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

[Medyo Bastos]

looks great! 

[Ilja]

Okay been looking into this clutch-thing for a while.

Since I've got an F1 engine apparantly the APE clutch kit doesnt cut it. Doesn't seem to be suitable for the later clutch baskets with a wide outher slot and double disc.

Does anyone know if there are any aftermarket clutch kits for the F1-F2 models which contain the right clutch plates? (with the double disc and the wider outher one?)

Can't remember the double one being in my bike... strange.

[turboguzzi]

somehow missed this build, very very cool!

 btw, another cheap ignition to run are 90's GSXR. they are very easier to setup as they use only one pickup and the rotor sort of bolts on to sohc crankshaft. used it on both my race bikes for 9 years, never had a failure.  another nice thing is that you can drive from the box also the rev counter. i simply dismantled a used GSXR rev counter from the panel one and put in in an old guzzi veglia clock housing (easy to find, were fitted to guzzis, benellis and other italian stuff)
 

[Ilja]

somehow missed this build, very very cool!

 btw, another cheap ignition to run are 90's GSXR. they are very easier to setup as they use only one pickup and the rotor sort of bolts on to sohc crankshaft. used it on both my race bikes for 9 years, never had a failure.  another nice thing is that you can drive from the box also the rev counter. i simply dismantled a used GSXR rev counter from the panel one and put in in an old guzzi veglia clock housing (easy to find, were fitted to guzzis, benellis and other italian stuff)
 

I have done ecactly the same with my gpz rev counter.. also running it from my ignition box and build in the stock gauge housing!

[Jim F]

And I thought I did a lot with my turbo
Well done and this might make me get off my arss
And finsh it

[Ilja]

Oh yeah, the turbo oil feed is taken from main gallery with a 1.5mm restrictor and oil return is gravity drained to the sump.
I made a catch can with a vent to the engine casing(rocker cover middle cap) as to have equal pressure everywhere since the drain is below oil level.
Otherwise it might backup in the line with the slightest crank case pressure.

NO scavenge pumps or oil pumps necessary! Dry-sump!!!

[Medyo Bastos]

Oh yeah, the turbo oil feed is taken from main gallery with a 1.5mm restrictor and oil return is gravity drained to the sump.
I made a catch can with a vent to the engine casing(rocker cover middle cap) as to have equal pressure everywhere since the drain is below oil level.
Otherwise it might backup in the line with the slightest crank case pressure.

do you have pics of how you did this?

[Ilja]

Oh yeah, the turbo oil feed is taken from main gallery with a 1.5mm restrictor and oil return is gravity drained to the sump.
I made a catch can with a vent to the engine casing(rocker cover middle cap) as to have equal pressure everywhere since the drain is below oil level.
Otherwise it might backup in the line with the slightest crank case pressure.

do you have pics of how you did this?

Yes.. my last post contains a pic of the catch can and the other oil system pics are a few pages back probably.

[Ilja]

Today finally a few hours without rain so I did 120km of turbo riding before I froze lol.

The bike is running awesome! It pulls the 18:39 gearing like a train, no problem at all. And only at 7psi!
Got a bit of clutch slip at around 7500rpm when riding WOT and a/f is a bit too rich at WOT also... something like 9.7-10 a/f.
But the bikes is a blast too ride..quiet, smooth, torqy, fast as hell and totally satisfied with it!


Only thing I'm getting worried about is the offset sprocket and the output shaft spline... sprocket is held by the dodgy clip and might go bad very quickly with all this power. I think its already a lot looser then 200km ago...

[turboguzzi]

now that you mention it, the sprocket fixing in sohcs is definetely not made for offset sprockets....

you could gain some stability for the sprocket by welding it to the spacer tube behind it...

[Ilja]

now that you mention it, the sprocket fixing in sohcs is definetely not made for offset sprockets....

you could gain some stability for the sprocket by welding it to the spacer tube behind it...

Spacer tube? There's nothing behind my front sprocket as far as I know... hmmz...

I just noticed browsing the internet that the cb750 K models has the bolt-style of sprocket fixing..(pic below).. I have the F model but I have the clip-style sprocket fixing.

But theres also something with the output shaft becoming longer at a certain point in time.
I probably have the longer shaft in my engine.

[Medyo Bastos]

[/quote]
 I probably have the longer shaft in my engine.
[/quote]

no, you have the correct one

[Ilja]

I probably have the longer shaft in my engine.
[/quote]

no, you have the correct one
[/quote]

The picture is from a CB750 K ..found it somewhere on the forum.

I have the F engine with clip-fixing... I wonder if they are the same length..

