how it all went was important too. Even though I would prefer NOT to do this again, it wasn't that bad. I can do it again if needed and then I would also replace all the crank and rod bearings at that time if this aftermarket clutch didn't live up to expectations.

I've got the whole bottom end back together. Amazingly all the gears shift properly. The cylinders got a fresh & quick hone and a new set of rings. The cylinder head will take a great deal of effort to prepare as I have yet to replace the valve seals or re-lap the valves. The head is disgustingly grungy but I won't be able to risk blasting it as there will certainly be some residual that gets into the nooks & crannies that I'll never get out....

Looking forward to getting the frame, swingarm, kickstands, and misc. small stuff back from the powder coater this weekend.....

Respectfully,
Kurt

 

I was able to get my head blasted and cleaned for ~$35 at a local machine shop.

 

Jayrodoh,
Darn! That looks beautiful! I have a machine shop I've used before for boring and milling heads etc. Hadn't thought of asking them to clean it ..... THANK YOU! I will call them in the morning.

I use to be the Maintenance Manager for a facility with a large variety of blasting and cleaning tools. My new Management position does not offer those resources. Forgot about the machine shop! Thanks again.

KURT!

 

Although anything is possible, it's somewhat unlikely, as Yamaha was pretty thorough with their assembly process. Besides built-in design issues/flaws (in the light of present-day standards) I can't recall ever reading about a factory mis-assembly (dealer issues were more common, but a starter clutch would not have been part of pre-delivery services, unless it was defective from the factory).

Looking good with the rebuild. Better picture of that engine stand?

 

Here are some pics of the stand buddy. This is just a really CHEAPO Harbor Freight Engine Stand. It's the 3-wheeler which it the absolute cheapest they offer ($35~?). I wouldn't trust this stand with one of Pontiac motors but it's more than up to the challenge of a Yamaha motorcycle motor (or two ). I actually have a few of these and they serve DOUBLE duty as you can see this stand is also a "Parking Spot" for a spare XS11 motor.

The ability to flip and rotate the motor is absolutely priceless for a rebuild like this! A couple pieces of scrap angle iron, drill a couple holes, a handful of good long high grade bolts, and a bunch of washers.

Unfortunately, when I got to the point of breaking the cases apart I had to disengage the lower attachment points as they are on the lower half. Obviously, this would no longer provide the necessary support of the 1/2 motor+. So, I just quickly fabricated an angle iron "pole" and supported the remaining lower case with this support from the stand leg to one of the bolts previously holding the drive point. I didn't take a photo while it was apart but you can certainly get the idea.....

I also use another one of these Cheapo Harbor Freight stands to hold a "Spare" XS11. This bike was a $100 spare parts donor. The motor is good but the frame was already hacked. I wanted to keep most of it but it just took up too much room. So......

The spare now holds a good bit more than the motor but takes up only a fraction of the space.

KURT

 

Very nice. Doubles as a tank rest, too!

 

Very nice on the engine stand!

 

Merry Christmas!!! I got an early present today!!!!

SECA 650 Frame back from the local powder coater!!
(The coater provided this nice publicity photo he plans to use on his web-site)


I'm incredibly stoked and want to start putting it all back together RIGHT NOW! Unfortunately, there's too much XMas Shopping to complete and a business trip on Monday to prepare for.

I may get to sneak in a little time with the SECA but the motor is still in pieces with the head still stripped down without valves installed & etc. I've gotta put the motor back together before I start messing with the "New" frame.


Without any doubt, this will be the finest RESTORATION project of the many Yamaha motorcycles I've brought back from the brink of death. Although not perfect, the area of frame repair on the left side looks really good. The kickstands, swingarm, and brake stay were also coated. I'm planning of giving this coater the headlamp mount and possibly a few other small bits to coat as well. This machine will absolutely be an active participant in the Vintage Yamaha Rally in Stecoah next year!!!

I will be in need of a couple "Tid-Bits" including some decent looking chrome lift handles (if I can find any). I'll likely post up a small list of the "Tid-Bits" needed to complete the project in the Wanted Section.

I hope everyone has a great holiday! Obviously, motorcycles are not the #1 topic for most of us this time of year......

Sincerely,
KURT

 

Pretty! If that doesn't motivate you, nothing will. "Cancel Christmas, I'll be in the shop!"

 

I hope that photo was taken after all the plugs were taken out of the threaded bosses. Cleaning powdercoat from threads is a PITA.
Pretty frame.

 

Thanks k-moe,

The coater did a pretty great job of plugging all the holes before he coated it. I was amazed he has even noticed the hole in the mount for the side stand safety switch plunger.
However, he didn't cover the steering neck. I will have to remove the coating in the bearing recesses to get the steering neck bearings back in successfully.

Otherwise, the parts look fantastic he didn't miss any small crevice or slightly hidden spot, everywhere has a beautiful black gloss.
Kurt

 

It looks great! That's an outstanding job on the frame repair.

 

Ugh, facepalm. The biggest holes in the entire frame didn't get covered!

 

Might have been wise to leave the old races in place to prevent this. I hope you're able to chip it out of there.

 

That’s exactly what I did. Steering and swing arm.

 

It's going to take a Dremel, and a careful hand.

 

Or chemical.....just dissolve it