ADVrider

Go Back   ADVrider > Bikes > Thumpers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-21-2011, 11:35 AM   #76
3uba296
Thumpcurious
 
3uba296's Avatar
 
Joined: Aug 2010
Location: Sweden
Oddometer: 133
Or... try to find a core plug in the right size?
__________________
Dr350(80)R-97
3uba296 is offline   Reply With Quote
Old 01-21-2011, 02:08 PM   #77
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
Quote:
Originally Posted by 3uba296 View Post
Or... try to find a core plug in the right size?
Yes, I was really wondering if these are available.
Pablo83 is offline   Reply With Quote
Old 01-27-2011, 12:08 PM   #78
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
Quote:
Originally Posted by BikePilot from DisTech's DR350 build thread
IIRC the primary drive ratio (crank to clutch basket basically) is different between the 350 and 250. I know that for a given final drive ratio my '94 250SE turns more rpm than my '96 350SE. Also note that your 250 motor is a 250SE. The plain S was kick start only.
primary drive ratios:
DR350 20:64 (3.200)
DR250 22:62 (2.818)

I'm led to believe that the lower ratio (from the 250) will be easier on the tranny and harder on the final drive. I'd rather be replacing chains/sprockets than trannies, so I'm going with the 250's primary.
Pablo83 is offline   Reply With Quote
Old 01-27-2011, 03:23 PM   #79
HeadTrauma
\_(ツ)_/
 
HeadTrauma's Avatar
 
Joined: Aug 2008
Location: Antelope Valley, SoCal
Oddometer: 1,260
Yeah, what the numerically lower ratio does is transfer less torque through the geartrain by making it spin faster. A numerically higher final drive is then required to multiply the torque back up again. That's why Honda's HRC kit for the XR600 included an NX650/XR650L primary drive set with a lower ratio.
__________________
1995 XR628R -Lots of goodies...room for more.
"Another breakdown, suicidal shakedown,
Feels like I'm livin' on a chain gang."
HeadTrauma is offline   Reply With Quote
Old 01-27-2011, 04:53 PM   #80
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
Quote:
Originally Posted by HeadTrauma View Post
Yeah, what the numerically lower ratio does is transfer less torque through the geartrain by making it spin faster. A numerically higher final drive is then required to multiply the torque back up again. That's why Honda's HRC kit for the XR600 included an NX650/XR650L primary drive set with a lower ratio.
I reviewed your comments on my NX build when I was deciding what promary to use. Thanks for all the help. BTW, since when are you into DR's?
Pablo83 is offline   Reply With Quote
Old 01-27-2011, 05:02 PM   #81
HeadTrauma
\_(ツ)_/
 
HeadTrauma's Avatar
 
Joined: Aug 2008
Location: Antelope Valley, SoCal
Oddometer: 1,260
I was considering one as a possible alternative to an XR250.

I was also thinking about DR650s until I saw the thread about some grenading the gearbox.
__________________
1995 XR628R -Lots of goodies...room for more.
"Another breakdown, suicidal shakedown,
Feels like I'm livin' on a chain gang."
HeadTrauma is offline   Reply With Quote
Old 01-27-2011, 05:45 PM   #82
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
Quote:
Originally Posted by HeadTrauma View Post
I was considering one as a possible alternative to an XR250.

I was also thinking about DR650s until I saw the thread about some grenading the gearbox.
So far, the bike's been real easy to work on. I love the engine, it's very simple; much easier to work on than the RFVC. There are big bore kits available up to 460cc and with the 250, 350 ,street, and offroad versions, there are a number on interchangeable engine components.

The flexible chassis is an issue, but maybe I can get that sorted out. I'd love to have this engine in a CRF250 chassis; that'd be a lot of fun.
Pablo83 is offline   Reply With Quote
Old 01-27-2011, 05:49 PM   #83
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
The neutral switch looks like it's missing a cover. I checked the fiche and it doesn't show one, so I guess this is right.

Pablo83 is offline   Reply With Quote
Old 01-27-2011, 05:50 PM   #84
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
One tranny down, one to go...

Pablo83 is offline   Reply With Quote
Old 01-27-2011, 05:53 PM   #85
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
specs

I did some measurements on the different bores I have. "Sleeve" means the overall height of the sleeve.


The pins with two thicknesses are tapered on the inside; they get thinner towards the edge. Notice the pin dia is different between the 250 and the 350, so you can't put the 350's piston on the 250's rod (I was told you could).
Pablo83 is offline   Reply With Quote
Old 01-27-2011, 06:03 PM   #86
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
this is the counterweight drive gear on the crank. Jesse Kein says there is a problem with the pin slipping out and causing catastrophic damage. I can't remember what Jesse's solution was. I decided to weld mine.



I did a fusion weld (no filler rod) so I wouldn't upset the balance.
Pablo83 is offline   Reply With Quote
Old 01-27-2011, 06:06 PM   #87
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
What a mess

And the second engine's apart. Now to see if I can get them back together.
Pablo83 is offline   Reply With Quote
Old 01-27-2011, 06:15 PM   #88
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
Reassembly Notes

Flywheel weights:
91 DR250S: 4lb, 3oz
98 DR350: 3lb, 15oz

The manual suggests jamming a penny between gears to stop them from spinning when you're trying to torque things down. I tried this to torque the flywheel bolt down (95 ft/lb) and I broke a tooth off the oil pump drive gear ($30 replacement). So don't try that.

When swapping the trannies I swapped all the internal parts (gears, shafts, forks, and drum). The reassembled trannies both bound up. I spent a long time trying to figure out what was wrong. I finally swapped the drums back and they worked. I examined the drums closely and couldn't find anything different about the two, but it appears the drum needs to stay with the case it was meant for.
Pablo83 is offline   Reply With Quote
Old 01-27-2011, 06:23 PM   #89
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
In order to get the primary drive ratio I want, I need the 91 DR250S's clutch basket. So I put in the whole clutch from the 250. Does anyone know if there's a difference between this clutch and the '98 350 kicker's?
Pablo83 is offline   Reply With Quote
Old 01-27-2011, 08:09 PM   #90
Pablo83 OP
Sleep, Wrench, Ride
 
Pablo83's Avatar
 
Joined: Aug 2008
Location: Woodland Park, CO
Oddometer: 4,772
Valves

DR350 valve sizes (these are not exact)
intake: 30mm
exhaust: 26.5

DR250S
intake: 28
exhaust: 24.5
Pablo83 is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 01:09 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014