Tough read but necessary regarding the Captain's parts

Posted: Sat Oct 30, 2021 2:29 pm

As I said in the title this is a very unfortunate situation. The initial thread was was moved to the for sale/wanted section (rightly so) but I feel that there may be members out there with parts they already purchased from the Captain's and have not been installed yet (some of our members take awhile assembling their projects.)

I tried to focus this thread on the technical aspects of the parts and not on the pain caused to members by the failures. There are members on this site that are very knowledgeable and you should carefully consider their advice.

If you need to see the original cluster F@#% click here:

https://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=90257&postdays=0&postorder=asc&start=0

So IF you have Captain's parts you are planning to use here is some critical into IMHO:

Captain's heads:

(Paraphrased from Jjam)
Only problem is they are all warped in the cam tunnels. V&H did my head assembly and never said nor noticed the warp. Thats when I found the cam tunnel was warped by .011" with the center being the high spot. I think they are just welded up too fast. The heads that I weld up the combustion chambers in have not warped. I take a whole day to weld them. It's not as profitable a job as it would seem. I know that where these heads are done.

Shift stars / chain guides:

(From Krgood0)
Re shift stars…As f4fast asked if could you have them treated, yes you could provided you knew what material they were made from, but as you would have hoped they would have been made using a process they were going to last for many years of reliable service

Had they been made from high grade tool steel there are grades that a very tough without heat treatment and would have been very durable

When I fitted my first set of Brents guides in 2015 to my CB1100RC engine I did a dry build first with just the crank ,the A chain, the A guide and the Cylinder, Head and head and base gasket I found I could not get the exhaust Cam wheel on so I looked at the cylinder where the rear guide fitted and got to work with my file removing metal from the rear of the cylinder where the guide fits,

It was almost there so I removed the head gasket which was the stock 0.043’’thick and replaced it with some 0.020’’ shim then refitted the head and got the cam wheel on easily, so I had 0.020’’ skimmed from the head the assembled the engine properly and it fitted easily
When I built my second engine in 2016 I used the same method but only had to remove 0.015’’ from the head this time

Both those engines were using the series 1?? front guide I believe

In around 2018 I built an engine for a customer using Brents series 2 front guide and it was a bit tight still so I contacted him and he sent me one of his hot of the press series 3 front guides FOC to try and was a perfect fit

I have built another 3 engines since then using the latest front guide with good results

One thing to bear in mind is if you are using Cruzinimage head gaskets they are quite a bit thicker than the oem and Wiseco 0.043’’ gaskets so it may cause you a problem, I always now use Wiseco gaskets with the Cruzin piston sets as the cruzin gaskets are a poor fit anyway
All the engines I have built have been using the OEM 0.020’’ base gasket

Now on to the B guide, my experience of fitting the first one was on a 900 461 and I needed to have around 0.040’’ machined from the boss in the head to get the required slack in with a new B chain from Brent

The second I fitted was to a MA3 CB1100R head, I had a genuine OEM B chain that was pre stretched that had done approx. 3000 miles in another of my engines, this fitted perfectly with no machining of the head, when I measured the depth of boss on the MA3 head against a spare unmachined 461 head on the MA3 head the boss was lower on than the 461 head which indicates not all heads are the same in that area

And Jim is correct that for most of the engines that are not revved too high the stock guides are adequate especially as the CB750/900 ones are still available, the main reason I have used Brents in a few engine’s as I have had no decent MA3/MG5 ones to use

If using the stock guides it would be important to adjust the guide on a regular basis to stop the chain running slack

Lightened crankshaft:

(Paraphrased from Jjam)
Broke a brand new primary chain from Brent after one race. Built the engine again with a stock crank and it has no issues. Darrin won on the bike just yesterday. Something else Darrin and I noticed was. When we started the engine with the POS "Supercrank best on the planet". The engine sounded like an old worn out one with a worn primary chain, hard primary rubbers and hard clutch rubbers. You know the rattle sound they make. I didn't know what to do because everything in the engine was brand new and supposedly "The Best you can buy" all from Brent.

When we started this new engine with the stock crank in it. The 1st thing Darrin says is "listen to how quite it is" further proof that it's just too light and will destroy a primary chain in no time.

