Author Topic: 2016 sohc4 road racing reports, open to all road racers.  (Read 19846 times)

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Offline Haybus

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #50 on: July 25, 2016, 02:41:54 PM »
Scottly, my worst chatter always occurs in long sweeping turns. Same in this case, a 60mph (?) left hand turn. I had a little bit of chatter in that corner all weekend, but it wasn't too bad. Typically when I get chatter it means I'm going too slow in that corner. If I hit the gas it usually calms down. Our race was after 3pm and it was in the 80'sF, not normal for us. But at the end of the race there was no calming down that level of chatter. John worked through this over a couple seasons and ended up with the GL front end to calm his down. He said he did have some bounce in that corner but he thought the track was just rough there. Could be a combination of rough track, a bit of my normal chatter, more laps than we usually get and really hot tires were the perfect combination for severe chatter. My pit mate Chris has almost the exact same setup as I do and he described the same level of chatter after the race. Perhaps John's solution is the answer for us. A friend I used to work with has been vintage racing for 35 years and he suggested a smaller front tire might do the trick. Maybe an AM26 90/90-18 in race compound or something from Heidenau. That's a bit cheaper solution, but I'd have to go back to PIR to really test the theory as the chatter I get at our other 2 tracks doesn't really bother me that much.

Slikwilli, I'll let you know if I decide to go that route. I don't have any GL front end parts yet. I've had a line on forks a couple times but the people always seems to flake out.

Alan
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Offline simon#42

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #51 on: July 25, 2016, 03:20:55 PM »
front end chatter is not always caused by the front end dont rule out the rear suspension as the cause , have you tried changing tyre pressures to see what effect that has ?

Offline scottly

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #52 on: July 25, 2016, 03:35:40 PM »
Since the problem seems to get worse as the temps go up, I am also thinking tire pressure. Are you filling the tires with air or nitrogen? Another possibility is too much oil in the forks, which expands with heat. And Simon is correct about issues that are felt in the front can be caused by the back. 
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Offline bwaller

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #53 on: July 25, 2016, 04:35:32 PM »
"In slow out fast"  ;D Worth repeating I suppose and I know you know this.

All good points above to check. Don't let pressures increase more than 10%. A narrower front tire will help it turn slightly, but with a heavier bike that 90/90 will give up contact. I think I'd stick with the 110/80.

Do you use 20mm hollow axles?

Offline Retro Rocket

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #54 on: July 25, 2016, 04:52:03 PM »
"In slow out fast"  ;D Worth repeating I suppose and I know you know this.

 I think I'd stick with the 110/80.


Gday Brent, just curious, what size front rim is Haybus using the 110/80 on..?
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Offline scottly

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #55 on: July 25, 2016, 05:39:32 PM »
Speaking of chatter, does it ever happen to anyone when using the rear brake?
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Offline bwaller

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #56 on: July 25, 2016, 06:01:53 PM »
Rear brake?  ;D  Mine really only chatters when I over ride it, get in too hot and have to shut the throttle completely. Otherwise it's very civil.

Alan are you touching anything down? Could you pull the forks up through the triple clamps another 10mm or so?

Mick I think Alan was using a 2:15 front rim, not sure if he's done something different since.


Offline JohnN

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #57 on: July 25, 2016, 06:44:54 PM »
Alan:
 I actually eliminated most of my chatter problems before the GL for upgrade. I found a setting that stopped virtually all chatter at Pacific and The Ridge, but then found it occurring at Miller. This also included more sag in the rear and as Simon pointed out this can be part of the solution.I finally went to KFG for assessment and Barry added a couple of clicks of rear damping and had me reduce the front preload by 3mm. Next trip to Miller was much better. Can't say I never encounter chatter, but it is rare now and much reduced in scope. I installed the GL forks for other reasons.
By the way, I'm really happy with the AM22/23 combination. I have not tried anything else in 5 seasons but the bike is feeling really good now so I don't want to change anything.
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Offline Haybus

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #58 on: July 25, 2016, 09:00:26 PM »
Air or nitrogen? Hmm, since our air is comprised of 78% nitrogen I guess I was technically running mostly nitrogen? I was running 30 psi front and rear. I'm not that confident with pressures relative to temperature. I really only ever adjust a couple psi up or down, with 30 being the highest I've gone in hotter temperatures. It was in the 80's yesterday, should I have gone higher? I need to keep better notes on tire pressures vs temperature so I can react better in the future.

Brent, I'm running the stock front axle right now. I'm dragging both sides of my belly pan. I've trimmed it as much as I can, next thing to hit is the exhaust, but that's only maybe another 0.25". All that business is getting binned over winter in favor of a new 4-1 exhaust and belly pan. My right muffler cracked 270 degrees around, right behind the hanger bracket on Saturday, so it's gotta go anyways. I do have rear shock spacers to raise the rear up. Would drop my rake another half degree while reducing my trail only 0.12". But our next two races are at a track that I don't really experience much chatter, or at least not that I remember. I can give it a try and see what it does. And you're correct, 2.15 front rim.

