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mytzlflick
05-31-2003, 04:44 PM
ok how does one go about making this kind of power? its for an all out racebike, no streetability required at all, fairly constant maintenance is not a big concern for me.

ecumike
05-31-2003, 05:16 PM
Buy a TZ250 :)

Or this 250... www.gpstar.net/show_produ...ycles2.php (http://www.gpstar.net/show_product.php?id=17&back=%2Fmotorcycles2.php)

mytzlflick
05-31-2003, 06:23 PM
I can't afford either and the aprilia is paid for so I'm stuck with it (yeah thats hard to live with right)

rs
06-02-2003, 06:24 AM
you wont,

about 75bhp is your maximum, and that comes at a high cost. you'd be better aiming for 70bhp

mytzlflick
06-03-2003, 03:44 PM
lets assume for the sake of argument that I like many people cannot part with the bike for something faster. I am willing to buy racing fuels (114-116 octane both sunoco and trick are available here) replace rings and pistons on a depressingly regular basis say every second race weekend, I'm planning to run slicks so hooking it up shouldn't be too hard.
what mods does it take to make competitive power and how light can you make the bike without exotic components? (don't think I can handle $200american for a ti front axle to save a half lb or so)

Duc995
06-03-2003, 03:47 PM
You won't reach 70 bhp without spending over $3000 US for a 316 cc plus a pipe...the laws of physics can't be bent with a can of gas....sorry:(

ecumike
06-03-2003, 04:03 PM
You can get some work done by Speedwerks for ~1K (I think) to get ~67/68 + weld crank + pipes = ~$2K.

Joe (he's on the board at times) did this to his bike and it's pretty damn fast. He could tell you more accurately about how much $$ it was.

Joe?

mytzlflick
06-03-2003, 05:36 PM
I have arrows on it now, the big bore kit is out, I don't even want to consider what class that would put me in, probably open

micah apriliaforum com
06-03-2003, 05:50 PM
70bhp (dynojet) should be atainable with 250cc....I am going to try. I have run stock cup bikes on a dynojet that did 65.5bhp so I know 70 is atainable....I know it is.

ecumike
06-03-2003, 06:47 PM
Yes, the work that SpeedWerks does keeps the bikes at 250cc. However I don't know the exact 'secrets' that they do to it.

Stu Jones
06-03-2003, 11:16 PM
Fitting the Suzuki full factory kit electrics and exhausts and doing some mods to the airbox and air system will see you get around 68hp. A bit of tuning work on top will see just over 70 and be reliable especially if you can run a decent race fuel. Only problem is the genuine kit pipes are not made any more, the best I have found to work with the higher revving kit ignition are the Lomas pipes.

makkko
06-04-2003, 06:52 AM
=> Stu Jones


who is Lomas (pipes)?
i'm new here... :rolleyes:

RegganiRS250
06-04-2003, 12:51 PM
Stu, I found a link to Sugaya Exhaust's web page and they list like 3 or for pipe designs for the rgv and 2 for the RS. I cant make anything out other than the bike types, because its in Japaneses. But is it still possible to order Sugaya pipes? Would any of these be the same as the "kit pipes"? Or have you heard about or tried any of them? Also they show an CDI unit, would this be the same as the kit one or one of their own?

Here is the link:
www.srs-sugaya.com/special.html (http://www.srs-sugaya.com/special.html)

mytzlflick
06-04-2003, 03:10 PM
ok I'v read everything i can find and it seems the common things are:
straight plug heads, more squish, up compression
tz250 pistons with single ring, mods required
port cleanup / smoothing
epoxy cases, match volume side to side
already have arrows, keep em for now I think.
dry clutch?
magneseium magneto (generator) outer
38-39mm carbs
open up airbox

going to do some work to try thin the bike down to 300lbs fueled, anyone have an idea how much faster than stock this will be?

65hp stock? dosn't feel like it on mine at all, I need more.

ecumike
06-04-2003, 03:36 PM
"300lbs fueled" is that with a full tank? Is that even possible on a Cup bike?

Don't forget the Blackstone Tek carbon wheels, but those'll only drop ~5 lbs.

And BTW.. When Micah said he has had 65HP for stock bike on the dyno... I don't think that was meant to be taken that ALL 250s should have 65HP. From what I've read and heard, I think the norm for stock HP ranges around 60-62.

Dude, don't get me wrong here, I love this bike, and I'm not trying to discourage you from modding it or even keeping it. I'm just trying to keep it real so you won't be dissapointed and badmouth your bike if what you want doesn't happen.

If you can get all the parts, and spares and have the reliability factor still there for 70+ HP for under $3000, I'd be interested in doing it to my bike, as an option to the 316 kit.

Have you priced out all this and reliability factor... would it be as cheap/cheaper to sell the Ape, and pay the difference for a used TZ?

keean
06-04-2003, 04:33 PM
You seem to have got most of the standard mods... my thoughts on what to do would be slightly different... This is basically my todo/wishlist - don't know what anybody else will make of these mods - They are carefully chosen (I hope) to improve performance without too much loss in reliability.

- straight sparks, truncated hemispherical chamber, sloping squishband (not flat). Set compression for 98RON pump fuel (super-unleaded)
- blueprint transfer ports, change powervalve profile, to increase exhaust exit velosity - the lip on the static part is ground to a smooth slope blending with the other two stages when fully open.
- lighten conrods (use titanium ones) this will improve max rpm limit from conrods... keep flywheel weight standard for easy idling (as the weight is not reciprocating it does not have much effect on max RPM)
- fit ceramic or ceramic-hybrid bearings throughout crankshaft and gearbox - also wheels.
- flow (by grinding) then pack crankcase to improve primary compression...
- use enlarged airboxes (two separate ones, with one carb inside each airbox - connected to front air scoop and fuel tank for ram-air)

The next few mods will require a new ECU - there is nothing on the market at the moment that can do this... but its not impossible to DIY...

