Can't start my CRM.

Post by **kingoftheswing** » 25 Nov 2013, 20:47

Hi guy's,

A couple of week's ago when I was out riding, I had a sudden loss of power. The only way I can describe it was it feeling like I had run out of petrol.

After checking the petrol in the tank and seeing that was almost full I checked the fuel cut off and then decided to change the spark plug. After changing the spark plug the bike fired and I was able to limp it home, however, it was running funny. Felt a bit like when a car develops a miss-fire.

The brand new spark plug is now black and oily, as well as the old one. I have cleaned the air filter, changed the oil, checked my 2t pump and my power valve, and cleaned the carb. The bike doesn't feel down on compression, I don't have a tool to check this though.

After speaking to a few people I have suspicions that it could possibly be the piston ring's. I am just hoping that by riding it the 5-6 mile journey home I haven't done any proper damage.

Can anyone with more experience with these thing's than me possibly shed some light on my situation please?

Post by **knackeredMk1** » 25 Nov 2013, 21:11

Sounds very much like a partial seizure.

First of all take the expansion chamber off and look through the exhaust port at the piston and cylinder. If you see anything more than a very little scoring and any melting in either then you might need a rebore and new piston.

Even if you don't see a problem in this investigation it is worth taking the barrel and head off if this hasn't been done recently. You can get a much better look at the bore and rings and measure the piston. You would be surprised at how little visible wear on the piston and/or bore can put them out of spec and the engine needs a rebore and new piston.

Post by **kingoftheswing** » 25 Nov 2013, 21:56

Are you suggesting a top end rebuild?

Post by **knackeredMk1** » 25 Nov 2013, 21:57

I'm suggesting that might be necessary and you need to investigate. Taking the expansion chamber off is a quick and easy way of spotting significant damage. Even if this is clear I think you should go further unless you are confident that the piston and bore have been recently serviced.

I can't tell much from your description as I wasn't present. It's not a problem with how you told it but just that I (and anyone else) wasn't there and we haven't experienced these events.

Post by **kingoftheswing** » 25 Nov 2013, 22:09

I understand, I haven't done this job before so I'm a little apprehensive about doing it. I have had the bike for about 8-10 weeks now and all I have done in the way or servicing is oil changes, plugs and filter cleans. I don't know when the piston and bore were last serviced, I would imagine over 6 months ago.

Will the expansion chamber come off with the engine still in the frame?

clint · Post by **clint** » 25 Nov 2013, 22:26

Piston was replaced in November. It was like new when I rebuilt the bottom end. I inspected that before finding out the main bearing had gone!

God I miss that bike. Been looking at buying another as I have a new job but the prices are through the roof all of a sudden

Post by **kingoftheswing** » 25 Nov 2013, 22:34

This weekend I will get the top end off and have a look then report back with my finding's. I think I'm off the road until the new year though with the run up to Christmas though!

Post by **fallenmikethebike** » 26 Nov 2013, 18:48

Drain ALL the old fuel out and store. drain off the carb completely by removing the float bowl, check for water or crud in the float bowl[ make sure to keep an eye on the float pin]. clean all the jets especially the pilot jet. Take out the plug and kick the bike over a few times to vent the crankcase. drop a NEW BR8ES in there.
Put about half a ltr of NEW fuel in the tank, now fire her up and see what's it like.
Mike

Post by **kingoftheswing** » 26 Nov 2013, 22:18

I have drained the carb by turning it upside down, it was the only way I could do it as 3 of the 4 screws holding the bowl in place are knackered and I can't get them out. I haven't tried replacing the fuel, although it was brand new fuel from a petrol station that it was running on when the problem occurred.

Post by **twistednuts** » 26 Nov 2013, 22:53

Theres a drain screw on the carb.

The knackered screws will sometimes come out with grips, other than that its the tap method.

If you manage to get them out - ive got some allen bolts to replace the goosed ones. Price of postage.

Post by **pudzie83** » 26 Nov 2013, 23:03

what you need to do with the screws is get a small hack saw and cut into the posy groove making it large enough for a flat head screwdriver,

clean your carb,breather pipes,jets before you go any further as it could be just simply a bit of dirt

Post by **kingoftheswing** » 27 Nov 2013, 06:57

I'm sure I have enough persistence to get them out, just haven't wanted to because I have no replacements. Allan key bolts sound like a good idea, I will PM you.

I will update at the weekend when I get a chance to get my spanners out.

Post by **kingoftheswing** » 03 Dec 2013, 19:34

So guy's, an update. I have removed the head and piston, here are some images. I don't know what I'm looking for, however I'm pretty sure the piston shouldn't be the colour that it is?

I am taking it to be inspected by a motorcycle mechanic but any advice I can get here would be very welcome. Thanks in advance.

http://i977.photobucket.com/albums/ae25 ... 4a876b.jpg

http://i977.photobucket.com/albums/ae25 ... 217384.jpg

http://i977.photobucket.com/albums/ae25 ... 944108.jpg

http://i977.photobucket.com/albums/ae25 ... 71c3fe.jpg

http://i977.photobucket.com/albums/ae25 ... d87c97.jpg

http://i977.photobucket.com/albums/ae25 ... bb4ebb.jpg

Post by **knackeredMk1** » 03 Dec 2013, 19:52

A few things -

1) I'd like a closer look at the inside of the head please.

2) Can't really see but your bore doesn't look bad but it could be just worn without any major scars. How many hours has it done since the rebore? If you run your finger around the bore, particularly in the top cm can you feel any ridges or lips?

3) The piston top is fine but there is a bit of 'blow by' past the rings. The black carbon deposits should not go much below the lower ring on a well running engine. It could be that the rings are worn or the bore is worn. I've also seen, but I'm not suggesting this has happened, the wrong sized piston put in. In the case I found there was a standard piston (66.0mm) put into a 0.75mm overbored cylinder

. It ran, and had been running like that (with a bit of piston slap) for at least 6 months before I found it.

Post by **kingoftheswing** » 03 Dec 2013, 20:28

I don't know how many hours since the rebore, I haven't had it done since I took over ownership about 8 weeks ago. I can't quite reach to the top of the bore with my fingers but can't feel any ridges or lips.

I know that the piston was brand new last November.

How do you identify if the ring's are gone?

Inside the bore:
http://i977.photobucket.com/albums/ae25 ... 4ce986.jpg
http://i977.photobucket.com/albums/ae25 ... 204120.jpg

Closer look at the piston:
http://i977.photobucket.com/albums/ae25 ... cc5566.jpg
http://i977.photobucket.com/albums/ae25 ... 9d593a.jpg

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