Griffon chaincases

[Dick F]

Hi can anyone out there give a reason, and a remedy as to why the griffon chaincase gets ground away on the back !! the chain is the correct one,
and the wheel is in line.

Would fitting a chain tensioner close up to the front of the swinging arm help.

Rob (No comments please I know what you will say) he has a pile of them anyway looking the same.

I am sure Dave Harper, Greg Radley, Adrian etc must have got over this .

Dick F

[Bearingman]

Hi can anyone out there give a reason, and a remedy as to why the griffon chaincase gets ground away on the back !! the chain is the correct one,
and the wheel is in line.

Would fitting a chain tensioner close up to the front of the swinging arm help.

Rob (No comments please I know what you will say) he has a pile of them anyway looking the same.

I am sure Dave Harper, Greg Radley, Adrian etc must have got over this .

Dick F

Hi Dick,

Don't be confused... The stock Reynolds chain were pretty narrow, when new chains were to be installed for a new race, a lot guys purchased any brand 520 chain, but most of the other chain manufacturers (Japan) used thicker sidebars of the chain than Reynolds did, hence the rubbing on the inner chain case and in some cases, the chain rubbing against the frame...most of the Griffon's here in the states are worn in these two areas. So when you purchase a new chain, check the the width of the chain first before laying down your hard earned money.

The best chain I could find over here in a narrow width and with good strength was Diamond chain...I think RK makes a narrow type.

I hope this helps.

Regards,
Kenny Sykes
USA

[mudmonkey]

chain cases

hi all

i fit a chain tensioner mounted to the foot peg subframe cross tube.
ive made mine from scratch as i haven't found one that just 'bolts on'.
also fitted a proper chain guide in front of the rear sprocket.

it saves the inner part of the frame, front part of the swing arm & haven't had a chain come off all year.

it looks like there is room to take a wider chain but.....do you need a wider chain ???.... after every meeting i remove the chain, wash in petrol & 'cook' in a old fashion pot of chain wax. im a big lump, fairly quick & my standard width chain has lasted me all season.... but it is a very good quality chain in the 1st place

know what you mean about the inner case, been looking for a good one for ages, just cant find one anywhere !!!!

david
265

[druid]

There's not much holding the chaincase on bcause its not a structural item. When the bike gets laid down on the left hand side there is a tendency for the chaincases to bend (cast from softish LM6) especially at the rear towards the chain. Unfortunately they stay bent and don't spring back. This reduces the minimal clearance even more and helps cause the rubbing.
Both Kenny and mudmonkey are right though.

Druid

[mudmonkey]

chain case

yeap druid is spot on..

the inner case's get bent somehow & stay bent...causing the primary chain & clutch adjuster bolt/nut to rub the inside of the case.
the rear chain then rubs away the back park.

ive tried to repair the inners cases before but as the cool the distort badly, my poor alloy welding probably ha ha !!!

ive even considered making them from mild steel but now druid has opened my eyes to the bending issue i probably wont bother.. don't want the crank case cracked as well is the chain case get a side impact

ive heard a whisper that a certain greeves specialist is having some new inner cases cast......

david

[John Wakefield]

Chains

"The stock Reynolds chain were pretty narrow, when new chains were to be installed for a new race, a lot guys purchased any brand 520 chain, but most of the other chain manufacturers (Japan) used thicker sidebars of the chain than Reynolds did"

I think this can be a problem on other bikes including roadsters. The new wider DID chain on my 25DC just rubs slightly against the gearbox casting (speedo drive protrusion) Not enough to case a problem but worth noting.

[stormer254]

Just look at the back of a Stormer or Starmaker chain case or even a Goldstar ,nothing to do with all that mud getting dragged round the sprocket Probably the biggest design fault on British bikes

[Dick F]

RE the Griffon chain problem

[
Hi all that have replied to my question,


The answer is like you all say. due to several points contributing to the problem, thanks very much to all Dicky

[Bearingman]

hi all

i fit a chain tensioner mounted to the foot peg subframe cross tube.
ive made mine from scratch as i haven't found one that just 'bolts on'.
also fitted a proper chain guide in front of the rear sprocket.

it saves the inner part of the frame, front part of the swing arm & haven't had a chain come off all year.

it looks like there is room to take a wider chain but.....do you need a wider chain ???.... after every meeting i remove the chain, wash in petrol & 'cook' in a old fashion pot of chain wax. im a big lump, fairly quick & my standard width chain has lasted me all season.... but it is a very good quality chain in the 1st place

know what you mean about the inner case, been looking for a good one for ages, just cant find one anywhere !!!!

david
265

Hi David,

I use a piece of UHMW (teflon bearing material) fitted to the inside of the stock chain guide and this seems to help as well...and still looks stock, which I like.

