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A bike like the 'toy' 250 isn't on Heli's radar and probably won't ever be...
Don't be so sure. It's business, it's a numbers game. If theirs enough bikes out there, and enough demand, I bet they'd be only to happy to take your money.

Case in point, I've got a set of Heli Risers on my FJR. Not a high volume bike by any means. Hell, most ppl have never even seen one before and think it's a BMW. But they make risers and replacement top clamps etc..
 

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Don't be so sure. It's business, it's a numbers game. If theirs enough bikes out there, and enough demand, I bet they'd be only to happy to take your money.

Case in point, I've got a set of Heli Risers on my FJR. Not a high volume bike by any means. Hell, most ppl have never even seen one before and think it's a BMW. But they make risers and replacement top clamps etc..

That's kind of what I'm afraid might be the case, only a nutjob would want to make the 250 a long haul bike. There won't be any massive demand :)

If Tyga has some machinery to easily produce small batches or even one-offs of some tallers bars off of a pattern, then I'd be happy to give them my money...
 

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Discussion Starter #44
Excellent, thankyou very much, thats a quality bit of kit and looks further forward as well as 25mm lower, i'll put a pic up in the morning of the std bars same overhead aspect to compare.

Down and forward is what I want, and a little wider.

The bars are drilled for 2 positions where the control tabs lock in - and yes, they're wider than stock, if you set them up that way. Also somewhat lighter, too, especially if you leave the barend weights off/out as I did. A little buzzy, but not bad IMHO.

WW
 

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Decided late yesterday that im going to do a track day. I've been dragging the stock pegs since day one on the local mountain, so I want rear sets for the track. Called Bill up and he went out of his way to make sure they get here by friday. Great customer service, and o will for sure be ordering from him again soon. Thanks again Bill
 

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Discussion Starter #48
tlh89 - thanks for the props. Don't hesitate to call if you need help or have any issues: (775) 293-TYGA.

arn - no 15T fronts or 35T steel rears. Long life steel is your goal I suppose? I'm curious how long the life of an aluminium sprocket will be on this bike. Pretty long with proper care, I'm betting.

WW
 

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Have you guys done any testing with the sprockets, had seen written 2 teeth up give a bit more acceleration, a bit more pulling power in the top of 6th while leaving top speed relatively unchanged. Sounded a bit weird to me, but I don't no squat about gearing.
 

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Discussion Starter #50
Have you guys done any testing with the sprockets, had seen written 2 teeth up give a bit more acceleration, a bit more pulling power in the top of 6th while leaving top speed relatively unchanged. Sounded a bit weird to me, but I don't no squat about gearing.
Would rather not quote heresy, as I've not tested on this bike personally - however - based on past experience - the above sounds about right. The top speed is mostly a factor of drag/HP relationship, and gearing doesn't actually change that. Don't know the final drive ratio of 6th off hand, but regardless, 2 up on the big sprocket (rear) will only help acceleration, and RAISE cruise RPM (thereby lowering MPG a tad).

It is a tough call where to go with this bike. I tend to swim against the current with gearing. Just had this discussion a few days ago with a member here. My plans are to actually drop a tooth or two in the rear, or possibly bump one up in the front.

Why?

Well, 1st gear is already basically useless. This makes it useful. Yes, in the end 6th becomes less useful for acceleration (the fun is in shifting, you do know that, right?) and ultimately drops RPM's at highway speeds (read - potential MPG increase with the right twist of the wrist). Effectively, you might turn your 6 semi-useful gears into 5 quite right gears.

That's the path I plan to take. If I fail, using aluminum sprockets, I haven't broken the proverbial bank at least!

WW
 

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At less than 8000 km, the stock front sprocket is already showing signs of the teeth bending, and that is why I was keen on replacing it with something harder. FYI, the hardness of the stock sprocket is 58.

I've noticed that the bike seems to be running itself out of the powerband in 6th fairly easily. Higher top speeds are not of much interest to me, but cruising speed is. Hopefully, with the extra tooth , 7500rpm should give me 120kph (gps) or about 127 speedo. I'm planning to redesign the front fairing as well, which should give much better aerodynamics sitting upright, so, hopefully, the slight drop of torque at the rear wheel due to the taller final drive ratio should not make a difference, esp as there is more engine torque at lower rpms once the motor is past peak torque.

Seeing the difficulty in fabricating the inner splines, I'm really tempted to make a two piece sprocket (design similar to the brake rotors) so that I can simply swap the worn out teeth with a fresh set, reusing the inner splines, which never wear out anyways.

Pity there are no readymade 15T front sprockets on the market....
 

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Discussion Starter #52 (Edited)
At less than 8000 km, the stock front sprocket is already showing signs of the teeth bending, and that is why I was keen on replacing it with something harder. FYI, the hardness of the stock sprocket is 58.

I've noticed that the bike seems to be running itself out of the powerband in 6th fairly easily. Higher top speeds are not of much interest to me, but cruising speed is. Hopefully, with the extra tooth , 7500rpm should give me 120kph (gps) or about 127 speedo. I'm planning to redesign the front fairing as well, which should give much better aerodynamics sitting upright, so, hopefully, the slight drop of torque at the rear wheel due to the taller final drive ratio should not make a difference, esp as there is more engine torque at lower rpms once the motor is past peak torque.

