Juddering when the powers down

[smudge]

Hi Guys
Took my SP1 to Silverstone this weekend around the track. Weather was crap so morning session was wet. Into the third session it rained heavily and in forth the bike seemed to shudder like it was intermittently shutting down and picking up. Thought misfire because of the wet. Striped down and found no damp around any plugs, leads or coils. Went out again and same thing. Let it stand for an hour to have lunch as the sun came out. Went out again and now it started doing it in every gear but noticed when giving it some the engine seemed to race like the clutch was slipping. It's not the clutch as I've just changed it for complete EbC kit and springs and the bolts are still all right. It's just like I'm flicking the clutch lever in and out quickly and keeping the power on. I thought if it was gearbox jumping in and out of gear the box would be noisey. Thought it might be chain slip although front sprocket is worn it still does the job and chain it slightly over tight if anything. Any ideas? It's always has the missing a gear thing the sp1 has but it's only between 2nd and 3rd but read that adjusting the shift rod will sort that out. Although at one point I shifted down backing it into a corner and there was a bit of vibration on the left peg but it was at the same point in the track every time. The problem pretty much screws my day up as could only get 80 out of her down the straights because of it jumping and revving. Any advise or anyone had this before. Never had a problem on the road although I do now but it did get a hammering yesterday. Just to mention I tried going all the way up the box at one point and it wouldn't go into 4th, 5th or 6th but then went down to second and it went all through the gears up and down fine. Thought I'd it was box fault it would either be in or out of gear and not keep jumping in and out by itself.
HELP ME PLEASE

[Sppete]

I'd guess it's electrical.
Have you pulled the plugs to see if it's front or rear?
Have you checked the fault codes to see if that give you any clues?

Pete

[smudge]

Yeah I thought it was electrical because it seemed like misfire. Only did it under load though. Plugs look ok as there new. It wasn't until the last session the judder or miss started to get really bad it would power out of the corner and like skip like some of the gear was missing and then bite again. But what through me after chasing a misfire all day was if I gave it more throttle it would do it bad and then intermittently rev out like the clutch was slipping or the chain had come off and got back on again. So either its transmission jumping and throws it out of gear and back in because of the severity of the jultjng or it's a misfire and it caused the transmission to do the same thing. I've ordered a set of chain and sprockets for her. Going to check the clutch spring bolts are still tight and try again. Can't find any coils for it apart from eBay but there ones you have to cut to length and don't come with the flash cap that pushes down the tube onto the top of the spark plug

[Sppete]

You had mentioned in you first post your front sprocket was pretty worn. If it's worn to a point you think it could be jumping cogs you know a new chain and sprocket kit is a must
I've had a worn clutch in the past.My symptoms were different. In top gear the revs would get to about 6.5 and then race to the red line without me going any faster. It all felt pretty smooth though
Of course, if the chain is jumping that could just make the drive rough enough to cause the friction plates to brake contact just momentarily.
Personally,I'd do just as you are doing, I'd go for the new chain and sprocket first and then see how it behaves.
Good luck Smudge, keep us posted.

Pete

[smudge]

Hi Guys
Do any of you know where I can get some coils for my SP1. Don't really want to buy the cheap ones off ebay and Honda have no stock until August. A friend of mine said some of the SP1 owners have done a mod. Something to do with fireblade coils. Anyone heard of this. Apparently SP1's are prone for coils failing and power commander feed wires coming loose?

[smudge]

Me again. Might have found the problem. On the rear bank there are light blue/white marks like powder burns. So think the rear lead has been tracking across to the head. Honda can't get coils or caps until August but have been doing a bit of digging and found a mod that a lot of sp1 owners have been doing. It's to use the pencil coils from a cbr 600 rr and fitted those instead of having plug leads. Question is do you just hard wire them into the old cool wiring and let the ecu tell it when to deliver the spark. I guess that's how the old ones worked just with leads. Has anyone done this mod or heard how it's done?

[smudge]

Hi Guys
If anyone is interested here's the link for how to modify your sp1 to pencil coils

http://www.rc51forums.com/forums/showth ... opics/6482

[smudge]

Ok guys update so far. It's not a misfire. I find the coils and plugs. Checked the power commander. Changed chain and sprockets. Checked clutch. Road tested and problem still there. Removed complete right engine cover, clutch basket assembly and put a magnet through oil in sump. Not metal partials anywhere. I can see a few of the gears and all seem to be intact with no sign of slipping or metal on metal wearing. Bearings seem fine with no play. However I've never had a gearbox apart on a bike before but the input shaft (the one the clutch basket sits over) when out of gear is smooth as silk to turn. When in gear it has what only I can describe as back lash. The movement is about 1/5 of a turn before is moves the gear set. The amount it with turn freely gets less and less the higher the gear its in. Obviously when the basket is on the shaft and in sync with the primary gear off the crank there is no movement. Question is how much movement is there supposed to be without the basket attached. When you turn it by hand there is no roughness to it in or out of gear and obviously when the bike is running it only turns one way any how. Surely if this was excessive wear there would be signs of metal in the sump which there are not. Anyone on here rebuilt the rc51 gearbox before who understands what I'm in about. The feeling I'm getting when riding is a juddering from the bike like misfire but when put under full load in a high gear normally he engine torque pulls you away but at the mow it juddered then revs with a bit of a vibration sound and won't pull. It's just like I'm flicking the clutch lever and then slipping the clutch but with s vibration noise. The only other thing I will say is when I checked the clutch plates only the outer friction plates were wet and all the inner ones where mostly dry with small marks of oil on indicating the inner and outer plates haven't been doing a tearing lot while the inner ones have been working hard. Steel clutch plates have no heat marks on so I'm a bit confused as to what's going on with her
PLEASE HELP. Booked Oulton Park track day 14th July and need her fixed

[smudge]

Found the problem. Gearbox fooked. New engine on way. Brand new engine and throttle bodies still with the factory tags on. So engine miles 0. She'll be like a new bike

[Sppete]

Oh Crap!
Oh Well, like you say,she'll be like a new bike when you get her sorted

Any idea what shagged the gearbox?

Pete