77 Jarota Timing/Valve Shim/Carb setup

Thanks for the tip on the sleeves and castings.
Timing check complete, we verified a few things with the valve cover off.

Cam timing is approximately set at intake 104 exhaust 113 off of the outbound (Cylinder #3) cam lobes, per Phil Todd's recommendation. We did notice several of the followers seem shimmed pretty tight, as they wouldn't spin by hand. The plan is to recheck after some more miles on the road and determine next steps. The new cam blocks were an "Oh thats right, I did opt for those, didn't I?" moment. Really nice looking setup. I'm glad they're in there. Hats off to Scott Potter, who prepared this motor, for making me aware of this option. Really pretty stuff.

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Hats off the IAG Bob Colbert again, as his carbs were swapped on and has helped out tremendously. Carbs were rebuilt after ultrasonic cleaning, all gaskets and seals replaced, clogged jets replaced with new, and the floats raised up a few millimeters to around 16.5 mm. This allowed the pump jets to activate easily on this set. Still on 135 mains, K1 needles in the second slot, but now with the 58 idle jets that I ordered versus 55s. This and the float adjustments made all the difference in the startup and idle. Fired up after a few cranks, idles for 10 secs with about 1/3rd choke, and settles into a 1000 rpm tick over with the choke off there after.

A quick run around the block shows pickup from low speed to progression and high speed ranges is great when the motor is warmed up. I'm keeping it under 4k, looking forward to some higher speed roll ons today on the highway. The motor sounds and pulls strong. Chassis is excellent, steering is excellent, but I have some issue with the rear tire as it was down to less than 10 lbs before I went out on the neighborhood run. Thankfully we checked pressures before the short ride. I want to see how it is today before I go for any fast or longer rides. Just another bump in the road.

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I'll have my carbs on by EOD with the same float height and jetting, and will look at the followers/shimming again right before the first oil change at 600 miles or so. Only 597 to go!
 
angonemoto said:
Thanks for the tip on the sleeves and castings.
Timing check complete, we verified a few things with the valve cover off.

Cam timing is approximately set at intake 104 exhaust 113 off of the outbound (Cylinder #3) cam lobes, per Phil Todd's recommendation. We did notice several of the followers seem shimmed pretty tight, as they wouldn't spin by hand. The plan is to recheck after some more miles on the road and determine next steps. The new cam blocks were an "Oh thats right, I did opt for those, didn't I?" moment. Really nice looking setup. I'm glad they're in there. Hats off to Scott Potter, who prepared this motor, for making me aware of this option. Really pretty stuff.
Click to expand...

Great idea, they'll really like that...  :o

For crying out loud, if they're tight, they need to be adjusted, or find out why they're tight!  But maybe you've got a cam and follower tree in your garden, just pick some new ones when they're ripe? ::)

piet
 
angonemoto said:
The new cam blocks were an "Oh thats right, I did opt for those, didn't I?" moment. Really nice looking setup. I'm glad they're in there. Hats off to Scott Potter, who prepared this motor, for making me aware of this option. Really pretty stuff.
Click to expand...

cam blocks are made in Camira by us, can tell they are our cam blocks by the 0.2 on the face, means the camshaft has been raised by 0.20mm from standard

adjust your shims sooner rather than later

 
Not a mechanic, so thanks for the advice.

I'll get some proper measuring tools and figure out where I'm at, what size shims are in there, and thanks to Dellortoman's spreadsheet I should be able to get the correct size shims from Wolfgang and move on. I really wasn't expecting to go this deep on this bike, but here we are. I appreciate the help. Kinda just want to ride the damn thing but I understand the risks of ignorant exuberance here.
 
Yep dont ride it with no valve clearances or next thing you will have valves that no longer seal along with damaged cam lobes and buckets.
If you have .2mm offset cam blocks I hope you have got shims that are thicker than 2.0mm.
Best get this clearance issue sorted before you continue trying to tune your engine as correct valve clearances are an essential ingredient for proper engine tuning.
 
Great information, thanks again.

