Simmy's Naked Turbo Project

Something tells me you like green.

Awesome bikes!
I remember going through the Seca X thread of yours and am still amazed you pulled that off.

And now you create the 650Seca Turbo.
Needless to say, I'm seriously impressed.

Tony

 

Wow, the 900 was built in '97....
Impressive build.

 

Yep, green is not just for Kawasakis anymore!
I think Kawasaki claimed the ugliest shade of green there is.

Thanks guys, your comments are greatly appreciated.

 

Nooo, the two tone green with the dark green flake was a great color scheme from Kawasaki.

 

agree, that looks sharp!
I was alluding to their racing colour, thinking Scott Russell's Muzzy superbikes.

 

I've been reserving judgement on this until I had some more saddle time.
So after some riding this last weekend I feel I can comment.
The difference in handling with the 16" wheels is huge, combined with the weight loss there is no longer any resemblance to a stock Turbo.
There is no way the stock bike would stay with this in real twisties.
It's no track day weapon but it wouldn't be completely out of place, maybe if I wasn't 60 yo I might be tempted.
I prefer its handling to my 88 FZ600 which is really too small for me.
The supermoto stance suits me better than the sportbike crouch for the corners.

I've got some chatter in the front brakes, hopefully new pads will correct this.
After the 1st ride last fall I noticed my left freshly rebuilt caliper was leaking fluid, I suppose the seal wasn't properly seated and it leaked fluid on the pads.
I replaced the caliper and the pads with some used ones I had so currently they are mix-matched set.
I haven't felt the urge to play with the boost controller. It's currently set to 14 psi and I'll probably leave it there.
I'll ditch the boost gauge and put the left mirror back.

 

I've taken inspiration from Mezzmo's videos and plan to begin building my 900 from completely bare cases.
I have a question to the motor rebuilders. How do you remove the bearing shells?
I'm not sure how much hammering or prying to get them loose they can tolerate before they're deformed.
Here's a pic of the Turbo cases with the worst bearing shell. You can see in the pic how deep the gouge is.
I'm not using these cases so I can practice with these.

Also the bearing for the alternator is captive with no access to the back side.
How is this removed? I'm thinking about leaving it in place and sealing it over to protect it from degreasers, sandblasting and water.

 

Wow, I just realized how long it has been since I was that far into an engine...... in the early 70's I think. And those were car motors but still I don't think the bearing shells should come out with any difficulty. Your picture shows an opening on the outside of the shell you should be able to get something small and pointed into and pop it out without great issue. But this is far from recent or expert opinion so take it for what is worth.
John

 

I tried prying the bearing shells and most of them just popped right out.
That was the case with the Turbo motor but the 900 had a few shells which didn't budge so I struck them with a wood block and a hammer until they rotated out.
I was gentle so no damage done.

The 900 cases are etched as follows

the 900 crank stamped as follows

so all the main bearing shells are #2's if I'm understanding this correctly.
4(etched on the case)-2(stamped on the crank)=#2 shell.
This is convenient that they're all the same size.

the Turbo cases were etched as follows:

Turbo crank stamped as such

So the Turbo motor had
1st Journal 4-1=#3
2nd Journal 4-1=#3
3rd Journal 4-2=#2
4th Journal 6-3=#3
5th Journal 5-2=#3

Seems the 900 has the more consistently machined components.
What are the 2 lower etched numbers on the cases?

Something I wasn't aware of until the shells were removed, there are metered orifices I guess to keep the
oil pressure even across all the journals. They look like carburetor jets. Only 1 3 and 5 have them.

 

Middle gear shim thickness; see page 9:

http://www.xj4ever.com/catalog/frame-engine-id.pdf

That is correct. Debris and gunk can collect in those passages, so be sure to purge them adequately.

 

I took some time tonight to compare the connecting rods between the 650Turbo and the 900.
I measured the 900's to be about 1.25 mm's shorter than the Turbo's.

Turbo on top, 900 below

the difference is obvious in this pic

The Turbo big end has an oil groove that the 900 doesn't have.

I measured the cylinder blocks - 900 is slightly taller at 77.44 mm and the 650 is 76.98 mm.
I connected 2 900 pistons to a Turbo piston, there is a slight space under the Turbo piston but the 900's are domed so there is a lot of volume
around the edges of that dome. This really doesn't tell me much at this point without using a liquid to measure this volume.



