Malossi BBK for People 50 2T

[blufx]

I've been reading the posts between chaz and pace on jetting hoping to learn something. I have learned, but none of it would apply to my bike. I have been through jetting hell. Nothing was doing what it was supposed to. It wouldn't even do the same thing twice. I ordered a 19 mm Keihin that turned out to be a clone. It didn't have Keihin jets,but I tried the ones I had. Same results. Didn't run worth a crap. Out of lack of anything else to try, I dropped the exhaust and started it. BINGO! It couldn't breathe. I tried to clean it out, but ran a little better for a short while. Then I sawed off the last 3 inches of the muffler. It sounded like a chainsaw but ran faster than I ever thought it would. I have a Tecnigas Next-R on order now.

[mclark999]

I've been reading the posts between chaz and pace on jetting hoping to learn something. I have learned, but none of it would apply to my bike. I have been through jetting hell. Nothing was doing what it was supposed to. It wouldn't even do the same thing twice. I ordered a 19 mm Keihin that turned out to be a clone. It didn't have Keihin jets,but I tried the ones I had. Same results. Didn't run worth a crap. Out of lack of anything else to try, I dropped the exhaust and started it. BINGO! It couldn't breathe. I tried to clean it out, but ran a little better for a short while. Then I sawed off the last 3 inches of the muffler. It sounded like a chainsaw but ran faster than I ever thought it would. I have a Tecnigas Next-R on order now.

What year is yours?

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[blufx]

 Mine's an '07 with very low miles and Hoca 70cc BBK. I got it a little under a year ago from an auction. The paperwork with it indicated it had just top end job and a note stressing the importance of quality oil and proper mix. I didn't know it at the time, but it had been de-restricted. The first few days I road it, it ran much like it's supposed to with around 35 being top speed. Then it started going downhill fast. Getting slower and slower each time I road it. Everything I checked seemed to be fine on it. This is when I started realizing it had been de-restricted. My old compression tester had a leak in the hose, so I had a friend bring his hand held gauge over. As I cranked the motor over, he told me I didn't have any compression. I ordered the BBK because I had an idea of what 50cc would do and I didn't want to be in traffic when I can't get out of my own way. I now know there was nothing wrong with the 50cc jug and piston. It might have not needed the first top end job. This exhaust was so clogged, gas would only very slowly run through it. When trying to test the compression, it was building pressure in the exhaust. I've worked on a few 2 cycle engines before, but I've never heard of this extreme before. After cutting off the end of it, I found that's where the clog was, so while waiting on my new exhaust, I used a hammer and chisel open up that last baffle. I put it back on by wrapping it with some 3/4" 3-M semi hard rubber tape. I have no idea what it's purpose is, or where it came from, but it's been here for years and I finally found a use for it. I then wrapped a piece of 4" aluminium around that with 4-1/2" dryer vent clamps at each end. It doesn't make much more noise than stock, but it is robbing me of a little power. I can live with it a while. On flat ground it hits 45 MPH fast and will do over 50 downhill. This is with the stock 14mm carb. It has a #35 idle jet and a #105 main. The needle isn't adjustable, but I made a .040" washer and raised it. That helped a lot on take off.

[paceneedsstides]

lol nice job on that exhaust as I read more and more about these things people complain about the oil pimp leaking oil while sitting into the case and exhaust and more when the do BBK delete it though not everyone and if you ride it daily shouldn't be too much of an issue. I'm going to go out on a limb and say get a Dellorto or Dellorto clone for your carb they seem to be the most popular type though I wish I had gone 21mm instead of 19mm I hear they get better mileage. also one of the things I will be ordering next month is a bigger intake manifold there is one that looks just like our stock ones that is 20mm instead of the 16 or so that our stock ones are. The NextR is a good pipe and what I run but after looking at dyno charts and stuff next time I will go with either the Tek or Triops from Tecnigas or a Stage 6 Pro rep. Good luck bro we can tune on these things forever.

[blufx]

lol nice job on that exhaust.  Good luck bro we can tune on these things forever.

Thank you. I know you can tune them forever, because I've already spent far, far, too much time working on it. Now I can finally ride the damn thing. I liked the Dellorto for several reasons, but if get a larger idle jet, I think this 19mm Keihin clone will work fine. It's a genuine Keihin body, just full of aftermarket jets. I'm not looking to race this thing, and as flimsy as it is, I don't wan't to go real fast. Just get me whee I need to go. My last ride was a '77 -74 CID Harley Davidson  Lowrider custom  with dual plugs,a Sifton 440 cam and S&S "E" shorty carb, which I had to let go a couple years ago in order to avoid foreclosure on my house. It'll never be the same .

[chaz35]

Have W6 needle installed and I think this may be it.  1st I set it all the way up and appeared too rich, wouldn't idle, so I set it all the way down and went for a ride.  W6 all the way down was about the same as the W16 needle all the way up, so W6 definitely richer than W16.  Next I set it one slot up, changed out starter jet 55 for 50, and changed out idle jet 42 for 40.  Previously, had been really rich at idle and starting after hot, so I thought idle jet and starter jet were probably too rich.  I am not thinking idle jet does anything above idle now, have 38 to try, if that doesn't do it, will probably order 36, 34.

With W6 needle installed at 2nd notch up, 50 starter jet, 40 idle jet, maybe 108 main jet?, I went for ride.  Was bestever!, would cruise for long time at 80km, but would eventually get too hot.  Idle was much better, deceleration was more normal, sounded more like my Super 9, a little lopping, not just dead like it does too rich with closed throttle with this engine.  Engine still doesn't want to rev past approx 9500/ 9600 revs, but very happy below that.  Pretty fast at that rpm, I am very happy if that's all it will do, acceleration is massive, very fun to ride.  I haven't messed with CVT at all, 100% OEM, so will probably accelerate harder and have higher top end with CVT mods.

