So it wasnt the plugs

Miztaziggy · Post by **Miztaziggy** » Thu Sep 22, 2011 7:16 pm

Changed the plugs yesterday and took it for a quick ride tonight to test...

Hesitation still there at about 6k. Feels as though it burbles and stutters for a half second, then goes again, but definitely down on power overall.

Here are my thoughts as to what it could be...can anyone tell me if these might or might not be the cause please, bearing in mind my bike was fine, and the only things that changed were an oil change, remove and refit exhausts and a wash.

- HT Leads gone and/or coils? How do I check?

- Carbs full of crap? But wouldnt this affect all rev range, not just over 6k?

- Blockage in exhaust? I wonder if in trying to seal the downpipe joint and using gun gum, I may have ended up with some across the opening and narrowed the pipe on the back cylinder by half or even less maybe restricting it? Would this cause a high rev problem and loss of power?

- Something more serious - damaged cylinder or something?

- Bad fuel? Filled it on Tesco normal unleaded as usual, but is it worth emptying it and trying better 99 octane stuff?

- Air leak somewhere? How do you check other than visually inspecting it all?

jdugen · Post by **jdugen** » Thu Sep 22, 2011 7:32 pm

Coud be ar filter, especially if you jet washed under the tank.....?

Miztaziggy · Post by **Miztaziggy** » Thu Sep 22, 2011 7:36 pm

jdugen wrote:Coud be ar filter, especially if you jet washed under the tank.....?

May be, I'll check it

Didn't jet wash anywhere though, and didn't touch under the tank

AMCQ46 · Post by **AMCQ46** » Thu Sep 22, 2011 7:44 pm

strange one

the gun gum would get blasted away by the exhaust gas as it was setting

Carbs - could be as sh1t gets in each jet in a different way

HT - could be - a swap is the best way, but running it at night with a bit of moisture [fine jet mist plant spray ], you should see any arcing

I would try a compression test to eliminate other engine issues

Miztaziggy · Post by **Miztaziggy** » Thu Sep 22, 2011 7:55 pm

AMCQ46 wrote:strange one

the gun gum would get blasted away by the exhaust gas as it was setting

Carbs - could be as sh1t gets in each jet in a different way

HT - could be - a swap is the best way, but running it at night with a bit of moisture [fine jet mist plant spray ], you should see any arcing

I would try a compression test to eliminate other engine issues

Thanks AMCQ. Much appreciated.

How do you do compression test? Finger in spark plug hole, or properly with gauge?

AMCQ46 · Post by **AMCQ46** » Thu Sep 22, 2011 8:11 pm

Proper gauge, I can post mine up to you if you want, send me your address

Miztaziggy · Post by **Miztaziggy** » Thu Sep 22, 2011 8:29 pm

Brilliant thank you will pm

Will need to know what it should read when testing I think.

Assuming compression ok, anyone ideas on where to start looking? Leads, carbs, something else?

tony.mon · Post by **tony.mon** » Thu Sep 22, 2011 8:48 pm

If the only thing you disturbed was the plugs, they're your most likely candidate.

Miztaziggy · Post by **Miztaziggy** » Thu Sep 22, 2011 8:57 pm

As in the new plugs might be causing it?

I was getting the problem with old plugs, now running new ones and still exactly the same problem. I hoped that ruled out problems with the plugs.

tony.mon · Post by **tony.mon** » Thu Sep 22, 2011 9:13 pm

Ok, fair point, then coils/leads/plug caps are next.

Does it by any chance get better or worse with the lights full on?

Miztaziggy · Post by **Miztaziggy** » Thu Sep 22, 2011 9:21 pm

Lights full on?

Hmmm...if you mean headlight I always have headlight on full, never turn it off

Should I try with it off?

tony.mon · Post by **tony.mon** » Thu Sep 22, 2011 9:28 pm

Yes, it's a way if eliminating voltage/regulator/battery problems.
Have it running at about the point where it misfires, turn everything off (or on) and see if it changes.

Miztaziggy · Post by **Miztaziggy** » Thu Sep 22, 2011 9:46 pm

Ok, will try that tomorrow when it's light

I hope it isnt the reg/reg etc as it is a finned one and shouldnt have blown

darkember · Post by **darkember** » Thu Sep 22, 2011 10:33 pm

Very much doubt it would be an earth issue as the problem would be constant from the off. From what has been disscussed so far coils/HT leads & plug caps should be next on the list as mentioned before.

What I have noticed is that the plug caps can be a real pain to remove even if you have small fingers its really hard to get a full purchase on the cap & you can tend to twist it off thus possibly cracking it in the process. Check them closely for visual cracks & also run the bike in the dark to see if there is any arching of the spark. The safest method I have found to remove the caps is to use a shoelace looped round the cap elbow then allowing you to be able to pull the cap off in the most virtical position possible and avoiding any twisting motion.

Miztaziggy · Post by **Miztaziggy** » Thu Sep 22, 2011 11:21 pm

Ok so in the dark, where do I look for arc? Does it go between leads and frame or something, or does it come from coils or will it be around spark plug sockets?

Is it easily visible? Do I have to rev it to get it to arc?

I don't have baffles in my exhausts and none to fit either...so the neighbours wont appreciate me running the bike after 9pm when its dark...lol :-)

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