Topic: CB 836cc f1 turbo - spoked kickstart street turbo

[Ilja]

Rick Racer has a set of new turbo pistons for sale, look in the ebay craigs section fir his Lester mags auction, then click other items.

Thanks, thats almost too good too pass up as they are hard to come by. Nowadays only Dynoman also sells forged turbo pistons for 599 inc. mls gasket.

As long as you prevent detonation and have your fuel sorted, cast can also be reliable.
But when experimenting, forged is nice as it gives you a little bit more room to mess up.

On the other hand... on a cast piston the ringlands blow when detonating, ending up with compression loss without further damage if your lucky.
On a forged one the ringlands don't blow but the conrod and bigend gets hammered flat or the piston overheats and locks up.
Something else simply goes if theres something wrong with your engine.

If we didn't have the cheap 836 cast pistons and only the expensive ones, I would have definitly bought a forged kit in the first place.
If I was racing I would have also bought them..

But I'm not racing, just using it on the street.. and I will soon add another safety factor which is the ignition with boost retard.
To get them to the Netherlands is also expensive.. They will turn into 650$ pistons. (Thats another 4 cruzinimage kits. )

So, I'm gonna stick to my current pistons and should they fail in the future I can always buy the dynoman ones.

[turboguzzi]

with all your notable wizardy, cant you fit a detonation detector?

[Ilja]

We have a thing called "Sinterklaas" in the Netherlands who brings presents to little kids through the chimney on 5 december...

Look what he brought me! 
Forged Cruzinimage pistons!

(Changed my mind, gonna keep em as backup for now. Thanks for the tip 754!)

[Ilja]

with all your notable wizardy, cant you fit a detonation detector?

Yes I think its possible but the word on those is they also go off on mechanicall noises... which the CB has quite  few. 😄
I'm looking into it to see if it's possible to make something for it.
Knock sensors are easy to find, but you also need a controller that filters the right Hz frequency from the signal.

[Medyo Bastos]

We have a thing called "Sinterklaas" in the Netherlands who brings presents to little kids through the chimney on 5 december...

Look what he brought me! 
Forged Cruzinimage pistons!

(Changed my mind, gonna keep em as backup for now. Thanks for the tip 754!)

those look like mtc flat top pistons to me?  the seller is a great guy to deal with !

[Ilja]

We have a thing called "Sinterklaas" in the Netherlands who brings presents to little kids through the chimney on 5 december...

Look what he brought me! 
Forged Cruzinimage pistons!

(Changed my mind, gonna keep em as backup for now. Thanks for the tip 754!)

those look like mtc flat top pistons to me?  the seller is a great guy to deal with !

Yes they are forged MTC flat top pistons... but basically identical to the cruzinimage ones, only those are cast and have a very slight 1.5mm high dome.

Since they are hard to get when you don't live in USA I just placed a bid.. and got them for a reasonable price.
I think the current pistons are fine, but if I break the current pistons again by experimenting, I can install the forged ones and almost nothing changes except slightly honing the barrels from 0.05 to 0.065mm clearance.

[Ilja]

Hi guys!

Well, the #$%*ty winter is almost over SO did some work on the bike and did quite a bit of riding the last few days.

I installed the Ignitec ignition with 11-250kPa MAP sensor and thats working awesome!
Rev limit is set at 9300rpm and im retarding ignition from 30 at 100kPa (atmosferic pressure) to 22 degrees at 200kPa (1 bar / 15psi). No more pinging..
I dont know where the limits are, could be that I can run like 25-27 degrees at 15psi, but I didnt try just to be safe.

Officially you need to put it on a dyno and find the ignitions "MBT" point. Max Brake Torque means the point where both advancing and retarding will result in less power.
This points is reached at a lower ignition advance value under boost and at a higher value under vacuum. If you keep the stock athmosferic ignition values you are pumping more heath into the engine as necessary as probably you are over this MBT point.

Got the electronic speedo to work... untill the ebay hall sender died.. :p and installed a electronic tacho off an old gpz900.

I've also got a dual port actuator on the turbo at the moment, but it leaks quite a bit through the shaft "seal".. and if the regulator fails the wastegate doesnt open and I risk blowing up the engine.. so im taking it of again. I had a few spikes of 20 psi yesterday because of the dodgy pressure regulator..

