Racing 2021

SteveA

VIP MEMBER
Joined
Dec 20, 2011
Messages
2,547
Country flag
They are starting to make them again now days, not the Dunlops but most of the others, I heard Avon are about to release a new race tyre soon. Even Pirelli have a race compound of the Phantom.
A new offering from Avon is somewhat overdue....not much has changed in more than 10, maybe 15 years.

Conti seem to have been the only ones doing development! But apparently, not all good.
 

SteveA

VIP MEMBER
Joined
Dec 20, 2011
Messages
2,547
Country flag
A lot yes, but I believe by design. When I first noticed the slack a while back, I had a look inside the box and all was good. I guess it is one of the reason the TTI boxes are so slick in use. Nothing I can do about it and judging by Chris's comments, I am not the only one.
Quite a lot of slack (backlash) in mine too!
 

storm42

VIP MEMBER
Joined
Jul 20, 2011
Messages
1,119
Country flag
I recall your earlier thread about the slack making riding a bit tricky at times. Now I can see why.
I have to wonder where all of this slack develops in the workings of the TTI box. Its not great for the rider can't be great for the box, although the boxes have a reputation for endurance.
I once rode a newish BMW 1200 that had all kinds of driveline slack. The model is known for it and the owner had forewarned me.
The slack combined with a very twitchy throttle made for an interesting riding experience.
I made a real spectacle when attempting to navigate the big thing through a parking lot. Had some spectators chuckling though, so it was worthwhile!

Glen

I don't think the slack develops, they are made like that. I would say that I noticed at Darley, the speed that this box changes gear, It is as fast as anything else I have used, they are a very good box, I need to develop my riding to cope with the slack.

One of the worst gearboxes I have used was on a BMW, a 1600cc 6 cylinder tourer, it was the pits.
 

storm42

VIP MEMBER
Joined
Jul 20, 2011
Messages
1,119
Country flag
I like your idea to use alloy plugs over the through bolts. If you continue to have head gasket issues, you might consider fitting a copper o-ring to the cylinder. Back when I first started racing a 920 with sleeved iron barrels, I had similar head gasket problems until I cut a groove in the top of the liner for an o-ring. This is a picture of the area around the through bolt counterbores, showing the o-ring details. The lip on your liners looks a bit narrower than mine, but probably still enough width to cut o-ring grooves.

View attachment 80035

Ken

I like the ring idea, what did you use for the copper ring? I feel the plugs cannot hurt but we will see.
 

storm42

VIP MEMBER
Joined
Jul 20, 2011
Messages
1,119
Country flag
Hi Al, that would be nice !
Ralph what do you think? Let's chase up all those that were going to come out last year.
Access Norton ride out to Cadwell Park ?
Time to get all of us on the grid at the same time as well?
That would be a grand day out lol

If the weather is good then a ride out to spectate would be a good day or two for those not racing, a good reason to get the bikes out and meet up. be good to put some faces to the names on the board.
 

storm42

VIP MEMBER
Joined
Jul 20, 2011
Messages
1,119
Country flag
Ralph, any plans for Spa this year? So far, it seems to be on. My friends went last year and reported that they had a really good weekend, so I’m very much hoping to make it this year.

Hi Steve, no, not booked it as I couldn't be sure we would be able to travel etc. hopefully the year after next will be OK.
 

storm42

VIP MEMBER
Joined
Jul 20, 2011
Messages
1,119
Country flag
Avons are good, but my experience says Heidenau are better when wet and slippery! Not so good when it's hot, by which I mean South of France hot and dry, not Darley Moor hot! However, your 920 would probably turn them to gum in anything other than the wet!

Other people's experience says that Continental are 'variable', some have reported Contis of a certain vintage being excellent.....and then removing later ones after the first race on them.

The Supermono guys complained like hell when they were told to use treaded tyres, most of them think their bikes can only work on slicks!

They are never going to be as big a market as the range of classics supported by both Avon and Heidenau.

