I have a 1981 SR250, great bike, but I don't know much about it... Firstly, I need to reset the timing due to tapping in the top end. I opened those little caps on top of the cylinder that use hexes, and found the ignition points. Thing is, which one is exhaust, and intake?

Also, has anyone experimented with performance? Coming from a dirtbike background I'm thinking shaving the head, doing a big bore conversion, etc. But are there better more efficient ways for these little streetbikes?

little intro first twist, helps lube the information pathways.

first port of call, a manual like Haynes if your starting from scratch. Good bedtime reading

Good bedtime reading

True that!

As far as I go, I don't see how telling everyone I don't have a job and I'm attending college will help solve any problems with my bike =)

True that!

As far as I go, I don't see how telling everyone I don't have a job and I'm attending college will help solve any problems with my bike =)

Attending college might not fix your bike either, but reading the book might, The tappets you found by removing the caps aren't the pionts they are the valves/cam rocker arms !

All drewpy was sayin was say hello in the new members section first, then ppl will maybe help..... if they feel like it!

Attending college might not fix your bike either, but reading the book might, The tappets you found by removing the caps aren't the pionts they are the valves/cam rocker arms !

All drewpy was sayin was say hello in the new members section first, then ppl will maybe help..... if they feel like it!

Oh yeah that's right, for some reason I always get the vales and points mixed up... And yeah I can go say hi there for all the two people that care lol.

I am not sure if these were officially imported into the UK. The ex valve is the one towards the front of the bike and the in valve is to the rear. I have the tappet and other specs for the sr125 I can post when I get home but I am not sure if these are the same. It may help though.

Oh yeah that's right, for some reason I always get the vales and points mixed up... And yeah I can go say hi there for all the two people that care lol.

don't dis yourself TK, you have a bike just say hello and the good folks will respond positively.

I am not sure if these were officially imported into the UK. The ex valve is the one towards the front of the bike and the in valve is to the rear. I have the tappet and other specs for the sr125 I can post when I get home but I am not sure if these are the same. It may help though.

Yeah this is true. I found a small owners manual online for free that listed how to set cam chain timing, as well as valves. I'm not sure if it's ok to post links like that here though?

no I wouldn't, the copyright police are scanning this forum all the time

Specs for a SR125 - if it helps

Ignition timing (B.T.D.C.) 9 deg at 1,300 r/min

Advanced timing 29 deg at 5,500 r/min

Valve clearance (cold):

Intake valve 0.05 to 0.09 mm

Exhaust valve 0.11 to 0.15 mm

The SR250 Was officially imported here in the UK. Quite a popular bike with the Lady's as it had a low seat height. The data I have for the UK spec bike is.

SR250 1980 - 1983

Valve clearance set on TDC on the compression stroke with a Cold engine.

Intake Valve 0.05mm - 0.10mm or 2 - 4 thou

Exhaust Valve 0.12mm - 0.17mm or 5 - 7 thou

i loved my sr 250

had it from new in 1981

was great on fuel but found it was sore on chains and rear sprockets

just make sure it does not have the original yokohama front tyre on ( or you will die if the road is wet )

Specs for a SR125 - if it helps

Ignition timing (B.T.D.C.) 9 deg at 1,300 r/min

Advanced timing 29 deg at 5,500 r/min

Valve clearance (cold):

Intake valve 0.05 to 0.09 mm

Exhaust valve 0.11 to 0.15 mm

Thanks man. I found that on my left side panel it lists the sizes. Thing is, I just finished adjusting it, spent a good 5 minutes getting it just right, put the tank and seat back on and it goes all CLACK CLACK CLACK on me...

Then you did it wrong,when adjusting the valves they need to be done with each valve in it's fully seated position, by rotating the eng to the proper position on the flywheel. Most will have marks I and E. This will take much longer than 5 min

Then you did it wrong,when adjusting the valves they need to be done with each valve in it's fully seated position, by rotating the eng to the proper position on the flywheel. Most will have marks I and E. This will take much longer than 5 min

By 5 minutes I meant the actual process of sticking the gauge in, loosening the nut, tightening the valve, tightening the nut, back and forth until it's just right. I presume the flywheel fell out of place when the handlebars fell from the right to the left while I was working on it. It seems like the TDC marking is RIGHT before it wants to fall, but that's probably because it's TDC

Just a quick question, when is the compression stroke? And how do I know when to stop on that one?

Valve clearance adjustment should be made with the engine cool, at room temperature. When the valve clearance is to be measured or adjusted, the piston must be at Top Dead Center (T.D.C.) on the compression stroke.

Take the plug out and when you turn the engine the compression stroke is when the piston is rising (air coming out).

Valve clearance adjustment should be made with the engine cool, at room temperature. When the valve clearance is to be measured or adjusted, the piston must be at Top Dead Center (T.D.C.) on the compression stroke.

Take the plug out and when you turn the engine the compression stroke is when the piston is rising (air coming out).

Also when it's the compression stroke the valves should be moving, where as 180* around they're going to be pumping. If that wasn't already said. I fixed it by the way.