College CCT help

[Beamish]

Hopefully someone can help, I am covering the CCT issue for a HNC project, I no longer own a Storm and I am after some CCT measurements.
These are the measurements that are essential but any others would be brilliant.


Thanks in advance

[warby221]

hi Jim got the internals of a CCT if you want them m8 haven't got the body converted them to a set of manuals for some one on here
if you want then pm the address and I'll send them off to you

[Beamish]

Warby,

Thanks mate, I just need the dimensions as I have to create a CAD copy in order to design a solution. The Tutors want a failsafe with an indicator ! B**stards! I think that the best design IMO has to be Chris's with the stopper bar under the plunger head set at X dimension allowing some flexibility, looks like I am going to have to come up with some type of hydro/pneumatic or possibly a ratchet mech on the plunger. Thing is, it has to be done, published, and back at Uni in 5 weeks. Doesnt leave me much time for research. I am no genie with a planetoid for a head and brain to match so it will be tough. Any help would be appreciated.
Stay safe

[ChrisC]

Hi Beamish, let me start by saying "these measurements are taken with a digital caliper bought at Aldi" make of that what you will .The body i make to be 58-85 mm long , 47-75mm wide , the plunger shaft has flats on the sides,the Diameter is 11-95mm and across the flats is 9-90mm the end piece also has flats and is 23-42mm in diameter and 22-40across the flats.Thats as near as i can give you ,If anyone wants to confirm these sizes it would be great. Hope this helps, good luck with the course.

ChrisC

[bazza696]

Hopefully someone can help, I am covering the CCT issue for a HNC project, I no longer own a Storm and I am after some CCT measurements.
These are the measurements that are essential but any others would be brilliant.


Thanks in advance

Email me at bazza696@hotmail.com. and I will type a lengthy explanation on my manual conversion, maybe hand sketch and email.

Never thought of drafting a cct, being a draftsman. Might do that one lunch time.

[Beamish]

Brilliant thanks Chris, and thanks Bazza for your extremely kind offer. Warby has put me on to this idea
http://cdn.cheapcycleparts.com/images/KA/75559.png It fits perfectly with the University's idea of a good mod as I can add a failure indicator pin to the secondary plunger. I will post a copy of the CAD effort after completion. Dont expect anything perfect though as I am no proffesional with this software.
Thanks to evryone who have been helpful.

[Beamish]

This is in my opinion could be the ideal solution to our woes.




The top plunger (primary) sits against the secondary locking plunger. In the event of a primary spring fail the plunger is allowed to act on the secondary. The secondary acts as a lock to prevent full retraction but at the same time pushes out the red indicator pin, that way we would know of the spring failure. Spring rates could easily mimic the OE honda items and the components could be manufactured from light alloys giving a double wammy benefit.
The CAD drawing is just a hypothetical picture, dimensions are close ish and it is early stages so no cut outs or transparency. Thanks for the help.

[bazza696]

If you are redesigning the cct, then could you design it to a length tba the cam chain would not slip over the sprocket, and have a red pin in the end when failure happens gives you tba indication.

This solves two problems, no more mangled valves, and easier to manufacture.

[Beamish]

Yep, that would be a quick ideal solution, I like the idea of the secondary plunger though as it should still allow the original OE chain deflection (post primary spring fail) so the replacement of the primary would not need to be so immediate. The design sort of ticks all the Uni boxes so may be a bit over complicated cheers Bazza.

[warby221]

I know it’s just a representation Jim but the spring on the secondary plunger is on the wrong end
This would actually push the plunger away from the primary

[Beamish]

I know mate, will stick the later photo on, on this photo the secondary is also 20 mm too long, that picture was just an early draft to give me some idea of how it will look.

[Beamish]

Warby i have changed the CAD to more clearly represent the mock up. Yopu should be able to get the drift from the later picture

Like this

[Rider on a Storm]

Just my 2 cents worth but anyway here goes, supplying manual ccts for close to a year now, all reported failures were spring related rite? tensioner design was never the issue, it works fine and you should not have to worry about adjustment if it is a trusted auto tensioner. the fault is in the material used for the spring which breaks at the end of coil, caused by over stressing the wire on such a tight bend and lack of oil. Why then why would you double the chances of failure with 2 springs? the simpliest fix is for Honda to ensure that the chemical properties of the spring wire are to a grade that is not prone to corrision and has the required stress related properties to overcome stresses when formed to the required loop. Its the spring that is the achilles heel of the tennsioner not the function so why why would you try to re-invent the wheel if it already works, dont mean to sound negative but the failure is spring related and re-designing the tensioner for the sake using of better material sounds like a waste of time, Honda will probally agree with this as its easier to make the spring from a better material than changing castings, toolings, forgins or what ever. SP1' SP'2 have overcome this problem and Honda must be aware by now its the grade of material that is used is the problem, not the design, ok now got that off my chest hope no one is offended.

[Rider on a Storm]

Oh btw I dont think Honda will re-design a replacement cct for older models, they might offer upgrades, if honda rely on college grad's to come up with a design I for one will be putting my bike in storage, a multi milion pound industry should be capable of employing a design engineer who has all the necessary qualifications and not offer a student a design change to fix one of their engineers wombles ups, use the correct material, test it, and then use it, if it works you have the test results to prove it, if it fails you improve it until it works, simple, u dont need a collage degree to understand results, ok done now

[tony.mon]

I see what you're saying, Tray, but to be fair the SP1/2 didn't solve the CCT problem, they just used gear-driven cams and so didn't need a tensioner.

Seems to me that Beamish is using a reasonable example of a design fault in practice to base his thesis on a better-designed replacement.

I don't suppose he's going to try to sell his idea to Honda, and even if he was they certainly aren't going to buy it and then retro-fit all of the bikes they've sold already.

There are a number of alternatives which will suitably address the problem- a manual tensioner will do the job but will need to be re-adjusted and tensioned correctly for ever more, a "stopper mod" will prevent the spring failure from allowing slippage of chain over sprocket teeth which is the Achilles heel of the design IMHO, lots of bikes can suffer CCT failure but only a few allow the chain to become so slack that it can jump teeth and so encourage valves to met pistons....

But Beamish's propose solution would alleviate all problems.

TBH, I don't suppose that he'll ever make one apart from for his thesis......or is that the plan, Beamish?