What did you do with your GRiSO today?

@Mark 111 - That's a great post and very helpful to others.

Charlie J wrote:

Paid for a 2015 Rosso Nero GRiSO, an Agostini x muffler and the factory service stand. Bring it on.....

Congrats from me too!

Took yesterday afternoon off - collected my wife and rode off into the Cotswolds. Got completely lost - didn't care really. Then we found a pub. Ordered a pint and a bowl of chips, and the Sun was out.

Eastleach Turville
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Josh.C wrote:

mark111 wrote:

tocino,
Check all of the spoke tensions before you do anything else.
My front wheel was loosing pressure, a few psi in a couple of days after travelling on some rough roads (plenty of them here in Oz). My experience would suggest the rims are pretty tough.
After retensioning the spokes the leaks stopped, I had purchased spare nipples and O rings to fix the leaking items but haven't needed to use them since retensioning..
I recently rechecked them with a spoke tension wrench and all bar 8 spokes on both wheels needed a nip up. I had done around 4,000 km since I last checked them so maybe this is something we should be checking regularly to ensure the remain correctly tensioned.

Any trick to this? I haven't used a "spoke tension wrench" before. Do I need a motorcycle version (a quick Google search brings up a lot that seem targeted at bicycles?)?

I'm losing pressure faster than normal too, so I'm thinking this might be the problem.

There's a reasonable risk it's not just a simple spoke re-tensioning particularly if the rim has developed an impact-related flat spot. Just running the nipples up to std tension over a flat spot won't fix it - a minor flat spot can be pulled out with careful spoke tensioning. Spin the wheel and see how it looks.

If you don't want to tackle it, some bike shops will do it in-house but often quietly sub it out to a specialist. One of the better wheel rebuilders in Australia is John Titman Racing in Capalaba Brisbane. They rebuild / manufacture spoked wheels of all description.

Pete Roper wrote:

What I did today was try and get a handle, in a very amateurish way, on what the fuck is happening with the roller cams and their effect on fueling.

Al's map, which as I suspected was closest to what would work with my bike in rollerised form, still gets 'Flat' at the top end. Tried Mark's Mistral/dbk map and it just runs into a brick wall at 6,000 rpm at anything over about 70% throttle. Felt lean so I tried the no dbk map. Still flat but surgey, anyone who follows my ranting a knows 'Surging' seems to cover a multitude of sins but this was really 'Flat'-'Go'-'Flat'-'Go' surging. Really odd. Whatever the roller cams do to the timing they have a radical effect at higher rpm/throttle opening.

Valves are set at 3&5 stone cold and the roller system opens up the gaps appreciably in service so the rollers pas will probably be built with much see settings than the at tappet maps.

This is the stuff that to me is really interesting as it is taking into account the factors that the 'Open the air box/exhaust and throw in more fuel' mob can't see even though it's staring them in the face.

Pete

I've been wondering what would be the nett effect on valve timing with roller upgrades. Hard to know if there is additional lift however perhaps theres been a compromise worked out by MG between duration / open and close positions and lift ?

Regardless of my theorizing, I've always interpreted surging as "lean" / needs fuel in that rev range so if the map was good before the roller work then maybe the slightly amended valve timing pumps more air ?

Josh C I would like to hang on to the 1100 and give him a freshen up. If the 1200 gives me the jollies that the 1100 has I will be well pleased.
Pete , it would be nice to not have my bike aerated.

Good stuff Charlie.

Pete, you've set tappets at 3 & 5 thou. You've mentioned several times that very accurate valve clearances are absolutely necessary.

Al's map was built around .006" both inlet and exhaust, would this difference have an effect on your bike?

Charlie J wrote:

Josh C I would like to hang on to the 1100 and give him a freshen up. If the 1200 gives me the jollies that the 1100 has I will be well pleased.
Pete , it would be nice  to not have my bike aerated.

I wish I'd kept my 1100. It's an iconic bike.

Don't worry Charlie. I'll fuck it up some other way....

Pete

Lenz9753 wrote:

There's a reasonable risk it's not just a simple spoke re-tensioning particularly if the rim has developed an impact-related flat spot.

What Lenz says is entirely correct, if the wheel rim has a flat spot resetting the spoke tension won't resolve your problem and you will need an expert to sort the issue.
My comments are based on the spokes having lost their tension on a rim in sound condition which will happen over a period of use especially in harsh road conditions common on Oz rural roads. Unlike other wheels with spokes, those on the GRiSO rims also rely on correct tension to seal the rim correctly, if the tension is reduced then they are an area of potential air loss.
My recent experience would indicate this is something worth checking periodically, of course the need will vary from one bike to another depending on usage.
My post was just to emphasise that the simple things should be checked first, i.e. a slow leak from a tyre puncture, dodgy tyre valve, leaks from the spoke nipples before you go puling things to bits.
These are all easy to check and if eliminated then the issue is more serious and should be treated with a degree of urgency.

Thanks Lenz and Mark.

I can't recall ever having any major impact on the wheel rims. But after 26,000 kms there's certainly been the occasional pothole. Also the tyres are losing pressure at about the same rate, if that makes a difference. I might be imagining things, but the issue of pressure loss seems to coincide with installing new Pirelli Angel GT's.