With the combustion chambers I plan to slope the edges out to the 900 bores so that will gain some volume.
There is a slight bulge opposite the spark plug I've circled. I think I can gain some volume here by removing some of this.
With custom low compression pistons I think I can keep the external dimensions of a 900 close to the 650T.

 

question for @chacal
below pic is the cam chains out of the Turbo and the 900.
You list a different P/N for the 900 but they appear to be the same?
Price on the 900 chain is greater by twice? How come?

 

The aftermarket chains between the XJ650/700/750 engines and the 900 engines are about the same price ($10.00 difference); the OEM cam chain for the 900's is considerably more than the aftermarket chains (as is typical). Although they may be the same length, there may be a side plate or material (strength) difference between the two, I really haven't checked, but the OEM chains did carry different parts numbers (and used different master links), so there was something different about them. The 900 chains were made by D.I.D., which is a premium level supplier, while the 650/700/750 chains are made (I think) by Tsubaki, also a well known manufacturer, but not as well regarded as DID......but again, all this is supposition.

 

Note that the 650T uses a modified 750 rod (casting 5G200) which has an extra oil spray hole (both sides of the beam), whereas the 750's have only a single spray hole. The 650T also has those grooved bearing shells that you don't see on the other engines. Very heavy-duty-ish.

700 air-cooled engines use the 650 (non-Turbo) rods. 700 water-cooled engines use a unique rod, of course.

And the 900 rods (the 700 water-cooled, also) have the cap bolts installed from the "bottom up" (bolt goes thru the cap first) with the nut on the beam side, unlike all of the other XJ engines.

 

Hmmm, so ideally the 900 rods would be drilled for the 2nd hole and the Turbo bearing shells installed. Turbocharging really loads this bearing, Yamaha determined the need for it.
I'm sure you're going to tell me they aren't available as you don't list them in the catalogue.
Even if they were the cost starts to spiral out of control.
Perhaps I need to reconsider this project, why spend a bunch of money on this motor if it's long-term durability is uncertain.
I hadn't planned to mess with the conn rod big ends but I'll compare the 650T bearing shells to the 900's, perhaps I have most of what I need for this conversion.

This I was aware of, having read this was a solution to clear the cases, rotating around a 4 mm larger radius than the 650.

Thanks Len, this makes sense, I was probably comparing the OEM 900 price to the 650 aftermarket.

 

Unfortunately you are correct. They haven't been available for a l-o-o-n-g while.

I think that will work, so it depends on what shape those 650T bearings are in. Another option would be to make (have made) a set of custom pistons to accomodate the differences.

Either way, some bucks heading out the door.....

 

The ink numbers on the conn rods for both motors appear to all be 4's.
Stamping on the Turbo crank
3 3 3 2
so bearing shells are 1 1 1 2

Stampings on the 900 crank
2 2 3 1
so bearing shells are 2 2 1 3

So I need to find another #2 and a #3 conn rod bearing shell from a Turbo.
Then verify with Plastigauge of coarse.

 

There were 8 sets of Turbo connecting rods on eBay last night with the bearings in place.
I could buy one set and get lucky or buy all 8 sets and strike out, a crap shoot.
Maybe I'll contact the sellers and see if they will sell just the bearing shells so I'm not paying $60 shipping.
An option would be to just drill the 2nd oil passage through the 900 bearing and rod without the groove.
The 3rd option is to just use the 900 stuff as is and forget about it.
I suppose the 4th option is to just ride a 650 Turbo, LOL.

 

first thread on here I'm addicted to.. love to see other custom builds and like minds. nice!!

 

here's a walk around video of the bike



I hooked up the Colortune again, I was getting a blue flame but gave the mixture screws another 1/4 turn. They're all at 2-3/4 out and it's running really sweet now.

I'm still getting some shudder from the front brakes so I'll be trying another set of rotors I have.
I'll have another look at the wheel as there may be some powder coated areas not allowing the rotor to sit all the way home.
I found a listing on eBay for some Brembo floating discs listed for the 1100 Virago but they would be almost $600 for the pair.

Other than that I'd like to take a little off the fork spacers to soften them up a bit.
This thing really handles now, still haven't scraped anything even with it lowered an inch.