"Small bore" kits?

WDSRCR
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WDSRCR 5/6/2021 10:12am
5/6/2021 10:12am
Black Diesel Bomber wrote:
You guys are wanting exactly what Beta is already doing...if they offer the 390 in their new MX line you will see a ton of them...
You guys are wanting exactly what Beta is already doing...if they offer the 390 in their new MX line you will see a ton of them at the track:



WDSRCR wrote:
Yes, Beta is offering a 390, and Husaberg offered one in their 70* engine some years back. I have rode the Husaberg 390 and it wasn't...
Yes, Beta is offering a 390, and Husaberg offered one in their 70* engine some years back.

I have rode the Husaberg 390 and it wasn't bad.

I have only rode 2 stroke Beta's and I won't be buying one. I'm sure it is a decent bike but the 3 people near me who have them have all had problems with the electronics on them.
Black Diesel Bomber wrote:
Which model and what years for the electrical problems?
2017 X Trainer, 2018 300 (regular version with sachs), 2020 300RR.

The X trainer shorted something out while on the trail cooking the battery.

The 2018 chafed the harness raw in numerous places causing the bike to short out.

the 2020 CDI fried. I suspect its the same as the 2018, chafed wires that shorted the electrical system.
SilverSpurs
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SilverSpurs 5/6/2021 10:58am
5/6/2021 10:58am
Stuntman949 wrote:
How about a big ass flywheel
Big flywheel increases the gyro and makes changing direction more difficult- as well as adding weight.
SilverSpurs
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SilverSpurs 5/6/2021 11:00am
5/6/2021 11:00am
SilverSpurs wrote:
Small bored to 350, any decent engine's valves will hit the cylinder. If they don't hit the cylinder the valve clearance cutout's will be somewhere in...
Small bored to 350, any decent engine's valves will hit the cylinder.

If they don't hit the cylinder the valve clearance cutout's will be somewhere in the piston rings.

Not happenin.


Upscaled 250: much, much more feasible.
BobPA wrote:
This is exactly what I was going to say. I highly doubt you'd have the clearance to run a smaller bore netting you -100cc's.
Ray Knight wrote:
I'd think +/- 30-50cc should be possible with just about any.
The discussion is about a 100cc reduction not 30cc.
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Autotech1957
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Autotech1957 5/6/2021 12:29pm
5/6/2021 12:29pm Edited Date/Time 5/6/2021 12:30pm
WDSRCR wrote:
Yes, Beta is offering a 390, and Husaberg offered one in their 70* engine some years back. I have rode the Husaberg 390 and it wasn't...
Yes, Beta is offering a 390, and Husaberg offered one in their 70* engine some years back.

I have rode the Husaberg 390 and it wasn't bad.

I have only rode 2 stroke Beta's and I won't be buying one. I'm sure it is a decent bike but the 3 people near me who have them have all had problems with the electronics on them.
Black Diesel Bomber wrote:
Which model and what years for the electrical problems?
WDSRCR wrote:
2017 X Trainer, 2018 300 (regular version with sachs), 2020 300RR. The X trainer shorted something out while on the trail cooking the battery. The 2018...
2017 X Trainer, 2018 300 (regular version with sachs), 2020 300RR.

The X trainer shorted something out while on the trail cooking the battery.

The 2018 chafed the harness raw in numerous places causing the bike to short out.

the 2020 CDI fried. I suspect its the same as the 2018, chafed wires that shorted the electrical system.
All of those preventable by regular maintenance. So many people are spoiled. When I was buying new bikes you ALWAYS removed everything down to bare frame. Reassembled while looking for exactly these types of issues which were corrected. Was it built on Monday or Friday? New guy/girl? Mass produced stuff is mass produced. GET IT OUT FAST!

Seems a lot of you are perfectly fine buying a $10K bike, then spending $15-20K on suspension and engine mods. No problem. But giving the bike a good once over to check for potential issues like wiring chafing is a deal breaker.

While I'm ranting, the whole "I'm not riding same thing everyone else is riding" has NEVER made sense to me. If everyone you ride with has same make, when someone breaks something, you always have that guy that saves his old (not worn-out) parts as spares. But I was also a woods rider. 6-8 hours of riding in a day were common. You moto guys ain't got the staying power.

