Author Topic: Let's go roadracing...continuing saga (Read 199561 times)

turboguzzi · « **Reply #1425 on:** December 16, 2019, 04:11:58 PM »

a bit odd brent... 1st gear sees so little use and nevertheless damaged like that? sure it does have the highest tooth loading due to being the smallest diameter, but still....

bwaller · « **Reply #1426 on:** December 16, 2019, 04:32:50 PM »

I agree TG. And until a year ago it really ever only barely showed a footprint from its mate. No way I can ever re-use now.

scottly · « **Reply #1427 on:** December 16, 2019, 07:18:21 PM »

Does the damage on the gear face appear to be etched, rather than worn? Material missing where nothing can reach below the surface, slight cavities?

bwaller · « **Reply #1428 on:** December 17, 2019, 06:37:37 AM »

Definitely material missing.

simon#42 · « **Reply #1429 on:** December 17, 2019, 10:08:13 AM »

i think its a heat treatment problem . aprilia 250 gears have always done this . when i complained they asked how many had failed which of course was none as i always changed them as soon as they looked damaged . italian logic stated that as none had failed there was no problem !

bwaller · « **Reply #1430 on:** December 17, 2019, 11:12:37 AM »

I feel it's heat treat too. Problem with my stuff is it's all one off. No calling the dealer!

754 · « **Reply #1431 on:** December 17, 2019, 11:12:58 AM »

Brent , back to the spare crank.. I would call it stain.
If you can find a tenths dial indicator, I would roll it around and check with that.. I mean ten thousants of an inch, .0001 per line. It will tell you if there is wear..

bwaller · « **Reply #1432 on:** December 17, 2019, 03:43:36 PM »

I won't be using that one anyway Frank, but thanks. It had a broken bolt in the right end also.

scottly · « **Reply #1433 on:** December 17, 2019, 06:20:50 PM »

Quote from: bwaller on December 17, 2019, 06:37:37 AM

Definitely material missing.

I've seen similar on VW lifters, which was finally attributed to lack of ZDDP in the oil...

bwaller · « **Reply #1434 on:** December 17, 2019, 08:29:08 PM »

Have always used ZDDPLUS. Pretty sure it's a heat treat issue.

RAFster122s · « **Reply #1435 on:** December 18, 2019, 09:32:25 AM »

Brent & Michael, what kind life can one expect from either OEM or K&White springs in a steet application (mileage ballpark number?)? Racing stresses components and motors far faster than a street bike would since they spend most of their time at very high rpms pushing a motor to max perf and output which yields very hot temps on our air-cooled motors.
Thanks for fielding a little off topic question...not related directly to racing.

Any of what you are seeing in your race motor a thing to look for with a street motor that has around 30-35k miles?

Thanks!
David

RAFster122s · « **Reply #1436 on:** December 18, 2019, 09:38:27 AM »

Quote from: simon#42 on December 17, 2019, 10:08:13 AM

i think its a heat treatment problem . aprilia 250 gears have always done this . when i complained they asked how many had failed which of course was none as i always changed them as soon as they looked damaged . italian logic stated that as none had failed there was no problem !

The auto manufacturers here have adopted this same attitude about motors in new cars for past decade or more allowing them to call a new motor which is burning or leaking or consuming up to a quart or a bit more between oils changes! That is with 7500-10k mile service intervals...not sure if any new cars have 3000 mile service intervals...

bwaller · « **Reply #1437 on:** December 18, 2019, 11:45:04 AM »

David, I remember when I first started testing seat pressures that a used stock spring set (inner & outer) yielded about 42 lbs. so quite low. I wouldn't hesitate to recommend Kibblewhite springs and following their installed height should give 60-65 lbs. Naturally they will sag with time but not as much as OEM springs would be my best guess. Mike probably has more experience.

I highly recommend the ZDDPlus Zn additive. They recommend 4oz per oil change. I use only 2 oz but change oil after each weekend. In a used oil sample I sent to Blackstone labs, the Zn levels were right in the sweet spot according to them. I don't particularly believe in additives, except for this stuff.

bwaller · « **Reply #1438 on:** February 20, 2021, 11:24:45 AM »

I'm laid up with a bum knee so thought I would post a few updates since the last time on here.