I've made enough changes on the bike it would probably be prudent to go through my suspension setup again. I'm not going to run out and make whole sale changes right now. I was really happy with how it handled at the Ridge last round, so maybe it is something simple like pressure, fork oil or sag to make it handle better in adverse conditions like yesterday.

Alan
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Offline Retro Rocket

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #59 on: July 25, 2016, 11:11:14 PM »
Rear brake?  ;D  Mine really only chatters when I over ride it, get in too hot and have to shut the throttle completely. Otherwise it's very civil.

Alan are you touching anything down? Could you pull the forks up through the triple clamps another 10mm or so?

Mick I think Alan was using a 2:15 front rim, not sure if he's done something different since.

Thanks Brent. The reason I asked is I've been "told" to run a 100/90 on a 2.15x18 front, I also have a 2.5x18 front and a 2.75x18 front wheel and was told to run the 110's on them, I was told the steering would be heavier with the 110 on the front of the 2.15. Now to contradict this slightly I've also read that it also depends on the make of tire, So depending on which brand you use, these size recommendations  can change. You'd think after all the years of motorcycle evolution that these choices would be easier.....Apparently not... ;D ???
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Offline bwaller

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #60 on: July 26, 2016, 04:01:23 AM »
A 2.5" (WM4) is recommended but Avon says 2:15 to 3" is perfectly fine with a AM22 front. The limitations are usually with the rules.

Offline simon#42

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #61 on: July 26, 2016, 11:34:29 AM »
we were only allowed a 2.5 front rim and that did work fine with the 110 am22 , i would have preferred a slightly narrower tyre on that rim though .

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #62 on: July 26, 2016, 03:00:50 PM »
we were only allowed a 2.5 front rim and that did work fine with the 110 am22 , i would have preferred a slightly narrower tyre on that rim though .

That's what i was getting at Simon, the 2.15 would steer better with a 100 size tire.

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Offline bwaller

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #63 on: July 26, 2016, 06:50:19 PM »
No doubt the 110 is a large foot print plus on a narrow rim isn't a perfect combination, but it does work. I started like turboguzzi with a 90/90 AM20 front, then when they disappeared switched to their AM26 in 90/90. Good tires but in a combination with the AM23 I like the AM22 110/80 better They just don't have a 100 tire.


Offline HondaFreak

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #64 on: July 31, 2016, 11:34:10 AM »
I asked JD what they are running on the 350 & 500/4 bikes, tyre & rim wise.
110 Avons Front & Rear with 1.85 front rim & 2.15 rear, both bikes.
They are used with own cnc yokes and cartridge conversions on own stanchions and cartridge conversion. That is with a solid front axle.

As far as I know, chatter isn't a complaint with that set up & Alan O is a stickler for handling as he carries a lot of corner speed.


Offline bwaller

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #65 on: August 16, 2016, 04:43:46 PM »
Our VRRA vintage festival was last weekend. This is a big place. Thursday & Friday we were into the 40's on the humidex, Saturday morning was foggy with rain forecast. It was so foggy at the south end of the track the corner marshalls were unable to see each other so we were on hold. After an early lunch we got through a complete practice session before the skies opened with really heavy rain. The day was called. Sunday unfolded well with a great day of racing.

Here is a video from a rider in my P3Light bumpup class. I don't know the rider but seems he's on a R75?. He's well off the pace but I thought his lap timing gadgets are cool plus it gives a pretty good idea of the track. It still doesn't give an accurate view of elevation changes but worth a look.



I finished second to Scotty McKenzie in the Masters class and we didn't get much of a chance to wow the crowd, huh Scott? In the above P3L class I led for a while but Chris Spargo got past for the win, another 2nd.

In our actual P2M class we started behind the P2 Heavy's, with an older third class of British bikes behind us. There really should have been a second wave for the middleweights as the start was insane.  ??? I chose to be cool and take a little time getting clear, but there were some crazy #$%* happening in the first half lap, worst I have ever seen! Tim Voyer ( with balls of steel) squeezed through on a good inside move in the middle of all this and I don't remember where I was able to catch him up. Poor Tim retired with a flat rear tire.

This is the first year for Spargo at Mosport, I've followed his exploits though and it seems like he's been on a tear in AHMRA for a few years. His bike is a missile, 260lbs and 80HP. He told me this engine was brand new and the bike is faster than it's ever been. He didn't, but someone else told me the engine was built by some F1 guy in the UK. Good for him because the thing really goes. On the back straight at the speed he went past, reminded me of a really good early TZ.  ::) Good motor.