So gonna run the old setup again with the simple ball & screw boost regulator in the pressure line to the wastegate actuator.


Made a riding vid and published it on youtube... no crazy ghostrider stuff but it shows a bit how the bike performs.
Gearing is still quite high at 18:39, the tacho barely moves lol.
Im riding 80-90kmh and when accelerating I stop between 150 - 180kmh. 

[PeWe]

Next is that you add everything needed in a box. All hardware and description how to... Maybe different settings (boost pressure) as economy, hot street and racing. (+ maniac)
Name the box "CB750 upgrade". Then a price tag...

Wait a moment!... Gearing 18:38 and still hungry when twisting the throttle?  Must be a good Autobahn tourer
This information is not good for my wallet since I have a K2 project in pieces....

[Ilja]

Next is that you add everything needed in a box. All hardware and description how to... Maybe different settings (boost pressure) as economy, hot street and racing. (+ maniac)
Name the box "CB750 upgrade". Then a price tag...

Wait a moment!... Gearing 18:38 and still hungry when twisting the throttle?  Must be a good Autobahn tourer
This information is not good for my wallet since I have a K2 project in pieces....

Yeah thing is I had to change to 18 in front to clear the swingarm.. so gearing is a bit high... 😂😂
But it pulls it fine. Topspeed was around 240kmh on the dyno but I only dared upto 200kmh so far. It feels quite fast without a fairing..

Im installing a TL1000S swinger now since its a few cm shorter. Got a 43t rear sprocket ready to swap once the new swinger is in. 😜

[Ilja]

 
This swinger also has the caliper on the bottom side and mounted via a torsion rod.

[Ilja]

Made the shock mounts with high and low setting holes.. 
And had to take about 8mm of the right side of the swingarm because it was aligned too far to the left.

The tl1000s swinger is 227mm at the frame and the cb frame us 235mm.
Swinger length is 51.5cm from axle - axle with rear acle all the way in the front.
The stock F1 swinger was around 46cm so 6.5cm over stock.

[Ilja]

http://www.innovatemotorsports.com/resources/myths.php

A nice read about the effect of ignition timing. :-)

[PeWe]

Thank you very much for very interesting reading. Posts like yours add golden nuggets to a good forum like this!
//Per

This is interesting too. I think about my last carb tune when reading it. My pilot jets were too lean for cruising speed. Mains comes later or WOT
http://www.innovatemotorsports.com/resources/Stan1.php

[CR750]

Great Ilja !
This is still on my to-do list for my k or f project bike..
If only had more hours in a day... or less work and more hobbytime, of and more money for those 😉

[Ilja]

Ordered a DP295 camshaft in US because I expect it would be an improvement..

If I simulate it on my pc with Engine Analyzer, it isnt... but the software might be off.
It shows the same thing for my xr650r with bigger cams, losses over the entire range except the last 2000rpm. 

[Ilja]

This is my current ignition table, now the bike works fine at 15psi. 

I went on a ride with a guy with a quite new R1 and a VFR something.. at 10psi I was just as fast accelerating out of corners and on the straights. 

[Ilja]

Well the dp295 cam was a fail.. it lost all bottom end and the turbo spooled 1000rpm later or something.. just as the simulator showed.
After 10mins riding with the dp295 I returned home and installed the stock f1 one back in.

I did make a small beginners error turning the cam a bit when screwing in one of the cam sprocket bolts, lightly contacted a valve by turning the engine over by hand 30degr. without the cam... And had some (0.25mm) more valve clearance on the same valve after that.. 😐 or I forgot to adjust it.. leakdown test showns within 5psi of the other cylinders though so no problem there. Hopefully it stays that way.

And got some blinkers on the bike... 😄

[754]

Changed cam after 10 minutes..now that is funny...

[Ilja]

Changed cam after 10 minutes..now that is funny...

Those were 10 expensive and labor intensive minutes allright.. 😅
But jeah, sometimes you win sometimes you loose with this stuff.

Cam has a new owner now. 

I consider the engine finished now, maybe lean it out a bit in the cruize area for fuel economy.

