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Just when I thought we were getting along so nicely. baaa! lol
Did my valve adjustment
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LOL, I'm not the one talking like eminem in my videos!
I checked clearances at 700 and swapped shims at 3,775 miles after a couple weeks of rough starts. The exhaust valves had tightened from .009s when I checked to .008s when I swapped, causing the rough starting.
Removing the fuel tank is overkill especially since the quick connect fitting is complicated/fragile/specified to be replaced with new one on every removal. However, propping up the fuel tank does not require this and I found helped substantially. Propping up the fuel tank allows the wiring harness to get pushed out of the way for extra visibilty and workspace.
I think anyone attempting this job should have both a telescoping magnet AND a good long pair of tweezers on hand. I was able to remove all four shims and install the exhaust shims using only the magnet. However, after several fruitless attempts to install the new intake shims, I had to run to Walgreens and get a pair of tweezers to finish the job.
Another thing I learned the hard way is that the radiator hose going into the engine completely obstructs the intake rocker arm axle. As such, in order to remove that rocker arm axle, I had to disconnect the hose, spilling about an ounce of coolant in the process.
Removing the fuel tank is overkill especially since the quick connect fitting is complicated/fragile/specified to be replaced with new one on every removal. However, propping up the fuel tank does not require this and I found helped substantially. Propping up the fuel tank allows the wiring harness to get pushed out of the way for extra visibilty and workspace.
I think anyone attempting this job should have both a telescoping magnet AND a good long pair of tweezers on hand. I was able to remove all four shims and install the exhaust shims using only the magnet. However, after several fruitless attempts to install the new intake shims, I had to run to Walgreens and get a pair of tweezers to finish the job.
Another thing I learned the hard way is that the radiator hose going into the engine completely obstructs the intake rocker arm axle. As such, in order to remove that rocker arm axle, I had to disconnect the hose, spilling about an ounce of coolant in the process.
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2,049 Posts
I was under the impression that the CBR250R had shim freeplay different than the older 250cc engines. My NX250 has 0.009 +/- 0.001 inch (0.23 +/- 0.03mm) for the valve clearance. Doesn't the CBR250R have different clearances for the intake and exhaust settings? I seem to remember 0.006 and 0.010 inch, respectively, but it's been a while since I saw that cited in this forum.
Yup, check Sendler's thread: http://www.cbr250.net/forum/cbr250-service-maintenance/1603-did-my-valve-adjustment.html#post20168
Yup, check Sendler's thread: http://www.cbr250.net/forum/cbr250-service-maintenance/1603-did-my-valve-adjustment.html#post20168
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1,377 Posts
From the Owner's Manual:
ENGINE
Bore and stroke Compression ratio Displacement Spark plug
Standard
Spark plug gap Idle speed
Valve clearance (Cold)
124
76.0 × 55.0 mm (2.99 × 2.17 in) 10.7 : 1 249.6cm (15.23cu-in)
SIMR8A9 (NGK) 0.80-0.90 mm (0.031-0.035 in)
1,400 ± 100 min (rpm)
Intake 0.16 mm (0.006 in) Exhaust 0.27 mm (0.011 in)
So, yes, you are about right.
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115 Posts
I got my adjustment done yesterday took it in for the 600 mile service at 11:30 and they had it done at 2-2:30.
Repair order invoice reads:
"inspected valve adjustment IN at .16 and EX at .27"
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2,049 Posts
FWIW, I go to the large side of the tolerance when replacing shims (I don't want burned valves), but then I have to pull the fuel tank and a large valve/cylinder cover to measure the clearance, and pull camshafts (and loosen the camshaft chain tensioner) to replace the shims. I try to minimize the number of times that I do this.
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This is one of the reasons that I urge buying the service manual and at least doing the routine stuff yourself, if you have reasonable patience and can pay attention to details.
No one has a greater interest in your bike being safe and running well than you.
No one has a greater interest in your bike being safe and running well than you.
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Yup, a newer, and higher revving design.
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3,789 Posts
Surely that should be mm not inches
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Some dealerships run cold water from a hose on the engine for a while. They obviously let it sit for a while to cool down first. The engine doesn't have to be ice cold, I think the manual says below 90 degrees.
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So I decided that I should do my initial valve clearance inspection, before I rack up too many more miles. At 1670 miles, the intakes were both @ 0.006" and the exhausts were both @ 0.011"... right at factory specification (yes, I did confirm the measurements - 0.007" and 0.012" feeler gauges were a "no go").
No wonder my bike has been running like a champ, and delivering great MPG without even trying!
No wonder my bike has been running like a champ, and delivering great MPG without even trying!
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Still, that's within the +/- 0.001" tolerance. It pays to run these bikes hard during break in!
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4,996 Posts
Yes, and doing what you did is best, waiting a bit longer.
On my next cbr250 I'll be waiting longer as well.
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Aufitt, this whole valve clearance thing has me wondering just how many of these 250R motors leaving the factory are right on spec, and how many are just "close enough" to the spec? Do you think that they set the initial clearance to the "loose" side of the spec, assuming that they will get tighter with mileage? When I read that others have had shims changed at 600 miles, it makes me wonder if those particular engines weren't in fact "off spec" right from the assembly line.
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Ive said it before and I'll say it a again, you're a smart man Mike
Honda has tried to get a balance just right, they didnt want engines failing.
The ones that have not been fully bedded in (ie babied) seem to be the bikes that needed adjustment at the early vlalve clearance check.
I wont know till I check mine again one day.
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