- new powervalve controller that uses a combustion pressure sensor ( www.optrand.com/intro.htm (http://www.optrand.com/intro.htm) ) to measure the exhaust return pulse and adjust powervalve to time it exactly.

- electronic pressure release valve for crank-case allowing reduction in primary compression using a chamber attached to the crank-casing. This allows a reduction in pumping losses due to crank compression in the powerband.

- electronic valve to vary the length of the loopback pipe on the carb rubbers. This allows the pipe to appear connected at low RPM and disconnected at high RPM (best of both worlds).

- electronic valve on airbox throat to reduce area of opening at low RPMS...

- electronic water injection into exhaust header at low/mid RPMS for better exhaust timing. (not sure about this one as it requires a water tank)

- a combustion pressure sensor actually in the cylinderhead can be used to prevent detonation and adjust mixture - if the carbs are replaced by an EFI rail firing into the crank-case, Its not DiTech, but the ECU can adjust the mixture in ways a carb can't.

micah apriliaforum com
06-05-2003, 01:22 PM
Most of the totally stock bikes were in the 55 to 61 horse range.

TedMeyer
06-06-2003, 07:41 AM
I wanna get back to the "300 lbs fueled" question. That seems not-too-aggressive to me. Assuming the 295 claimed unfueled weight is right, what is the full-wet weight? 330? I didn't weigh them, but it seems like pipes alone would get you close to your goal.

Here's what I've done, the cost, and the weight savings:
JM Pipes, $600, -20 lbs (estimate)
BrakeTech rotors, $550, -4-5 lbs
Compact sealed battery, $15, -2.5 lbs
Twist-off gas cap, $50, -1.25 lbs
GPTech fairing bracket, $140, -1.5 lbs (estimate)
Alloy sprocket, $40, -.5-1.0 lbs (estimate)

Every single item on this list I bought for a reason OTHER than weight. The weight savings were a factor, no doubt, but this stuff is also more functional.

Other obvious areas to cut: Ti shock spring should shave about 2 lbs of partly-unsprung weight ($475). Race bodywork cuts some weight ($550+). You could ditch the key-switch for a dollar or two. I suppose you could do the Ti nuts and bolts, but that seems to be about the worst value on the planet on a $/gram basis. And the other big one is the wheels -- the most expensive option, but possibly the best one.

Anyone found any other obvious weight-savings? The one I'm working on now is slimming down my own fat ass!

Ted

ecumike
06-06-2003, 08:00 AM
<blockquote><strong><em>Quote:</em></strong><hr>Anyone found any other obvious weight-savings? The one I'm working on now is slimming down my own fat ass![/quote]

Hehe, yea, it's probably the best and cheapest one to do, ironically though, the hardest. ;)

spanairRS125
06-06-2003, 08:49 AM
Why not just buy an RSV, you can get 1 for about 13000 and they make 97 hp :cool:

Stu Jones
06-06-2003, 11:08 AM
300lbs is very easy to achieve. You are looking at a bike that tips the scales at 140kg dry standard. The pipes will knock off around 6-7kg on their own, the rest comes from bodywork and removing things that are not needed. I had my 91 RGV down from the 139kg standard to around 120kg dry with no fancy bits added. For racing a two stroke you should be starting the race with enough fuel to complete the race and leave enough for the regs. This normally equates to about 10kg of fuel, water and oil is around 2.5kg so you should be somewhere around 132.5kgs(291lbs) pretty easily.

With regard the question about who or what is Lomas pipes, they are pipes made by Jim lomas, badged either as Cougar or the earlier Scorpion.

makkko
06-06-2003, 04:53 PM
hello Stu.


..so these are Jim Lomas' pipes..:

www.50cc.nl/2stroke_pleas...asp~TsMain (http://www.50cc.nl/2stroke_pleasure.htm?jl_exhausts.asp~TsMain)


i read that Sugaya's pipes seem to be THE best on this forum, but i never find anyone who has them.


in your opinion, which is better? Sugaya or JL? and what about Tyga and Jolly Moto?



oh my God :(

Stu Jones
06-07-2003, 02:15 AM
Those are the pipes. With regard sugayas I was under the impression they were not being made any more but have recently seen someone who has gone over to japan and can get them for the VJ23 model RGV. They are the best especially if you are running other kit parts like the SAPC box. Running on a standard bike there is not a lot of difference between all of them.
My opinion in terms of performance would list them like this-
1. Sugaya and genuine Suzuki kit ones
2. Lomas
3. Jolly moto
4. Arrows and Tyga
5. Nikon
If you are just a road rider wanting a different system then the Lomas and Tyga Stainless pipes look very good and don't need the same looking after.

makkko
06-07-2003, 03:38 AM
i see.


i don't know if sugaya produce them now or not... they haven't any e-mail address too.

i'm going to build an rs 250 for race use, so i think i'll go for Lomas, Tyga or Jolly. stainless stell isn't a bad idea...
i'll have a look to find a pair of Sugaya too.

could you find out info on sugaya? [your friends? i don't know]

mytzlflick
06-07-2003, 08:17 PM
going to have to revise the 300lb goal, bought a scale today, 150lbs for the front tire, 128 for the rear, guess I better aim for 250 huh?