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FGR01
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FGR01 5/6/2021 12:40pm
5/6/2021 12:40pm
Stuntman949 wrote:
How about a big ass flywheel
SilverSpurs wrote:
Big flywheel increases the gyro and makes changing direction more difficult- as well as adding weight.
This. The best part of the KTM 350 is the light, flickable, non-tiring feel compared to the 450. Having the reduced power of an under bore but still having the heavy inertia of the 450 crank sounds like the worst of both worlds to me.
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Ray Knight
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Ray Knight 5/6/2021 1:48pm
5/6/2021 1:48pm
WDSRCR wrote:
I keep wishing a company would release a kit like RedMoto's 400RX for my KX450X. I have both, a KX250X and KX450X, and I'd like more...
I keep wishing a company would release a kit like RedMoto's 400RX for my KX450X. I have both, a KX250X and KX450X, and I'd like more than the 250 gives me, but the 450 is too much in the tight enduros.
Black Diesel Bomber wrote:
You guys are wanting exactly what Beta is already doing...if they offer the 390 in their new MX line you will see a ton of them...
You guys are wanting exactly what Beta is already doing...if they offer the 390 in their new MX line you will see a ton of them at the track:



No italian bike will ever be in my possession. My kids had italian mini race quads. Complete garbage! I'll never look at any TM, Beta, etc and want anything to do with it. Lol. Otherwise, I'll do any KTM group bikes, Honda, Kawi, Yamaha or Suzuki.
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Ray Knight
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Ray Knight 5/6/2021 1:50pm
5/6/2021 1:50pm
Stuntman949 wrote:
How about a big ass flywheel
SilverSpurs wrote:
Big flywheel increases the gyro and makes changing direction more difficult- as well as adding weight.
FGR01 wrote:
This. The best part of the KTM 350 is the light, flickable, non-tiring feel compared to the 450. Having the reduced power of an under bore...
This. The best part of the KTM 350 is the light, flickable, non-tiring feel compared to the 450. Having the reduced power of an under bore but still having the heavy inertia of the 450 crank sounds like the worst of both worlds to me.
That's what i'm wondering because the 350 has more inertia and more engine braking then the 450. More vibration too. So wondering how an underbored 450 would feel.
dbx33
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dbx33 5/6/2021 1:50pm
5/6/2021 1:50pm
a fully done up 270sxf is the hot ticket. all the juice of the 350 up top and much lighter feeling. a stock-ish 300sxf based on the 250sxf bottom end would tick the boxes for 90% of people tho
Ray Knight
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Ray Knight 5/6/2021 1:51pm
5/6/2021 1:51pm
BobPA wrote:
This is exactly what I was going to say. I highly doubt you'd have the clearance to run a smaller bore netting you -100cc's.
Ray Knight wrote:
I'd think +/- 30-50cc should be possible with just about any.
SilverSpurs wrote:
The discussion is about a 100cc reduction not 30cc.
50-100cc.
Ray Knight
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Ray Knight 5/6/2021 1:51pm
5/6/2021 1:51pm
Stuntman949 wrote:
How about a big ass flywheel
Thwt would make it rev slower snd have MORE inertia. I want to opposite.
Black Diesel Bomber 5/6/2021 2:05pm
5/6/2021 2:05pm
WDSRCR wrote:
I keep wishing a company would release a kit like RedMoto's 400RX for my KX450X. I have both, a KX250X and KX450X, and I'd like more...
I keep wishing a company would release a kit like RedMoto's 400RX for my KX450X. I have both, a KX250X and KX450X, and I'd like more than the 250 gives me, but the 450 is too much in the tight enduros.
Black Diesel Bomber wrote:
You guys are wanting exactly what Beta is already doing...if they offer the 390 in their new MX line you will see a ton of them...
You guys are wanting exactly what Beta is already doing...if they offer the 390 in their new MX line you will see a ton of them at the track:



Ray Knight wrote:
No italian bike will ever be in my possession. My kids had italian mini race quads. Complete garbage! I'll never look at any TM, Beta, etc...
No italian bike will ever be in my possession. My kids had italian mini race quads. Complete garbage! I'll never look at any TM, Beta, etc and want anything to do with it. Lol. Otherwise, I'll do any KTM group bikes, Honda, Kawi, Yamaha or Suzuki.
Well I think times have changed. I'm new to Beta and can't say for sure but I do believe they are just as reliable as any bike out there now. I contacted my dealer about WDSRCR's comments above and Beta did have a problem with charging voltages several years ago. From what I heard Beta changed the harness for the '19 bikes and offer it as a free upgrade to those older bikes free of charge. Supposedly the new bike's with the 19+ harness don't have this charging voltage issue. Maybe someone else with more knowledge can chime in with more information to set me straight.