(from petrat)
From my perspective, especially early on in the availability of these components (specifically the front guide, B-chain tensioner, and rear tensioner), it became apparent to me that the inherent variabilities between each DOHC engine (e.g. differences in deck heights, casting flash, previous engine modifications, etc.) would cause some issues (or not) with installing these components, and therefore never put myself into a position where I simply became a re-seller who allowed buyers (who may not appreciate the significance of these variables) to install them. Both Jim and Keith have installed enough of these that they too have found these variabilities BUT have the knowledge and capability to deal with them on the spot (some more challenging then others). Not everyone has the ability (sorry) or resources to deal with them and so of course there will be issues reported. I think only once out of maybe 7 sets I've installed have I never had to modify or adjust anything to install them. To me it was just part of the game and was willing to go that distance to ensure they were installed to what I felt was correct. I've also never had any customer report back of any issues (failures or wear), and several have removed their sumps (at my request) just to report back on what they saw. I've only built one race dedicated engine (that will be campaigned around some NZ circuits soon) and so will see what happens then. My customer has a race mechanic to look after his bike to make sure the tensioners and chains stay within spec before each race weekend, so fingers crossed. I'm to assume that the latest versions of the guides and tensioners might tolerate some of these variabilities and make them "a bit more" plug and play, but I expect some issues will still need to be addressed. Seems like most need the casting flash removed (down inside the A-chain tunnel) so it doesn't interfere with the operation of the rear tensioner.

(My addition in that thread)

I installed the Captains tensioner with a stock front guide in one 1100 engine. It was a real problem getting the cam gear onto exhaust cam. (I know where you are and I am watching you.....!) You use must use the Captains tensioner & guide as a set (or stock with stock.) Furthermore IF YOU USE the Captin's parts You MUST ...... emphasis on must .... degree the cams. Period. The bulge on the bottom of the front guide pulls the cams forward a significant amount (sorry but I never installed a stock exhaust sprocket and degreed the cam with Captain's stuff but it is significant / possibly a worn & stretched chain would tolerate it but why would you build an engine with a suspect chain.) When using the captains parts I don't bother slotting the cam gears in any direction other than what is needed to rotate the cam anti-clockwise.

Posted: Sat Oct 30, 2021 3:59 pm

I am running Brent's A tensioner set with all CruizinImage parts on my 1123 build and had no problem installing the exhaust cam. I didn't bother with the B Tensioner but just installed an NOS one. No cam degreeing was needed at all as everything lined up.

Posted: Sun Oct 31, 2021 1:58 pm

In response to my observation about the Captain's front / long / A guide it is simple mechanics supported by more than a few engines assembled as part of my friends and family plan. The Captain's front guide has a bulge on the bottom, this bulge (if you believe in the hype) takes a high RPM oscillation / chain whip out of the equation thereby retaining more accurate cam timing. If you wrap a string around two two round things and deflect one of the strings the two round things will move towards each other. If you attach a cam chain to a crankshaft and a camshaft and push the front in the cam will rotate counter clockwise when viewed from the ignition end of the crank (the crank does not move due to the added resistance of 9 bearings plus the piston to cylinder resistance.)

Two factors are required to consider when altering cam timing (1) valve tip to valve tip contact which in this case is not a concern since you have moved both the intake and exhaust cam equally in relation to the crankshaft (unless you use the Captain's B tensioner which would then alter the relationship between the two cams.) ... and ... (2) Valve to piston (top) clearance which may not be an issue in applications using stock pistons and Cruzin Image pistons since the compression ratio is a relatively low 9.71 to 1. If you install Wiesco 11 to 1 pistons you need to know what the piston to valve clearance is.

In a 4 stroke engine the piston is coming up on the exhaust stroke pushing the spent gases out. The exhaust valve continues to stay open past top dead center utilizing the cavitation effect of the exhaust header to suck the rest of the spent gas out of the cylinder. Before the exhaust valve closes the intake valve is beginning to open leading to a period of "camshaft (valve) overlap." This is an intentional design feature of the camshafts which when combined with intake and exhaust flow, valve lift and valve timing cause a specific powerband.

Enough theory (I hope this helps people understand what is happening in your engine.) Building engines with non-stock parts requires attention to detail, the purchase of a degree wheel and dial indicator is less then the purchase price of the Captain's parts and way less than the price of a replacement engine if you guess wrong.

So I guess I overstated my position by saying "must" ... my ignorance was caused by never assembling an engine without degreeing the cams combined with the surprising amount of slotting the cam gears needed to bring the cams back to the factory secs of 100 Intake / 105 Exhaust lobe center numbers @ .050 lift. when using the Captains A guide and tensioner.

A few years ago I created a cam degreeing thread. I left it intact with my stupidity of mis-reading the dial indicator I have used for years (I was enduring a cranial-rectal inversion situation at the time.) The simple beauty of Sonicrete calling me an idiot in his own special way makes that worth a read even if you don't degree cams... I miss him and the world is lacking since he died.

https://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=61228&postdays=0&postorder=asc&start=0

Posted: Mon Nov 01, 2021 1:11 am

I've never had my hands on one of the curved tensioners but pushing in on the chain would indeed advance the valve timing. However, the 'push' from the curved guide seems to be pretty minimal and I'm thinking the timing would would be advanced only fractions of a degree. I actually asked this very question about the 'new' curved guides and was promptly shit upon by the V&H fan boys. In any case, surely any valve timing advance due to the use of a curved guide isn't going to be much worse in comparison to the delay introduced by cam chain stretch as a motor ages.

