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Old 11-28-2012, 08:27 PM   #1186
Bake
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Quote:
Originally Posted by Ed@Ford View Post
I can't tell....is your 280 prototype a 2 ring piston or a 3? Reason I ask is I don't think the 2 ring big bore kit Athena made for the Yamaha WR250R was well received. I know I would buy a 2 ring big bore. From WAAAY back, I can remember when Scott Summers bored his XR250R Honda to 280, it was THE hot setup! I hope your kit is equally impressive.
Thank you for the kind words. It's Bill Blue's kit, I'm his riding friend, I help out around the shop some and I do small batches of sheet metal work like skidplates, racks, Rotopax carriers, and other small protector plates. Bill is retired now, he and I worked together for many years at Cessna.
It is a 3 ring piston. A note on the OEM Honda 3rd ring; I've never seen such a dainty bit of work. It's a full oil scraper style ring, but very small...low drag.
I only know one customer that had the Athena kit in his WR250 and it seized on him, and he knew of others. He said the bike vibrated bad after the kit was installed, as others had reported. Something was up with those kits, having such a tight fit, but I don't know what went wrong. We found when we tore his bike down that the bore and the base of the cylinder were not square, which is a hellava thing. That's pretty basic engine parameters to not meet.
I know Bill tries very hard to bring the piston/rings assembly weight as close to the original parts because the balancer systems are engineered for a specific reciprocating weight. The bigger the bore change, obviously, there's only so much that can be done. One could match the piston assembly weight exactly with a big bore, but if it fractures a piston skirt, building it for light weight wasn't the right trade-off for a vibration issue. It's finding that balance between weight, component expense, the strength of the materials, etc. My observation of the crank and rod were they were massive, bigger even than the KLX parts, and those are very robust. Honda has made a small engine that appears to be very tough, with the robust parts as you mentioned, the low friction features such as the roller rockers, small rings, that I predict these engines will go a very long way. They might be 100,000 mile engines. The water jacket is really big, the aluminum radiator is oversized, the thick iron bore will resist warping. I read somewhere the crank has automotive style plain bearings. The water passages in the head are considerably bigger than is found in the KLX. We found a metering jet function in an oil galley feeding the upper end. A tiny hole where the oil will be forced under pressure into a temperature reducing mist, flooding the rockers. Not wild, brazen things, but the attention to detail is great. Very interesting stuff when you start looking at it. And the whole thing adds up to a bike that handles extremely well, has a super shifting transmission, and has very very low vibration levels.
Think of a modern 2 liter, 4 cylinder car engine, that makes 144 horsepower. My Camry is rated about like that, the body will rust and fall to pieces before it's engine has any issues. This CRF engine isn't highly stressed at all.
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Bake screwed with this post 11-28-2012 at 08:53 PM
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Old 11-28-2012, 10:24 PM   #1187
'Flagger
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For all you "noise is not a concern" folks, it looks like Big Gun Exhaust has joined the list of vendors supporting our bike: http://www.biggunexhaust.com/ex_mx_hon.html

I had one of their units on a XR650L ... loudest thing I've ever owned.


Apologies if this has been posted previously.
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Old 11-29-2012, 03:37 AM   #1188
PeterS
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Mileage with fuel controller?

How bad does the fuel-controller affects fuel economy?
I want to use the bike for traveling but also like a extra bit of power.
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Old 11-29-2012, 04:14 AM   #1189
SugarDust
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Quote:
Originally Posted by Lost Rider View Post
....
Here's a short video I threw together about the Little Red Piggy That Could and a few photos from the day.
I really like riding this Honda, and feel confident we bought the perfect bike.







Great video and excellent photo! look forward to more. I love the name the LRP!
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Old 11-29-2012, 05:29 AM   #1190
Ed@Ford
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Quote:
Originally Posted by Bake View Post
It is a 3 ring piston. A note on the OEM Honda 3rd ring; I've never seen such a dainty bit of work. It's a full oil scraper style ring, but very small...low drag.
I have a KLR 650 with the 685 kit from Snitz and the piston is lighter than stock, and the engine is smoother than stock. Their big 705 kit piston is also lighter and is reportedly smoother than stock as well. Honda has a very unique patent on how they cast that iron cylinder liner in place in the aluminum block that forms the open deck style cooling system. It takes a very unique head gasket to seal such an open deck cylinder sleeve. I think they also patented the head gasket. I was trying to get a similar patent about the same time as Honda got theirs. They were lucky....I wasn't.

After rereading your comments, it makes me think of comments on the new honda 700 engine, and how EVERYTHING about it has been reconsidered in terms of weight, reliability, and especially friction. It certainly seems the CRF has been designed with with all these criteria in mind. "No stone unturned" comes to mind. Also makes me think it is designed with "room to grow" in mind. We can always fantisize that the CRF250R street bike growing to 300cc to keep up with the new 300 ninja twin.....and the CRF250L inherits the displacement as well.

Ed@Ford screwed with this post 11-29-2012 at 06:23 AM
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Old 11-29-2012, 08:17 AM   #1191
espi
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Lrp!!!

