Topic: Let's go roadracing...continuing saga

[FuZZie]

Glad you didn't get hurt!
Nice video too really enjoyed watching your work tru the coroners!!!

[Tintop]

His engine is finally together tonight, new swingarm needs a little machining, then fork rebuild, fiberglassing, waiting for parts. By hook or by crook my new sprocket carrier will be finished this week. We're doing a trackday Monday...hopefully. Why the hell does everything always come down to the wire?

I've always figured that if you think it will take 3 months, it will actually take 6.  Mainly because that supplier who said you'd have it in a week, took 3 to get it to you.  Then the machinist who had time two weeks ago, is now booked up.

Just some cosmetic damage to fix on the chair fairing (d*m turtles!), otherwise good to go.

[bwaller]

I know people have been on the edge of their seats waiting for sprocket news. 

Between TG (thanks Yoss) & I an idea was hatched. I hope Simon doesn't stop by to see I'm still using the CB350 cush drive. I may be wrong but I still like the idea of some damping, anything to baby my 6 spd. This particular hub doesn't "give" much but it has to reduce some drive line snatch.

Fabbed an adaptor on a bearing which is held in place by the wheel spacers. Shaved the nose off the hub down to the bearing so the adaptor is snug to the hub & the studs are full length inside the bushings.

The chain broke some pieces off the bottom case half and might have been worse had it not been for the shark fin toe guard. It keep the chain on the wheel spacer or it might have lcoked up the rear wheel & done more damage. Thanks to TimV840 for that piece. 

The rear wheel is now dead center in the frame plus the sprockets are perfectly aligned. It was a bigger job than I ever dreamed.











My sons bike has a ways to go, but it'll be ready to race next weekend.

[simon#42]

im still keeping an eye on you brent !

nice work but over complicated and unnecessary .

[bwaller]

im still keeping an eye on you brent !

nice work but over complicated and unnecessary .

Wow you were watching!  Actually Simon with another race next weekend this was about the best alternative. Sourcing another hub and matching spokes would have left me without enough time. There was no other way I could imagine mounting the sprocket far enough from center, but you're right it was a tad complicated. It is brick #$%*house strong and it will work fine!

[Tintop]

Nice piece of work Brent.   The pins remind me of the pin drive hubs on my brother's Elan +2 S130.

I expect to get to Shanny Friday PM, see you there.

[scottly]

im still keeping an eye on you brent !

nice work but over complicated and unnecessary .

Wow you were watching!  Actually Simon with another race next weekend this was about the best alternative. Sourcing another hub and matching spokes would have left me without enough time. There was no other way I could imagine mounting the sprocket far enough from center, but you're right it was a tad complicated. It is brick #$%*house strong and it will work fine!

Looks good to me. Now that I have a better grasp on what you're dealing with, that appears to a proper solution.

[RAFster122s]

Overbuilt has its place as long as it does not cause the next weak link to rear its ugly head. Hope the issues are out of the way for the rest of the season now that is done. What is your son racing?

[MRieck]

All that frame for a 400.

[bwaller]

All that frame for a 400.

True Mike, it had to be ahead of it's time. We've improved the chassis/handling (I think!) and will shoehorn a 600 into it next winter.  For now as TimV840 said the 15K screamer will be fun.

[RAFster122s]

Good luck with the races this next weekend. I hope you are ready, have any needed spares, and it is an uneventful racing weekend for all competitors.

[bwaller]

I wasn't a happy pup Friday morning at the track when I discovered there were gearbox issues. This is leftover from the sprocket failure at Laconia when the rear wheel locked for a split second and obviously sheared four teeth. End result is four ruined gears.

I feel like a bonehead for not dreaming there could be gearbox damage and starting the engine once the sprocket carrier was built. I just missed one of four races....and the points I need.

The next issue will be whether or not I can get my parts back from undercutting in time for the next race in four weeks. One little failure has spread into a nightmare.

[Retro Rocket]

OUCH....

[TimV840]

Heart breaker for sure Brent. Like you said at the time, good thing it happened heading out to the track, and not at full speed. Hopefully you have a back up plan in case those gears don't show up. At least the young fella did ya proud on the little FZR4!

[Tintop]

Heart breaker for sure Brent. Like you said at the time, good thing it happened heading out to the track, and not at full speed. Hopefully you have a back up plan in case those gears don't show up. At least the young fella did ya proud on the little FZR4!

+1....and now we know why he's in a different class.

[RAFster122s]

Brent, Ugh! What an unlucky break. Some of those teeth failed with a sheer break that was pretty clean. That one gear took it especially hard. Hope there is no case damage or bearing damage.

Hope you have the replacements back with sufficient time to install and adjust and test things before the next race.

So, I take it from the other comments the son's new bike did well?  Do you have a thread or photos you can share?
Kudos to him for the outing performance sound like they are in order.

David

[simon#42]

cant see the sprocket failure causing the gearbox problems , more likely the gearbox failing locked the wheel and caused the sprocket to fall to bits .

[bwaller]

I wouldn't expect anything less than an astute observation Simon. The thought crossed my mind since that 3/4 mainshaft gear was missing three teeth from 3rd and one from 4th. 3rd on the countershaft was cracked, but 4th only a scar from where I think one tooth from 3rd may have lodged. I did say it was ruined and I sent it to Ellis in the UK for his observation or replacement. The gearbox doesn't show any other signs of locking, engagement dogs all seem fine, there is no extra play anywhere, I spent a great deal of time shimming for that. I know what it must look like, and l can't say with certainty it did not.

