Took a plunge... trying a PP LXR250 EFI

[JerryHawk250]

You may want to look into getting some kind of radiator guard fabricated. Bike does sound a lot stronger. There's no replacement like displacement.

[Megadan]

I honestly wouldn't be surprised if the radiator guards for the same KTM XCW200 the fuel tank is for would possibly work on this bike as well. A little meauring tape work would easily answer that question. If so, then the frame style guards like the Moose Racing units would be a good option.

Every time I come back to this thread it makes me keep considering trading up my Hawk for one of these guys or an SSR SR450S. Stuff like the big bore kit doesn't help either! lol

[BlackBike]

Time for someone with a 2015 out of warr rx3 to step up and pop one on. 280cc would be help with winds and the grades

[Megadan]

What I would love to know is what they did to drop 6hp from the motor for the rx3. Same compression ratio, so it might be the cam profile, or something with the ports on the head casting. I would guess the camshaft, but no way of knowing.

[ChondaChondaChonda]

Originally Posted by Megadan

What I would love to know is what they did to drop 6hp from the motor for the rx3. Same compression ratio, so it might be the cam profile, or something with the ports on the head casting. I would guess the camshaft, but no way of knowing.

I don't think there is any difference in the motors physically. There are 2 things going on here.
1. The specs on the Pitster are known to be innacurate. The weigh and the gearing are verified to be incorrect.
2. Emissions compliance probably costs the RX3 a few ponies. My hunch is that the Pitster runs a much more fuel rich AFR across the tables and especially rich at high load/high throttle conditions. (Think accelerator pump rich) I can tell you that the bike runs on the rich side, you can actually smell it at times. No way that would pass muster on a certification test.

I bet if you were to dyno them side by side, then difference is less than 2hp.

[JagLite]

Doesn't the RX3 use a Delphi FI and the Pitster (Kayo) uses a different FI system?
The tuning could make a big difference.
Are both systems self-learning or just the Pitster?

[ChondaChondaChonda]

Originally Posted by JagLite

Doesn't the RX3 use a Delphi FI and the Pitster (Kayo) uses a different FI system?
The tuning could make a big difference.
Are both systems self-learning or just the Pitster?

Yes.

Both have an O2 sensor and will adjust to changing conditions, but the Kayo efi will be capable of running fatter because it has no certification requirements.

I have another bike that has a Race ECM, and the diffence in how the bike runs is night and day better. But, it's technically not EPA compliant for road use. It is stamped "Race Use Only" .

[Huck369]

I can't wait to hear what a difference the bump in displacement makes...my RX3 has always needed more bottom end, and more power over-all wouldn't be bad either...

[ChondaChondaChonda]

Sunny day here and most of the snow has melted off the roads, so I took the LXR for a spin. I put the stock 13 tooth front sprocket back on. Added about 15 miles to the big bore kit and let it rev out to redline a few times.

Motor pulls much harder on the bottom and is noticeably quicker in the mid range as it pulls through the gears. Hard to tell on the top end if it has any more. Had it up to 70 mph for a short time; bike feels about the same at sustained higher speeds. (Getting out on some higher speed hills might tell more) No difference in vibration or sound that I can tell.

As the sun dropped I headed home before the black ice began to freeze over. It was very nice to get a little ride in.

[Megadan]

Originally Posted by ChondaChondaChonda

Motor pulls much harder on the bottom and is noticeably quicker in the mid range as it pulls through the gears. Hard to tell on the top end if it has any more. Had it up to 70 mph for a short time; bike feels about the same at sustained higher speeds.

In terms of total power, the larger displacement itself, you may not see any increase in peak power. The given head and cam profiles are likely already at their peak airflow capability, so increases in peak power will be minimal or may not exist.

Instead, you gained a big increase in power under the curve. That larger piston area will have unshrouded the valves due to the cylinder wall moving away a few mm. It will also increase the vacuum draw on the intake causing an increase in charge velocity at lower RPMs, thus giving you bigger and more effective cylinder filling and air/fuel charge swirl across a wider spread of the RPM range.

[GlennR]

Great thread. Very impressive bike.

How much did the big bore kit cost? I've been "needing" a 4t and this one seems hard to resist. Looks like the BB kit would make it better as a dual-sport since you can run taller gearing.

I really appreciate how you keep making high quality improvements, instead of cheaping out on it because it had a low purchase price.

I'm looking forward to seeing what PP offers in the future. Looks like they have a frame that will accept a few different engines, a 250 4t, 450 4t, and a 250 2t. Also see there's an auto-clutch avaliable. Have you considered trying one?

[Megadan]

Originally Posted by GlennR

How much did the big bore kit cost?

A quick search turned one up on ebay for $349.

[ChondaChondaChonda]

Originally Posted by GlennR

Great thread. Very impressive bike.

How much did the big bore kit cost? I've been "needing" a 4t and this one seems hard to resist. Looks like the BB kit would make it better as a dual-sport since you can run taller gearing.

I really appreciate how you keep making high quality improvements, instead of cheaping out on it because it had a low purchase price.

I'm looking forward to seeing what PP offers in the future. Looks like they have a frame that will accept a few different engines, a 250 4t, 450 4t, and a 250 2t. Also see there's an auto-clutch avaliable. Have you considered trying one?

I talked to Pitster about the auto clutch, but I'm not sure I want to make that investment right now. I'm having a bit of fun and learning about how to hop it up and enjoying the process. Spending a little more money than I probably should, but it has been a good "smiles per gallon" investment for me.

The new bikes will be rebranded as "GPX" from what I understand. Not sure these will really be China bikes anymore??? They are closer to "exotic" than anything currently classified as Chinese. I'm betting they will be priced a bit higher than most Chinariders will be willing to spend. The quality looks outstanding and that should lure buyers away from the traditional big 4 bike manufacturers.

Planning to get out and off-road test the big bore on Saturday. I will have a better idea about the power delivery and how it works after that.

[GlennR]

I bought an older, but well maintained KTM 300 2t with a Rekluse auto clutch. I'd never have paid the entry fee for a new one, but it has saved my butt many times in the steep rocky stuff, that required 99% of my skill & concentration and being able to downshift using the clutch was beyond my ability.

It's probably become a crutch that I would be better off without, but won't really know until I'm struggling to re-learn using a clutch again. I'll "blame" it on that regardless!!

$349 is a deal for the BB upgrade. Something to do over the Winter months even if you don't really need a rebuild.

[ChondaChondaChonda]

Originally Posted by GlennR

I bought an older, but well maintained KTM 300 2t with a Rekluse auto clutch. I'd never have paid the entry fee for a new one, but it has saved my butt many times in the steep rocky stuff, that required 99% of my skill & concentration and being able to downshift using the clutch was beyond my ability.

It's probably become a crutch that I would be better off without, but won't really know until I'm struggling to re-learn using a clutch again. I'll "blame" it on that regardless!!

$349 is a deal for the BB upgrade. Something to do over the Winter months even if you don't really need a rebuild.

My old ride was 2008 KTM300 with the Rekluse. It is one of the reasons I like this bike; the chassis has a similar feel.

If I do go auto-clutch, it will be for the left hand rear brake capability. There are a few switchbacks that kick my ass because I'm weighting the right peg while holding the rear brake pedal down.