CarbsAndCylinders
Careful With That Axe Eugene
Thanks, Cos.
SR250 Cafe build
- Thread starter cosworth
- Start date
crazypj
Split personality, I fake being smart
Most of the 'roller/needle/ball bearing Yamaha's run around 15psi max pressure but flow is way up there
Friend saw 20psi on XS650 at max rpm but normal running was 7~10psi.
XS 650 has various oil squirters in crankcase (they are just holes drilled to spray oil in general direction of big ends ;D )
I wouldn't worry about increasing flow to top end of engine, it will always come back down to the bottom plus the flow to big end happens before top end gets oiled
Friend saw 20psi on XS650 at max rpm but normal running was 7~10psi.
XS 650 has various oil squirters in crankcase (they are just holes drilled to spray oil in general direction of big ends ;D )
I wouldn't worry about increasing flow to top end of engine, it will always come back down to the bottom plus the flow to big end happens before top end gets oiled
sincerelyadam
Active Member
Very inspiring for my winter project. Thanks for documenting everything Cos.
I see you installed a kickstart. That's one goal I have for my SR250. Were you able to find a kit with all the parts, or did you just piece everything together from something like this? http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1980/SR250G/KICK+STARTER/parts.html
I see you installed a kickstart. That's one goal I have for my SR250. Were you able to find a kit with all the parts, or did you just piece everything together from something like this? http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1980/SR250G/KICK+STARTER/parts.html
cosworth
Coast to Coast
The parts list helped. I had a local guy with a few xt250 motors laying about. All the bits are there in the donor motor save for two critical things; the seal for the crankcase and the pressed in pin for holding the spring. I made a quick pin on the lathe instead of waiting for a $2 part and the seal was easily found since it's quite universal.
So yeah, it's not hard to do. And it has saved my bacon a few times in the cold weather with a trumpet carb and no airbox. She is a bit fussy to start.
So yeah, it's not hard to do. And it has saved my bacon a few times in the cold weather with a trumpet carb and no airbox. She is a bit fussy to start.
sincerelyadam
Active Member
cosworth said:
This is exactly why I want to install one. Seems like a bit of overmarketing for Yamaha to leave off the kicker. I think I read in an article that Jadus posted that they wanted the bike to be less intimidating to new riders or something like that. Kinda dumb if you ask me.
I wish I had a guy with some XT donor motors. I'll probably just piece it all together. Thanks for the info!!
cosworth
Coast to Coast
grcamna5 said:
Love 'em. I have 10mm preload on them, I weigh 230 pounds with no gear, and they have 10,000kms on them now. They have performed flawlessly. I highly recommend them. The anodising is getting a bit faded on the right side due to the sun and kickstand angle but that's it.
With zero preload you should be fine with the stock spring rate.
and I weigh 180lbs;I like a spring to be light enough for the shock to use most of it's travel while on the road,they seem to work better for me that way.
Hey cosworth, what Jets did you end up running with the velocity stack? You go up on mains and pilot? And needle clip position?
Cheers
Cheers
Thought I'd send an update on this SR250. I am the new owner! Just bought it as a not running machine that's been sitting for a number of years. The rear sets have been replaced (old ones are broken and came in a box), pipe is scratched so it may have gone down. The tank badly needs to be relined as the previous owner botched it pretty bad. Needs new rubber as well as carb work. Looks like the pilot jet port is cracked so a new carb body could work but will try to repair first. Grips have been changed out and it looks like the wiring has been re done which is nice, it's pretty simple either way. There is a new ignition in a box but I want to wire up a push button where the previous key was. The odometer reads 10732 kms. Seeing this thread was definitely what pushed me to get it! Excited to get her going! Cheers
Yeah, from what I gather there have been a few owners since Cos. Got it on the bench at my work the other day (I manage a motorcycle shop). Bought a 5$ 16mm push button switch from a local shop which fit perfectly into the previous gap and with the wiring already done it was only a few minutes to complete. I ordered in some new rubber which arrived quickly, unfortunately had to go down to a slimmer tire on the rear as my guy couldn't locate something as wide as before. One of my techs managed to fix the rear brake by adding a piece of metal as a stop when it's at the top of its motion. Also ordered some new Yamaha gold stickers to replace part of one thats been damaged. Coming together nice and quick. It's turned over but idle is rough, will be working on that today. Rock and roll, here are some pics!