I was fine leaving the timing set as is prior to this shim situation, but now I think the opportunity to bring those settings closer in to standard is not to be missed. Afterall, I'm not qualified to go exploring the outer reaches of timing and tuning. The 101/103 compromise feels right, so Maurice, what size main jets are you running with your 101 inlet 103 exhaust timing? I'll order them while I go in and figure out what shims I have.

Now that I understand from Red that the cam blocks have lifted the exhaust cams up on that side of the assembly. That wont affect the way I should check the clearance at each lobe bottom to each follower/bucket/tappet, but I wonder why these would be installed in the first place? Could it be the exhaust valve seats within the head have been worked on and are now set in deeper into the head, and raising this cam allows "thicker" shims with a wider size range to continue to be used over time rather than "thinner" ones? 

Even more confusing to me is the exhaust blocks are marked 0.2 and the intake are marked 0.0, which has me thinking the cam shafts are no longer parallel to each other. which shouldnt be a big deal considering the shims will "even things out" when they are set up correctly.

As far as cam block torque, I realize that's going to be a critical part of getting this all shimmed correctly alongside the risk of damaging the head. FML. Since published values are known to be inaccurate, any thoughts on safe technique and torque ranges for these studs?

Lastly, IAG Bob Colbert just sent some photos of the process of removing the shims for replacement. I am going to post them here for reference as they have helped me visualize this process specifically to our triple motors, which is a great help. Thanks again Bob!

Camshafts removed and cam chain secured to frame to avoid falling off bottom wheel teeth.
3073_1526910516813.jpg


Bucket/tappet/follower removed revealing shim on valve assembly.
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Shim removed showing valve assembly only.
3077_1526910538342.jpg


Removed bucket from underneath and shim for reference.
3075_1526910529373.jpg
 
angonemoto said:
[...]We did notice several of the followers seem shimmed pretty tight, as they wouldn't spin by hand. The plan is to recheck after some more miles on the road and determine next steps. [...]

Valve clearance to tight or cam followers with bathtub wear pattern? Neither of them is recommendable for extended use, especially not on open throttle/high loads, at least if you aren't keen on the engine swallowing one of it's valves. ;)
Click to expand...
 
Of course not. I'm very fortunate that the motor has very low run in and test ride time on it and will correct the shims now.

To confirm, seems the gap tolerance I am aiming for on the 4C cams when completely off of the followers are:

Exhaust: .010 (ten thousandths)
Intake:  .008 (eight thousandths)
 
Angonemoto, I have missed somehow the entire page 4 of this thread before answering, seems the other fellows already pointed you to the right direction. Sorry for stashing out another salvo on the valve clearance. Max. figures for the stud torques are 25Nm for the M8 and 35Nm for the M9, threads and washers oiled. On my old soft cheese 1. generation head I stayed below that figures, using 22Nm on the M8 and 32Nm on the M9 studs, works well and no issues with leaking head seal or so.
 
Thanks for the feedback on the torques and no worries, I'm going to get a lot of learning out of this and getting knocked about is part of the process.  :)
 
angonemoto said:
Now that I understand from Red that the cam blocks have lifted the exhaust cams up on that side of the assembly. That wont affect the way I should check the clearance at each lobe bottom to each follower/bucket/tappet, but I wonder why these would be installed in the first place? Could it be the exhaust valve seats within the head have been worked on and are now set in deeper into the head, and raising this cam allows "thicker" shims with a wider size range to continue to be used over time rather than "thinner" ones? 

Even more confusing to me is the exhaust blocks are marked 0.2 and the intake are marked 0.0, which has me thinking the cam shafts are no longer parallel to each other. which shouldnt be a big deal considering the shims will "even things out" when they are set up correctly.
Click to expand...

without knowing your engine I would guess that the reason the exhaust cam has been lifted is because your exhaust shim clearance is in the "low" range, post here what thickness shims you have and all will be clear
if your shims are less than 2.00mm than you have been duded, we aim for a shim thickness of 2.90mm - 3.10mm when we recondition customers engines

Lifting the cam by 0.20mm results in a shim thickness increase of ~0.26mm, change in dimensions due to the angle of the dangle  :D
Is fairly common to find the exhaust shims thinner than the inlet side due to the operating conditions experienced over the last 40 years of the engines life, exhaust valve seats experience more wear

as there has only been one camshaft lifted I would say your cylinder head overall dimension is standard at 94.00mm as in it has not been machined. Being standard thickness means you cannot raise both cams or you have issues joining the cam chain especially if cam chain has been replaced and is new.

