MC21 R7L with M parts "wire splice" Std engine, pipes, ignition, air filter.

This is the 2nd time this has happened, 1st time on a track day, now on the road.

easy ride for 40 miles or so then holding about 11K for about 4 miles then up to 11,500 then nothing. The engine cuts out completely dead. I slow down bd let the clutch out, and it fires back into life, but only on 1 cylinder and no its hasn't seized.

Ride home last 2 miles running on 1, remove the front plug and yes it's all oiled up

The side stand faintly lit (with the stand up and glowing properly with the stand down.

On the track day the bike ran for 3x20 min sessions before the same thing happened.

Any suggestions , apart from don't ride for more than 50 mins ??

Phil M
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MC21R ; MC21SP , plus some other none Honda 2t's

Could this be the pickup suddenly failing when hot ?

Or just a coil breaking down ?

Does anyone have the full spec of a std coil compared to an HRC replacement (primary/secondary resistance)

I can test them using this guide but would like an actual ohm spec for both sets

http://nsr250.net/forums/viewtopic.php?t=11280&highlight=ignition+coils+check+cheque

Cheers

Phil M

sounds like a faulty side stand switch have you tried removing it? might have a bad connection or corrosion inside they are a weak point on some bikes

I tested the coils and got the following readings

0.3 primary and 7.97 & 7.63 secondary (about 50% on the guide above) so I think they are knackered

Mmmm How wrong can you be

Any ideas what would cause this, and still let me ride for 2 miles home (OK on 1 cylinder) !!!

http://s1366.photobu...html?sort=3&o=5

Link doesn't work.
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Andy.
NSR-WORLD.COM

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ahh man thats bad luck give langcourts a call they have just done a really good job on my mate rgv barrels ive got a full gasket set for an mc21/28 i bought in error if you want it? cost me £50 you can have it for £35 delivered

Thanx Jodydid

I need to understand why it happened. At the moment I'm thinking pre-ignition causing the failure, maybe iffy coils (but why only the front has failed) and why this funny half glowing side stand light.

Is it the PGMIII that is failing, just the coils, a duff plug, ??? I dont have zillions to keep throwing at the bike as I have spent way too much on it already ;-( And to think the Aprilia has yet to miss a beat and has had probably less TLC and more abuse !!

Any help to get the bike reliable would make an old man happy

On closer examination there is 15mm of top ring missing from the front of the piston. The rest of the 2 rings are seized into the ring groves. So maybe it's a ring failure, and the bits have rattled around causing the damage.

So the next question is what would cause the ring to fail ?

It doesn't look like detonation.

Were the rings installed correctly? Top ring is half keystone, lower is standard. We've seen it before people have managed to fit them backwards. or upside down with disastrous results.
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If I have to take the carbs off once more...

Hi Stephen

The pistons are original (4k km on the clock). The bike is used on the road and has done a couple of track days since I got it. Regularly run up to 12K rpm in 4th and 5th (Cadwell/Oulton/M56)

The coils checked out at .3 ohm and 7.97 & 7.63 secondary. Are they knackered ?

Thanx

Phil M

I would think it has absolutely nothing to do with ignition.

Your looking at completely stripping the motor now anyway as any bits of ring could now be in the crank case. Finding the cause will be easier while stripping and rebuilding.
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If I have to take the carbs off once more...