Project Big Bore

router.exe wrote:

big bore and thumper racing are 2 different companies. i'm still waiting to see TR's dyno results. especially since powercommander is going to do map for them on the 30th.

Yes, I know.

The TR kit ($530.00) requires sending your cylinder to them so they can re-sleave it with a larger bore steel sleeve (280 CC's). The Big Bore Thumper kit (290 CC's) is supplied with a new cylinder that is aluminum and flash coated. With freight sending your original cylinder back and forth to TR, the Big Bore Thumper 290 cc kit ($699.00) is not that bad and it's just a straight bolt on affair (no machine work). I would rather get the additional 10 CC's and still have my stock cylinder and piston intact to go back to if needed or when selling the bike.

I'd like to see both on a dyno and get the piston weights for both. The TR piston is about 12 grams heavier then stock. I really want to keep this bike smooth!

Take care,

Greg

YamWOW! wrote:

Sweet can't wait for the review. Did you say they were going to have it in a magazine? I sent a pm to Travis I think it is on TT to post on this site in the vendor section or somewhere on the forum if he wants to.

Thanks. Just posted there. The kits are now available. I didn't want to post until the kits were complete and on the shelf. Maps for PC will be available Friday.

Also we are offering wr250r members an additional $50 off the kit with sleeve install until September 1.

DirtRider has expressed an interest in the bike as well as 2 other magazines Dirt Rider is first in line. I will know for sure once I'm done with the PC tuning next week

One positive point for the Thumper Racing kit is they will offer an oversized piston for re-boreing it if you need to. If you score or mess up a flash coated cylinder (Big Bore Thumerps kit) it's time to buy an new cylinder....

Just another point to consider when choosing....

Greg

Akoffroader wrote:

router.exe wrote:

big bore and thumper racing are 2 different companies. i'm still waiting to see TR's dyno results. especially since powercommander is going to do map for them on the 30th.

Yes, I know.

The TR kit ($530.00) requires sending your cylinder to them so they can re-sleave it with a larger bore steel sleeve (280 CC's). The Big Bore Thumper kit (290 CC's) is supplied with a new cylinder that is aluminum and flash coated. With freight sending your original cylinder back and forth to TR, the Big Bore Thumper 290 cc kit ($699.00) is not that bad and it's just a straight bolt on affair (no machine work). I would rather get the additional 10 CC's and still have my stock cylinder and piston intact to go back to if needed or when selling the bike.

I'd like to see both on a dyno and get the piston weights for both. The TR piston is about 12 grams heavier then stock. I really want to keep this bike smooth!

Take care,

Greg

The piston weight was a big factor when we desided on the bore size. a stock piston weighs in a 184g our 81 weighs in at 192g. If we had went to a 83mm bore we would have had to have used a bigger forging when making the piston and that piston would have come in at 205/207g and caused some vibration.

I've been beat up a little for this on the other forums but the fact is at an 83mm piston size the cylinder wall that slips into the case would only be 1.75mm thick (.068") the case opening is only 86.5mm (83mm-86.5mm\2=1.75mm). While this is ok for a steel or ductil cylinder it is very thin for an Aluminum cylinder like the other kit is made from. I worry about distortion and warpage under heavy loads and hi rpms. Most engineers I know won't go less than 3mm wall thickness when using aluminum which is pretty much the standard min thickness in the industry. -Just something to think about.

I stand corrrected, the TR big bore kit piston is 8 gram heavier, not 12 as stated in my previous post.

I think what most of us are waiting for is a dyno report to see we get out of a big pore kit for the money spent and hassle of doing it.

Take a slip on pipe or complete exhaust system for an example. We spend $300.00 to $900.00 for a 1.5 - 2.0 hp gain with an after market exhaust.

What does $570.00 for a big bore kit get us?

I personally woud ike to see a dyno run done on a stock bike to establish a base line. Then do a controller and airbox mod. run. Then add an after market exhaust (Q4 is the most popular so use it. Then add the big bore kit for the final run.

This would be something we could get our minds around when spending $$ for these mods.

Take care,

Greg

ThumperRacing wrote:

I will know for sure once I'm done with the PC tuning next week

Will there be a dyno chart that comes out the pc tuning?

Akoffroader wrote:

I think what most of us are waiting for is a dyno report to see we get out of a big pore kit for the money spent and hassle of doing it.

Take a slip on pipe or complete exhaust system for an example. We spend $300.00 to $900.00 for a 1.5 - 2.0 hp gain with an after market exhaust.

What does $570.00 for a big bore kit get us?