All I can tell you is the quality on my Beta is amazing and the bike is the best you can buy out of the box for a plated bike. KTM guys will tell you this. I own several brands so I'm not biased, but I would never say the Italian bikes are complete garbage. In fact just the opposite for now, unless I have problems with my bike.
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Ray Knight
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Ray Knight 5/6/2021 2:14pm
5/6/2021 2:14pm
Black Diesel Bomber wrote:
You guys are wanting exactly what Beta is already doing...if they offer the 390 in their new MX line you will see a ton of them...
You guys are wanting exactly what Beta is already doing...if they offer the 390 in their new MX line you will see a ton of them at the track:



Ray Knight wrote:
No italian bike will ever be in my possession. My kids had italian mini race quads. Complete garbage! I'll never look at any TM, Beta, etc...
No italian bike will ever be in my possession. My kids had italian mini race quads. Complete garbage! I'll never look at any TM, Beta, etc and want anything to do with it. Lol. Otherwise, I'll do any KTM group bikes, Honda, Kawi, Yamaha or Suzuki.
Black Diesel Bomber wrote:
Well I think times have changed. I'm new to Beta and can't say for sure but I do believe they are just as reliable as any...
Well I think times have changed. I'm new to Beta and can't say for sure but I do believe they are just as reliable as any bike out there now. I contacted my dealer about WDSRCR's comments above and Beta did have a problem with charging voltages several years ago. From what I heard Beta changed the harness for the '19 bikes and offer it as a free upgrade to those older bikes free of charge. Supposedly the new bike's with the 19+ harness don't have this charging voltage issue. Maybe someone else with more knowledge can chime in with more information to set me straight.

All I can tell you is the quality on my Beta is amazing and the bike is the best you can buy out of the box for a plated bike. KTM guys will tell you this. I own several brands so I'm not biased, but I would never say the Italian bikes are complete garbage. In fact just the opposite for now, unless I have problems with my bike.
What i mean is every italian machine i've owned has been super fast but complete garbage quality. Like everything broke and fell apart constantly. I'm sure the Beta is good but i personally won't/can't trust any Italian bike based on my experience with what i've had.
Ray Knight
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Ray Knight 5/6/2021 2:14pm
5/6/2021 2:14pm
dbx33 wrote:
a fully done up 270sxf is the hot ticket. all the juice of the 350 up top and much lighter feeling. a stock-ish 300sxf based on...
a fully done up 270sxf is the hot ticket. all the juice of the 350 up top and much lighter feeling. a stock-ish 300sxf based on the 250sxf bottom end would tick the boxes for 90% of people tho
Your 270 was pretty sick!
Bearuno
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Bearuno 5/6/2021 2:37pm
5/6/2021 2:37pm Edited Date/Time 5/6/2021 3:19pm
APLMAN99 wrote:
Aren’t most 250 rolling chassis slightly lighter than their matching 450? I thought that most were, which is why Service Honda used CRF250 chassis for their...
Aren’t most 250 rolling chassis slightly lighter than their matching 450? I thought that most were, which is why Service Honda used CRF250 chassis for their AF500 bikes.

If that’s generally true for most brands, it would seem to make sense that a big bore/upsize kit would make more sense than trying to downsize, especially if it’s due to a 450 being too tiring the more you ride.

I suppose that there would be exceptions to that idea, though.
There's a Very good market for 250F engines that SH sold those engines into.

It also gave them engines for their 'Jnr'.

Those points , to me, are the real reason they used 250 chassis, it was a great, nay, fantastic business model, though their propaganda, always touted the 250s chassis.

