Cam Degree Questions

You need to check squish and PTV with a thinner head gasket and redegree the cams. It's tight on a GSXR with thin head gasket/deck head.

 

So, are you putting titanium retainers in again? I will defer to the experts, but I don't think I would, based on my experience of a brand new parts engine only lasting 5 race weekends.

The engine wasn't abused either and had a rev limiter. I would think you need to inspect the retainers every 3 race weekends. I'm not sure if you can easily do that without removing the head. At a minimum you would have to remove the cams and buckets.

I religiously checked the valve clearance after every weekend and it had not budged. I was told that valve clearance issues are usually the problem with the motorcross based engine in a Moriwaki. I was ready to inspect and replace, once the valve clearances started moving. I wasn't aware I may have an issue with the retainers.

 

Like the stock GSXR 600 retainers never break :wow: I replace the stock ones every season. The have a built in stress riser.

 

There's a lot mo material on the GSXR retainers to start with than there is on the CRF's. On the Hot Rod Moriwaki I inspected the retainers every 600 miles along with the rest of the top-end components. The Valve cover never came off until then.

 

What I've done so far on degreeing the cams has really been an experiment to see how the process works. I haven't set them yet to a point where I'd be comfortable in saying it's ready to go, so they will have to be degreed again anyway. I can check the squish if I pull the head.

So what do you guys think? I'm considering a Yosh gasket that's .50 mm. It's actually thicker than one of the gaskets Cometic lists for only $20 more.

 

You should not have any problems with that, probably squish will be 25 thou or so. Obviously you should check.

 

WTF??? "they stopped at .005" due to hitting seats" UMM NO!!


You can take much more off a GSXR600 head than .005" trust me! Sure its no 750 but still... plus did they ever think to change the angle?? :wow:

Smitty,, you are a bit in over your head IMO. (dont throw keyboard at me..lol)... again....i would put in STOCK springs, STOCK cams, set v/c at .15 in and .20 ex. Run the 2 layer head gasket (.45mm or .50mm both work fine on stock block) and enjoy a nice solid, fast dependable engine. Sell the Yosh cams and springs for $4-500 and be happy. This si the tech section and im just being brutally honest.

Even with the 2 layer head gasket and the head "only" milled .005" off you will still have PTV issues with those huge cams...you will end up pulling lobe centers back to just get enough clearance... the head gasket .45mm or .50mm wont matter much if block is stock, the .45mm still is safe and ok to run on them.

Good luck.

 

I see heads on this model in my shop with 0.030" removed (hack method of increasing compression) and it's not into the 45 of the seat. However, that amount of material (0.005")will be about right if you use those cams and don't want astronomical lobe centers. Yosh tells you 0.9mm and 1.8mm on PTV? You can go a bit tighter, I've done it. Regarding the springs, you need to get access to a spring compressor and do some testing. Throwing 'recommended' arbor shims in there without precise measurement can be catastrophic. Those engines break valve springs regularly.

 

I appreciate you knowledgeable guys helping out us less knowledgeable folks. Did you mean .015 and .020, or do guys really run 150 to 200 thousands of an inch clearance? You used those large numbers in 2 posts, I initially thought it was a typo when you said .25 and .30 earlier in the thread, and now I'm wondering if guys run them that loose?

 

mm

some of us use thous and some of uses mm's

 

Ahhh, I read .15in and .25in as inches instead of intake....this is one of those times where the comment no question is dumb, is not true.

Thanks for clearing it up, AFM.

 

it's confusing. I always use thou, think in thou, even convert shims from mm to thou automatically in my head, but lots of guys use mm. Kinda personal taste thing. I grew up with thou

 

Thanks for the honest input and everyones patience and willingness to share their knowledge. It is greatly appreciated.

What I'm struggling to understand is what am I missing on this 600 engine that made these cams work on the other 600 engine? I didnt just buy these and are trying to make them work, they came out of a 600 that I've owned for almost 2 years now and ran strong up to the point the valve failed. Thats the idea my brain keeps holding onto is the cams were in a 600 that worked, and worked well. The fact that I dont currently have the compression to justify having them makes sense. My mindset was shim the springs per Yoshimura's specs, degree the cams, and check the clearances and the bike should run as good or better than it did previously.

I'm not trying to beat the topic to death. I'd just like to understand what the previous builder did right and what I might be doing wrong so I can save myself time, money , and frustration in the future. I'll get rid of the cams if thats what I have to do. I just want to make sure I ditch them because its was the right thing to do and not because I didnt want to make the effort to install them right.

 

+1
Used the Xceldyne RMZ-250 Ti retainers (pricing) on our 06-07 GSXR 600 but definately benefits with the spring work and we get our Ti retainers PVD coated.

Ran Web Cams
Squish @ .60mm
PTV-INTAKE-.75mm
PTV-EXHAUST-1.35mm

Did I memtion I have a set of Carrillo' and Cams for sale....

 

Yoshimura .50mm head gasket is on the way. I'm going to pull the head back off this weekend, clean everything up and start over. I've got the stock head gasket in now, so I'm going to check the squish with the stock gasket and keep the numbers as a reference. I'll check the Yosh gasket when it gets here.

I'm going to consider what I've done up to this point a trial run to see what I am up against. It'll be a pain in the ass taking everything apart but it'll be worth it having the peace of mind knowing everything is properly clearanced and where it is supposed to be.

 

You may also notice how much easier it gets, the more you do it...

 

LOL first time I degreed cams I spent a DAY writing down numbers for two cams.

Today I was playing with drop in cams on an SV and did something around 12-15 combinations and permutations in three or four hours. Gen 2 rear int as front intake, gen 1 front intake as rear intake, gen 1 rear int as rear exh, yosh front int as front, DL650 front int as front and rear exh. I have a lot of numbers now. I got some great numbers with the Gen 2s intakes but all the exh numbers suck. (This is with a motor with squish adj) I either end up with ex lobe center under 100 or over 115. Bah.

 

You should try to degree the yamaha Vision 750 cams when twingled...talk about pulling one's hair out :wow:

 

That's where it went?

 

Working on the Vision project took 1/2 of it...working with Babe for 3 years turned what I had left grey! j/k