Simmy's Naked Turbo Project

Most important thing is to stick with a project. Most guys get bored then stall out.
My next project is a mint OEM 650 Seca. I haven't done a thing with it since acquiring it but I did find the OEM operator's manual I've had since 89.

 

I hooked up my carb stick and tweaked the carbs as level as I could.
I've never used the YICS tool, maybe its more responsive to adjustment IDK
It idles really steady but reads real lean at idle.
As soon as I raise the throttle it reads under 13 which is good.
Maybe this is normal, I've never spent this much time idling with the wideband.
Anyway, good enough to go for a ride once I put the tank and side covers on

 

Well I have 32 kilometers on the new motor. I spent all the time under 5,000 rpm and the 02 levels stayed below 13 so currently no concerns. Throttle was very responsive, now there is good torque even at 3,000. I opened the throttle to 5000 and the boost gauge was showing boost at 4500 so big improvement.
There is nothing to adjust at the moment very happy

 

Believe it or not I have another failed base gasket.
I finally figured out what is going on,
When I had a mm skimmed from the bottom of the block I always had in mind to shorten the dowels to.
I swear I measured the depth of the holes for the dowels and determined their was clearance. Maybe I was wrong.
I think the dowels are bottomed out and not allowing a proper clamping of the gasket between the block and the cases.
Any pressure in the cases is blowing the gasket out
There's no oil leaking out anywhere and the bike is running incredible so I'm going to clean this up and fill some gasket goo for now. I'm not sure how many kilometers I need on these rings before giving it boost.
If there's any carb changes to make I'll do that while changing the base gasket again. Sheesh




Today was just awesome riding this bike even though I didn't give it the gas, the bigger bore really gives this some grunt
Weather was warm just an awesome ride. Looking forward to more testing

 

Impressive work on the build. Sorry to hear about the dowel/gasket issues. I can only imagine the disappointment. I really hope you can make it to the CNYCC.

 

Just ordered another base gasket.
I'm getting pretty good at top end rebuilds now.
At least I know the low rpm jetting is good, I can be pleased about that.
The motor is very smooth, I never did compare the weight of the pistons.

 

After some retrospect I'm not going to do anymore riding in the present condition.
With the block not sitting square there would be unknown stresses on everything, especially when making big hp on boost.

 

I'm attempting to dismantle the top end without removing the carbs.
I left the surge tank attached to the carbs and have both pulled clear of the head.
If I can get away with this it saves a lot of work.
Removing the cam chain tensioner was a challenge.
I had to make a very deep #5 allan to get it.

 

It's going to be fun lining up the gasket and tensioner screws when reassembling.

 

You're right, I think the carbs will need to be out of the way for the reinstall.

 

this was a very careless oversight on my part.
I remember measuring the locating dowel at #1 cylinder and determined there was clearance.
These dowels are precision fit as they need to carry the oil to the head without leaking.
I'm sure I checked them but must have screwed up.
Whatever I took off the block I need to take off these dowels.
One O-ring was cut up to so apparently I needed to go back in here to fix that, ha.
They are slightly bent so I need to sort through my junk pile for new ones then sand, grind or file them down.

 

I took 1.6 mm off the block so I did the same with these dowels.
Started with a file then sandpaper and got them to the correct size.


after file and sanding


new o rings

I received another 900 base gasket but I had another look at the OEM turbo base gasket.
Its still completely intact, the holes are just slightly too small.
Its metal and rubber, I could try enlarging the holes with sandpaper, maybe a rotary burr, it won't take much.
And the 1st thing I'm doing tomorrow is double checking the clearance on the locating dowel at #1 cylinder.
I'm not removing this block again.

 

I took a rotary file to the OEM Turbo base gasket.
2 passes around each hole and a cleanup with a knife it fit perfect, so I went with it.
The head is torqued back in place.
The cams I can install quick as I have a technique now.
I could work for Yamaha's assembly line.

 

OK I have the motor back together.
Any short cut of trying to leave the carburetors in place was a foolish idea.
Everything in this cavity needs to come out to reinstall the cam chain tensioner


these are the components which need to come off to get the carbs out.
The nice thing about the Turbo is that the surge tank and air cleaner assembly can be removed and reinstalled with the motor there, unlike the normally aspirated air box which needs to be installed before the motor


All back together and ready for another ride, basically a 2 week set back since the last ride.
I had the mercury stick attached but it didn't really need much tweaking.
Unfortunately it's pouring rain here today so no riding this.

 

Actually January 17th is when I blew out the 1st base gasket during a compression test.
April 18 is 3 months set back. 3 months of unnecessary extra wrenching if I had measured that properly or just clued in sooner.
We haven't had riding weather yet. It's ready to roll now.
I had a Turbo new in 84 and I don't think I put too many kilometers on it before opening it up.
I wonder if the Turbo operator's manual specifies any different break in period from their other motorcycles?
I had fun when I did ride it and I stayed below 4000 for 32 kms maybe once to 5000
I know how smooth it was then, now that the block and cases are actually sitting together I have big expectations for this motor.
Once I have 100+ kms on these rings I'll start giving it the gas.