However I do know I was taking a risk with that rear sprocket as it was. I was bound to make that race...however foolhardy. When it let go I barely felt a tug at the rear. The shark fin toe guard held the chain on the axle spacer after the sprocket came apart, but the gearbox was not locked at any time after I was aware the sprocket failed.

I have one gear on the way to the UK in case it needs replacing, it's a 32T. The original is 33T and I sent that with the other three original CB360 gears to Fast by Gast for undercutting. Worst case if I don't get the 32T back in time I'll use the 33T and have the 3rd gearset at a slightly wider ratio, 1.375 instead of 1.333.

I'll also clean up another crankshaft & cases and assemble with an undercut 5spd I have here, then just put this top end on it it all else fails and F by G don't deliver.

Murphy's law boys, and I'd just rather be racing. 

[simon#42]

put the shafts between centres and check they are straight brent ,  when a tooth comes off and jams the force is trying to push the shafts apart, there probably wont be any axial damage or damage to the dogs from this type of failure . when 250 aprilias do this it normally wrecks the shafts and cases . hard to tell what has caused the initial problem but i would guess at a manufacturing fault in one of the gears [ on one gear a tooth has come off very neatly , i would suspect this one . ] .  its about time you got professional and started taking a spare engine with you anyway !

[bwaller]

put the shafts between centres and check they are straight brent ,  when a tooth comes off and jams the force is trying to push the shafts apart, there probably wont be any axial damage or damage to the dogs from this type of failure . when 250 aprilias do this it normally wrecks the shafts and cases . hard to tell what has caused the initial problem but i would guess at a manufacturing fault in one of the gears [ on one gear a tooth has come off very neatly , i would suspect this one . ] .  its about time you got professional and started taking a spare engine with you anyway !

The cases are fine but I didn't check that the shafts are straight. I'll do that on their return.

I was fit to be tied last weekend. There's nothing worse than watching your class run. You're right and I am going to start working towards a spare engine even if it's not fully developed right off. Better than sitting on the sidelines. I would like to build a new gearbox with heavier "square dogs" anyway. My friend and pit neighbour has a spare engine & was rubbing it in....somewhat easier with a Ducati 250 single.

[RAFster122s]

I understand that frustration and heartbreak Brent. Experienced it a few times myself when I raced RC cars and things went "sideways" during a heat race or the like...

At least with the 550 you can put the motor in the frame without pulling the heads, so it is potentially a lot faster than trying to replace a motor into a frame for a 750.  You would want some air tools to speed things along on the removal and good wire cutters for the wired fasteners. It would be a race against time I'm sure.
It would be something I would want to practice once or twice to see what kind of time is needed for the job so you know what you need for catch containers and fasteners and bolt sizes.
Would be a good idea to build a book with fastener sizes and torque values so you can have a summary chart to have the tools on hand/laid out so you can be faster at doing the work.
No need to make the job harder than it needs to be, and job aids are a good quality item to have on hand.
Laminate them to keep them oil free and if they are precision/tedious, then add checkboxes and use a "China marker" to check them off when sequence is critical.

Good luck!

David

[FunJimmy]

Would be a good idea to build a book with fastener sizes and torque values so you can have a summary chart to have the tools on hand/laid out so you can be faster at doing the work.

Na, what he needs is a crack pit crew like you & I, David.
We could bring a compliment of the finest cordless air tools, spares and gitter  done.

Sorry to hear (and see) this major setback Brent.
Keep your eye on the prize.

Jimmy

[RAFster122s]

Would be a good idea to build a book with fastener sizes and torque values so you can have a summary chart to have the tools on hand/laid out so you can be faster at doing the work.

Na, what he needs is a crack pit crew like you & I, David.
We could bring a compliment of the finest cordless air tools, spares and gitter  done.

Sorry to hear (and see) this major setback Brent.
Keep your eye on the prize.

Jimmy

Brent, Yes, definitely keep the eyes on the prize and focus on the track.
Jimmy, Would be fun to pit for Brent and get to wrench on the bike a bit. Letting him focus on racing.
He could pay us in apple cider between tasks on prepping the bike.  It is good for you and apples have bioflavinoids which can help reduce occurrence headaches if you are prone to them. Apples and things made from whole apples (cider of both varieties might help but more likely soft cider rather than hard cider would be better for you nutrionally speaking...) Save the hard cider for the celebrations.
David

[turboguzzi]

hi brent, simon is definetely onto somehitng.... could be that the two problems are even un related.... when did the sprocket colapse exactly? when you let the clutch out in 1st, upshift to 2nd? if yes, then the broken gear is unrelated.
meaning, good that you improved on the carrier solution, but sounds like it was gear failure.

if it borke on the upshift to 3rd its another story....

[bwaller]

It was the instant I grabbed 3rd gear, so agreed, it logically smells like a gearbox issue. The 3rd gear input shaft is missing three teeth, 3rd c/shaft is cracked through. The cleanly broken tooth is 4th gear input shaft. The rear wheel lockup was barely noticable so whatever happened was over in a heartbeat.

I'll be without both shafts for the next while so cannot say for sure if they straight...sure hope so. I went through the thing with a fine tooth comb looking for the wrong signs, obviously didn't think to check shafts in my haste to get them sent out with the new gears.

As much as I hate to say this, but if it wasn't the sprocket, I really hope the cause was gear failure. If indeed a manufacturing fault caused a tooth to break it is the best solution for me. Hell of a thing to hope for, but I don't need to be worrying about anything other than my riding!