[Anff]

I have a CRF250 with a 300 kit on it. The bike is a hybrid of an 'R' and an 'X' in that it has everything 'R' apart from has the 'X' crankcase etc to permit the use of an electric start. All is normally good and the bike has been run competitively for a season. The engine has been rebuilt and the main components replaced. I stalled the bike whilst out on a run and I hit the electric start and it span over but did not start (normally and excellent starter hot or cold. On kicking the engine over it felt wrong, like the starter was engaged and giving resistance to the turning of the engine. This was the same even with the clutch in. I have stripped out the clutch which appears fine, kicked the engine without the plug in or the clutch and the resistance is still there. As I need to remove the cylinder to remove the starter, has anyone had this happen or any ideas as to what it could be

[riddler9]

do you need to remove the cylinder for sure or can you remove the timing chain tensioner? reason I ask is you can get it past the stock cylinder by removing the tensioner.

[Anff]

Update, removed clutch totally, all good, removed starter and replaced it with a spare I have. Still have the problem. Upon kick the bike over it feels like there is too much resistance. it is not seized, it just feels too much, like the gearbox is turning over even though I have the clutch assembly totally out! Baffled!
Any CRF engine builders out there or anyone who has had the same problem or something similar it would be great to hear from you. Thanks

[450man574]

Seized Main Bearings? Lower rod bearing?

[Anff]

I really hope not as the bike has just had a full rebuild with quality parts. These were all replaced and have been run for 20+hrs. The oil is clear in both engine and gearbox, no signs of any metal waste etc.

[Aussiecrf230]

Have you taken the cam cover off and made sure things are OK in there.

Is the resistance constant or only for part of kicking it over.

[Anff]

Many thanks for your comments. The latest thinking is that it could be the starter motor clutch mechnaisum sticking which is resulting in the resistance when turning the engine over.....Has anyone had such issues?

[motosicko]

Auto decompressor working correctly?

[Dirtdiver73]

Take a close look at your engine oil level and trans oil levels to verify that you don't have an oil migration problem. Not sure how common this is but it is a known issue. Hope you get it sorted out.


Dirtdiver

[riddler9]

Many thanks for your comments. The latest thinking is that it could be the starter motor clutch mechnaisum sticking which is resulting in the resistance when turning the engine over.....Has anyone had such issues?

Pull the starter back out and turn the motor over without the plug. See if it still has resistance.

[JimDirt]

If its the same as the 450X (i do not have a 250X manual so i cant confirm) , it should have a Starter Clutch , which is located behind the regular clutch (you have to remove the right side crankcase cover , the clutch and it should be the back gear in the assembly that drives the main clutch , Remove the primary drive gear bolt, washer, clutch
outer, needle bearings, clutch outer guide and primary
drive gear. , it is a 1 way gear

DISASSEMBLY/INSPECTION
Check that the starter driven gear turns counterclockwise
smoothly and does not turn clockwise.
Remove the driven gear and needle bearing from
starter clutch outer.

Remove the snap ring and one-way clutch from
clutch outer.

Check the needle bearing for abnormal wear or
damage.

Check the starter driven gear for abnormal wear or
damage.

Measure the driven gear boss O.D.
Measure the driven gear boss I.D.
Check the one-way clutch sprag for abnormal wear
or damage.

Check the starter clutch outer sliding surface wear
or damage.

Check the reduction gear A and idle gear for wear or
damage.

Measure the reduction gear A I.D.
Measure the idle gear I.D.
NEEDLE BEARING
SERVICE LIMIT: 45.660 mm (1.7976 in)
SERVICE LIMIT: 36.034 mm (1.4189 in)
ONE-WAY CLUTCH
CLUTCH OUTER
SERVICE LIMIT: 12.050 mm (0.4744 in)
SERVICE LIMIT: 12.050 mm (0.4744 in)

Hope that helps some