Overbore on black motor = no go?

[alextrx850]

now this is getting interesting.....

[phuk72]

Cheers, guys I think thats enough to let me know that I'm safe to go ahead

I'll let the guy know he was misinformed. He's got a six speed gearbox setup there too, what do you guys reckon it is worth? It's all new, still in packaging. A 260kph top speed is rather inticing for the tracks I'll be running the bike on.

I`m intruiged, one of Over`s 6 speed creations redkiwi?
Would be likely to have been at least 1,500 English quids worth if it is truly Over stuff, oh and a top whack of 160 mph for a TRX? Even a higher final drive ratio and tuned one might hit that on the 5 speed box.
According to the calculations a 17 / 33 sprocket arrangement might see you achieve it but don`t expect a clutch to cope with the racing starts on that gearing!

According to the dyno runs, mine hit a real 153mph on 17/42 gearing on the redline in 5th. On the autobahn in top I've seen an indicated 160mph @9000rpm (running a 70 section tyre) but it wouldn't pull any more.

As I understand it, the Over box used the same five gearbox ratios as the TRX with 6th acting as an 'overdrive' - this allowed you to play with the final drive ratios.

FWIW, even on fast tracks like Silverstone and Donnington, I wasn't hitting the rev limiter in top.

Aria pistons are 12.5 comp if memory serves - Zanx on here runs them.

A 6 speed box that bolts straight in will probably sell for well over £1000 - maybe double that to some folk!

[redkiwi]

He had an OVER OV15a 'customer bike' which he has sold and this is the left over spares package. He's asking $3k nzd, the gearbox parts are all yamaha bits from the TRX/XTZ/YZF750, I think the only special part is the selector drum which is worth about $500nzd wholesale on its own.

With the pistons I had, (probably 12.5:1), FCR41s and a full system I was only seeing ~230kph on a 1.25km back straight with a 60kph lead in. The OV15A was supposed to have a top speed of 270kph on 115hp and a fair bit less weight than your average TRX.

[cobbadiggabuddyblooo]

I find a poofteenth under 230 with a 16/40 gearing fcr's and local made 2 into 1 system..thats 9200rpm
stock motor

[redkiwi]

As I understand it, the Over box used the same five gearbox ratios as the TRX with 6th acting as an 'overdrive' - this allowed you to play with the final drive ratios.

I saw some thing recently that compared them, I think first gear is identical, but the rest are a different on the six speed.

[cobbadiggabuddyblooo]

look back also theres something about modding a 6speed from a yzf 750 wasn;t there..sure it isn't one of them

[phuk72]

He had an OVER OV15a 'customer bike' which he has sold and this is the left over spares package. He's asking $3k nzd, the gearbox parts are all yamaha bits from the TRX/XTZ/YZF750, I think the only special part is the selector drum which is worth about $500nzd wholesale on its own.

With the pistons I had, (probably 12.5:1), FCR41s and a full system I was only seeing ~230kph on a 1.25km back straight with a 60kph lead in. The OV15A was supposed to have a top speed of 270kph on 115hp and a fair bit less weight than your average TRX.

It was 115 at the crank and it wasn't as light as everyoen thinks - viewtopic.php?f=6&t=7939&p=81733&hilit=wasn%27t#p81733

Maybe it would make 170 mph on a runway but I very much doubt it would pull that in track gearing.

[phuk72]

As I understand it, the Over box used the same five gearbox ratios as the TRX with 6th acting as an 'overdrive' - this allowed you to play with the final drive ratios.

I saw some thing recently that compared them, I think first gear is identical, but the rest are a different on the six speed.

I'd love to see one (and ride a bike with one) but I really can't see it being worth the money

[redkiwi]

Alrighty then. I think I'll just get the pistons then, don't think I can justify $2k for the titanium rods either, which brings me to my next point.

My small end bearings are on the way out apparently. Can they be pressed out and replaced or do I need to get new con rods? If I do, what is the price difference like between carrillo and stock, as the prices I've seen have them at the about the same price ($375au ea) but I don't know how accurate or recent that is.

[emway]

He had an OVER OV15a 'customer bike' which he has sold and this is the left over spares package. He's asking $3k nzd, the gearbox parts are all yamaha bits from the TRX/XTZ/YZF750, I think the only special part is the selector drum which is worth about $500nzd wholesale on its own.

With the pistons I had, (probably 12.5:1), FCR41s and a full system I was only seeing ~230kph on a 1.25km back straight with a 60kph lead in. The OV15A was supposed to have a top speed of 270kph on 115hp and a fair bit less weight than your average TRX.

Alan Cathcart´s Over BOTT racer had a top speed of 258 kph(mettet)

[cal]

look back also theres something about modding a 6speed from a yzf 750 wasn;t there..sure it isn't one of them

Has Chris NWS (alloy frame) not got a modded gbox with yzf internals, dunno if its 6 speed though, enlighten us pls! also think he runs FCR41 carbs,
he might be able to tell rwhp top speed/ gearing final drive ratios/ sprockets