Me, I'd want the 450 chassis, especially when it got updates before the 250, but, I've done quite a few 250 conversions, when Ive been 'cornered' by mates wanting AFs. Hopefully, no more of them want one, I have no interest in doing any more conversions. I need to make money from my skills, not help mates all the bloody time ..........
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davis224
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davis224 5/6/2021 2:52pm
5/6/2021 2:52pm
Has nobody mentioned that Cairoli's YZ450s were actually 400cc?
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Bearuno
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Bearuno 5/6/2021 3:09pm
5/6/2021 3:09pm
davis224 wrote:
Has nobody mentioned that Cairoli's YZ450s were actually 400cc?
They weren't.
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Darrin Willis
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Darrin Willis 5/6/2021 3:39pm
5/6/2021 3:39pm
I have a ducati and a moto guzzi. And previously a husqvarna 144 and a beta 250. all made in Italy. A few quirks ----yes. But awsome bikes .
max schnell 5/6/2021 3:39pm
5/6/2021 3:39pm
Big bore 250f would need updated drivetrain .clutch at a minimum, some transmissions could handle power increase better than others.downsized ( less power)450f would not have this issue.

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davis224
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davis224 5/6/2021 4:11pm
5/6/2021 4:11pm
davis224 wrote:
Has nobody mentioned that Cairoli's YZ450s were actually 400cc?
Bearuno wrote:
They weren't.
Really? I'd always heard they were sleeved down to a 400, which is why he opted towards the 350 when he went to KTM.
griddle922
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griddle922 5/7/2021 3:33am
5/7/2021 3:33am
davis224 wrote:
Has nobody mentioned that Cairoli's YZ450s were actually 400cc?
I got curious after you mentioned that and did some research. Looks like you’re correct that he did race a yz450f that was 400cc in 2009. I had no idea. Pretty cool.
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SilverSpurs
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SilverSpurs 5/7/2021 4:11am
5/7/2021 4:11am
davis224 wrote:
Has nobody mentioned that Cairoli's YZ450s were actually 400cc?
Proof?
davis224
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davis224 5/7/2021 4:21am
5/7/2021 4:21am
davis224 wrote:
Has nobody mentioned that Cairoli's YZ450s were actually 400cc?
SilverSpurs wrote:
Proof?
I don't have any articles on hand, but I remember around that time it was widely and openly talked about. He thought 450s were too harsh and liked the more controllable 400 version.
WDSRCR
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WDSRCR 5/7/2021 4:33am
5/7/2021 4:33am
davis224 wrote:
Has nobody mentioned that Cairoli's YZ450s were actually 400cc?
SilverSpurs wrote:
Proof?
davis224 wrote:
I don't have any articles on hand, but I remember around that time it was widely and openly talked about. He thought 450s were too harsh...
I don't have any articles on hand, but I remember around that time it was widely and openly talked about. He thought 450s were too harsh and liked the more controllable 400 version.
Mike Lafferty did the same thing when KTM went away from the 400 and went to a 450. He was riding a sleeved down bike. His opinion was the 400 was the perfect size for him. When he rode the one year on Husaberg, he was reportedly riding their 390 instead of the 450 then, as well.

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davis224
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davis224 5/7/2021 5:43am
5/7/2021 5:43am
After a quick Google, this thread popped up

moto314
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moto314 5/7/2021 7:21am
5/7/2021 7:21am
HT racing used to offer a sleeved CRF450R cylinder back in like 2007-08 that was like 400cc. Big bore / stroker 250's work so well though, I've ridden 276cc, 282cc, 302cc, and 315cc, bored and stroked 250's and they all were awesome.
Ted722
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Ted722 5/7/2021 7:41am
5/7/2021 7:41am
Stuntman949 wrote:
How about a big ass flywheel
Maybe that's why I like my '18 RMZ450 power delivery so much. In stock mode, fits this 53 year old's skills just fine.

In all honesty, though, I'd probably like a 250 even more...and yes it would be an RMZ for me.

You'd think with all the trickery to get that last ounce of power out of your 450, there might be a market for turning your 450 into a docile companion. Probably is, just don't hear people talking about it too much(on this forum). Keep that extra rotating mass of a 450(that some have referenced) with a mellow map...hell tune it to match the Beta 390 power curve or at least make that the target (for example).

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