Topic: Turbo Charged CB550 Landspeed Project

[LiveeviL81]

I had my GT-12 clone have a carbon seal installed from G-Pop Shop, Gerry was super helpful, and it only took about 2 weeks with shipping and a bit over $100. He also had an assortment of different compressor wheels, that if you're up to snuff on turbo design could be used to eek out some more performance for the turbo.
https://www.gpopshop.com/

[HondaMan]

The bike idles just fine.  Did a lot of it while waiting for the green flag.
Got the dyno session scheduled. 
Road testing would be unwise.  Bike is a real handful.

Wow, what plumbing!

Um...did you ever do in-house plumbing in my area?

[BomberMann650]

Scottly, affirmative, shop is now free of mosquitoes.
It actually wasn't that bad.  Took until the oil warmed up to put some smoke out the pipe.  Confirmed is blue.  So a few minutes after watching the idle hold a steady 13:1, it just begun dropping to 10:1.  Smell went from the Ratman race gas to lucas oil.

Good lookin out LiveeviL - i hadn't prioritized the carbon seal install due to the nature of LSR.  Bike gets built, runs like hell for a couple miles, then gets tore apart.
Would be neat if GPop had a turbine wheel that would react to the lower exhaust volume quicker.

[BomberMann650]

Wow, what plumbing!
Um...did you ever do in-house plumbing in my area?

Haha no 😆

My coworker thought i would make more money as a plumber when she saw the sidewinder too.

[scottly]

So a few minutes after watching the idle hold a steady 13:1, it just begun dropping to 10:1.  Smell went from the Ratman race gas to lucas oil.

Sounds like maybe the turbo oil drain is too small? The G-pop site that evil posted has some good info! It looks like most of the rebuild kits include seals, and there are specific instructions on how to replace them; apparently they are easily damaged?

[BomberMann650]

Am pretty confident the drain is not the issue with the 4 series installation.
On the tiny turbo, it definitely was.

The carbon seal is an upgrade to help the turbo resist the vacuum force.  Which is 1 bar psi in the negative on my motor meter.  (12somethingG on the mercury scale).
Wouldn't have this issue with a blow through or throttle bodied injection setup.  The slides and butterflies effectively shield the compressor shaft and bearing from all the suck at the valve..

Also wouldn't have this issue if i just quit being a cheap bastered!
(and ordered a hybrid turbo with ball bearings that could run on grease!)

[scottly]

So the turbo you have didn't come with the carbon seals standard?? When the turbo was spooled up and you closed the throttle, the vacuum would have been the greatest, sucking the most oil past the seal. Was there any evidence of excessive oil after shutting down at B-ville?

[BomberMann650]

Generally, these small(ish) budget turbos aren't chock full of features. 
Its not a Garrett after all.

Trace amounts of oil could have made it to the piston on decel, sure.  But compared to a v twin with a crumbling breather valve, it was nothing. 

Did I mention the trailer worked brilliantly!?  Seeing the support rig comin from the pits was the best part of this years runs.  I could second guess all my build decisions with air conditioning!

[BomberMann650]

https://youtube.com/shorts/0Nu_b8fpKLE?si=wsrpF-mDSZ7hZa-Y

After spending the week dealing with wires and sensors and computers.  Got back to the old motorcycle project.
Carb ran okay with a 30 pilot and the bb0+240 jet combo.  Dropped the jetting from 37.5 to 25 after a couple of starts.  Trying to see 12.5 at idle.  LiveeviL was right about the impact of the bigger main/needle. It dumps fuel in along with the pilot circuit.  Haven't tested the 25 pilot.  Its late and im tired.  Beyond that, i would have to open the air jet.

Spooling the turbo improved too.  With the ability to open the carb, all that air flow put 2psi boost on the meter.  And it made the cool kid sounds.  Unloaded!

May have hurt the motor a little running it hot n dry at the track.  Compression on cylinder three is down a scoche.  Camera and Leakdown dont make me believe its valve.  It held 110psi with <10% bypass).  The issue may be elsewhere.  I don't wanna tear it apart yet.  I have some cores shipping in for phase 3 development.  While phase 2.5 continues.

Wish i would've done this carb modding back in August.  Will probably continue to kick myself until next August.  At least until june - if im able to make it to the pre-season test n tune.  Was able to get the zipper replaced on the suit.  Sweet little old asian ladies are the best..

[scottly]

That sounds NICE!!!

[BomberMann650]

That sounds NICE!!!

I guess it took a few miles for the turbo to run in.

But there's some audible unhappiness from the motor at idle.  Would be chuffed if the problem is just a spark plug.  Hitting napa soon.

[scottly]

Is a plug carbon fouled? It was a big jump in mains from 135 to 240..

[BomberMann650]

Is a plug carbon fouled? It was a big jump in mains from 135 to 240..

It wasn't pig rich for long.
Thinking more along the lines of heat exhaustion.  Number three experienced something that left a blemish in the dome.  Hard to tell from the camera alone.
But my ears are picking up something about the idle thats a little off still.