The 2020 race season was limited to one event in September but I was still waiting for a replacement mainshaft so my bike wasn't available. The deposit on this new shaft was made in Dec 2019 and I received it in October 2020! The delay was mostly Covid related so no more to say here. (Pic below). The issue with material chipping from teeth face I believe is with heat treating and we feel this shouldn't happen again. In speaking with smart people who should know...cryogenic treating of used gearbox parts probably wouldn't offer any protection, but that micro-polishing would certainly reduce friction. So I sent the gearbox, shift drum and various other bits for ISF polishing. (Pic below).

It all looks great but when I went to press on the shaft bearings, they were slightly loose. I was told by many people this would never happen....but it did. Perhaps the parts remained in the tumbler too long, not sure. So I used green Loctite and figure that will cure that.

The hard bits from that gear tooth scored the crank, pistons and sleeves. I polished up a new used, sent it to be balanced and installed all new crank and rod bearings.

I sent a cylinder to Millenium for replating and that was another fiasco which was eventually resolved, so new pistons, rings and bores to start 2021. I like to order my copper gaskets undersize and manually adjust bore size to closely match the sleeves. Then had to make up some new SS o-rings.

During the last couple races of 2019 we experimented with clutches, and ended up with a bit of a hybrid 550/650 clutch but used the CB650 primary gear ratio which spins the clutch faster. This should be a positive change, but at this point I feel only offers a minor improvement for race launches. Time may tell.

George was ordering new CB750 (296mm) cast iron rotors so I jumped onto that (thanks buddy) and had a set made to 5.25mm thick. After much deliberation and talking to George and Matt here I settled on a pattern and drilled them on a rotary table. Matt has had some issues with rotor cupping and cracking after dimpling (not drilling) but I'm hoping the smaller bike with twin discs will help avoid those issues. I had to make new caliper brackets, but now at least have a spare set of disc rotors that can be installed fairly quickly. The rotors are 170 grams heavier than what we used previously. However the higher coefficient of friction of the cast iron combined with larger diameter will make a marked improvement in braking. (pic below)

Tyler asked for shorter footpegs so will simply use hollow aluminum pegs that removes a few grams over what I made originally. These are cheap and made to break easily in a crash. I cut them shorter and re-welded. We use a modified Kawasaki brake lever.

So what's left to do? I need to order an OutEx tubless kit for the rear rim, install that, then mount a new rear tire. I am changing the rear brake caliper bracket to allow a pivot bearing, then will weld a tab on the frame for a new brake torque arm. This instead of the solid mount, and swingarm attached effort previously. Then change brake fluids and Bob's your uncle!

simon#42 · « **Reply #1439 on:** February 21, 2021, 03:26:01 AM »

you are right about cryogenic treatment . i know all about the theory of how it works but in practice it seems to be a waste of time . not a big fan of micro polishing either unless the gearbox is designed with this finish the shafts will always end up undersize . i think from memory mat went down this route with one of his gearboxes and it broke . check with him for the details .
the discs should work well ,i doubt you have enough pad area to overheat and warp them with the small brembos . if anything they seem a bit over the top! . glad you have posted , its been quiet of late and its interesting to hear what people are doing .

bwaller · « **Reply #1440 on:** February 21, 2021, 08:13:40 AM »

Simon, the minute I realized the shafts ended undersized I wished I hadn't done it.

It's not as if they are sloppy but my thinking is every piece will be the same. I didn't polish any bushings, but you get my drift. It is for certain friction will be reduced...fingers crossed there are no negative results.

Re front brakes, I'd appreciate opinions here. I had a few thoughts, two larger cast rotors with the small Brembo's, or one larger rotor and a larger caliper, or two larger calipers and the original smaller rotors. I have no spare discs so getting two larger ones gives me spares I need, plus options down the road in case I want to try one single and larger caliper.

I've always been concerned with twisting of puny forks with a strong single front brake. I have a fork brace and 20mm axle but single axle caps. I dress those SS Honda rotors with a rotor hone in a lathe every few races. Point is they kinda suck. I've sheared all the weight off them I feel safe with, same with the new cast ones. We'll have to be mindful of rain with the cast iron.

Tyler has always wanted better brakes, this will be a solid improvement. I'm open to what people thing .

simon#42 · « **Reply #1441 on:** February 21, 2021, 10:31:22 AM »

the cast iron will be much better in the rain , you should still be able to get a pad compound that works with them . try ferodo cp211 they should work ok , stay away from anything sintered cast iron is too soft for them . big discs do have draw backs . apart from the weight the gyroscopic forces are very noticeable . as the bike is pretty light i would go for one large disk with a bigger caliper . it might squirm a bit but it will stop and still be easy to turn .