[Ilja]

By the way, if you have a stock/10:1 compression bike with expensive forged pistons and then want to add a turbo without installing different pistons...you could add the dp295 cam and you would end up with roughly the same cranking compression as 8:1 + stock cam.
Then the cam could work nicely with possibly a massive topend.

[PeWe]

Turbo in general must have almost 0 overlap, right?

[Ilja]

That would be ideal but its not necessary. My gpz turbo has 45degrees overlap and plenty gsxr and bandit turbos are pushing 250hp+ with the stock cams.
But they just need to be very mild for bottom end mainly because you are running low compression. 

[NitroHunter]

By the way, if you have a stock/10:1 compression bike with expensive forged pistons and then want to add a turbo without installing different pistons...you could add the dp295 cam and you would end up with roughly the same cranking compression as 8:1 + stock cam.
Then the cam could work nicely with possibly a massive topend.

At one time some of the Funnybike guys were trying the high compression / lumpier cam set up - and it got me to thinking. 
I had a bunch of good used stuff, so put together a 915 motor with Wiseco forged pistons. I remember it cc'd out over 11:1. The cam was an un-marked regrind out of a very early CB road racer with noticeably higher lift but had been used with slightly valve pocket modified stock pistons, don't remember at all what it measured out as.
I unscrewed the wastegate spring compression screw completely, as I didn't want to chance putting any boost there yet.
Spent the summer riding around, it would flat run away from my pal's KZ with Smoothbores and pipe. I always had one eye watching the boost gauge, it never did more than slightly nudge the needle.
Friday evening Bike Night we ride out to the strip and I think 'Let's run this thing through the quarter mile and get a time slip', then head over to the burger joint hang out and look cool and brag.
And first pass shifting into 4th, the boost gauge pegs and #4 rod makes an abrupt exit. Uh oh.
Those neat 'Heat treated shot peen stress relieved' rods (that a guy had sworn had come in another dead motor) obviously weren't up to this task. 
#4 was shaped like a little 'S' hanging out of the case.
Cylinder pressure was fun - right up until it wasn't. And I had to get the bike a ride home. But it did coast across the line at 118mph.

[Ilja]

By the way, if you have a stock/10:1 compression bike with expensive forged pistons and then want to add a turbo without installing different pistons...you could add the dp295 cam and you would end up with roughly the same cranking compression as 8:1 + stock cam.
Then the cam could work nicely with possibly a massive topend.

At one time some of the Funnybike guys were trying the high compression / lumpier cam set up - and it got me to thinking. 
I had a bunch of good used stuff, so put together a 915 motor with Wiseco forged pistons. I remember it cc'd out over 11:1. The cam was an un-marked regrind out of a very early CB road racer with noticeably higher lift but had been used with slightly valve pocket modified stock pistons, don't remember at all what it measured out as.
I unscrewed the wastegate spring compression screw completely, as I didn't want to chance putting any boost there yet.
Spent the summer riding around, it would flat run away from my pal's KZ with Smoothbores and pipe. I always had one eye watching the boost gauge, it never did more than slightly nudge the needle.
Friday evening Bike Night we ride out to the strip and I think 'Let's run this thing through the quarter mile and get a time slip', then head over to the burger joint hang out and look cool and brag.
And first pass shifting into 4th, the boost gauge pegs and #4 rod makes an abrupt exit. Uh oh.
Those neat 'Heat treated shot peen stress relieved' rods (that a guy had sworn had come in another dead motor) obviously weren't up to this task. 
#4 was shaped like a little 'S' hanging out of the case.
Cylinder pressure was fun - right up until it wasn't. And I had to get the bike a ride home. But it did coast across the line at 118mph.

😅😅 That must have been spectaculair.
But honestly, how much rpm were you pushing?
Boost doesnt necessarily destroy rods. Most of the time its high rpms and/or heath which locks the small/big end up. Then its byebye for your rods.
Ofcourse the turbo can cause it but its more when you are running 20+psi, high rpm and fairly lean mixture with a lot of heath...which is exactly what a lot of people do. :-)
For a street bike I believe it can be made to last, with the right setup.

[PeWe]

For a street bike I believe it can be made to last, with the right setup.

Many cars have turbo and they last if oil changes are done in time.