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

[Ilja]

Did a small ride and filmed a few pulls today. 18:43 gearing is nice for this bike, not too high, not too low.

4th gear wanted to be free in this one..

After doing a few 14psi pulls I found the front and side of the cylinderhead, transferpipe and my leg coated with oil... I also had this after I did the first ride when I switched cams and installed the old one back in the engine. At that point I thought it was spilled oil from taking the valve cover off.
It however doesnt seem to happen when I ride at low boost and/or not rev it up high.

So either a puck or something was shifted when installing the cam towers back, OR my MLS gasket is leaking again or in worst case.. the head is lifting when running high boost...    Not so nice,
I will clean the engine and do another ride with low boost and see if it leaks again to be sure but it looks like its coming out of the front outside left & right corners of the headgasket near the stud...

At least its not coming out of the breather tube like last year, when I blew up the pistons.. 

[Ilja]

Hmmmm, I might have found something on the oil leaks.. but then it should have also leaked before..maybe it didnt because I didnt push the bike as hard as now.

Im using an f2 head with f1 barrels.
On the f2 head the inner studs have cap nuts because the stud is not an oil passage way and the stud is not sealed through the fins.
On the f2 barrels the inner studs are sealed
On MY f1 barrels they are open, and leading to the outside world via the f2 head I think...

Might be the cause of the oil leak.. 
And crap from the outside world can get in... farkk!
 

[scottly]

I can't comment on the current oil leak, but thought I should mention that your breather hoses are too short; they should extend below the swing-arm, and be directed to the right, away from the tire.

[Ilja]

I have one big breather hose hanging behind the kickstart because I still wanted to make a catch can for it, and to keep an eye out for excessive case pressure.

But now with the f2 head I basically have 4 extra breathers via the 4 inner cylinder studs through the f1 barrels.

So it could be that the engine is spilling oil through these studs because of 'normal crankcase pressure' or hard braking.. but it could also mean that the ring lands are broken again.

My breather tube doesnt pressurize or puke oil but thats maybe because its not the only path now.

Sadly enough it needs so come appart again anyways because I need to find a way to close the inner studs off...
Or find f2 barrels and have those bored to 836cc again.. that would suck.

[MRieck]

There is no problem using the F1 barrels with the F2 head.....I have done it multiple times with no problems. You need to use the copper sealing washers under the washers the unused oil return passages. I would use some Hylomar on the washers too. Did you deck the cylinder and mill the head??? You absolutely must do it when using the MLS head gasket. Surfaces must be flat and smooth.

[Ilja]

There is no problem using the F1 barrels with the F2 head.....I have done it multiple times with no problems. You need to use the copper sealing washers under the washers the unused oil return passages. I would use some Hylomar on the washers too. Did you deck the cylinder and mill the head??? You absolutely must do it when using the MLS head gasket. Surfaces must be flat and smooth.

I have used the copper washers and closed nuts on the inner studs between cylinder 1&2 and 3&4.
The thing is, on the F2 engines these studs are also closed with o-rings around the studs on the bottom of the cylinders and on the K+f1 engines they are open. I think the reason for the o-rings is that the stud channels are not closed all the way up to the copper washers...

I have read (but didnt check yet myself) that in the f2 head the hole for the studs is open through the fins but for a f1/K-head its closed because its used as drain back.
If the f2 head stud-holes are open through the fins this would mean that with K barrels oil and engine air can back up through the bottom of the cylinders, out of the stud holes through the fins.


Motomartin at the bottom of this topic describes this:
http://forums.sohc4.net/index.php?topic=51534.0

But I also didnt deck the head and the cylinders, so this could also be a problem...

At the moment I'm converting the bike to classic spoke wheels, fork and swingarm  .. after I'm done I will take the topend off and check whats going on. :-)

[MessnerMoto]

I have f2 head and f2 barrels. I used loctite 577 on 4 nuts exposed to atmosphere because I've got HD nuts from APE. HD nuts are open....

Havent tested it yet but I think this is a good solution

[MRieck]

There is no problem using the F1 barrels with the F2 head.....I have done it multiple times with no problems. You need to use the copper sealing washers under the washers the unused oil return passages. I would use some Hylomar on the washers too. Did you deck the cylinder and mill the head??? You absolutely must do it when using the MLS head gasket. Surfaces must be flat and smooth.

I have used the copper washers and closed nuts on the inner studs between cylinder 1&2 and 3&4.
The thing is, on the F2 engines these studs are also closed with o-rings around the studs on the bottom of the cylinders and on the K+f1 engines they are open. I think the reason for the o-rings is that the stud channels are not closed all the way up to the copper washers...

I have read (but didnt check yet myself) that in the f2 head the hole for the studs is open through the fins but for a f1/K-head its closed because its used as drain back.
If the f2 head stud-holes are open through the fins this would mean that with K barrels oil and engine air can back up through the bottom of the cylinders, out of the stud holes through the fins.


