Cam Chain Tensioner Gasket, and UNI Pods

[Firehawk068]

With the Central Rally about a month away, I figured I'd better get to work!

Since my Cam-chain tensioner gasket has been leaking oil all over the back of my engine for about a year now, I think it's about time to replace it.
Doing that involves removing the fuel tank, the air-box, and the carbs. I figured it was a good time to swap over to UNI pods.

Ditching the factory air-box means I will have to relocate my aux fuse panel, since it's mounted to the intake trumpet.



It was fairly filthy at the air inlet of the air-box.



I know there are a bunch of folks who dislike K&N filters, but mine always seem to work really well.
The carb throats are pretty darn clean!



The intake ports are pretty clean as well.



I decided to mount my aux fuse panel to the side of the battery box. (I double-checked that the screws aren't long enough to come close to the battery)



Now is also the perfect time to replace the vacuum caps with the correct ones I purchased from Randy.





Once the carbs are set aside, out of the way, I can access the cam chain tensioner.
I am pretty sure the mounting gasket is the culprit for my oil leak.







I had planned on using this. I figured I have to do some scraping to get the old gasket off of there.
As soon as I touched it, the whole gasket just fell off.



To remove the tensioner, I unscrewed the center bolt that holds the spring (there's a copper washer under it), then removed the two metric socket-head screws.



To reinstall it, I disengaged the ratchet mechanism and pushed the plunger all the way in.
Then bolt it onto the engine with a new gasket, then install the spring (with spacer) and holding bolt, with a new copper washer.
I could hear the tensioner ratchet into place as I pushed the spring inside.



Once you remove the factory air-box, if you take a close look at the rubber boots that attach it to the carb throats, you can see that they are actually velocity-stacks that extend into the air-box.
I pulled one out to measure the length.
They are a little over 3 inches long.



A whole bunch of folks have put UNI-pods, or other similar filter-pods directly clamped onto the carb throats.
I haven't seen or heard of anyone replacing the velocity-stacks when doing this conversion.  I am unsure if this is even necessary? 
A few people who have done the pods have chimed-in that they may have developed a stumble at certain engine loads or rpm, but there's no proof whatsoever that this might be caused by removing the velocity-stacks? It's just something I remember reading about.

It got me thinking.    It should be really easy to fabricate some sort of velocity-stack, and then mount the UNI-pods onto that. 

I started by measuring the outside diameter of the carb throat.
It is just a tick past 2-1/8 inches.



I sourced a 2-foot length of 2-1/8"OD exhaust tubing, a 1-foot piece of fuel filler-neck hose, and 4 additional clamps that I would need. (I already had 4 extra clamps in the garage, and the UNI-pods come with 4 clamps)



Using my sawz-all, I cut the exhaust tubing into 3-1/2 inch sections.



I used fuel filler-neck hose so it wouldn't degrade from any fuel vapors. (I originally thought about using radiator hose)



Total cost from Napa, $23.69



After a quick run of the edges on the bench grinder, then the wire wheel to remove any burrs or sharp bits, I wiped and rinsed them out with brake-cleaner to get rid of any metal dust.

A quick shot of primer, and some semi-gloss black that I had laying around the garage.





While I was waiting for the paint to dry, I moved on to cutting the hose for the intake couplers.



Then it was time to address the crankcase breather.
I raided my stash-box of scrap hose, and found a piece of 1/2" emission hose.





When I pulled the old breather hose off the engine, the fitting came out with it.  A little red lok-tite on it and tapped it back in it's hole.

I have (2) of these breathers sitting in a cabinet in my garage. I bought them on clearance a couple years ago, and didn't really have a use for them. (until now )



I used some fittings from my brass-fittings stash of drawers, to adapt the 1/2" crankcase hose to the 3/8" breather.



I set that aside until I knew exactly where the pods would end up.

Next step was clamping on the velocity-stacks.
I angled them upward slightly, so the pods would clear the sub-frame tubes.



Then the pods got a good oiling!



After using some brake-cleaner to get the oil off the rubber boots, I clamped them all into place.


I used a cushion-clamp, and a nut and bolt to attach the breather using the top hole for the factory air-box.







I'll monitor it on a regular basis to see it I get any oil vapor condensing, and dripping out of it.