LOVING the sizzle piece! YOU guys rock!!
Can't wait to get my own LRP!

Thanks for sharing!
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Old 11-29-2012, 12:48 PM   #1192
Rjatr
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Sprockets and things

After reading through this excellent thread and having just bought an "LRP", I was wondering why the consensus seems to be to change the front sprocket to 13 tooth, rather than adding a 43 tooth rear sprocket? making the front sprocket smaller will increase the wear on the chain (due to a tighter circumference) and possibly increase wear on the swing arm guard. Is it because the there is not enough adjustment in the wheel position to provide enough slack?
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Old 11-29-2012, 12:55 PM   #1193
Guerillah
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Thumb

I woke up to a beautiful sunny day in Southern Arizona (currently 70F) so I decided to gas up the bike and take her out on a trail i've never been on before. The trail goes around a small mountain range called the Tortolita's in Tucson, AZ. The complete trail was 40 miles, mostly 2 track. Overall it was pretty easy minus some very deep sand in the washes and one hill climb with lot of large boulders exposed with ruts mixed with large rocks, knocked me off balance, whoops! The rear suspension could definitely be stiffened up, perhaps someone will make a stiffer spring for the budget minded. After the loop I calculated my MPG and it came out to 46 MPG. This is with the following mods: 13T front sprocket, FMF programmer, FMF Q4 muffler, FMF megabomb header. This includes a good amount of wide open throttle so this is about what I would expect to always get with this combination. Some pics...


Tortolitta Loop Tucson, AZ by Guerillah, on Flickr


Tortolitta Loop Tucson, AZ by Guerillah, on Flickr


Tortolitta Loop Tucson, AZ by Guerillah, on Flickr


Tortolitta Loop Tucson, AZ by Guerillah, on Flickr

Cheers

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Old 11-29-2012, 01:36 PM   #1194
Ed@Ford
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Quote:
Originally Posted by Rjatr View Post
After reading through this excellent thread and having just bought an "LRP", I was wondering why the consensus seems to be to change the front sprocket to 13 tooth, rather than adding a 43 tooth rear sprocket? making the front sprocket smaller will increase the wear on the chain (due to a tighter circumference) and possibly increase wear on the swing arm guard. Is it because the there is not enough adjustment in the wheel position to provide enough slack?
It's probably a chain length thing
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Old 11-29-2012, 01:56 PM   #1195
ramz
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At first, there were no sprockets available. Then some of us found 13T front sprockets. Later, 42T rear sprockets became available. And now, there are 43T rear sprockets available. And maybe even larger.

Some history with pics:
http://rickramsey.net/CRF250Lmods.htm#gearing
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Old 11-29-2012, 04:30 PM   #1196
Brk4moose
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Not sure if anyone is looking for a fender eliminator kit for their CRF but I came across this one when cruising eBay. Not really my thing but I remember a few of you guys mentioning you were looking for one.

http://www.sportbikelites.com/HONDA-...er-kit-143.htm
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Old 11-29-2012, 06:14 PM   #1197
CRFSoCal
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I contacted two brothers exhaust and they are currently making a slip on muffler for the Crf250l. They said there's no eta yet but they have one in house they are using for R&D.
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Old 11-30-2012, 06:02 AM   #1198
taninthai
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Quote:
Originally Posted by Ed@Ford View Post
It's probably a chain length thing
I have just fitted a 43t sprocket to mine still have the 14t on front,however my bike is 6 months old and has 3500 km on it so the chain was a bit stretched and it just fitted on, if your bike is new i dont think a 43t will fit unless you change the front first
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Old 11-30-2012, 06:12 AM   #1199
swimmer
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Quote:
Originally Posted by Guerillah View Post
I woke up to a beautiful sunny day in Southern Arizona (currently 70F) so I decided to gas up the bike and take her out on a trail i've never been on before. The trail goes around a small mountain range called the Tortolita's in Tucson, AZ. The complete trail was 40 miles, mostly 2 track. Overall it was pretty easy minus some very deep sand in the washes and one hill climb with lot of large boulders exposed with ruts mixed with large rocks, knocked me off balance, whoops! The rear suspension could definitely be stiffened up, perhaps someone will make a stiffer spring for the budget minded. After the loop I calculated my MPG and it came out to 46 MPG. This is with the following mods: 13T front sprocket, FMF programmer, FMF Q4 muffler, FMF megabomb header. This includes a good amount of wide open throttle so this is about what I would expect to always get with this combination. Some pic..

Nice pictures.
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Old 11-30-2012, 08:50 AM   #1200
EEKAMOUSE
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Quote:
Originally Posted by ramz View Post
At first, there were no sprockets available. Then some of us found 13T front sprockets. Later, 42T rear sprockets became available. And now, there are 43T rear sprockets available. And maybe even larger.

Some history with pics:
http://rickramsey.net/CRF250Lmods.htm#gearing
We have a 13-48 combo on one right now it is nice you guys need to quit messin around and go big haha
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