Motomartin at the bottom of this topic describes this:
http://forums.sohc4.net/index.php?topic=51534.0

But I also didnt deck the head and the cylinders, so this could also be a problem...

At the moment I'm converting the bike to classic spoke wheels, fork and swingarm  .. after I'm done I will take the topend off and check whats going on. :-)

I understand the differences between F and F2 parts. Using the F2 head with the F cylinders is not a problem if you seal off the lateral oil return holes. I have converted a K head to an F2 head oil return system....same thing.
 I thought I read your leaks were up high....around the head gasket area.
 I would definitely deck and mill......especially when using turbo or nitrous as cylinder pressure gets up there.

[PeWe]

Ilja, your clutch withstand the turbo power?
Which clutch do you have in? Prepared clutch somehow for optimum grip?

[Ilja]

I bought some (super) heavy clutch springs from someone, according to him heavier then the normal hd springs and new ebc friction plates.
Its working fine, no slip!  To be honest I was surprised how well the clutch holds because the bike makes somewhere around 120Nm  of torque..
When it was stock, it slipped as soon as boost started!

Installed the rear f swingarm and my old f rear wheel.. jesus I forgot how heavy those spoke wheels are 
Need to figure out wheter to return the shock mounts to normal or not.. I regret changing it now but it started out as an F model and I had different plans back then. I like the classic look on these bikes.

I will open the engine later when I have the wheels back in.. might also install the forged mtc pistons as they are completely flat and drop the compression half a point over the cruzinis, can mill the head and deck the cylinder to offset that.

[PeWe]

OK, I'll use EBC too, CK 1145 + Barnett springs. I'll bead blast the metal discs.

[Ilja]

I used EBC CK1220 for my f1 clutch.
It had one disc which isnt used on mine if I remember correctly.
Didnt do anything to the steel plates.. 😄

[cbr954]

Cycle X and APE can both install brass sleeves in the open cylinder holes in the F2 head so you can run it on K cylinders.  Have had it done several times.  Dont know if you can see them in the picture

[Ilja]

Cycle X and APE can both install brass sleeves in the open cylinder holes in the F2 head so you can run it on K cylinders.  Have had it done several times.  Dont know if you can see them in the picture

Nice! This is exactly what I wanted to do when I have the head off again! Thanks a lot for the picture! 😎

[PeWe]

Order together with an APE Ultra crank to withstand your bike's wild horses and quicker response...

[Ilja]

Order together with an APE Ultra crank to withstand your bike's wild horses and quicker response...

Depending of the reason why that oil is suddenly flying out  of those stud ventilation holes 😅 I will remove the boost regulator and set it default at 10psi.

Could be that my case pressure has increased because I installed a T piece between my two valve cover case breathers.. (I welded on an extra one, but thought it might be overkill)
After that I got the oil puke through the fins.

But it could also be that a piston nipped a ring again or broke a ringland, though I didnt hear any detonation for a long time.

That, or the headgasket blew..

Anyways, I will (try to ) stop looking for more power because I think I'm pushing the limit a bit and the engine is already fast enough. The bike is too nice to wreck..
I might even remove the intercooler if I settle for 10psi for a bit more classic look.

So sorry APE, no crank for now. 😋😄

[Ilja]

Welll I did some work on the bike and almost finished the rear end. Need to think of and make a cable system for the rear drum brake.
Front end still needs to be done.. but the hardest part is finished (lathe work and shock studs).

Later on I will probably add a second front disc and lace a 3.5" rim into the rear wheel.

Its more of a sleeper now.. 

[PeWe]

Engine will continue to produce power as before?
Dual front brakes is important with more power.

[Ilja]

Engine will continue to produce power as before?
Dual front brakes is important with more power.

Yeah but set at 10psi (optimal point for the gt17 turbo).
On the other hand... its not like I have to brake from 250km/h but you do drive fast more easily like this.

[PeWe]

My bike has much more power now and the difference is that the corners are coming much faster when driving on curvy and sometimes bumpy country roads where the signs have 70-90 printed on them. 160-180 km/h is fast enough and good brakes a must.

[ivanhoew]

Yeah but set at 10psi (optimal point for the gt17 turbo).

Ilja , in case it helps , i run thesaab 9.5  gt17 up to 25 psi in my 1972  mini 1310 cc , and 7000rpm . it definitely produces power up to that boost level , i have a dyno chart of 248 bhp on 19 psi .

[Ilja]

 

[Ilja]

17x4.5" rear and fronts going to be 18" wm4 (2.50).
Rear is a chrome harley rim with ss spokes. 
Just laced it up..

Excited... 😄😄

[Ilja]

  Fits very good! No offset sprocket necessary with the 150 tire and stock f1 hub.

The only thing that doesnt fit is the oem rear caliper bar..
Im thinking about using a TL1000 caliper on the bottom side with a custom bracket.... or I need to make a custom caliper stay rod which clears the rear tire.

[turboguzzi]

neat, those cast wheels loked to modern indeed
hope you used heavy duty spokes!