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Rtc8 valve train geometry, Help!

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Phathead209

New member
Hey guys I installed new billet steel roller tip rockers on my rtc8 head and I noticed that on the intake side the valve stem does not line up straight with the rocker stud as it does in the exhaust side. Once I set the lash and turn it over a few times the intake rocker seems to ride on the side of the roller tip? I thought that it might just be a bad casting so I pulled the cover on two of my other heads and they are the same but they both have the stock rockers. Anyone else run into this issue? I'm wondering if once it's at high rpm it straightens out but would sure like some input before I make a film is pig out a this thing. Thanks.
 
Phathead209 said:
Hey guys I installed new billet steel roller tip rockers on my rtc8 head and I noticed that on the intake side the valve stem does not line up straight with the rocker stud as it does in the exhaust side. Once I set the lash and turn it over a few times the intake rocker seems to ride on the side of the roller tip? I thought that it might just be a bad casting so I pulled the cover on two of my other heads and they are the same but they both have the stock rockers. Anyone else run into this issue? I'm wondering if once it's at high rpm it straightens out but would sure like some input before I make a film is pig out a this thing. Thanks.
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Swap the rockers side to side. See if it still occurs on the same side, or does the problem follow with the lifter swap.
If it follows, return the lifters and explain the problem to the supplier and have them send you a correct functioning set.
 
It doesn't make a difference witch way I put the rockers, it happens both ways on the exhaust side. Either way it never toutches the guide plate. I don't believe that the rockers are defective, it looks like the rocker stud on the exhaust side just does not line up with the valve stem. Wish I could figure out how to upload a pic for you guys lol. Both my other heads look the same but it doesn't seem to matter with the stock rockers because they have a wider valve stem/rocker contact surface. If you look at the head, you can noticeably see that the intake rocker stud is almost straight "inline" with the intake valve stem where as the exhaust rocker stud is not quite inline but a little to the left.
 
Firstly if use lash caps.

Now you either have a bent pushrod or rocker stud, missed the lifter recess or have the guide plate a bit off. My guess is somethings bent. To check the pushrod put on a flat surface and roll it, if it won't roll it's ****ed.

Cheers
 
Can't use lash caps on the 5mm valves, everything is new and I did roll the rods on glass and they are ok. I have the same issue with out using the guide plate and have checked and double checked the pushrod/lifter contact. Thanks for trying though. I will try to get pics up tomorrow.
 
Who says you can't use lash caps on 5mm valves?

Without the guide plate in place the rockers should be able to move all over the place.
 
I have not been able to find lash caps for the 5mm valves, if you know where to get them let me know because I do believe they would help. I have also seen several post that said that due to the automotive style locks there is not enough room for them. As for the guide plates, I took them off just to think out of the box but with them on the rods never touch them weather the rocker is where it should be or when it gets off to the side. If I take the rockers and the guide plate off and put a square across the rocker studs then the exhaust stud boss is almost perfectly inline with the exhaust valve where as the intake rocker boss is at about a 5 degree or so angle of the intake valve. This is what makes me believe that the head may be a bad cast but when I checked my other two heads they were the same. I dunno, like I said I will try to get some pics up tomorrow but thank you guys for the help so far!
 
W5R said:
Swap the rocker studs around and see if problem follows the stud
Click to expand...

That's the only other thing I can think of W5R. Clone studs are weak and if you use a long socket to get them out and don't hold it straight you will bend them. If they are bent buy new ones. Take a look at places like summit auto parts or jeggs they should have them.

I always try to run lash caps unless it's a larger stem valve. The only time I wouldn't is if I ran titanium valves with stellite harden tips.
 
https://imageshack.com/i/plN1umtzj

If you look in this pic you can see that the exhaust valve on the left is almost perfectly inline with the stud where as the intake valve on the right is slightly farther to the right of the intake stud. Swaping the studs did not make a difference. If someone who owns an rtc6 or rtc8 head could take a look and let me know what they think. Thanks guys!
 
Go to your local motorcycle shop and ask for lash caps or valve rotators (same thing but proper name for them) for a Suzuki gsxR 1100. Only a couple years of those bikes used 5mm valves, can't remember for sure but am thinking 2000-2002 models had them. Any lash caps for a 5mm valve should work. You may have to grind them a little shorter or may not need to. I didn't have to do anything to the ones I got other than put them on. I used them in a rtc-8 head with stock valves and retainers using 26# springs
 
I would compare the billet guide plate to the stock guide plate, perhaps the slot was not cut correctly on the billet plate. You could either try the stock guide plate, or flip the billet guide plate over, if the slot was cut incorrectly the offset would move to the other side. I have built dozens of predators, never seen such an offset.
 
Hmmm you flipped rockers and still have the same problem did you also switch the adjuster that's goes down into the rocker ?jmo from looking at the pictures it looks like one is just a hair fatter then the other or is not true and causing the rocker to shift.
 
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