Tuning help needed... What am I missing?

[spreeinkc]

Ok I've been trying to fine tune my Elite since doing all the mods and cant figure out what the deal is. It's a AF16 with a 90cc bbk, 24mm carb, UNI filter, CT intake and reeds, and V8 pipe. It feels like it's running rich, plug looks like its running rich, it goes through a tank of gas in like 20 miles and yet my temps are still hitting 400 at higher speeds or under a load...? The crazy part is I started with a 135 main jet (44 idle) and I'm all the way down to 110 and it still acts like it's rich? It's definitely better but I'm afraid if I go any lower its just going to get hotter. Plus 110 already seems a lot lower than what most on here are using on modded engines. Am I overlooking something? Should I be running a cooler plug other than the bpr6hsa? I tried swapping the 24mm oko carb with a 24mm pwk I had on another scooter and didn't make any difference. (On a side note I'm not impressed with the quality of the oko! The chrome is being scrapped off the slide and the bare metal is showing through and you can see the gouges in it. Very cheap quality but I guess you get what you pay for...) Any help or suggestions would be appreciated. Thanks

[Wheelman-111]

Greetings:

Which "90cc" BBK? What was your compression reading at assembly? How are you supplying Oil? The plug can be dark even if it's lean when there's too much oil. Most big-blocks need a B8HS at least. I run a 9. Temps hitting 400 strongly suggest it's not rich. That 24mm needs a 125 Main at least with your setup. Is your petcock leaking fuel through the Vacuum line?

[spreeinkc]

Not sure what bbk it is. It's a cheap no name type but I inspected it well and hit the edges of all the ports with a dermal. My compression tester broke so not sure of the exact compression. I removed the oil pump and installed homemade plug. (which reminds me I should probably buy a real one. I pulled the o-ring off the pump and used it as well) I premix at 32:1. Petcock is not leaking b/c I prime it by mouth every time I swap jets and no fuel in mouth yet.

If I put a 125 main in then it won't hardly pull it's self unless WOT. Then have to keep it at like 90% throttle to maintain speed. With a 120 it's a little better but still have to give it 75% throttle to accelerate or maintain speed. I'm stumped. I don't understand why its running so rich with such small jets. I have had a 120 for last few weeks b/c anything bigger and it wont hardly take off from a stop. Today was first day I tried anything smaller which was the 110. (I had a 115 I wanted to try and I cant seem to find it now) Even with the 110 it still feels rich. Definitely runs the best so far but didn't take it far enough to get up to temp. Just went around the block.

[Wheelman-111]

Greetings:

Stock crank or Ministroke. You know you can't really get to 90ccs with stock crank, right? Unless you have a 52.5mm bore that is...

[spreeinkc]

Sorry, stock crank. Was just going off the side of the cylinder which says 89cc.

[paulpauly7]

did you port the intake windows on the block ?

[spreeinkc]

No porting, Just hit the edges to make sure rings didn't catch...

[Dio Dawg]

You probably have a Taiwan 51mm bore and it probably have a stamp 89cm3 on the side of the bore. You definitely have to port your intake in the block side and open your boost port in your block to accept the bore and the bigger carb. Otherwise you be restricting the flow and also I recommend you premix using a 44 to 1 or 50 to 1 oil/gas mixture, 32 to 1 is way too much oil and a reason it runs hot. And as Wheelman said, use a colder b8hs or a b9hs plug, a 6 plug is too hot. Hope this help and good luck. And yes the OKO carbs are cheaply made and they don't last for more than 2 years if you're lucky, usually the slide, the chrome will start to chip fall off and then other parts will break.

[Wheelman-111]

Greetings:

Chamfering the transfer ports is a Great Idea, if not Standard Procedure. However Pauly's question seemed to be about the crankcase port leading to the carb. Any work you plan to do here or at the boost post requires the cases to be split and the crank removed. Otherwise you run the risk of contaminating the crank bearings with aluminum powder. Opening up the intake is generally believed to eliminate a choke point for higher flow. Do NOT remove the splitter between the two case port openings. The metal above is too soft and a leak is likely to develop.

The 51mm bore yields 84.57ccs, not 90, with stock 4.14cm stroke. However some manufacturers like to state "optimistic" displacement numbers, or perhaps assuming a Ministroke crank.

Some like 32, some run 40 or 44 or even 50:1. Pick your oil ratio and then jet the carb to the temperature you seek. You can run cool even with 25:1 with big-enough jets. I like 32:1 and the Fab topped at 374 degrees last check ride.

[Dio Dawg]

Everyone tunes differently so you have to see what it works for you. We can generally give you tip but fine tuning its up to you. I'm pretty sure I'm the only one in here with a FAB that's running a ministroke with a modify Head and I'm my temp is no higher than 380 with a oil mixture of 50 to 1...so yeah if you know what I mean...not every bike is the same.

[LMH]

Back in the day we ran 20:1 on vast majority of the 2t and never had issues. Its all about jetting for larger oil ratios. 32:1 is optimal for anything running higher rpms. 40:1 may not lube her up enough at the faster revs. With too less oil you can jet all you want, if the oil isnt present its not present. I highly do not recommend doing 50:1 on any big bore kit, especially a high revver like the fabrizi.
Too each their own but do a little more R&D on your mini stroked fab build before you spout its efficiency to cool. Those cylinder are not the best for cooling features fyi. First thing my builder (http://flotekperformance.com/) said was these are some awesome port designs much like the yz125 but it lacks proper cooling surfaces. This is from an exceptionally recognized and accredited builder.

[spreeinkc]

I know everyone is different and every engine different. My main concern is my main jet seems pretty small compared to most with similar set ups. Plus it still acts a little rich and the temps are already hitting 400 so I'm afraid to go any smaller. It just seems to me like something it wrong and I can't quite put my finger on it. And really as far as temps go changing jets really doesn't seem to change it much. I hits 400 with a 110, 115, 120, and 125. Only difference is the bigger the jet the worse the low end is. Anything over 130 and its hard to get going and then pretty much gotta keep it WOT to accelerate. Anything less and your bogging out.

[Dio Dawg]

I would really try to get a compression test. You could be reasonably high and that would definitely explain high temp. And ALL my BBK i used 28mm carb or bigger with jetting minimal of 135 /55 or bigger for 72cc -86cc and i'm not saying go out and buy a 28mm carb . And compression I keep it no more than 150 psi. And your low end should be control by your pilot jet first then adjust your main jet to it after you get your pilot jet adjustment first. Also your needle position, air/fuel mixture...all these needs to be a factor in tuning your carb. These are my way of tuning...other members might say other things. I'm not saying my way is the best for anyone else but its my way approaching it.

[Dio Dawg]

And because it says Noob I don't know what i'm talking about LOL !!!

[LMH]

I have a friend who will be in KC Wednesday, I can ask him to take a look at it if you want. Pm me, I may be slow to respond but Ill see it when Im back in service.