Begs the question: did Honda design optimal valve timing for a motor with a new chain or a chain that was past it's 'initial' stretch period? In any case, it's seems there's a window of valve timing over-which the motor can run with acceptable performance ('acceptable performance' ≠ maximum performance). Does the use of a curved guide put the valve timing outside of that window? Anecdotal evidence by users here would suggest it does not.

As far as new vs old cam chains: there was a feeling (perhaps even consensus?) among F'ers at one time that even an old stretched cam chain was a better option than the (then) available new cam chains. Who knows if new chains we see today from V&H (and others, it seems) are any better than the originals or their supposed shitty replacements.

Posted: Mon Nov 01, 2021 1:31 am

The silence from NZ is deafening...

Posted: Mon Nov 01, 2021 5:08 am

The front guide matches the tensioner curve in these tensioners. As long as the markings line up, crank TDC, cam marks, everything should be fine.

Posted: Mon Nov 01, 2021 4:22 pm

cliffiec wrote:

The silence from NZ is deafening...

We’ll never hear from him. A narcissist just can’t face up once they have been discovered.

The only time he’ll surface is when and if he gets a crank to work with his sloppy gear drive. I’m sure he’ll succeed but not until he has spent thousands and thousands.

Another something I know about his stuff.

In one of our last conversations. I asked what was going on with his latest greatest crankshafts. You know the ones that got copper coated for the carburization process.
He told me one of them was cracked straight out of the oven. This made sense to me and didn’t shock me at all. I didn’t tell him what I had learned.
My buddy Keith had shown the picture Brent showed of the copper looking crank to the owner of Marine Crankshaft. The guy laughed and said “wow” those Kiwis are stuck in the Stone Age. We stopped using that material and process decades ago because if you made 10 cranks. Three or more would be cracked due to the extreme heat used to do the carburization process.

That can get pretty pricey at the 6 to 10K per crankshaft that Brent thought they were going to cost him.

Have a great week everyone. Jim

Posted: Mon Nov 01, 2021 7:43 pm

1337 wrote:

The front guide matches the tensioner curve in these tensioners. As long as the markings line up, crank TDC, cam marks, everything should be fine.

The amount chain 'slack' taken up by the tensioner has no impact on Valve timing (except for the fact that more 'slack' means the chain has stretched - which does impact timing) while the curve introduced by a curved guide (in a motor not originally equipped with a curved guide) does affect valve timing (but I'm thinking it's pretty minimal).

Posted: Tue Nov 02, 2021 2:28 am

I'm confused. Who is having issues with his cam chain tensioners failing? I know some have had trouble installing them but these are old cast heads with a pretty wide margin of manufactured tolerances. I'm pretty sure it's been stated many times that the head may have to be milled or the base gasket removed, or whatever, to allow for more slack. I dont think I've heard of any failures since the material was corrected 10 years ago.

Posted: Tue Nov 02, 2021 8:21 am

nathanhouse wrote:

I'm pretty sure it's been stated many times that the head may have to be milled or the base gasket removed, or whatever, to allow for more slack.

I suggested on Facebook that fitment of the V&H guide, and or tensioner, might required some head or barrel work and was promptly roasted by V&H who stated no modifications were necessary.

Posted: Tue Nov 02, 2021 9:34 am

btw. there are 'Installation Instructions' for the V&H ''B’ Cam Chain Tensioner' and 'Racing Curved Guide &
AHM Cam Chain Tensioner' out there. These documents cover the casting variations as well.

regards Kurt

Posted: Tue Nov 02, 2021 10:34 am

k3po wrote:

btw. there are 'Installation Instructions' for the V&H ''B’ Cam Chain Tensioner' and 'Racing Curved Guide &
AHM Cam Chain Tensioner' out there. These documents cover the casting variations as well.

regards Kurt

Right, Brent put together a pretty nice pdf and jim did a nice write up as well. So the main thing I've been reading regarding cam tensioners of any sort is that people have struggled to fit them or Brent rubbed them the wrong way for one reason or another. Cam chain failures and tensioner failures is what I keep hearing alluded to though.

Posted: Tue Nov 02, 2021 3:56 pm

nathanhouse wrote:

k3po wrote:

btw. there are 'Installation Instructions' for the V&H ''B’ Cam Chain Tensioner' and 'Racing Curved Guide &
AHM Cam Chain Tensioner' out there. These documents cover the casting variations as well.

regards Kurt

Right, Brent put together a pretty nice pdf and jim did a nice write up as well. So the main thing I've been reading regarding cam tensioners of any sort is that people have struggled to fit them or Brent rubbed them the wrong way for one reason or another. Cam chain failures and tensioner failures is what I keep hearing alluded to though.

