Topic: Hot Street Motor on a Budget

[stikman]

I know it's not that exciting.  Certainly not as much as Bill's recent engine trouble.


Here's a shot of the worst valves, all exhaust.  Probably not worth reusing?



The valves have "CR" on the stems and say "Made in Japan" and IN or EX in raised letters on top.  Are these just stock valves?

[dragracer]

I'll be swapping the F2 cam for a CX-1 (Webcam 41) in my Street E/T dragbike posted earlier and will be able to post results. Current best ET is 13.38 at 97mph. I'll try to do the comparison before any sprocket changes. I'll be switching sprockets to try and get 5th gear on top end since I'm currently hitting my shift point in fourth gear right at the stripe.

That will be very interesting for sure.  If you end up with the 60ft number comparison too, that would be awesome.  When are you planning to test your changes?

Hopefully before the end of the year. We just finished the season in Valdosta over the weekend, so it's time for wrenchin'! Current 60' numbers are right at two seconds.

Get busy bud. We've got a bracket race in Bradenton on December 9. Paying good money too. Even if you don't race, it'll be a perfect time to test at a nice track. All bike event by the way. Get that cam in there and bring the sprocket and extra chain- you'll loose wheelbase otherwise. Lets do it!!! Gladys said she's entering the ET class. What's your excuse??? 😁

[BPellerine]

I know it's not that exciting.  Certainly not as much as Bill's recent engine trouble.


Here's a shot of the worst valves, all exhaust.  Probably not worth reusing?



The valves have "CR" on the stems and say "Made in Japan" and IN or EX in raised letters on top.  Are these just stock valves?

I have never seen that type of valve,with markings on them,kinda cool.bill

[754]

Norris used to mark their cams on a flat spot..got a cam pic... Plus they were a grey color.

The big valve clearance sure hints at a cam..Did it have decent power ?

[TurboD]

Norris used to mark their cams on a flat spot..got a cam pic... Plus they were a grey color.

The big valve clearance sure hints at a cam..Did it have decent power ?

Or bend valves. hehe

[BPellerine]

I guess to answer your q they are not stock.bill

[TurboD]

Stikman What do the heads of the valves look like?

[stikman]

Norris used to mark their cams on a flat spot..got a cam pic... Plus they were a grey color.

The big valve clearance sure hints at a cam..Did it have decent power ?

Interesting.  I expect the excessive valve lash is more due to lack of maintenance.  The PO was that type to an extreme.  But now you've got me thinking and I'll have to do some measurements on the cam lobes.  The lobes are pretty worn, and the hardened surface of the rockers equally so.  I only ever started this motor once and it smoked like a pig.  Can't speak to how it felt.  But given the ring gap placements I can't imagine the compression was very good.  Ports haven't been touched before.

I was, however surprised to see 140 main jets in the carbs.

Stikman What do the heads of the valves look like?

Valves look straight to me.  Anything specific to look for on the heads?  Nobody seen those CR valve markings before?

[TurboD]

I was curious as to the shape of the valve head.

[stikman]

I was curious as to the shape of the valve head.

Valve heads look fine, albeit coated in carbon.  But they don't look to have been hitting the pistons.  The pistons measure about 2.4", so 61mm stock size.  Intake valve head measures 32mm, and exhaust 28mm.

Here's a shot of the cam marking, "K8".


Lobes are pretty worn with some pitting.  I'll get some lobe measurements shortly.

[TurboD]

Do the valves have the stock shape or flat like aftermarket?

[stikman]

Do the valves have the stock shape or flat like aftermarket?

They are dished in the center like stock valves.  Just the raised lettering in that dish that I've not seen before.  You can see that in the pic I posted earlier.

[TurboD]

The head side, where the shape is. I can see the flats. Lol

[stikman]

The head side, where the shape is. I can see the flats. Lol

Got it  .  They have the same ski slope lip around the edge as stock valves.





From what I can tell, the cam lobes measure similar lift to a stock cam, if not a hair shorter from wear.  I compared with a good K1 cam I have.

Base lobe:  1.110"

Intake lobe:  1.396"  (1.405" at the less worn outer edge)
Exhaust lobe: 1.386"

This cam left, K1 cam right

[754]

Sound like around  .375 lift..more than stock. To my eye it looks like a bit more duration.
The cam looks sorta grey in the R8 pic....does it look different in color than the K1 cam ?

