Got the DR350Se project bike running!

[BikePilot]

Finally got it together. My basic plan was to put it togther mostly stock, then if I liked it, I'll mod it to suite me (big tank, alu bars, handguards, heated grips, power outlets for heated vest and gps....).

The day I brought it home
http://www.postwhore.biz/albums/userpics/10047/normal_IMG_0053.jpg (http://www.postwhore.biz/albums/userpics/10047/IMG_0053.jpg)

Even the motor was in bits
http://www.postwhore.biz/albums/userpics/10047/normal_DSC06371.JPG (http://www.postwhore.biz/albums/userpics/10047/DSC06371.JPG)

The frame was a lovely shade of purple
http://www.postwhore.biz/albums/userpics/10047/normal_DSC06370.JPG (http://www.postwhore.biz/albums/userpics/10047/DSC06370.JPG)

Would be a real shame to put it back together in stock form:devious
http://www.postwhore.biz/albums/userpics/10047/normal_Picture%20004.jpg (http://www.postwhore.biz/albums/userpics/10047/Picture%20004.jpg)

http://www.postwhore.biz/albums/userpics/10047/normal_Picture%20005.jpg (http://www.postwhore.biz/albums/userpics/10047/Picture%20005.jpg)

1pt more compression and forged rather than cast
http://www.postwhore.biz/albums/userpics/10047/normal_Picture%20008.jpg (http://www.postwhore.biz/albums/userpics/10047/Picture%20008.jpg)

Got the frame sprayed with Line-X
http://www.postwhore.biz/albums/userpics/10047/normal_Return%20from%20Harvard%20visit,%20May%202007%20069.jpg (http://www.postwhore.biz/albums/userpics/10047/Return%20from%20Harvard%20visit,%20May%202007%20069.jpg)

http://www.postwhore.biz/albums/userpics/10047/normal_Return%20from%20Harvard%20visit,%20May%202007%20068.jpg (http://www.postwhore.biz/albums/userpics/10047/Return%20from%20Harvard%20visit,%20May%202007%20068.jpg)

http://www.postwhore.biz/albums/userpics/10047/normal_Return%20from%20Harvard%20visit,%20May%202007%20066.jpg (http://www.postwhore.biz/albums/userpics/10047/Return%20from%20Harvard%20visit,%20May%202007%20066.jpg)

I have some pics of the assy, but they are on my desktop which is currently in a box ready for the move:banghead

I rode it yesterday and I like it, so will order up another big tank and such shortly as I think BikePilette would shoot me if I stole parts of the 250 as origionally planned:laugh

After the ride yesterday I gave it a quick wash and pilette took a few pics:)
http://www.postwhore.biz/albums/userpics/10047/normal_July%204-July%2021%202007%20120%20_Custom_.jpg (http://www.postwhore.biz/albums/userpics/10047/July%204-July%2021%202007%20120%20_Custom_.jpg)

http://www.postwhore.biz/albums/userpics/10047/normal_July%204-July%2021%202007%20121%20_Custom_.jpg (http://www.postwhore.biz/albums/userpics/10047/July%204-July%2021%202007%20121%20_Custom_.jpg)

http://www.postwhore.biz/albums/userpics/10047/normal_July%204-July%2021%202007%20122%20_Custom_.jpg (http://www.postwhore.biz/albums/userpics/10047/July%204-July%2021%202007%20122%20_Custom_.jpg)

[BikePilot]

Notes on how the 350 and 250 compare. First off, quick description.

Bikes (in stock form) are exactly the same in all respects exept bore and stroke and primary gear ratio. Engine cases and even cylinder casting are the same. Both come stock with a 33mm CV carb (street model) or a 33mm pumper carb (off road model). they also have a very heavily baffled airbox (great for riding in deep water, but might not flow all that well) and a very quiet exhaust (this I like, but its also very heavy).

Differences:
350: 79mm bore x 71mm stroke
9.5:1 CR

250 73.7mm bore x 59mm stroke
10.5:CR

Redline
350 ~9250rpm
250 ~10250rpm


Motor related mods I did to my 350

33mm pumper carb from dirt model (TM33SS)
Cut the top of the airbox off as per Kientech racing's instructions
140 main jet (stock is 123.5 IIRC).
Unifilter (probably no better than stock, but the stocker was dry rotted)
10.5:1 Wiesco Piston.
Kibblewhite valve springs (stiffer) and Ti spring retainers (not needed unless I up the redline or add big valves and cam, but I got 'em really cheap and couldn't resist:laugh)

How it compares to a stock DR250.

throttle response is amzingly quicker - this is really down to the difference between a CV and a pumper carb rather than the difference in displacement I think.

Power off idle is much stronger and it outshines the 250 to about 6k rpm.

After 6k rpm the power goes pretty flat and feels like it even tapers off around 8k rpm.

The 250 just gets going around 6k rpm then picks up nicely and pulls cleanly to redline.

I suspect peak power output is pretty close on my two bikes and probably identicle stock for stock. I belive its really limited by the small carb, exhaust, mild cam and smallish valves rather than displacement. Both motors are very well ballanced and have minimal vibration. Even when buzing down the freeway at high rpms.

Overal, as they are (carb differences aside as that could be swaped in just a few minutes) I think I like the 350 a little better, but the difference isn't huge by any means. In some respects the 250 is more fun as it responds better to a good flogging and having its gutts reved out than does the 350. However, its handy having the low rpm tq to snap the front wheel off the ground without any clutch work, esp off road. Its also easier to get off the line quickly on the 350, as the 250 (with the tall gearing I'm running on it) tends to bog a bit unless you really rev it. That said, the 250 does make decent low rpm power and you really only find it lacking if you try to take off really hard or want to wheelie with just a bit of throttle (the latter might be cured just with the additon of the pumper carb though).

BikePilette likes the 250 so much I think I'll end up keeping both bikes. I'll use the 350 for myself and she'll ride the 250.

Oh, I have only ridden the 350 about 15 miles and don't yet know how it will do on fuel. The 250 is great in that regard. A solid 70mpg most of the time with a moderate to hard flogging. The worst I ever got was 65mpg and that was with a lot of flogging and a lot of bad traffic. Crusing on backroads you can easily see 75mpg:hail I have no clue what the 350 will do, but it won't be nearly that good I suspect, esp with the flat slide pumper carb.