I personally woud ike to see a dyno run done on a stock bike to establish a base line. Then do a controller and airbox mod. run. Then add an after market exhaust (Q4 is the most popular so use it. Then add the big bore kit for the final run.

This would be something we could get our minds around when spending $$ for these mods.

Take care,

Greg

I understand everyone's concerns. I have the same ones when spending my hard earned dough on mods. Altough we are only a few days from seeing the actual dyno results, having ridden the TR bike I will say the difference in power over a stock 250R is dramatic. I know this is just a "butt dyno" and take it for what it's worth, but Travis's 270cc kit is nothing short of amazing. It was difficult to keep the wheel down and I weigh 200. It feels more smoother and powerful than my tuned WR250F which sits around 34hp.

I think the bigger picture after all this blows over, and we see the benefits of either system, is who you want to fork your money over to. Someone like Travis who has taken the time to work with us and address our concerns or Athena, which has provided limited feedback to the community, at least, to my knowledge.

I've posted a few question on this on TT and at this point I'm just waiting for the PC tune to be done.

The only decision I have left to make is do I buy a new cylinder and send that to get the sleeve put it. (no waiting for UPS and machine work = 1 day of down time) Or do I tear down my bike and be out of being able to ride for a week or two. The first option always allows me to go back to stock and sell the BBK if I feel the dumb urge to do something like that.

I would really like to keep my stock pipe but gain some more hp. I've done the air box mod and have an FMF fuel tuner. Just can't bring myself to pull the trigger on an after market pipe with the additional noise and repacking.

One of the reasons I like this bike it because of the long service intervals. Repacking a pipe every thousand miles or so, kind of takes away from the "ease of ownership" of a WRR.

Funny thing... I was just viewing the Yamaha Tenere site (www.xt660.com). In the mod section the biggest hp gain for the work and $$$ spent was opening up the airbox and adjusting fuel delivery through a PCIII. The next biggest gain was a big bore kit and cam. Adding a pipe did not do that much for gaining HP....

Greg

Dyno results are in: click here

This was the same Dyno DynaJet used to test a stock WR. Athena/GYRT kited bike and the Thumper Racing built bike. Results from all 3 are attached. :)

Thanks for posting the dyno data
Q: How come the Thumper kit makes more @ the 5000 zone?, is that just in the EFI tuning?
And what fuel controller does the Athena kit use?

0007onWR wrote:

Thanks for posting the dyno data
Q: How come the Thumper kit makes more @ the 5000 zone?, is that just in the EFI tuning?
And what fuel controller does the Athena kit use?

It's mainly due to the Powerbomb header. the stock head pipe would move the power up in the curve.

I only know what I've been told as I have not seen the GYRT kit personally: The factory GYRT kit (made by athena) comes with a non programmable ecu set to GYRT specs.

Quote :

It's mainly due to the Powerbomb header. the stock head pipe would move the power up in the curve.

I would like to move the power down the curve on my stock WRR. Would installing the PowerBomb header on an otherwise stock WRR give me a little more oomph down low? Stock, as in no mods, exhaust, engine, intake, or other.

Akoffroader wrote:

One positive point for the Thumper Racing kit is they will offer an oversized piston for re-boreing it if you need to. If you score or mess up a flash coated cylinder (Big Bore Thumerps kit) it's time to buy an new cylinder....

Just another point to consider when choosing....

Greg

Not true at all. The Aluminum cylinder with Nicosil liners can be resized and refinished to spec as long as the aluminum is not damaged beyond repair. The company I use Millennium Tech can also weld aluminum barrels that have cracked and reflash the bore then finish to within 1 ten thousands. I have used them on my racings engines and they do excellent work. Easier than fitting a new steel liner for sure and very quick turnaround.

[quote="ThumperRacing"]

0007onWR wrote:

Thanks for posting the dyno data
Q: How come the Thumper kit makes more @ the 5000 zone?, is that just in the EFI tuning?
And what fuel controller does the Athena kit use?

It's mainly due to the Power bomb header. the stock head pipe would move the power up in the curve.

I have not had that experience with my dyno testing. The smaller diameter header (IE stock) will enhance low end power at the expense of top end power. My understanding of the power bomb is that it is a larger diameter than the stock header and therefore would move the peak power higher in the rpm range. Have you dyno'd both header pipes with the same muffler?

10Cup wrote:

Not true at all. The Aluminum cylinder with Nicosil liners can be resized and refinished to spec as long as the aluminum is not damaged beyond repair. The company I use Millennium Tech can also weld aluminum barrels that have cracked and reflash the bore then finish to within 1 ten thousands. I have used them on my racings engines and they do excellent work. Easier than fitting a new steel liner for sure and very quick turnaround.