Fuel Tank bolted back in place, ready for side-panels, seat, and a test-ride! 
One thing I noticed, is that I can now access my fuel petcock without lifting the tank!



Just before I put the bodywork back in place, I installed a new one of these.(my old one was not fused)



After taking her on an hour test-ride, I didn't notice there was anything different about the way the engine runs or responds. (this is a good thing)

I did however notice the intake noise. It is quite loud, and will take me some time to get used to it. (I'm not sure if I'm going to like it or not)
When you hit the kookaloo zone, it really HOWLS!

I'm going to keep an eye on my fuel mileage also, to see if I notice any change.

The velocity-stacks may have been overkill, and they are probably not required, but the factory put some on there so I figure I'll run them for awhile.
They didn't cost hardly much $$, and were easy to make.

Next-up..................Tires! 

[X-Ray]

Great report with clear pics, thanks Alan. I have no experience with the stacks (benefits wise), but certainly can't see any harm in it. 

[Bones]

Good job Alan, a bit of thinking outside of the square there. You can do your own experiments now between the two to see if there actually is a difference with the stacks or not.

When I put the uni pods on mine,  I didn't at first notice any change in how it ran, mainly because I was getting up it all the time just to hear the induction roar, but once I settled down and rode sedately I noticed a little bit of jerking while cruising at low revs and it felt a bit flat accelerating from there, so I pulled the slides out and lowered the clip a notch to raise the needle and make it a bit richer and it seems to have fixed it.

One disadvantage I can see doing it your way is you've lost the extra space where the airbox was in case you wanted to mount anything there in its place, but that's purely up to the individual if they do or not.

                                                              Tony.

[FJ1100mjk]

With the Central Rally about a month away, I figured I'd better get to work!

I hear that. I took my swingarm off yesterday to clean and lube pivot points, and found the shock shaft seal is leaking. Good thing I went in there.

Nice write up, and with all of the pics too, to highlight all of your work. I smiled when I saw your stash box of hose and tubing. I have one of those too  I figure anyone that works on a lot of things, has one of those.

What engine is that that is in the upper portion of your first pic, above the carbs?

[ribbert]

Alan, I can feel the 'incoming" already and may regret venturing an opinion on this but think it is reasonable to have a say before this becomes the next "mod du jour"
I see it as simply having an opinion of what you've done, no doubt some will see as deriding your efforts, that is not the case.

There is a difference between velocity stacks and air filter spacers, you have made the latter.
Gas flow, in and out, in an IC engine is at the pointy end of achieving efficiency (power). I would think the original manifolds extending into the airbox was simply to position the opening in less turbulent air.

A velocity stack is a finely tuned part of the engine and deals with a number of very techy things that are not worth going into as the gains are at best somewhere around a couple of percent, good if you are racing and chasing down every last whisker of power but not much use on the road with so many other factors on an old bike that are running at less than 100%.

However, one very basic function of them is improving the lamina flow of the air, or smoothing it out. The essential element of the stack for this to happen is is the 'trumpet' end.
Technically, what you have done may even be less efficient than the original air box in terms of smooth air flow because of the abrupt inlet. The trumpet end smooths this out.



Many modern bikes in fact have a trumpet end on the manifold where it fits into the airbox, rather than have it protrude into the box.



The bottom line however is you will probably notice no difference other than losing the space the removal of the air box frees up.

As far as pods causing stumbles, surges, flat spots or whatever - it has not been my experience and there is no reason why it would if the carbs are adjusted accordingly.
I don't believe what you have done has any downside, but equally, I don't believe it offers any benefit.

The workmanship, ingenuity and (my favourite) the recycling from your stash box, is first class, but I don't believe there is any advantage in efficiency in what you have done.

This of course is only my opinion and if history repeats itself, will be dismissed immediately on that basis alone.

Usual Disclaimer.....

The induction noise actually hurts my ears at full throttle and lots revs. I decided this was not a bad thing as it kept me off the throttle around town and I always wear ear plugs on the road, but heck, it sounds nice.