Will remove the turbo when i get the time and look at the manifold side.

[scottly]

What sort of blemish? Melted spot right under the plug??

[HondaMan]

https://youtube.com/shorts/0Nu_b8fpKLE?si=wsrpF-mDSZ7hZa-Y
Was able to get the zipper replaced on the suit.  Sweet little old asian ladies are the best..

Here, too! They saved the zipper on my Brooks Leather jacket (now over 50 years old). Looks new!

[BomberMann650]

What sort of blemish? Melted spot right under the plug??

Sigh, yesh... I'm gonna poke at it with the camera again.

[scottly]

What about the plug? What's it look like?

[BomberMann650]

What about the plug? What's it look like?

It was chalky with heat ring at the threads. 

I examined things again, and this time with feeler gauges!  It had gone tight.
Gave it a proper gapping and compression jumped back up.
Cheers to ten years of adjusting these rockers!

Still haven't got the idle afr above 12.  Its in the tens.  Probably the oiler.  Hopefully gpop will come thru with a service estimate.

[scottly]

I examined things again, and this time with feeler gauges!  It had gone tight.
Gave it a proper gapping and compression jumped back up.
Keep an eye on it. Back in the air-cooled VW days when the valve clearance suddenly tightened up it might mean a valve was stretching and was about to have the head break off.

Still haven't got the idle afr above 12.  Its in the tens.  Probably the oiler.
I didn't see any oil in the exhaust in the video. Is that with the 25 pilot? If so, switch to a leaner needle jet, since you are running the richest one.

[BomberMann650]

I adjusted both 2 and 3.  Two wasn't as bad.  The valves were brand new from common motor.  Thick and heavy basterds.  Only 8 miles on the motor!  Lol.  Is .002" a worrysome break in?

The exhaust color was promising.  But i still managed to smoke out the mosquitoes.
Saw wisps of black smoke today.  Not much blue.  But the combination of race gas and lucas oil smell was eye-watering.
Testing the 25 pilot.  I started at 3-1/2 out.  And saw 10.8 a lot. Turn the screw in 2 turns and only saw 11.4 briefly after revving it up.  I dug out the size 20 to try before the dyno session.

Not sure about reducing that needle jet until i can see things under load. Soon, am confirmed to areive at the race teams garage this weekend. 
If it spools easy on the dyno.  I want to run this bike north of 12psi on the track.  Will work with the local experts how far to push it at sea level.

[scottly]

Remember, the needle jet over-laps with the pilot jet, and is pretty out of the picture by 5/8 throttle. Leave the 25 and try a leaner needle jet.

[BomberMann650]

Its worth trying.
I got a couple errands for tomorrow.  Nww plugs from napa, hitch up the trailer, tinker on race bike, pack the tool bag for dyno sesh, stash fuel cans and paddock to go - and don't forget to feed the cows.

Not sure which intake to take to the dyno.  The bellmouth is quicker to de/attach.  But the naca scoop holds fast on the road.
Fwiw The big bellmouth didn't make a difference on the bench test.

[scottly]

Not sure which intake to take to the dyno.  The bellmouth is quicker to de/attach.

Keep it simple and use the bellmouth. When is the dyno session scheduled for?

[BomberMann650]

Well, i tried the smaller needle jets.
Which led straight down a rabbit hole.

Found that troublesome spark plug had broke its ceramic/metal seal.  Replaced it, now have 3 spares.

Also found out the z6 nj i got was a mislabeled y-4.  So i have a z2, a z4, and bb0 to adjust with.  Along with the whole run of pilots and mains.

Whereas the bike running with the BB0 nj has a -3merc vacuum, and catches revs and boost easy.
With the Z series nj the vacuum pressure goes back to -15merc, and though the idle can be adjusted to a happy 12/12.5 afr - whacking the throttle open results in motor stall.  W ith my accelerator pump reduced to what it is - i cant put enough of it through to keep the motor running.  It will boost, but not without some issue.  I toyed with needle clip positions.  But mostly just left it at max fuel.  I haven't resorted to the alternative needle series yet.  They're the correct lengths but the tapers are totally different.

I went back n forth making a few notes along the way.  I'm packing up for tomorrows dyno appointment.  Will consult with the race pros what they think the compromise should be.
Cause i can manage to bench tune it so it either picks up revs like a beast, or idles politely.

It was a frustrating day.  With no concrete results.  Learned a lot about how the bike reacts to changes.  Smaller nj likes more pilot and accelerator.  Big nj basically doesn't need a pilot.

Wish i had some air jets.  Or at least remove the one thats currently stuck in the carb.  The air jet may help tame the bb0 nj - i dunno yet.

[scottly]

With the Z series nj the vacuum pressure goes back to -15merc, and though the idle can be adjusted to a happy 12/12.5 afr - whacking the throttle open results in motor stall.  W ith my accelerator pump reduced to what it is - i cant put enough of it through to keep the motor running.

Can you increase the accel pump output?