I heard the same about the Contis being variable and the first gens were better, I had the first gens on when I built the bike and at my first meeting at Mallory I was 3 secs a lap faster than the other day, I was very cold the other day though.

I went back to Conti on the advise of John Cronshaw who is convinced they are better than the Avons. Maybe I need another set of wheels with Heidenau tyres fitted for the damp.
 
Last edited:

lcrken

VIP MEMBER
Joined
Mar 15, 2009
Messages
4,499
Country flag
I like the ring idea, what did you use for the copper ring? I feel the plugs cannot hurt but we will see.
I used .039" diameter copper wire. I bought it at the local hardware store. It was labeled as 28 ga copper craft wire. Readily available nowdays on Amazon, etc. I ground a tool from HSS to cut the groove. It was a tight fit for the wire, needing it to be tapped into the groove with a small hammer. I cut the wire close to length, and then trimmed it with a file to get a tight joint between the wire ends. I cut the groove shallow enough to leave the wire .008 - .010" above the deck. It's been a long time since I did the last one of these. Back then, I jigged the cylinder up on a lathe faceplate to cut the groove. If I ever do another, I'll probably try doing it on the mill with a boring bar and custom ground tool. I thnk that would be a lot more efficient. Stainless safety wire is also popular for o-ringing cylinders in the car world, but I thought the copper might be a bit more forgiving in the machining tolerances, and it always worked fine for me. I did replace the wire periodically during engine tear downs.

Ken
 

Fast Eddie

VIP MEMBER
Joined
Oct 4, 2013
Messages
16,476
Country flag
Ken, Ralph,

Your method might even work without the wire Ken, IF using a copper gasket.

Machining a grove in the top of Triumph barrels was a mod that Degens used to do. The idea being that the copper gasket would depress into the groove, so creating a similar (but reverse) effect to the wire idea.
 

storm42

VIP MEMBER
Joined
Jul 20, 2011
Messages
1,119
Country flag
I used .039" diameter copper wire. I bought it at the local hardware store. It was labeled as 28 ga copper craft wire. Readily available nowdays on Amazon, etc. I ground a tool from HSS to cut the groove. It was a tight fit for the wire, needing it to be tapped into the groove with a small hammer. I cut the wire close to length, and then trimmed it with a file to get a tight joint between the wire ends. I cut the groove shallow enough to leave the wire .008 - .010" above the deck. It's been a long time since I did the last one of these. Back then, I jigged the cylinder up on a lathe faceplate to cut the groove. If I ever do another, I'll probably try doing it on the mill with a boring bar and custom ground tool. I thnk that would be a lot more efficient. Stainless safety wire is also popular for o-ringing cylinders in the car world, but I thought the copper might be a bit more forgiving in the machining tolerances, and it always worked fine for me. I did replace the wire periodically during engine tear downs.

Ken

Thanks Ken, I have just measured the top of the liners and only have .097" to play with. I will put it in the mill and try and cut what will amount to a scribe mark and like Nigel says below, the gasket should press into that and have a similar effect, I still think the gasket was pulled thin where the bolt holes are but no harm in giving it every chance to seal.
 
Joined
Nov 26, 2009
Messages
2,637
Country flag
I used .039" diameter copper wire. I bought it at the local hardware store. It was labeled as 28 ga copper craft wire. Readily available nowdays on Amazon, etc. I ground a tool from HSS to cut the groove. It was a tight fit for the wire, needing it to be tapped into the groove with a small hammer. I cut the wire close to length, and then trimmed it with a file to get a tight joint between the wire ends. I cut the groove shallow enough to leave the wire .008 - .010" above the deck. It's been a long time since I did the last one of these. Back then, I jigged the cylinder up on a lathe faceplate to cut the groove. If I ever do another, I'll probably try doing it on the mill with a boring bar and custom ground tool. I thnk that would be a lot more efficient. Stainless safety wire is also popular for o-ringing cylinders in the car world, but I thought the copper might be a bit more forgiving in the machining tolerances, and it always worked fine for me. I did replace the wire periodically during engine tear downs.