Two weekends ago I corrected the pressures on Saturday morning, went on a ~350km ride and then on Monday morning each tyre had lost ~4 PSI. Then after correcting them Monday morning and riding ~150km, by Saturday (no riding since Monday) they'd lost ~5 PSI (each) again.

I do ride a lot of rough roads around the border of QLD & NSW. It sounds like that isn't helping.

I'm not far from Capalaba, so getting them checked professionally is an option. But I think I'll just try the routine maintenance option first and see if that helps.

ghezzi wrote:

Pete, you've set tappets at 3 & 5 thou. You've mentioned several times that very accurate valve clearances are absolutely necessary.

Al's map was built around .006" both inlet and exhaust, would this difference have an effect on your bike?

Yes, but I've now tried various clearances and, like the flat tappet bikes, a roller motor is still sensitive to change but no matter what I've tried it still goes dead at six or close to it. As soon as I've got time to scratch meself I'll hook up the logging gear and start doing a few runs to give Mark something to play with. I really want my top end back .

Pete

Is it possible during the download that your laptop had a hiccup and part of the map is missing.
Actually sounds like you forgot to put the main jets in. Ok, I accept i'm a dinosaur.

Nah, I've tried three different maps and about seven different valve lash combinations now, I've been in and out of the top end like a rabbit's cock on the vinegar stroke and it makes no difference, well it does, some set-ups are worse than others but none of them are good.

Once again, when I have a minute, I'll graph the cams.

Pete

Got the front end off the ground so I could spin the wheel and check for flat spots / warpage and see if any spokes looked bent. Nothing.

Tapped each spoke - while some didn't sound quite as "bright" as the others none sounded way off / dead. Also looked at the tire and felt for embedded objects. Nada.

So got some soapy water and sprayed the rim to see what I could see. I just saw soapy water.

Spray the whole darn wheel. Aha! Two tiny bright spots in tiny little divots show bubbling. Looks almost like two posts from a staple. Must have been from the aluminum ramp when I hit it.

Feeling lucky I don't have a bent / damaged rim (and the tire held enough pressure for me to get home).

Looks like I'll be getting a new front tire, or maybe a pair.

tocino wrote:

Got the front end off the ground so I could spin the wheel and check for flat spots / warpage and see if any spokes looked bent. Nothing.

Tapped each spoke - while some didn't sound quite as "bright" as the others none sounded way off / dead. Also looked at the tire and felt for embedded objects. Nada.

So got some soapy water and sprayed the rim to see what I could see. I just saw soapy water.

Spray the whole darn wheel. Aha! Two tiny bright spots in tiny little divots show bubbling. Looks almost like two posts from a staple. Must have been from the aluminum ramp when I hit it.

Feeling lucky I don't have a bent / damaged rim (and the tire held enough pressure for me to get home).

Looks like I'll be getting a new front tire, or maybe a pair.

Maybe you could totally deflate the tyre and then inflate it to re-seat the bead on the rim - worth a try.

plantboy wrote:

Maybe you could totally deflate the tyre and then inflate it to re-seat the bead on the rim - worth a try.

Sadly, not a case of the bead not seating. There's a hole in the tire.

Just a tip on minimizing air pressure loss- Often when we do tire changes we see quite a buildup of tire rubber residue sticking to the bead mount surface of the wheel. This can interfere with the best bead to wheel seal so we always clean that surface thoroughly. My guess is many shops don't take the time to do this properly contributing to more air pressure loss over time.

Tocino,
If the holes in the tyre are only staple size then the tyre should be easily repaired.
Competent tyre people should be able to remove the tyre and place a patch on the inside of the tyre much the same as you would do if you were patching the outside of a tube.
If it is a new tyre and displays no obvious structural damage this is a valid procedure to rectify this type of leak.
of course if the tyre is well worn or has any obvious structural damage then find a bin and throw it in.
Tyres are obviously a critical item for safety so you shouldn't be slack about replacing them but if being run at the correct pressures they are remarkably robust.
Once they pull the tyre off the rim they should be able to asertain if it is worth repairing.

mark111 wrote:

Tocino,
If the holes in the tyre are only staple size then the tyre should be easily repaired.

Thanks - I'll see if anyone does that, but I fear here in the US I won't find a place that wants to chance a stupid lawsuit from someone who crashes and looks for anyone to blame.

Pete Roper wrote:

Nah, I've tried three different maps and about seven different valve lash combinations now, I've been in and out of the top end like a rabbit's cock on the vinegar stroke and it makes no difference, well it does, some set-ups are worse than others but none of them are good.

Once again, when I have a minute, I'll graph the cams.

Pete

Hey Pete - I'm interested to hear what your findings are on the valve timing changes following "rollerization". (whenever the level of "alligators" or bills drops"

Is the kit you're using a complete replacement of cams and roller followers or only partial ?

The conversion involves replacement of the entire cambox assembly.

I did a basic write up covering it here.

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pete

Pete Roper wrote:

............I really want my top end back .

Pete

If you get it back let us know as I really miss the rage of the flat tappet as well.
My 09 put my 2013 to shame past 5000rpm and popping wheelies on second gear was easy compared to the roller set up.

I fix.