Druid nailed it again, I know the primary cases are pretty flimsy as well, and this makes complete sense... maybe I can come up with something to make my primary case more rigid...thanks Druid!

Most off the Griffons I picked up were used in the Southwest desert, wider chains were installed...the chain will also hit the shock springs when using gas shocks mounted upside down...that chain whips not just up and down, but side to side side as well...bottom line... not much room to work with.

Kenny Sykes
USA

[Rob]

Dick isn't one to do things by halves and up at Marks Tey, the chain wore through 2 of the 3 rivets and the oil seal and holders fell inside the case. This, together with my inability to remember to tighten up the gearbox bolts (which didn't quite fall off!) means I now have a pile of bits on the bench.

Regarding the bikes falling on their left sides and pushing the cases over, the same can happen on RE Bullets but being 'built like a gun', it takes a big bash to shift them (but it can be done!). Just another (unwanted!) similarity with Greeves!

Interesting to hear about the chain as I have an inner case that appears not to have been used for donkeys years and is not (very) worn. Wonder if this is because it comes from the days when Renolds were the chain that everyone used?

Looks like we've got a bit of 'up-armouring' to do before next season but thanks for the suggestions.

Regarding new cases, I have spoken to said specialist and there were 2 sets of cases cast up north for specific customers. Said specialist said he could get some more done if people wanted them. Not sure if he was aware of the demand.

As a matter of interest, I am pretty certain there are some drawings of these in the archives.

Cheers,

Rob

[ADickerson]

Griffon Chaincases

I don't believe I've come across an inner case that isn't either bent or been welded, so if the price is right for a new item then I'm sure there would be sufficient demand to make the exercise worthwhile for all concerned.
As Druid said the case isn't particularly well supported, in fact to the rear of the two bolts which hold it in place are two pegs of a minor diameter which the case sits against. When I rebuilt my Griffon these two pegs had fretted against the Chaincase and worn both items such that the chaincase was then sitting even closer to the rear sprocket and chain. I turned up a couple of caps to fit over the pegs, this pushed the chaincase back towards the Clutch as far as it would safely go while also offering a larger bearing area for the case to sit against!
With regard to the chaincase bending when dropped on the left side I had wondered whether it was feasible to add a spacer between the inner case and say the engine plates just to the rear of the gearbox sprocket. No doubt if it was possible someone would have done it by now!

[Rob]

Good idea Adrian!

I'll have a look and see if it is possible to fit some sort of stand-off device.

I seem to remember the Challengers had some sort of bolt and spacer arrangement to help with this?

Even the good old Villiers had the chaincase fixed at the back!

With Dick riding the Griffon, I'm thinking of jamming a slice of railway track behind the cases and see if he can destroy that!

Cheers,

Rob

[Colin Sparrow]

Good idea Adrian!

With Dick riding the Griffon, I'm thinking of jamming a slice of railway track behind the cases and see if he can destroy that!

Rob

So it's going to be longer than four foot eight-and-a-half inches then?

[Rob]

Spotter!! I suppose I should have said 'rail'!

Now then, on to more sensible things.......

I rang the good lady at Sprockets Unlimited.

She said that Regina make a chain that is 15.6 mm across the pins. This is Regina RESR. Normal Japanese chain is about 17.35 mm. Heavy duty is wider still. Apparently early Nortons suffer from a similar problem with anything other than a narrow chain.

So, now we know what we need and we already have a new gearbox sprocket... just need a new rear sprocket to complete the set!

[ADickerson]

Thanks for welcome additions both, I'd be interested to learn if it possible to fit something in. Although I might draw the line on anything associated with railways, due to their inconsistent timing issues, I wouldn't want to tempt fate. Adrian