double spark problem?

[peejay]

hi peeps
currently setting up a new motor with RT225 kit, BGM flywheel and crank, indian stator.
with 450 miles done with a self imposed rev limit of 5000 it's just been on the dyno to get the jetting correct.
a problem was immediately apparant, above 6000 the graph is more like an earthquake reading.



dyno man says it's probably the pick up alignment with flywheel causing a double spark.

flywheel and pickup have now been checked and appear to be in perfect alignment.

it's been suggested to try another stator and /or flywheel.

i bought the indian stator cos the BGM flywheel is compatable with "any stator" supposedly and i've done mega miles on several motors with the humble standard indian part.

just wondered if anyone else has had this issue with BGM flywheel and indian stator

[piskie]

Throw the bgm flywheel away try amother makr

[mickyb]

That's what I said

[Wack]

Last time I had a misfire after changing to a BGM stator from a faulty Indian one, I changed the CDI first and it cured it

[peejay]

Last time I had a misfire after changing to a BGM stator from a faulty Indian one, I changed the CDI first and it cured it

since the dyno run i've fitted a new CDI and scoot feels perfectly smooth even when revved high but like when on the dyno the rev counter goes ballistic

[Loneranger]

Are you using a resistor spark plug?
Helps with this situation on the Dyno?

[peejay]

Are you using a resistor spark plug?
Helps with this situation on the Dyno?

nope, NGK 8ES

could this really be the answer, anyone else got thoughts on this please?

i'm sure it's worth a try

[Adam_Winstone]

Sounds like the same kind of double/dirty spark issues that people often note on dynos when running the AF light flywheels (the copy of the Ducati 80s AF), which many people have suggested may be down to the method of manufacture, particularly how the magnets are located. However, the only issues that I've ever had with these was resolved by addressing pickup and trigger alignment issues, suggesting that manufacture is unlikely to be the cause of most examples of people having issue with these. Likewise, pick-up/trigger alignment has been the issue that I've found when others have swapped out a working Indian stator for a BGM stator... alignment resolved = problem resolved.

All of the above probably has little or no relevance to the BGM double/dirty spark encountered here, as alignment has already been addressed, however, it does show just how critical this issue is.

Hopefully a dyno operator with experience of these new flywheels will be along shortly, to confirm that they have dyno'ed bikes fitted with these flywheels without issue.

Adam

[peejay]

thanks for your comments Adam

scoot is back on dyno in the morning with a few things to try so will keep you all posted.

[dscscotty]

PM sent

[Adam_Winstone]

Any update on this one?

[mickyb]

Standard Indian GP flywheel put on and no problems with dyno or rev counter. I expect PJ will be on later for fuller version

[peejay]

hi peeps
sorry for delay in replying, i'll post more sunday afternoon after i've done some more miles but looking good at the mo

[gaz_powell]

the good old indian flywheel to the rescue.........again !!!

[Adam_Winstone]

^... that's not what the owners said the couple of times that I've witnessed the alloy fan come loose and break up, taking the mag housing out! Nor the couple of owners that had the steel magnet covers come loose and catch on the stator laminate core

Sure, in most cases SIL flywheels are perfectly good, however, there is plenty of room for improvement, which is why people will be watching this thread with interest.

Adam

[dscscotty]

indian SIL for me every time, lighten them, strengthen cams-weld or replace rivets with 6mm counter sunk allen screws and generally they're fine, Oh they also sort out issues encountered with other more expensive flywheels. Stick a strobe on a BGM and see what happens

[Captain Pugwash]

indian SIL for me every time, lighten them, strengthen cams-weld or replace rivets with 6mm counter sunk allen screws and generally they're fine, Oh they also sort out issues encountered with other more expensive flywheels. Stick a strobe on a BGM and see what happens

I haven't ever fitted a BGM flywheel, if a BGM is fitted what could be the cause of the double spark ???

Mark.

[mickyb]

I've never fitted a BGM flywheel either but I had exactly the same problem when I fitted one of the new type AF light flywheels, rev counter went mad. Back to lightened Indian and everything is fine

[piskie]

Agree with scotty seen a couple of bgm with a strobe try as you might couldnt time up look nice behave terribly xxx

[peejay]

hi peeps
since the last dyno run i had changed just one thing, a new CDI, it made no difference on the dyno, above 6,000 revs the readings go haywire.
i was advised to try a different flywheel first. on went a new Indian one, pickup alignment was checked, spot on.
timing was now slightly out, after adjustment back on the dyno, immediately readings were spot on.



so now we have standard Indian flywheel and stator performing perfectly just like on my other scoots

right at the start i had a clearance issue between the BGM flywheel and Indian stator but resolved that.

the worrying thing for me is that i did over 400 miles running it in below 6,000 rpm, doing plug checks and thinking everything was ok, i can't get my head round this issue cos on the dyno at high revs it sounded fine so i was unaware of a high speed problem so glad it went on the dyno before i thrashed it.

since the dyno run i've done 50 miles and although it's no rocket ship it pulls strongly in top up hills and feels good at 55/60 on the open road