Oh dear, what can the matter be?

GRiSO Capo Posts : 835 Join date : 2014-05-06

This is what happened: It was a beautiful sunny fall day so I decided to take the GRiSO for a spin. I was happily cruising along, 110 km/h, enjoying the beautiful scenery. Up comes a very long straight stretch and not a single other road user in sight from any direction, so I decided to speed it up a few notches, just for the thrill. Around 150 km/h (6th gear, 6000 rpm) the bike suddenly lost torque, and as if it got into neutral the RPMs went up, speed went down. I released the throttle and at 4000 rpm the bike returned to “normal”. I continued my journey back home and noticed that the bike had changed: less torque, more vibration, some more engine sound/rattling, bike is somewhat reluctant to go fast.

Before you guys tell me to take the TBs apart, check this or that valve, loosen this or that bolt: please, I am seriously technologically handicapped. I really have no experience in motorcycle repair. I am one of those guys who probably shouldn’t even own a motorbike, but I thought; “what the heck: I have a dog without having any veterinarian knowledge, a computer and no IT skills, so why not get a motorbike?”. What I hope to find out from you guys is what I can expect to hear when I am bringing my beloved GRiSO to the MG dealer. Any ideas? Question

GRiSO Capo Posts : 10200 Join date : 2013-09-30

It's gone lame. You'll have to put it down, I'm afraid.

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GRiSO Capo Posts : 10711 Join date : 2013-05-29 Age : 67

No idea but it doesn't sound good. First thought though is slipping clutch. have you changed your brake and clutch levers?

pete

GRiSO Capo Posts : 835 Join date : 2014-05-06

Pete Roper wrote:: No idea but it doesn't sound good. First thought though is slipping clutch. have you changed your brake and clutch levers?

pete

No. The bike is completely stock.

GRiSO Capo Posts : 257 Join date : 2015-09-09 Age : 65

Out of curiosity; how many miles on your bike?

GRiSO Capo Posts : 904 Join date : 2015-05-16 Age : 72

Hi BM
How many ks you got on this bike ? Has the bike had an easy, hard life ? Has the bike had any previous dramas ?
As Pete suggests from your brief explanation, first check the clutch and it's control circuits.
Good luck with it
Keep us posted as you go please
Each one of us out in GRiSO land learns from these situations.
Caoi

GRiSO Capo Posts : 10711 Join date : 2013-05-29 Age : 67

Look at the lever on the handlebar. there is a little barrel with a plunger coming out of it. if the grub screw that holds the plunger has come loose and the plunger, which is threaded, can turn in the barrel it may of wound itself out far enough to prevent the bleed port opening in the master cylinder. It may also have just been misadjusted ex-factory.

This is the commonest cause of clutch problems.

pete

Grignapoco Posts : 148 Join date : 2014-01-20

Um the more vibes bit has me thinking spark plug cap to head issues....found this out last week after removing the suspect tape on my cap bike ran fine for 40 min after a 5 min stop only had one cylinder.... lucky I had silicone tape at home to fix..

GRiSO Capo Posts : 835 Join date : 2014-05-06

H-E-ROSS wrote:: Out of curiosity; how many miles on your bike?

The bike (2007) has 45,000 km.

Scot p wrote:: Has the bike had an easy, hard life ? Has the bike had any previous dramas?

I bought it last year with 40,000. It has always behaved perfectly: I really LOVE it. It looks like new and has always been maintained by the dealer I bought it from.

Pete Roper wrote:: Look at the lever on the handlebar. there is a little barrel with a plunger coming out of it. if the grub screw that holds the plunger has come loose and the plunger, which is threaded, can turn in the barrel it may of wound itself out far enough to prevent the bleed port opening in the master cylinder.

I will look at the handlebar lever to see if this grub screw is still there.

wardentm wrote:: Um the more vibes bit has me thinking spark plug cap to head issues....found this out last week after removing the suspect tape on my cap bike ran fine for 40 min after a 5 min stop only had one cylinder.... lucky I had silicone tape at home to fix..

Dumb question: is there a simple test to find out if it only runs on 1 cylinder?

GRiSO Capo Posts : 361 Join date : 2014-09-02

Dumb question: is there a simple test to find out if it only runs on 1 cylinder?[/quote]

Start the engine and pull one spark plug lead at a time, this should cause the engine to loose power on one cylinder and should cause noticeable vibes. Try this on all the plugs on one cylinder first then put them back and try the other cylinder. If there is no difference to power when you pull one then it is probably that lead or coil that is causing the problem!

BE CAREFUL not to get a shock if HT leads are damaged and leaking current, slip a cable tie around the plug cap and use an insulated pliers to pull leads off, be careful not to damage plug caps(leads)

Otherwise pull leads off one at a time before starting engine, best if nervous of getting a shock afro

GRiSO Capo Posts : 10711 Join date : 2013-05-29 Age : 67

Won't work on the 1100, it's twin plugged.

I doubt it's only firing on one, idle would be really slow and it would shake like a cheap sex aid.

Pete

Grignapoco Posts : 148 Join date : 2014-01-20

Pete Roper wrote:: Won't work on the 1100, it's twin plugged.

I doubt it's only firing on one, idle would be really slow and it would shake like a cheap sex aid.

Pete

Oops I missed the fact it was an 1100, nothing gets past Guru Roper...

Was amazing how close my bike was to normal at Idle, but died as soon as it got loaded up...anyway back to normal, may get around to doing the NGK cap mod in the near future..

cya
Scot.

GRiSO Capo Posts : 835 Join date : 2014-05-06

Update: I put on my reading glasses, looked at the clutch lever and found the plunger and barrel and grub screw as they were before.

And regarding 1 vs 2 cylinder: the bike was vibrating a little more than normal, but certainly not like a cheap sex aid (more like an expensive one). I checked the 2 outer spark plug leads and they sparked nicely.

But while I was trying this out (and ran the engine at different RPMs) I found that there was some dark oil being sprayed on my garage floor:
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It came from the connection between pretzel and exhaust. I found that the bolt that tightened the clamp was quite loose, and I could tighten it several turns. No more spraying.
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I then took the bike out for a very quick test up & down the road, and it seemed better. Difficult to say, as I so WANT it to be resolved. I didn't have the time to go for a long test drive.
Could it be that a leaking exhaust system causes the symptoms (less power & less eagerness, more vibration & noise, funny behaviour at high RPMs/speeds)? Or is this totally unrelated?

GRiSO Capo Posts : 10711 Join date : 2013-05-29 Age : 67

No. I think you'll find the stuff being sprayed out was just water that had condensed out of the exhaust gasses on the cold pipe.

Pete

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