As someone lucky enough to ride all year round, put in big day rides and do up 4 or 5 trips a year, I can tell you, all this worrying and over thinking that goes on in the garage building up to a ride, is never given another thought when you are out on the road.
I went away last weekend and rode 3 dawn to dusk 10 hour days. Before leaving I was worried about all sorts of things, the carb sych I never got around to after having them in pieces, some dodgy wiring I didn't have time to fix, the fuel pump that needs a rap with a hammer to stir it into life if it hasn't been started for a few weeks, the uni pods I didn't wring out properly, The rear wheel (and new tyre) that only got an eyeball alignment, no chance to re check chain tension, seeing if the new bracket for my chain oiler nozzles would hold their position, what have I left loose and many other things that had been fiddled with, removed, replaced and no time for a shakedown ride, not even around the block.
I was convinced worrying about some of these things would spoil my ride.

Do you know how much time I spent worrying about them once I hit the road or over the next 3 days? not a moment!

Just get out and ride it. The longer it sits in the garage unridden, the more you fixate on things that aren't worth worrying about.

Noel

[mark1969]

Just get out and ride it. The longer it sits in the garage unridden, the more you fixate on things that aren't worth worrying about.

Great advice that I too will be taking..!

[movenon]

Good write up Alan.  Nice to experiment that's how we learn.  I don't think there is any harm in real terms and who knows there might be something yet discovered.  Like intaking cooler air?  Remember the old "Ram Induction" intakes in the old Plymouths, Dodges, Chrysler 300F's . "Sonoramic Commando Power" http://www.simplexco.com/auto/ramply/ramply1.html http://www.allpar.com/corporate/bios/weertman-chron.html.  Heck even my Dodge Diesel has "Ram induction"  

I don't notice to much induction noise from my POD's.  It is there but not overwhelming.  But I have some hearing loss because of age and past work related events most of it is high pitched loss. (some of it is around my lovely wife's voice frequency it seems  )

I am impressed on how clean your carb intakes were. Testimony to your excellent maintenance.

Hope you can give us a test report after you get some miles on it. How are your carbs set up ? I know you are a slightly higher altitude than most of us.  

And yes the rally dates are closing in on us . Spent some time last night plotting a route from here to there.

George

[Firehawk068]

What engine is that that is in the upper portion of your first pic, above the carbs?

It is a BSA A50 (500cc) twin. I am unsure of exactly what vintage the engine is, but the frame I have is 1965. 
That is a project for another time.

[Firehawk068]

Many modern bikes in fact have a trumpet end on the manifold where it fits into the airbox, rather than have it protrude into the box.



The induction noise actually hurts my ears at full throttle and lots revs. I decided this was not a bad thing as it kept me off the throttle around town and I always wear ear plugs on the road, but heck, it sounds nice.

The factory extensions that are inside the air-box don't really have this flared-out "Trumpet" end on them.  They are pretty much a straight shot in from the end.

Like you stated, they may just be there to move the air pick-up point to further inside the air-box.

I am probably wrong in calling them "velocity-stacks", and as such am not really interested in the benefit of a top-end power increase, as I rarely ride in that range.
The main effect I was shooting for was an overall intake runner length, and getting it close to what the factory length is.

Without going into extensive detail here, engine characteristics (and what they are designed, and tuned for)  respond in certain ways to changes in intake runner length.
I'll use a V8 performance engine as an example, as that's what I'm most familiar with.
If you design, build, and tune it for mostly high-rpm track use, you would tend to use a "Single-Plane" intake manifold. It uses very short runners, basically the shortest possible route from the plenum to the intake ports.
If you want to use your built engine more for street use, and want better low-end drivability, you would use a "Dual-Plane" intake manifold. It has much longer intake runners, and usually allows the engine's power to occur lower in the rpm range.

Anyway, without over-thinking it, that's kinda where my head was at.
I was mainly trying to get the overall intake length close to what the engine was designed with.
My hope was that low and mid rpm usage wouldn't suffer any by changing to the UNI-pods, as that's where most of my riding occurs.


I do value your opinion, and I know that you have years and years of experience.

It is possible that I ended up going the wrong way with this, and I end up taking it off. 
It was very inexpensive for me to do, and I was curious that no-one else had ever seemed to try it.  (there might be a reason for that)

And you are right. The intake noise at full throttle, on the top-end is getting into pain territory. 

[Firehawk068]

As far as losing space under there by adding additional length to the air intake?

I still have all this extra space that was taken up by the factory box.





I can get both hands in there now. (and my hands are fairly large)

I didn't really have any plans to mount anything under there anyway, as it would have to be fairly heat-resistant.