[TurboD]

1.396 - 1.110 = .286

[754]

My math sucks today..

[stikman]

IN 1.396 - 1.110 = 0.286
0.286 x 1.1 rocker ratio = .315 valve lift

EX 1.386 - 1.110 = 0.276
0.276 x 1.1 rocker ratio = .304 valve lift

And color looks the same to me.  The cam has the normal R#, on this one it's R13, but the K8 stamping on the flat spot is extra.  It's weird and all, but the cam still looks to be stock to me.

[MRieck]

I have a set of CR rods here....they are POS parts.

[stikman]

I have a set of CR rods here....they are POS parts.

Hmm okay, good to know.  Probably just cheap stock-type replacement parts eh.  Well I'm planning to replace the valves anyway, seeing as the rockers hammered a few of them and the raised letters can't be good for flow.  Do you think oversize intakes would be overkill with a wiseco 836 and webcam 41?  (I'll be deshrouding them anyway)

Also considering removing the valve guides to be able to grind out that cast lump around them.  Is this okay to do on a street motor and what guide material would be recommended?

[MRieck]

I have a set of CR rods here....they are POS parts.

Hmm okay, good to know.  Probably just cheap stock-type replacement parts eh.  Well I'm planning to replace the valves anyway, seeing as the rockers hammered a few of them and the raised letters can't be good for flow.  Do you think oversize intakes would be overkill with a wiseco 836 and webcam 41?  (I'll be deshrouding them anyway)

Also considering removing the valve guides to be able to grind out that cast lump around them.  Is this okay to do on a street motor and what guide material would be recommended?

That is a great idea...have the seats ID's bored to .9 and blend into the port. Here is what I would do. Leave the old guides in and bore the seats. Remove the guides and work on the guide boss and seat area. use the Kibblewhite iron guides. If you have a lathe taper the guides. You will need to have the guides honed and a valve job

[stikman]

I have a set of CR rods here....they are POS parts.

Hmm okay, good to know.  Probably just cheap stock-type replacement parts eh.  Well I'm planning to replace the valves anyway, seeing as the rockers hammered a few of them and the raised letters can't be good for flow.  Do you think oversize intakes would be overkill with a wiseco 836 and webcam 41?  (I'll be deshrouding them anyway)

Also considering removing the valve guides to be able to grind out that cast lump around them.  Is this okay to do on a street motor and what guide material would be recommended?

That is a great idea...have the seats ID's bored to .9 and blend into the port. Here is what I would do. Leave the old guides in and bore the seats. Remove the guides and work on the guide boss and seat area. use the Kibblewhite iron guides. If you have a lathe taper the guides. You will need to have the guides honed and a valve job

Okay, perfect!  I was hoping you'd chime in on that, Mike.  So would you recommend doing this for both intake and exhaust;  guide taper and boss removal?  I've got it in my head for some reason that removing the EX valve guide boss would expose the guide and make it prone to getting too hot.

Also, any recommendation for running without valve seals on the street, like the earlier models?

Final question for the day, what would be the recommended piston to wall clearance for NOS forged Wiseco 836cc pistons (4016PS - no micro grooves) in stock sleeves for my application?  Is less than .0020 getting too tight or is it reasonable as long as you take your time breaking it in?

[MRieck]

 You can remove or taper the intake boss. I taper the exhaust boss after the guide.....the exhaust flow really well without much work. Bead blast the ports before removing the guides.
 Valve guide seals are a must
 I'd run those old Wiseco's at .002

[stikman]

You can remove or taper the intake boss. I taper the exhaust boss after the guide.....the exhaust flow really well without much work. Bead blast the ports before removing the guides.
 Valve guide seals are a must
 I'd run those old Wiseco's at .002

Sounds good.  Thanks alot for that, Mike.

[stikman]

Couple more questions.  Is there a good place to get those CBX exhaust studs to replace the four 6mm head bolts?  And do you install the studs with anything, like locktite?

Any recommendations on what would be a reasonable amount to advance the webcam 41 to move the powerband down lower (going in a chopper)?  I'm considering drilling a stock cam sprocket to get between 5 and 10 degrees advance.

I assume I should be fine using the Kibblewhite chromed stem SS valves in the cast iron Kibblewhite guides.