That said (and not to be immodest) I was able to pass him everywhere else. It was fun, he'd show me a wheel but I could keep him at bay. Two laps to go I rode past on the outside of T1 and put me head down, & clicked off a couple really good laps, felt great, right on the edge. Into the back end of the track in T5 I slipped into neutral for a second, ran it into the rev limiter on 5c, then missed that shift right at the worst place.  SOB  >:( It gave him the whole straight to get away. He was obviously following but I know I could have held him off until further up the straight and then got him back in the chicane. As it was I pulled alongside (outside) in T8 but he had the line and if I pursued the pass would have had to force him wide in T9 and felt like an #$%*, so I let up and followed him home in 2nd. He's a good guy, obviously a good rider. We got past all the Heavyweight except Jeff Peters on his Rickman CB750 and Mark Hekkles on the Gianinni CR750. I never even saw those guys with the chaos of the start.

Tyler worked through lots of jetting issues with his FCR's on Thursday during practice and finally found happy land. He rode the wheels off that FZR against all bigger bikes. He snagged a solid 3rd in one race and was .005 seconds out of 4th in another. This was against a young CSBK Pro rider (who's been sponsored to ride in VRRA P4) who he's become good friends with. They swapped positions all race then squirted out of T10 side by side and elbowed each other all the way to the finish line!. They laughed about that all day. The other kid says he never gets close racing like that in Superbike and it was the most he'd ever enjoyed a race. I know under his breath Tyler would have loved to finish ahead....that would have been 2 for 2 against a pro.  ;D

All in all I had a ball, the bike ran great. I came to within a second of my best time there but rode as well as I could have, very satisfying. Three 2nd's... nothing to sneeze at for an old guy!  ;) Next race in a little over three weeks.

The Gianinni CR750




Gunther's chain drive R65 BMW at speed





L'il Blue on the prowl.





Cool down lap. (thinking phew, it's finally over!!)





Dave Crussell on his TZ750





« Last Edit: August 16, 2016, 06:26:59 PM by bwaller »

Offline simon#42

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #66 on: August 17, 2016, 11:42:16 AM »
As it was I pulled alongside (outside) in T8 but he had the line and if I pursued the pass would have had to force him wide in T9 and felt like an #$%*, so I let up and followed him home in 2nd. He's a good guy, obviously a good rider.

this is really really bad brent you dont go racing to be nice to people !

Offline bear

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #67 on: August 17, 2016, 04:52:34 PM »
Nice one Brent, it sounds like your back in the groove.  ;)
Don't you listen to that cranky old Pommy, it's a gentleman's sport :o.....................right? ;D
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Offline bwaller

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #68 on: August 17, 2016, 05:37:13 PM »
Hah. Yes I do at times listen to my conscience Brian. It would have been a bonehead move Simon.

Tyler's girlfriend was watching the race from the tower and afterward asked " do you think you could have made it"? (the pass that is) Probably not, was my reply. Then she asked "did you pump your fist because you were happy finishing 2nd?"   No, was my reply!

Offline Old Scrambler

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #69 on: August 17, 2016, 08:17:51 PM »
Good read...err, ride, Mr. B..................Its a GREAT feeling to be so close :) :) :) :) :)
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Offline Haybus

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #70 on: August 17, 2016, 10:16:49 PM »
Excellent report Brent. I enjoy following your racing. Sounds like a good weekend. The gadgets in that video are really cool.

Alan
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Offline simon#42

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #71 on: August 18, 2016, 11:10:14 AM »
Nice one Brent, it sounds like your back in the groove.  ;)
Don't you listen to that cranky old Pommy, it's a gentleman's sport :o.....................right? ;D

no bear, thats country dancing you are thinking about

when i saw mark hekkles name i thought it might be my old mate mark heckles from liverpool , he moved to new york a few years and is racing an r6 in the ama 600 championship
then i saw the photo and thought if it is him he likes those big american dinners !

Offline turboguzzi

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #72 on: August 18, 2016, 12:21:24 PM »
sounds like a good day in the office brent! what does this spargo guy ride?

Offline bwaller

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #73 on: August 18, 2016, 01:18:46 PM »
Country dancing and lawn darts huh Simon?  ;D

TG, Chris Spargo rides an RD400, but man does that thing fly. First time I've felt so inadequate on the straight! Reading back through my mess I haven't given him enough credit. It's his first time at Mosport, and hadn't been allowed much practice because of the weather. All that considered I told him recently he wasn't welcome back.  ;) LOL

Offline gschuld

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Re: 2016 sohc4 road racing reports, open to all road racers.
« Reply #74 on: August 18, 2016, 01:54:30 PM »
Brent,

Nice report.  Looks like you had fun.  Didn't even scratch up the paint... ;D

This is Chris Spargo's RD400 I think.  Picture is not super recent.  It sure looks lightweight.

George