The instructions do not cover the casting variations for the b tensioner. It reads " in very rare instances you might have to remove 1 or 2 mm" from the mounting boss. We removed 4.5 mm (.180") from the head I installed it in and still did not have enough slack in the chain for the cams to even seat into the cam journals. To remove more from the head would have entailed taking much more material from around the boss than we were comfortable with removing ( my brother was doing the machine work. He is a very accomplished machinist.). I then tried to contact Brent and never did hear back from him. My brother then wrote a quick program to remove 2 mm (.080") from the curvature of the tensioner. That allowed it to fit correctly. After discussing this with Jim and a few other members here I found that this is common with the 1000c heads which Brent has not had any exposure to. That does not excuse the absolute silence I received in response to my questions. No follow up, just silence.

Posted: Tue Nov 02, 2021 4:38 pm

Ok, so again, some folks are having issues with his communications but his chain tensioners aren't failing. Granted you had to modify yours. I dont think I have a 1000cc head to compare to the others to see what the difference is. Seems weird for Honda to change something like the bolt boss thonkness but I've seen OEM manufacturers make changes like that before. I've only fit maybe four B tensioners but they all went real smooth. Clearanced the side a bit to allow for the rivet on the tensioner to have some room and milled the bolt boss down around 2mm on all of them give or take.

Posted: Wed Nov 03, 2021 2:35 pm

nathanhouse wrote:

I dont think I have a 1000cc head to compare to the others to see what the difference is. Seems weird for Honda to change something like the bolt boss thonkness but I've seen OEM manufacturers make changes like that before. I've only fit maybe four B tensioners but they all went real smooth. Clearanced the side a bit to allow for the rivet on the tensioner to have some room and milled the bolt boss down around 2mm on all of them give or take.

The one I recently installed on a 1000C head did not require any mod at all except to remove some material (on the head "around" the mounting surface) to get the hole in the tensioner mounting tab to align with the threaded hole on the head and to sit flush.

Posted: Wed Nov 03, 2021 5:46 pm

petrat wrote:

nathanhouse wrote:

I dont think I have a 1000cc head to compare to the others to see what the difference is. Seems weird for Honda to change something like the bolt boss thonkness but I've seen OEM manufacturers make changes like that before. I've only fit maybe four B tensioners but they all went real smooth. Clearanced the side a bit to allow for the rivet on the tensioner to have some room and milled the bolt boss down around 2mm on all of them give or take.

The one I recently installed on a 1000C head did not require any mod at all except to remove some material (on the head "around" the mounting surface) to get the hole in the tensioner mounting tab to align with the threaded hole on the head and to sit flush.

I've seen some pretty big differences between OEM manufacturers. I think I've told this story before but I was building a Ford Winsor V8 once and there was a .017" difference from one deck to the other Shocked

that's a huge amount! I dont think this happens too much anymore bc of the processes and equipment used. It honestly wouldnt surprise me if there was a 3mm differences in bolt boss thickness on an engine from 40 years ago.

Posted: Wed Nov 03, 2021 7:37 pm

nathanhouse wrote:

petrat wrote:

nathanhouse wrote:

I dont think I have a 1000cc head to compare to the others to see what the difference is. Seems weird for Honda to change something like the bolt boss thonkness but I've seen OEM manufacturers make changes like that before. I've only fit maybe four B tensioners but they all went real smooth. Clearanced the side a bit to allow for the rivet on the tensioner to have some room and milled the bolt boss down around 2mm on all of them give or take.

The one I recently installed on a 1000C head did not require any mod at all except to remove some material (on the head "around" the mounting surface) to get the hole in the tensioner mounting tab to align with the threaded hole on the head and to sit flush.

I've seen some pretty big differences between OEM manufacturers. I think I've told this story before but I was building a Ford Winsor V8 once and there was a .017" difference from one deck to the other Shocked

that's a huge amount! I dont think this happens too much anymore bc of the processes and equipment used. It honestly wouldnt surprise me if there was a 3mm differences in bolt boss thickness on an engine from 40 years ago.

After we got the b tensioner in I measured every type of head I have from the top of the mounting boss to the parting line of the cam journals. I have 750 (425) heads, 438 and 461 (900) heads, 1000c (MA3) heads and an 1100 (MA5) head. They all measured 66.7 mm's if I remember correctly. I know this is not the only critical distance (cam spacing center to center, position of lockdown rod hole) but I was suprised by the consistency considering all the talk of the manufacturing differences.