[MRieck]

 77/78 K output shaft is the same length as the 77/78F shaft. They are shorter (and beefier) than the earlier shafts. My choice for any SOHC engine making some power.

[Ilja]

Ok thats good to know.

I'm thinking about making an outside bearing support to the front sprocket.

A lot of the older kz1000 bikes had it.. but I never really understood how it could work.
On those bikes the front sprockets are secured with a nut.. so your basically adding a 3rd bearing to one rigid shaft.... which in the engineering world can snap shafts with the slightest misalignment. But apparently it wasn't a problem.

I could make an outside bearing support for the front sprocket...but then I think the support bearing would need to be able to take a slight mis-alignment since the sprocket is secured by a clip and will move a little.

[754]

I think mreick meant they are longer, and beefier, the late shaft. They dont use the lockring, just a bolt and washer.
They're 10 mm longer.
 The outboard carriers you mentioned were not made for our bikes, as they would not fit due to two major constraints... First being rear of. Engine case at the trans cover, it is in the way.Second is the frame, you cant go out an inch without the chain hitting the frame.
 Some of the Suzi and Kaw offsets are 2-3 inches.

Now I have to ask,why the very high gearing ?

[Ilja]

The gearing doesnt feel high and its very relaxed doing highway speeds this way. 

I'm going to make the first cb750 output bearing support then... lol.  I think I can make it work.

Got the whole of next week to do it since I have holiday and its raining continuesly anyways..

[754]

I think I can make one work too, but I would probably have to trim the case, and the part going to the bearing would be a small shaft like 20 mm. Tricky..
 The trick is to let the outer bearing support, float on its bolts, then when it slips into sprocket and lines itself up, then tighten in place.. Good luck.
 But you can get about 3/4 inch out from the short shaft you have now, with bolt on stuff...then you be beside the frame.

[Ilja]

I think I can make one work too, but I would probably have to trim the case, and the part going to the bearing would be a small shaft like 20 mm. Tricky..
 The trick is to let the outer bearing support, float on its bolts, then when it slips into sprocket and lines itself up, then tighten in place.. Good luck.
 But you can get about 3/4 inch out from the short shaft you have now, with bolt on stuff...then you be beside the frame.

Thanks for the advice!
I was thinking the same about fastening... I will also use a double row self-aligning bearing so it can take some misalignment.

My offset right now is 9mm and thats enough. Its ok like this but the problem is the clip and the support of the offset sprocket.. too much torque it will destroy the shaft.

[MRieck]

I think mreick meant they are longer, and beefier, the late shaft. They dont use the lockring, just a bolt and washer.
They're 10 mm longer.
 The outboard carriers you mentioned were not made for our bikes, as they would not fit due to two major constraints... First being rear of. Engine case at the trans cover, it is in the way.Second is the frame, you cant go out an inch without the chain hitting the frame.
 Some of the Suzi and Kaw offsets are 2-3 inches.

Now I have to ask,why the very high gearing ?

Correct Frank....thanks!

[Bill/BentON Racing]

And I figured Mike was already in the Apple Pie! Lol, Bill 

[Ilja]

Well, I've ordered a bearing for the sprocket-support! 2 row self aligning bearing with seals... inside 25 outside 52 and width 17 or 18mm.
Will weld and then machine/lathe a boss to the sprocket for the bearing to sit in.

I'm just figuring uit how to get the bearing out of the sprocket again... since it probably has to be a bit of a press fit to prevent it destroying the bearing housing.
But the other bikes with outside bearing support should also have this issue?

Sketches for the support construction are made and I think its doable. :-) 

[MRieck]

Well, I've ordered a bearing for the sprocket-support! 2 row self aligning bearing with seals... inside 25 outside 52 and width 17 or 18mm.
Will weld and then machine/lathe a boss to the sprocket for the bearing to sit in.

I'm just figuring uit how to get the bearing out of the sprocket again... since it probably has to be a bit of a press fit to prevent it destroying the bearing housing.
But the other bikes with outside bearing support should also have this issue?

Sketches for the support construction are made and I think its doable. :-) 

I would try to speak or correspond with Jay @ APE if you have questions about runout etc. He has made quite a few of those outboard drive units.

[Bill/BentON Racing]

Yep, Jay been working on SOHC's since early 70's!

[turboguzzi]

now that you mention it, the sprocket fixing in sohcs is definetely not made for offset sprockets....

you could gain some stability for the sprocket by welding it to the spacer tube behind it...

Spacer tube? There's nothing behind my front sprocket as far as I know... hmmz...

yes, you are right, was thinking about my kwasakis that have one

on the other hand, it could still be a good idea to make a small tube welded behind the sprocket to stabilize it?

check your pm's got a question for you..