turbocharged cb550 bobber

Well after I had the bike out the first time a month or two back, I ran into some cylinder head troubles due to wrenching under the influence. After enjoying several adult beverages I decided it was a good time to re-torque the cylinder head. Long story short, I managed to misalign the tappets when reinstalling the valve cover and destroyed the valve guides and valves. Took a little time to get a freshen up a new head and get it going again, but it is running again!

I've put 87 miles on this thing now, and it is really something else to ride. The turbo loves everything between 7-12k rpm. Builds scary boost, 5-10psi fairly frequently all the way up to 14 psi a few times. Maybe my head studs, mls gasket and extra low compression ratio will keep this thing together forever. Maybe it will all grenade in another mile and I'll have to throw in an ebay engine and dial down the boost. It's way too much fun as is to tone things down right now!

Currently back up on the operation table for electric work. Battery went from good to bad in short order on a ride Sunday. Thinking I fried my reg/rec from having it mounted too close to cylinder heat, and this took out the battery. Parts on order.
 

Attachments

  • zzUntitled.png
    zzUntitled.png
    659.4 KB · Views: 938
Looks like you ran into some gravity troubles when taking the picture.






Good to see it is running and on the road. Are you going to limit the boost to around 10psi or just let it free spool?
What is the compression ratio that your are running?
Also that is one hell of a linkage rod for the rear brake.
 
Brodie said:
Good to see it is running and on the road. Are you going to limit the boost to around 10psi or just let it free spool?
What is the compression ratio that your are running?
Also that is one hell of a linkage rod for the rear brake.

current plan is to let it be and use my wrist as the boost controller. I have not come up with a clean way to get a wastegate working on it.
I haven't calculated the compression ratio, but am pretty curious with what it is. Stock is 9:1. I have stock pistons and a head with doubled base gaskets and a .060 head gasket. Stock head gasket is supposed to be around .040 but I am unsure how thick a base gasket is. If I knew the thickness of a base gasket I would be able to measure from there.
 
Alright, just did my best to measure the base gasket thickness and calculate a compression ratio. I came up with a 7.6:1 compression ratio. Sounds to me like 14psi is just what this engine needs!
 
That is not to bad for a turbo engine.

What octane ratings do you get over there?
We have 91, 95 and 98 in Aus. A few places have 105 but that is full of ethanol
 
91 no ethanol is the best pump gas we get around here, and it's even hard to find at times. So 91 it is. I do still need to wean down the main jet a few sizes, I'm running plenty rich at the moment.
 
Brodie said:
That is not to bad for a turbo engine.

What octane ratings do you get over there?
We have 91, 95 and 98 in Aus. A few places have 105 but that is full of ethanol

yep, found the 105 one day and thought to myself, that's exactly what a Vmax needs....turns out it doesn't work very well on carb'd engines in general and vmaxes in particular, no power, overheating and lots of stalling. but on the plus side when you get home and drain a whole tank of it, it makes the best weedkiller I've ever found, that was two years ago and theres still nothing growing there
 
Brodie said:
A few places have 105 but that is full of ethanol

You lucky b*st*rds. That's just the go-juice for your turbo-powered death-wheel. (Can't get it over here - at least not within a 50 mile radius, but would make tuning the ol' Turbo TR1 soooo much easier!)
 
der_nanno said:
You lucky b*st*rds. That's just the go-juice for your turbo-powered death-wheel. (Can't get it over here - at least not within a 50 mile radius, but would make tuning the ol' Turbo TR1 soooo much easier!)

of course they won't let you have it, you're in hollandshire, way too close to Germania, they'd assume people were going to use it in an unauthorised manner

(and what the hell has happened to RBZ too?)
 
Err no, not Hollandshire, from Nazi-Land (Austria). No idea, contacted Mouse and some others and haven't heard back. (as of yet)
 
" data-source="" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch">
Sonreir said:
115 Octane a couple of miles up the road from me. Not cheap though.
115? Is it VP leaded or Sunoco unleaded? Price?
 
der_nanno said:
Err no, not Hollandshire, from Nazi-Land (Austria). No idea, contacted Mouse and some others and haven't heard back. (as of yet)

my apologies herr der nanno, please forgive this ignorant inselaffen
 
Ze reperkussions will last a sousand yeaaaaars!. ;D
(Holland would be way more cool anyway...)

Back to the topic at hand please.
 
Back
Top Bottom