I use Millenium for all our aluminum work as well but to say they are faster and easier than overboring and or replacing a sleeve is not true. We can turn around a cylinder in 2-3 days. Millenium is a minimum 10 days to 2 weeks. Stripping the old plating and then replating takes time it's not something that can be done in a day or two.

[quote="10Cup]"I have not had that experience with my dyno testing. The smaller diameter header (IE stock) will enhance low end power at the expense of top end power. My understanding of the power bomb is that it is a larger diameter than the stock header and therefore would move the peak power higher in the rpm range. Have you dyno'd both header pipes with the same muffler?[/quote]
It all depends on how the head pipe is configures and the motor itself. The Powerbomb is a stepped header meaning the first 8" is a smaller dia (same size as stock) than the next 8 inches. This configuration is a trade off between a hiflow large dia header and stock sized straight header and it tends to make better bottom/mid power over a straight large dia header which will usually make better peak power.

well i would hope that the big bore kit would put out more than 30 whp as mine is putting out 31 whp with a pc3, opened airbox and the gytr exhaust (plus dino tuned).

i have een considering the athena kit... could cope with another 5 or so hp so am looking forward to hearing how this kit goes

MrZ32 wrote:

well i would hope that the big bore kit would put out more than 30 whp as mine is putting out 31 whp with a pc3, opened airbox and the gytr exhaust (plus dino tuned).

i have een considering the athena kit... could cope with another 5 or so hp so am looking forward to hearing how this kit goes

if you are making 31hp with those mods you will add another 4 hp or so with a big bore kit. Don't focus on the numbers you see on any dyno sheet. In all honesty dyno numbers don't mean much they are only a base line for the change you will see. Did you do a before and after run on your bike with the same variables applied to both runs, on the same dyno with the same operator when you got your peak reading of 31hp? Or did you make your changes add your bolt ons and then went to the dyno? I'll bet the later. One little change in a variable can drasticly change the readings for a specific run. The only way you can know for sure what the bolt ons added to your bike is to have a baseline run before making any changes. I'll bet if you had a baseline run your bike would have dynoed at 29hp or so. And there wouldn't be near the power increase you thought you got out of the few bolt ons you added. I'm not trying to disrespect you or anyone else just offering an insite to the realities of dyno testing.

ThumperRacing wrote:

If you are making 31hp with those mods you will add another 4 hp or so with a big bore kit.

Makes sense based on my butt dyno. You can read about my big bore experience https://wr250rforum.forumotion.com/oh-those-sweet-mods-f5/thumper-racing-big-bore-installed-t974.htm.

the bike before the mods was putting out 23whp... back in feb (only had 2000kms on it at the time) was tested with the mods at the same place... similar temp day but with the mods and 12500kms under its belt.

MrZ32 wrote:

the bike before the mods was putting out 23whp... back in feb (only had 2000kms on it at the time) was tested with the mods at the same place... similar temp day but with the mods and 12500kms under its belt.

Not to beat a dead horse but a 7hp gain is not realistic for the mods you did. Something changed in your testing.

[quote="ThumperRacing"]

10Cup wrote:

Not true at all. The Aluminum cylinder with Nicosil liners can be resized and refinished to spec as long as the aluminum is not damaged beyond repair. The company I use Millennium Tech can also weld aluminum barrels that have cracked and reflash the bore then finish to within 1 ten thousands. I have used them on my racings engines and they do excellent work. Easier than fitting a new steel liner for sure and very quick turnaround.

I use Millenium for all our aluminum work as well but to say they are faster and easier than overboring and or replacing a sleeve is not true. We can turn around a cylinder in 2-3 days. Millenium is a minimum 10 days to 2 weeks. Stripping the old plating and then replating takes time it's not something that can be done in a day or two.

Gett'n kind of sensitive aren't we? Go back and read my post again. I think arguing about the turn around time was not what was being questioned, I merely said "very quick turnaround". Secondly I did not say one was faster than the other on turn around, quit making up BS fella. My only point was that Nicosil cylinder can can be repaired just as easily as replacing a metal sleeve and that is a fact. I'm not taking sides here not sure which I might opt for should I choose to go with the big bore its just clearing up the point on repairing Nichosil. Chill

I've not been able to find the actual dyno charts for the TR 280 kit. Can anyone provide a link to them? Since this thread is pretty old, can anyone update their experience with the kit -- sort of a long term report? TIA