|
|
Post by scottkooi on May 14, 2011 19:41:49 GMT -5
You've got me by a foot and 100lbs. Would love to get this scoot running prime and hope for a stiff wind, then I should be able to get 60! lmao
|
|
|
|
Post by 90GTVert on May 14, 2011 20:21:09 GMT -5
Definitely get that crackle covered before you worry about anything else. That's a scary sound once you understand what it means and what it can do. Another suggestion would be to consider a BR8HS instead of a BPR8HS. The tip is not projected on that. Won't make a huge difference in compression, but it I know other members have made small changes like that and had good results. As suggested, getting a squish clearance measurement and doing a compression test would be good ideas.
You mention an HP carb. Any idea what size and what jetting? A lean engine is more likely to heat up and have these issues. If that plug has been in there a while it's a bit on the light side.
|
|
|
|
Post by scottkooi on May 14, 2011 20:50:25 GMT -5
I have no idea what kind of carb or what jets are in it, those are things that he did after he blew it up the 2nd time. I asked him to get me a list of everything that he did including part make/model, jet sizes, etc. He did tell me that he wasn't sure of jet size b/c the maker of the bbk usually grinds the #s off as a way of protecting their "formula". Not sure what info I'm actually going to get.
|
|
|
|
Post by scottkooi on May 14, 2011 20:56:31 GMT -5
it's taken me almost 3 weeks to put 100 miles on it, that's how long the plug was in it. Providing that it was a new one that he put in when he 'fixed' it.
|
|
|
|
Post by 90GTVert on May 14, 2011 22:02:23 GMT -5
Looks like it might need a larger main jet than whatever is in there. Never heard of manufacturers grinding the numbers off of jets. Most BBKs don't even come with jets.
|
|
|
|
Post by jmkjr72 on May 14, 2011 22:13:09 GMT -5
from what i can see of the plug it looks like that crakeilg you hear is the verge of detonation
60 is a hard mark to hit without upgears if you still have the oe crank in there sure you can rev high engouh to hit it but you will kill the oe crank
and there arent many iron bores that will rev that high the top performance trophy can if you have the right oe gearing the corsa kit might rev high engough im not reving that high with mine but my pipe is holding me back to 55
my first advice is to switch wrenches if thats what he is giving you as a tuned scoot
he should have at least given you a sheet with what jet and rollers that he has in there
i know every build i do for some one i give them a list of what parts were installed to include jet size a/f settings and rollers
|
|
|
|
Post by reveeen on May 15, 2011 4:26:50 GMT -5
Without taking it apart, you can control detonation by:
Cooler plug (maybe even the short tip as was suggested)
Premium fuel (which you should be running anyway, and depending where you live, it's the only fuel you can buy without ethanol)
These two will cost you performance:
Retard the timing
Flood it with fuel (with an over rich fuel mixture)
Taking it apart:
extra base gasket(s) (cylinder to block)
extra head gasket(s) (I don't much care for this one)
Then you can concentrate on tuning the transmission/ consider an up-gear.
|
|
|
|
Post by scottkooi on May 15, 2011 6:32:42 GMT -5
Uggghhh! To be honest, this is increadibly frustrating. I have considered and contacted a new mech., but he said he wanted to put everything back to stock to establish a baseline. One, I am not thrilled about removing everything that I have spent hard earned cash on, and two, I am reluctant to loose the scoot again-I was just reunited after a year without it. I will change the plug and run premium fuel to see what that does for me. I guess, if it is for the best, I may have to part with it again.
|
|
|
|
Post by scottkooi on May 15, 2011 6:41:16 GMT -5
To aid the process, what jet sizes should I have in there. I'm going to contact my new mech. but I want to be able to point him in the right direction. I know that I can work closer with him, however, his expertise lies with snowmobiles and atvs, not scooters.
|
|
|
|
Post by reveeen on May 15, 2011 7:26:37 GMT -5
To be honest, this is incredibly frustrating.
Clearly you have never had something taken apart 10+ times until it is just "right". (of course maybe you have... paying for it every inch of the way)
what jet sizes should I have in there
I don't have enough information to make an intelligent guess. With a stock, or under 19mm, carb I would guess 90-95. The bigger the carb, the more an engine tends to lean out quickly, 20mm, or bigger I'm *thinking* 100+. The smaller the carb the quicker it get's rich.
If it was mine: I would have installed a #90 with the BBK (on a stock carb) and tuned from there, shooting for a bit rich, until it was broken in, then lean it out a bit (a small bit watching my plug closely).
If I built it with a flatslide OKO carb (22-24mm) I'd try 105, a 24mm Mikuni (flatslide) a 110.
Numbered, or no, anyone with a set of number drill bits can tell you the size of a jet just by checking the hole with a drill bit.
BUT really, try the cheap stuff first: the colder plug and premium fuel, paying attention to what that gives you.
|
|
|
|
Post by scottkooi on May 15, 2011 8:31:19 GMT -5
ok. I'm just going to go down to the garage, pull the seat bucket, and snap some pics of it. Hopefully the pics will show what needs to be seen. I know I can see the #s on the carb, so I'll write those down and post them with the pics.
|
|
|
|
Post by scottkooi on May 15, 2011 10:08:05 GMT -5
|
|
|
|
Post by lshigham on May 15, 2011 10:42:17 GMT -5
You've landed yourself a 17.5mm PHVA Dellorto carb, excellent  They're much better quality than the ones you get stock. It takes 6mm dellorto jets, and I'd guess you'd be needing 70-80's, but can't be sure as I've never used one on a AC mina. |
|
|
|
Post by jmkjr72 on May 15, 2011 11:21:11 GMT -5
i would take a stab at an 90 mj thats what i start with on the zumas with that carb
thats the thing too when i do a build on a scoot i havent done a build in before or useing diffrent parts then i have used in the past i revert back to the one part at a time and get it running right and on to the next part
it may take a bit longer but you are also only chaseing one part at a time instead of the whole system
|
|
|
|
Post by scottkooi on May 15, 2011 11:29:34 GMT -5
Thank you. Because I pre-mix @ 32:1, should I adjust that ratio to compensate for the jet size? Or will that have no effect? Based on the look of the 100 mile plug, is this the right mix ratio?
|
|