Good write up Alan.  Nice to experiment that's how we learn.  I don't think there is any harm in real terms and who knows there might be something yet discovered.  Like intaking cooler air?  Remember the old "Ram Induction" intakes in the old Plymouths, Dodges, Chrysler 300F's . "Sonoramic Commando Power" http://www.simplexco.com/auto/ramply/ramply1.html http://www.allpar.com/corporate/bios/weertman-chron.html.  Heck even my Dodge Diesel has "Ram induction" 

I don't notice to much induction noise from my POD's.  It is there but not overwhelming.  But I have some hearing loss because of age and past work related events most of it is high pitched loss. (some of it is around my lovely wife's voice frequency it seems  )

I am impressed on how clean your carb intakes were. Testimony to your excellent maintenance.

Hope you can give us a test report after you get some miles on it. How are your carbs set up ? I know you are a slightly higher altitude than most of us. 

And yes the rally dates are closing in on us . Spent some time last night plotting a route from here to there.

George

I don't have any changes to the carbs from stock. (other than removing the factory plugs that cover the low-speed mixture screws)
They are as they came right out of the box.
I think they work well at the altitudes I normally ride at  (5,000-10,000 feet mostly)
If I still lived at a more air-friendly altitude, I would consider changing some of the jetting.


Those old Cross-Ram intakes on the Dodges and Plymouths sure had some crazy long intake runners. I bet those engines had some awesome low-end grunt!

A friend of mine back in NY, (who has more going on inside his head than anyone I have ever met) once did a study on the sound-wave pulses, that travel back through the engine, and their effects on intake efficiency of an engine.............I always told him he was crazy, but I'm certain he is a genius way beyond my ability.

Anyway, I'm looking forward to getting away to the Central Rally to see all you guys again. 

[Pat Conlon]

Hey Alan, interesting experiment and easily reversible to compare power characteristics.

If I may, a suggestion is to move that crankcase breather filter to directly under the foam element of your UniPod.
Sitting at a stop light at idle, most of the blow by gasses (not all) will be gobbled up and recirculated thru your engine.
The stink will be lessened.

Is it rally time yet?

[Firehawk068]

Hey Alan, interesting experiment and easily reversible to compare power characteristics.

If I may, a suggestion is to move that crankcase breather filter to directly under the foam element of your UniPod.
Sitting at a stop light at idle, most of the blow by gasses (not all) will be gobbled up and recirculated thru your engine.
The stink will be lessened.

Is it rally time yet?

You know, I actually thought about drilling a hole in one of the extensions I made, and threading in a tube nipple.
I could attach the breather hose directly to that. But then I thought about all the crankcase vapors getting sucked into only one cylinder. (Do these engines generate a lot of crankcase gasses?)

As it sits right now, the breather sits directly behind the pod for cylinders 1 and 2, so I'm hoping any vapors get sucked into there.

[Mark Olson]

Looks good Alan, with the extenders on now you could have used the k&n filters .

Great write up and please do a test without them to see if it does make a difference .

[Pat Conlon]

(Do these engines generate a lot of crankcase gasses?)

As it sits right now, the breather sits directly behind the pod for cylinders 1 and 2, so I'm hoping any vapors get sucked into there.

I wouldn't say a lot....but yes, on a heat soaked engine you will smell it when you stop at a signal...lift up your visor, you'll see...
Our air cooled engines run larger cylinder wall clearances (vs. water cooled engines) to account for expansion.

I found that placing the breather filter in front of the Uni foam was not effective. At idle there was not enough vacuum to pull the gasses thru the filter into the carbs...and the crankcase gas rises.
Putting the breather filter under the pod filters worked better, not perfect, but better.

I like your idea of the sleeves, not for tuning reasons, but with some shorter tubes you could drill and tap for 4 ports to run the crankcase gases into..... I'm not worried about the carbs getting dirty from ingesting the oil mist, that's the way the oem air boxes are set up, except the oil mist enters the oem air box in front of the panel filter.

The smell annoys me.

[Arnie]

Great suggestion Pat.  I'll do that today.
Arnie

If I may, a suggestion is to move that crankcase breather filter to directly under the foam element of your UniPod.
Sitting at a stop light at idle, most of the blow by gasses (not all) will be gobbled up and recirculated thru your engine.
The stink will be lessened.

Is it rally time yet?