Ken
I did something similar to Ken but used a 60 deg cutter and .018" diameter copper wire so it stood .008" proud of the surface - I went around the cylinders and also around the pushrod tunnels and oil return. Needed 2 or 3 re-torques but never leaked a drop. The wire flattened out to conform. I did this after my composite gasket started leaking - end of problem and I was able to bump up the compression without the gasket (image from my race manual).

191852823_10220871010424665_6086467910112579762_n.jpg
 
Last edited:
Joined
Jun 30, 2012
Messages
10,845
Country flag
Has anyone used the Bridgestone Battlax tyres in the racing compound on their Commando ?
 

SteveA

VIP MEMBER
Joined
Dec 20, 2011
Messages
2,547
Country flag
I heard the same about the Contis being variable and the first gens were better, I had the first gens on when I built the bike and at my first meeting at Mallory I was 3 secs a lap faster that the other day, I was very cold the other day though.

I went back to Conti on the advise of John Cronshaw who is convinced they are better than the Avons. Maybe I need another set of wheels with Heidenau tyres fitted for the damp.
Cronshaw is someone I would take the time to listen to!

Yamaha Classic Racing Team under Ferry Brower used Heidenau exclusively for a long time and put many former champions on track on them, not one of these former professionals complained!

But if you are interested talk to Tony Salt, he is the official UK importer, and the only UK supplier, because he is the only one who keeps them at the proper temperature.

With Heidenau there are stories, some people don't like them, complain of bad experiences. Some didn't listen to rim size recommendations from Heidenau, generally wider than for Avons, or tyre pressure recommendations from Tony, generally lower than for Avons. And some of those who complained had been delivered road compound tyres, or badly stored race tyres, or didn't bed them in! They come feeling quite hard but properly run in they are a different beast.
 

storm42

VIP MEMBER
Joined
Jul 20, 2011
Messages
1,119
Country flag
I did something similar to Ken but used a 60 deg cutter and .018" diameter copper wire so it stood .008" proud of the surface - I went around the cylinders and also around the pushrod tunnels and oil return. Needed 2 or 3 re-torques but never leaked a drop. The wire flattened out to conform. I did this after my composite gasket started leaking - end of problem and I was able to bump up the compression without the gasket (image from my race manual).

191852823_10220871010424665_6086467910112579762_n.jpg

I wouldn't get away with no gasket, I need the clearance. I am going to look at putting the grove in the head though, might work.
 

storm42

VIP MEMBER
Joined
Jul 20, 2011
Messages
1,119
Country flag
Put a groove in the lip of the liner you mean right ?

No, the head, the lip of the liner is only .097" thick and doesn't look wide enough for a groove, really, it shouldn't need anything and may end up with nothing, but it won't hurt to explore all the possibilities. I haven't looked at the head yet to see if a groove is possible.
 

Fast Eddie

VIP MEMBER
Joined
Oct 4, 2013
Messages
16,476
Country flag
No, the head, the lip of the liner is only .097" thick and doesn't look wide enough for a groove, really, it shouldn't need anything and may end up with nothing, but it won't hurt to explore all the possibilities. I haven't looked at the head yet to see if a groove is possible.
I don’t think the alloy head has the same bite as an iron barrel or liner Ralph. Can’t see that working matey.

Maybe there is no engineering solution. Maybe you just gotta resign yourself to an annual head gasket change (hardly excessive really)?
 
Joined
Jan 6, 2009
Messages
737
Country flag
No, the head, the lip of the liner is only .097" thick and doesn't look wide enough for a groove, really, it shouldn't need anything and may end up with nothing, but it won't hurt to explore all the possibilities. I haven't looked at the head yet to see if a groove is possible.

Did a 920 head that way about 30 years ago. Machined a groove for some coax inner cable (tv aerial wire). Never had a problem after that. It's probably still on a shelf in storage if I can ever get back to it
 
Top