Old Scrambler · « **Reply #1442 on:** February 21, 2021, 10:46:44 AM »

Off-Season = Work Time

Nice Safety Wire

Good used parts are better than new.......but will continue to wear. My thoughts are that spring degradation is less of an issue with the beehive design........and that removing your front wheel between events will allow for a coating of spray-on zink to the rotors and prevent rust at the pucks....... you will need to buff the rotors before re-installing.

I back-off my rocker-adjusters when the bike is parked to relieve spring tension. We continue to learn from your experiences and I wish for your success in 2021

turboguzzi · « **Reply #1443 on:** February 22, 2021, 11:13:03 AM »

hei brent, good to see you alive, kicking and wrenching. not exactly whats happening in my front, but wont hack your thread....sounds like you lost some night's sleep over that micro finish...

bwaller · « **Reply #1444 on:** March 14, 2021, 09:48:52 AM »

I'm looking for any thoughts on using a bushing or bearing on the rear brake caliper bracket. My wheel spacer on that side is quite long so should be lots of easy options. Any cool pics would be great. I'm making a new torque arm and will weld an attach point on the frame instead of swingarm.

Truth is I've been lazy lately in making a decision how to proceed.

turboguzzi · « **Reply #1445 on:** March 14, 2021, 11:06:51 AM »

I think that a "floating" rear caliper was more a fad of the 80-90s, havent seen them in anything more recent,

ducati tried them for a few sessions last year, didnt give any advantage, then went back to fixed to swingarm

bwaller · « **Reply #1446 on:** March 14, 2021, 12:26:57 PM »

Even if attached to the arm, the caliper should probably still float. I plan to test a couple options on swingarm movement with shocks removed and brake applied.

simon#42 · « **Reply #1447 on:** March 14, 2021, 01:00:45 PM »

pro squat was all the rage . the idea being the more you braked the more weight was on the rear tyre . this fad ended when it was realised that A nobody used the back brake and B the last thing you need when you are trying to turn is the bloody back squatting .

turboguzzi · « **Reply #1448 on:** March 15, 2021, 12:09:12 AM »

i just attached the torque rod to the original anchor point in the front of the arm.... it is "floating" only when the axle nut is untorqued, when its torqued you clamp the bushing (or rather hole in the carrier) you dont need any free movement in the bushing...

RAFster122s · « **Reply #1449 on:** March 15, 2021, 03:20:39 AM »

Only advantage of having a bearing in the caliper carrier over a bushing is a bearings ability to have less wear to the axle, theoretically at least.
But, a properly lubricated oilite bushing is riding on a lubricating film of oil and not the actual metal in the bushing. Modern oilite bushings are often made of a oil impregnated nylon instead of one of the traditional bronze oilite alloys.

Boron Aluminium Magnesium (BAM) is the latest and most slippery substance we know about. Its coefficient of friction is 0.02, it is substantially slicker than Teflon (0.05) and lubricated steel (0.16).

It is a ceramic and can be a fantastic coating to reduce friction and wear. They were searching for a super conduction substance when they created it back in '99. It is the third hardest substance know to man, up there with diamonds and cubic boron nitride.

So, any race engine coatings using BAM yet? Imagine the coating makers have perfected their coating. I have no idea of the expense of BAM or usefulness in our context discussed here.

If you could develop a coating film that would hold up and not shed itself over time can you imagine the gains of reducing friction on orders of magnitude of previous ceramic coatings. But, with it being so hard, the destruction BAM would do to other parts inside an engine is mind numbing.
If every rotating part were to have a ceramic BAM coating the frictional reductions would transfer loads to other parts and you would cascade the wear to parts previously not thought of as a weak link but merely a component that wears. Or, you could transfer the load the uncoated parts were balancing within a motor causing that part to start seeing failures because of changes in the dynamics and loads in a motor.
A previous undersized component having a ceramic coating of bam on it and its related friction interface (bearing or bushing) and you see the classic weak link issue being transferred to the next link in the chain.

So, what are you making your caliper carrier bushing from???

David

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Author Topic: Let's go roadracing...continuing saga (Read 199561 times)