SR250 Maintenance Part 2: Valve and cam chain tension adjustment
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- Опубліковано 22 сер 2024
- Part two (and final) engine maintenance video for the Yamaha SR250. In this part we go through valve tappet clearance, cam chain tension, ignition timing and spark plug inspection. As mentioned at the end of the video, there are many other things that should be checked as part of your routine maintenance schedule, but these videos have focused on the engine only.
We failed with the filming of the ignition timing (camera was not turned on) but you can see what this looks like in these videos:
• SR250 Ignition Timing ...
• Yamaha SR250 Classic: ...
And the ignition advance brackets are available here: modelikocafera...
Specifications from video:
Intake valve clearance (cold): 0.05 - 0.10mm
Exhaust valve clearance (cold): 0.12 - 0.17mm
Cam chain adjuster nut torque: 3.0 m-kg (22 ft-lb)
Adjuster cap tightening torque: 0.5 m-kg (3.6 ft-lb)
Specified idling speed: 1200 rpm
Basic ignition timing: 10° degrees +/- 2° (non-adjustable), peak advance: 32°
Spark plug type: BP7ES or BPR7ES (resistor type alternative)
Spark plug electrode gap: 0.7 - 0.8mm
Spark plug tightening torque: 2.0 m-kg (14.5 ft-lb)
As always, any questions, shoot right here in the comments :)
Cheers from Jadus!
Helpful videos you gives all time for SR250 lovers.. thanks dude. Keep it up..👊🏻
Can’t tell you how much I appreciate these videos, Jake, you a f***ing legend!
5'53, you are super right. Has to be serviced at cold engine. Thanks for the video.
Dude this is awesome - glad to see some love for the SR250!
Hi Jadus, great video. I'm in the process of doing up my SR250 classic and have had trouble getting any info on this model so its great to find your channel. Do you have any tips for finding parts. Cheers
We use ebay a lot and CMSNL :)
@@JadusMotorcycleParts thx for the tip
Molto utile e ben fatto, grazie
Hi, my I ask you about the valve adjustment? I had my engine serviced by a mechanic, he checked the valves, they are in a good condition. He checked the gaps, the valves were too tight so he adjusted them. The problem is, I had the valves adjusted like 3 times within a span of 1 thousand km, and it doesn't make sense why the valves keep getting tight. And I mean absolutely tight. Would you know why is it happening?
Really enjoying all your SR250 videos - so much I just bought a very early 1980 model to rebuild.
What is the extra breather with silver device on the crankcase - is it for a pressure valve?
Also - are you driving the new speedo via a sensor on the rear wheel?
I like how you've rotated the front brake plate to better route the brake cable and the rear brake rod above the axle - nice mods!
Hi! Cool you bought yourself an SR250. Now you have plenty of guides to work on it :) The extra breather is just a normal crank case ventilation filter. The silver device is a PCV pump from a XS650 which I have not connected yet. It will operate off of a vacuum pipe tapped into the exhaust header working on the venturi effect. Yes, the new speedo is driven off of a hall sensor on the rear wheel. All of these mods have been inspired by other successful builders. If you want to know more detail you can check out the build blog for the bike: www.dotheton.com/index.php?threads/ton-up-sr250-100mph-100kg-30hp.74386/ All the best!
hello, i have a question, ive set my valve clearance to the middle figure on the feeler guadge but my tappets are still very noisy, would it do the bike any harm to set it on the lower side of the clearance range instead of the middle?
Where is your battery. My son's 185 is right below the air filter. It's only a 150 CCA and after a few starts( he is learning to ride) I have to charge it. Yes it is a new battery. I m thinking if I modified the Air filter like you have and modify the battery box we might be able to get a bigger battery in. Thoughts?
Great vid. Il try apply to my '83 SR 500
I like the drop down bars look in the sr, mine are up, ya reckon i can just loosen necessary bolts and rotate down or ud need a new handle bar?
Next week I collect brand new R7 so I'm looking forward to the old and new comparison
good! I congratulate you for the magnificent video, it is amazing, I would have a question, what would be the battery that you mounted on the motorcycle and also the adjustment of the carburetor on the jets, Thank you!!!
Thanks! The battery is an Antigravity 4 cell unit. The jetting for this set up is a 120 main and a 50 pilot, 3.5 turns out on the air/fuel screw. But these settings are very specific for this set up and would likely not work with other exhaust and intake combinations. You can find a suggested jetting chart here: www.jadusmotorcycleparts.com/post/2018/05/17/yamaha-sr250-carb-rebuild-maintenance-tuning
Thanks a lot for the video 😀.
Is there any difference between SR models/years, as far as concern the valve clearance numbers?
Thanks again
Hi! No, there is no difference.
Hey Jadus MP! Thank you for these awesome videos. Do you happen to have a link to the manual for the 1980 Yamaha SR250? I haven’t been able to find one.
Hey man! You can join the SR250 facebook group and they have a pdf copy there that you can download 😊
Thanks for the video, was the engine moved into a different TDC position before checking the exhaust valve, if it was you didn’t show it.
Hi! No it was not. Both valves should be checked in the same cam position at TDC on the compression stroke.
@@JadusMotorcycleParts Thanks, it’s the first time I will be doing this so just wanted to check, mine is an SR125 though so a little different
Great and useful guide. An advice, please: I saw your carb tips, and I have a doubt... My exhaust is stock but modified, quite opened up: do you think I should go with a 125 main jet or could be ok the stock 122? I could increase the fuel/air screw to compensate...
You should probably go to the 125 to be safe - the 122.5 from the factory was probably borderline lean as it is.
@@JadusMotorcycleParts Ok.. SUPER thanks !!!!
Hi thanks for the video.My wife's old sr has got a ticking tappety noise with oil reaching the top bleed screw ok so I am assuming it's not oil related.Do you think this videos adjustments may work?
Thanks.
It could if you tappets are loose :)
My sr250 is seized. Tried turning the nut on the flywheel counter clockwise, but it just comes off. How do I rotate the flywheel if the nut comes off?
Bummer man. You need a clutch holding tool - often they have round pins on one side and they slot into the flywheel and you get good leverage to turn it.
Where did you get the rear sets? Thanks for the videos, great information.
Hi, thanks for watching. The rear sets are a combination of custom machined brackets plus standard folding footpegs from TEC.
hi, could I ask you what measure of squish are you running on your engines? I'm having troubles with engine knocks and I can't find reliable information about the squish value for an sr250
Hi there. I actually have no idea sorry. I only measured the combustion chamber volume and calculated what compression would be with the new piston and thinner 0.5mm thick copper head gasket. I have personally not heard of other SR250's having problem with knock so I wonder if your problem source is something other than squish?
@@JadusMotorcycleParts maybe, I'll try to find out. thank you
Did this ever make it 100mph?
Sure did! We're taking our time making a video about it ☺