Racing cams

[MarioR]

Folks,

Just picked up spare engine 1200 with 25km only. Engine is clean stock with 160-165 compression across. Stock cams were taken away to legend car however I got as a replacement racing cams. No info about cams. Looks like old stock inventory, brand new. Nothing I can find on the cams them self's. So I measured them yesterday and looks like intake lift is 0.375 and exhaust is 0.365 (raw measurement with caliper so there maybe a bit tolerance). Looking for the cam lobe profile, nose is pointy and overall base shape is slightly bigger than stock. Looking through out webcams, megacycle, Yoshi, Kent, etc. and it is hard to say what I have....
1. Based on the measurements, do I need stronger springs? I think I do...
2. Since cam brand is unknown, how to find tolerance for shims?
3. What shims should I start with to set it up as a beginning?
4. Can someone clarify shims on top vs under? My understanding is that stock design motor has shims on top. And for example FZR1000 motor has small shims under bucket. That being said, with high cams conversion is needed to shims under?
5. What about cam sprockets? Does it need to by modified to adjust timing?


Thanks

[Pat Conlon]

Paging Chris and Randy.

Mario, are you wanting to use these in a street engine?
Have you ever experienced a race built engine on a street bike?
Which today's electronic safety features, that's one thing, but an old school lumpy peaky carbureted race engine is a different beast....

[MarioR]

Paging Chris and Randy.

Mario, are you wanting to use these in a street engine?
Have you ever experienced a race built engine on a street bike?
Which today's electronic safety features, that's one thing, but an old school lumpy peaky carbureted race engine is a different beast....

Hi Pat,

I am not racing anymore so for sure street engine. More to keep my mind busy working on something.
Yes, this is not my first rodeo Pat. But for sure not high cams or anything like track motor. Street or weekend pleasure. I want to build something that is street able use but the same time much higher power. I know there is tons of options but I need start somewhere.... so I got an engine and cams, that came with it. I thing this is good starting point.
Lol, you taking about high cams V8 beasts, old schools.....

[Pat Conlon]

Cool beans, carry on,  I'll follow along with your build.

Looking forward to see what our forum engine experts advise.

Do the cam base circles match the oem?

I can understand the need for shim under bucket for high rpm's and/or pointy cams but it seems like a PIA to have to remove the cams every time for shim adjustment.

Cheers

[MarioR]

Cool beans, carry on,  I'll follow along with your build.

Looking forward to see what our forum engine experts advise.

Do the cam base circles match the oem?

I can understand the need for shim under bucket for high rpm's and/or pointy cams but it seems like a PIA to have to remove the cams every time for shim adjustment.

Cheers

Absolutely Pat.

I will be more than happy to learn from experts that built many already.

Cam base I think is slitty bigger than stock but to be completely honest, I do not have spare cam to measure. This is just observation based on looking it from the side of the lobe, where material is added. To be checked and confirmed. Will try to post some pictures.

If shims under to be used, this will be the biggest PITA, for sure.

Since my other engine compression is theoretically back but still smoke throughout vent breeder (unfortunately, 10 minutes ride and you smell like BBQ sausage, lol), I may do swap with new engine on stock cams.

Then old engine build with new set of 1297, 1314 or 1350 big bore and full head job with those cams.

Still going use B12 product and see if oil rings are stuck or not. Apparently this is good product and should works well. B12 ordered. Never give up....

Sorry for changing topic.

Thanks

[MarioR]

This is what they look like:

https://fjowners.com/gallery/12/6885-080425214645-126621514.jpeg

https://fjowners.com/gallery/12/6885-080425214647-126661382.jpeg

[racerrad8]

Those a definitely welded cams. They will have a stamp on them someplace is done by megacycle or web.

Yes, you should use slotted cam gears to set the cam timing.

The stock shim configuration will work fine.

Don't turm those cams in that motor, the one photo ahows there is no shim in the bucket.

Randy - RPM

[MarioR]

Those a definitely welded cams. They will have a stamp on them someplace is done by megacycle or web.

Yes, you should use slotted cam gears to set the cam timing.

The stock shim configuration will work fine.

Don't turm those cams in that motor, the one photo ahows there is no shim in the bucket.

Randy - RPM

Hi Randy,

Yes, there is no shims at the moment, there are in my box with shims Eagle eye

Can not see anything stamp on the cams, however I will pull them out and double check including measurements.

What tolerance should I follow if no stamp brand on the cams???

[racerrad8]

O.E. clearances are fine.

We don't venture too far away from those regardless of what we are doing with an engine.

Randy - RPM

[fj1289]

With .375 lift - sounds like megacycle 268-00 grind.  I think these are a great street cam.  They could also be web cam 540 grind at .385 lift.  I have read issues with an earlier web cam grind with same lift and duration - 163 grind - but they tended to float the valves and put the closing ramps on the cams.  Supposedly the 540 grind replaced the 163 grind and had better valve train control.  https://forums.13x.com/index.php?threads/web-cam-hard-weld-camshaft-problems.307587/  (See post #13). 

Would be really good to find the markings on the cams.  I've seen them marked on the edge of the mounting boss for the gear, and have seen them marked on the shaft itself between two of the lobes.

[MarioR]

Cam shows at the front 555 009, other end P9C

[JMR]

To answer one of your original questions.....yes.....you need heavier springs. look in the Kibblewhite catalog.

[racerrad8]

Sorry, I missed the spring question. Here's the springs you need.

https://www.rpmracingca.com/proddetail.asp?prod=Head%3AValveSpringsHP

Randy - RPM

[MarioR]

Thanks guys, appreciate any feedback.

Like I said before, I was able to find is this number 555 009 on the front of the cam. Nothing else. Measured cams so I know approx, what they are.

So time to start collecting parts:
- new gaskets
-new valve seals
-new valve springs
- adjustable cam gears

In a meantime work begins.....Go big or go home......start to look for big bore.....

[Pat Conlon]

Curt Andrew's has a complete cylinder/sleeve/ Ross piston kits in 1350/1380/1410cc sizes.
You do have to relieve your engine case, they offer that service as well.
https://andrewsmotorsports.mybigcommerce.com/cylinder-kit-yamaha-fj-1412cc-84mm-ross-piston-cylinder-kit/
Randy @ RPM used Curt's 1380 kit on my engine and I and very happy...45k miles and counting, uses no oil.

Keep the updates coming! Cheers. Pat