Just installed BBK, need help...

[adiokid1188]

Just installed a 50mm BBK, new variator, new pipe, and a set of 9:1 gears all from Jiangwayne.com Everything went smooth. I've been adding a couple capfulls of oil to the gas in addition to the pump. Been trying to break it in slow... keeping it below 40% throttle, ride for like 10 min and then let it cool off. I have the stock Carby but I was able to tune it to a smooth idle, and a nice brownish color on plug.

I thought everything was perfect.

Today I decided to ride it to work. ~5mi. This was the first time I have ridden it for longer than 10 minutes. I made it about 4 miles... then I heard some kind of rattling sound when accelerating. When coasting sound was gone. I started to slow down to check it out and it just cut off like someone hit the killswitch. It started right back up after that. I'm guessing a heat seize? I don't think it did any permanent damage. What can I do to fix this issue? I used to ride my scoot everyday. I don't want to have to worry about overheating issues....


Thanks

[Trafficjamz]

What did you change the jetting to?

[dun rite]

Hello.. I have the same size bbk and had the same problem, going down hill soft seize. Found that the exhaust pipe had a crack under the heat shield ( hadnt ever removed it) I wonder if the bigger exhaust in combination with the stock carb, under deceleration might lean the fuel mix to much? try blibing the throttle as you slow. As for the rattling sound not sure but you might check the exhaust gasket or check torque on mounting bolts. Good luck

[adiokid1188]

I didn't re-jet the carb at all. It's completely stock. I just gave it a little more gas by adjusting the a/f mixture screw. I may have turned the screw te wrong way though.. maybe it's running too lean? I'll check the plug tonight and see how the color is doing. Is it possible to have a reliable running BBK without jetting the carb?


thanks

[dun rite]

Did your bbk kit come with a new jet?? mine came with a 100. recomended for use when using stock carb, exhaust, and airfilter. with your larger or free er flowing exhaust it might should be even larger (if posssible) . despite the plug color. not sure how you did the plug chop but there is a great article in the wiki that explains it. although with a not broken in cyl. full throttle chops i have not done, only at the throttle position I use, around half throttle. Not positive that is correct either but it seems to be working.

[adiokid1188]

Mine didn't come with a new jet. Would it be a bad idea to drill the stock one to 100? I don't really want to order a part so small and play the waiting game till it arrives. I want to ride this thing! haha

[dun rite]

drilling jets is possible, I have never done it or know what size drill bit would be used, would be a numbered bit, either search the forum or check the wikispreedia in performance technical section for proper sizes.( hondaspree.net/wiki/index.php5?title=Carb_-_Jet_Reference) cut and paste into browser. but you might want to order one or more in different sizes to get them coming.

[kingkamehameha]

Dude your not gonna have very good luck using a stock carb with that size bore kit. I'm surprised you haven't ruined that bore yet. You need to up jet or get a new carb and manifold. Make sure you don't have any exhaust leaks. Oh and plug the pump for heaven sakes the plug cost ten bucks. Do it right the first time if you don't want to be in the situation your in now.

[adiokid1188]

I'm not trying to cut corners. This is my first time doing any of this. I think I did an alright job. I tried to do it right. I bought good parts and I was told that ith the combination of parts I got, It would run nicely. It's hard when you don't have anyone helping you out. I also don't have a crap load of money sitting around. I took the carb off the bike and i'm going to see about jetting it. As far as the pump goes... My plan is to eventually stop pre-mixing and go back to just the pump. Too much oil is no good, its just needed to help break in the parts..

[Wheelman-111]

Greetings:

You increased your engine size about 60%. However the stock oil pump didn't get the memo. The Pump is calibrated to deliver sufficient oil for 49cc, running relatively low temperatures. When your engine starts sucking 82ccs worth of mixture per stroke, you no longer have enough oil. Thus began the arduous process of Wheel-Math:

I blew a lot of the few remaining brain cells I have attempting to calculate an acceptable oil ratio for a BBK: 75:1 premix Plus the Pump, adjusted to come on early. It actually works quite well on Low-Output kits like the Nikasil 49mm/78cc, which is also a very resilient bore.

On Ruima or other Tai 50mms, you don't have a lot of leeway. You can try 70 or 60:1, but my advice (having grenaded two - yes, 2! - 51mm kits) is to ditch the pump, plug the hole and run 32:1. You lose the bragging rights of Innovation, but you live to ride another day. Maybe two. "Too much oil is no good?" Well, maybe. But it's nowhere near as bad as too little oil. I speak from experience here.

Whoever told you the stock jet would run "nicely" on a 50mm bore should have his prostate checked by an Amputee Urologist and then be deported to Iran. The stock carb can be made to run a 50mm, but it sure can't with an 80-something jet. Minimum size is 95, and probably bigger. You still have the issue of a Pilot jet that is both too small and non-replaceable, but with enough Main jet, you can at least run at WOT. You just can't stop...

Ax around here before you go much further. Tai bores cook real easy.

[Bear45-70]

Hello.. I have the same size bbk and had the same problem, going down hill soft seize. Found that the exhaust pipe had a crack under the heat shield ( hadnt ever removed it) I wonder if the bigger exhaust in combination with the stock carb, under deceleration might lean the fuel mix to much? try blibing the throttle as you slow. As for the rattling sound not sure but you might check the exhaust gasket or check torque on mounting bolts. Good luck

Never ever close the throttle when going down hill with a stock carb with a non-replaceable pilot jet. It is a sure way to seize your motor. * the guys in NASCAR had this issue until they figured out only to back off to about 3/4 to 2/3 throttle.

[adiokid1188]

Ok so I'm going to order some new jets. I'll probably pick up a 95, 100, and 102 so i can play around. Did I make a huge mistake in thinking that I could ride a BBK'ed scooter as a daily vehicle? I didn't want it for show, or a quick ride... I'm starting to regret the conversion. haha. It ran sooo perfect before. Super consistent, and could go for hours without a break. I just live in virginia and we have a lot of hills so i was looking for some extra power. If I put up the cash for a new carby will that solve my issues? I just want to get what I need to get and make this thing happen.

thanks guys

[bakaracer]

if your going to use the stock carb, run the stock exhaust pipe. with the aftermarket exhaust, you will need to run a bigger carb.if not your going to run into heating issues. use the stock airbox and punch out the second tab on the inlet on the outer cover. start with a 88 main jet or 90 main jet since your adding some oil to the tank. set the airfuel screw to 1 3/4 turns out.

[adiokid1188]

I have this pipe: http://jiangwayne.com/scooter/p_i.php?i=59 I think that one is pretty close to stock. My stock pipe was busted when i bought the bike. Will my local honda dealer have bigger jets for my carb or should i order them from daywot? How long will they take to ship to VA?

thanks,

[bakaracer]

nope! thats not near stock. the inlet is 28mm on that pipe and the j pipe and internals are much larger. minimum size carb I would run with that pipe is a 18mm carb like a mikuni vm18. if not a 19mm will do like a oko 19mm flat slide. you will need the jet kit that goes up to 110 or 105 if your staying with the stock carb. yes daywot sells them.