Main reason we started to machine the offset cam blocks was so we could regain shim thickness on cylinder heads that have been decked in the past, is not uncommon to find cylinder heads that measure 93.50mm or less, seen a couple down around the 92mm mark FFS.
If the owner does not wish to spend the money for a full valve seat replacement job which is not cheap than option is to install offset cam blocks, we make them in 0.0mm, 0.2mm and 0.4mm

lifting one cam and not the other has no bearing on the engine as it does not really care where the cams are as long as you can join the cam chain
 
That makes total sense and I thank you very much for the explanation.
You are right, just got off the phone with Scott and he validated the head has not been machined, the reason the blocks are in there is to allow for more options in the standard range in future shimming.

I'm especially thankful for the note "Lifting the cam by 0.20mm results in a shim thickness increase of ~0.26mm", which will be helpful for predicting the size of shims to buy, fit and check. I will post the shim sizes that are in there for sure.

Thanks!
 
angonemoto said:
I'm especially thankful for the note "Lifting the cam by 0.20mm results in a shim thickness increase of ~0.26mm", which will be helpful for predicting the size of shims to buy, fit and check. I will post the shim sizes that are in there for sure.

Thanks!
Click to expand...

at this stage the 0.2mm cam blocks have no bearing on your valve shim measurements, my comment only affects the very first time you do the valve shims after installing the offset cam blocks which was back when Scott did the engine.
at this point you know what your valve clearance is as you measured it with a feeler gauge, measure the thickness of the shim in use with a Micrometer, take off the difference, you have your answer
 
Yes, I see your point and like you said it will all be revealed once I get the current cam to bucket  feeler measurements and then the removed shims measured.

 
angonemoto said:
Great information, thanks again.

I was fine leaving the timing set as is prior to this shim situation, but now I think the opportunity to bring those settings closer in to standard is not to be missed. Afterall, I'm not qualified to go exploring the outer reaches of timing and tuning. The 101/103 compromise feels right, so Maurice, what size main jets are you running with your 101 inlet 103 exhaust timing? I'll order them while I go in and figure out what shims I have.

Now that I understand from Red that the cam blocks have lifted the exhaust cams up on that side of the assembly. That wont affect the way I should check the clearance at each lobe bottom to each follower/bucket/tappet, but I wonder why these would be installed in the first place? Could it be the exhaust valve seats within the head have been worked on and are now set in deeper into the head, and raising this cam allows "thicker" shims with a wider size range to continue to be used over time rather than "thinner" ones? 
In 77 Jota the jets are 125 main and 58 pilot

Even more confusing to me is the exhaust blocks are marked 0.2 and the intake are marked 0.0, which has me thinking the cam shafts are no longer parallel to each other. which shouldnt be a big deal considering the shims will "even things out" when they are set up correctly.

As far as cam block torque, I realize that's going to be a critical part of getting this all shimmed correctly alongside the risk of damaging the head. FML. Since published values are known to be inaccurate, any thoughts on safe technique and torque ranges for these studs?

Lastly, IAG Bob Colbert just sent some photos of the process of removing the shims for replacement. I am going to post them here for reference as they have helped me visualize this process specifically to our triple motors, which is a great help. Thanks again Bob!

Camshafts removed and cam chain secured to frame to avoid falling off bottom wheel teeth.
3073_1526910516813.jpg


Bucket/tappet/follower removed revealing shim on valve assembly.
3079_1526910547336.jpg


Shim removed showing valve assembly only.
3077_1526910538342.jpg


Removed bucket from underneath and shim for reference.
3075_1526910529373.jpg
Click to expand...
 
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