Seeing the difficulty in fabricating the inner splines, I'm really tempted to make a two piece sprocket (design similar to the brake rotors) so that I can simply swap the worn out teeth with a fresh set, reusing the inner splines, which never wear out anyways.

Pity there are no readymade 15T front sprockets on the market....

Do we know that there are no 15T front sprockets for fact? I mean -let's be realistic here. Honda, a Japanese company, works diligently on profit margin, ROI, etc. I don't personally have any reason to believe the front sprocket is anything special. In fact, I'll bet there is another bike out there with the same spline!

Bike is new to the market. Aftermarket takes time to catch up (hey, they're in the business of making dough too). Somebody pull their front sprocket and mic/measure spline angle, etc. Maybe simpler is find the Honda OEM part # and micro-fiche/cross reference...

Just a suggestion :cool:

WW

(you can lead a horse to water, but....http://tyga-performance.com/cbr250r/CBR250RB PARTS MANUAL.pdf)
 

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Do we know that there are no 15T front sprockets for fact? I mean -let's be realistic here. Honda, a Japanese company, works diligently on profit margin, ROI, etc. I don't personally have any reason to believe the front sprocket is anything special. In fact, I'll bet there is another bike out there with the same spline!

Bike is new to the market. Aftermarket takes time to catch up (hey, they're in the business of making dough too). Somebody pull their front sprocket and mic/measure spline angle, etc. Maybe simpler is find the Honda OEM part # and micro-fiche/cross reference...
Digging for parts using the number is not helpful, unfortunately. There might be some obscure bike there somewhere with a similar part, but I'm not going to excavate for a month to find it. I already had the parts manual, thanks :)

Trying to measure angles is not an option either when the teeth are bent. I'm working backwards using the chain (fresh!) as a guide. As of now, the gear chaps are refusing to cut the the splines for a single piece (too complicated) so I'll have 3 pcs wire cut ($$$$) :( . However, I'll be cutting the teeth and hardening only one to 62, and then take the rest from there.

I'd have happily bought the chain sprocket kit from Honda, but as with every other part and consumable in India - it's out of stock (and will not be in stock for the foreseeable future).

I'll probably have to shop at your store for the OEM parts
 

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Discussion Starter #55
arn -

Let's throw our noggins together. Honda doesn't make brand new sprockets for bikes, at least not this bike. There must be a simple fix - I'm sure of it.

My CBR goes to a photoshoot with some fine females (and gents) on Friday - so no disassembly possible here. After that I can tear in full bore....

WW

(we don't have to measure the chain-side teeth - we know the chain pitch - just need to know the shaft spline count and width/depth/spacing. Easy measurements with a simple digital micrometer)
 

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Just machine and drill one to suit.

It only needs one or 2 teeth up on the rear.. std chain can be used.
 

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Arn, would that hardness be rockwell 'c' scale by any chance? The sprocket might be only case hardened, and the body of the tooth softer. I would use chrome moly, and through harden it to 45-50 Rc. This is a 250. Also it sounds more like a lube/dirt problem wearing the tooth down til it starts bending. I would definately go tougher, not harder. Maybe yours missed a heat treat, and another one might last longer.
 

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I'm not sure what scale they use here to check for hardness (Rockwell/BHN?), I'll find out and let you know.

I had made sprockets for my previous bike too, a Hero Honda Karizma (basically a castrated and cosmeticized CRF 230, 17ps at the crank) partly because I wanted taller gearing, and partly because as the Hero and Honda split became imminent, metal (and all spares) quality started to go right down the drain. I've had a chain stretch out completely in 3000 km...no, I did not miss a zero. The drive sprocket teeth took an interesting shape within 8000 km (almost 15 degrees of deflection, if not more!), and you have to bear in mind that Hero Honda and Honda shared the same vendors for a lot of parts, which might account for the crappy component quality in some of the bikes sold in India.

Lube / dirt wearing it out is a possibility, but then, it would have been a constant with my previous bike across all the chain sprocket sets, as I used wheel bearing grease combined with spent engine oil from a home made oiler for my longer trips (5ml/400km, basically just after every fuel halt on that machine). With the CBR, I am using Motul chain lube after cleaning (kerosene/motul cleaner) every 500 km or so.

My sprocket was made out of WBS (a die material), but hardened (not just case hardened) only marginally more as the machinist had the same concerns that you voiced. Well, nothing broke, but the teeth were bent when it was time for the chain to be replaced (Bajaj Pulsar 220 with 2 extra links) after about 25000 km of usage. Not to the same degree at all as the OEM chain after 8000km, but definitely bent, and 40% more power on tap will make it bend even faster for sure.

That was my reason for deciding to up the hardness over the (obviously too soft) OEM Honda sprocket. I will be only hardening and using one of the 3 blanks, the other two (with countershaft splines cut) will have the teeth cut/hardened once I see how this behaves, and that will take time. Actually, I have some trips planned once the bike is modded so, maybe it will not be that long. :)
 

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I emailed Tyga Performance in Thailand & they replied. (They already have rears 37T - 44T)

"Yes, we will hopefully have stock of 13, 14 and 15T sprockets for the CBR250R shortly."
 

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Discussion Starter #60
Well there you have. I should have all of the rears in stock in a week or so (just waiting on their arrival - not sure if current weather events are going to delay them or not). I didn't know they were working on the fronts - they're a quickly moving group of folks - sometimes it is hard for even me to keep up!

Bill
 
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