Next, will raise needle to 3rd slot up (4th slot up is all the way up, richest setting), 38 idle jet, and see how it does.

Have Tecnigas Trek pipe in transit, expected delivery this week or next.  I think should be very interesting to test.  I am thinking carb is not the bottleneck holding back revs, but pipe, we will see.  Cheers

[chaz35]

Raised needle to 3rd notch up, changed idle jet from 40 to 38, verified have 108 main jet, put it all back together and went for long ride.  Probably OK now, acted like wouldn't go over 400f, was riding hard, not really backing off to keep cool, eventually went over 400, 403f max CHT.  400f doesn't really bother me anymore, have been there so many times and no issues, but when gets to 400f need to slow down and let cool off.  However, now doesn't build heat so fast, and don't have to back off a lot to control temp, so becoming a non issue, but still have to watch CHT.

Another issue was oil pump linkage, seems to require adjustment more than you would think.  I like to have pump open the max setting at WOT, but have to be careful don't bottom out cable against stop and put undue tension on barrel end or might fail.  So I have been watching for that issue and today found it was loose and not opening as much as I wanted, wasn't pumping as much oil as I wanted, so had to tighten it up a little.  Anyways, good idea to check oil pump setting from time to time IMO, or might not be where you want it to be.

Going to 50 starter jet from 55 seemed to help, seems to start easier when hot.  Idle jet seems OK at 38, idles nice, and actually have idle mixture adjustment screw turned out 1 turn now, was 1/2 turn to 0 turn with 40 and 42 idle jets and still seemed to be too rich.  Noticed don't need screwdriver to adjust idle speed, nice big screw head you can turn with your hand, another nice Dellorto feature on this carb. 

Next can try smaller main jet and move needle to full up to test.  Probably won't do anything else now until I get Trek pipe and install, then see how it runs and go from there.    I am just going to ride it for awhile, it's a blast to ride.  Probably not as fast as Super 9 with CVT mods, but pretty close and definitely accelerates harder.  Cheers

[paceneedsstides]

glad you got it in tune Chaz I installed a W9 which is same tip diameter as W7 but longer taper and have 92 main and wow it takes off now lol I'm not sure how cool that will run at WOT I got up to 390 or so last sunday with a 94 in but riding 2up with my daughter on board. This Smoky Mountain Crawl (yes without the E in smokey) got me perplexed will be higher altitude, less oxygen, and over 90 degrees when we ride the Tail of The Dragon and A long 150 miles ride in the afternoon. I carry enough tools to take bike apart down to frame and all jets from 86-114 so I hope I'm prepared. Let us know how that exhaust works and also I think the intake manifold and reeds have alot of affect on our engines you can get the 20mm intake that looks just like out small 16.5 or 17mm manifolds should add more air and better mileage. Para over in the Like 50 thread found me on Facebook he's got a 60mph+ Like and he's a fount of information he changed his reedblock for a Malossi he thinks VL9 and runs Malossi Carbon Fiber reeds. I feel my clutch or belt starting to slip not on hot days on long rides so after this Crawl I'll probably start slowly upgrading and replacing CVT.

[chaz35]

pace, can you link where to get the 20mm intake manifold?  I think higher altitude will make engine run richer, less HP, will need to go to smaller main jet IMO.  Good luck on Crawl, have fun.  Cheers

[paceneedsstides]

http://scootertuning.ca/en/intakes/1110000-replacement-intake-manifold-20mm-kymco.html

http://www.racingplanetusa.com/intake-manifold-20mm-racing-kymco-p-250-1.html?backcPathco=25&cPath=2_26378#.V1l4DJErK00

I think scooter tuning would be your best bet since they are in Canada I haven't ordered from them but every order from Racing planet has taken 3 weeks or slightly more to get here.

[mclark999]

Mine's an '07 with very low miles and Hoca 70cc BBK. I got it a little under a year ago from an auction. The paperwork with it indicated it had just top end job and a note stressing the importance of quality oil and proper mix. I didn't know it at the time, but it had been de-restricted. The first few days I road it, it ran much like it's supposed to with around 35 being top speed. Then it started going downhill fast. Getting slower and slower each time I road it. Everything I checked seemed to be fine on it. This is when I started realizing it had been de-restricted. My old compression tester had a leak in the hose, so I had a friend bring his hand held gauge over. As I cranked the motor over, he told me I didn't have any compression. I ordered the BBK because I had an idea of what 50cc would do and I didn't want to be in traffic when I can't get out of my own way. I now know there was nothing wrong with the 50cc jug and piston. It might have not needed the first top end job. This exhaust was so clogged, gas would only very slowly run through it. When trying to test the compression, it was building pressure in the exhaust. I've worked on a few 2 cycle engines before, but I've never heard of this extreme before. After cutting off the end of it, I found that's where the clog was, so while waiting on my new exhaust, I used a hammer and chisel open up that last baffle. I put it back on by wrapping it with some 3/4" 3-M semi hard rubber tape. I have no idea what it's purpose is, or where it came from, but it's been here for years and I finally found a use for it. I then wrapped a piece of 4" aluminium around that with 4-1/2" dryer vent clamps at each end. It doesn't make much more noise than stock, but it is robbing me of a little power. I can live with it a while. On flat ground it hits 45 MPH fast and will do over 50 downhill. This is with the stock 14mm carb. It has a #35 idle jet and a #105 main. The needle isn't adjustable, but I made a .040" washer and raised it. That helped a lot on take off.

I have an 2007 also and the exhaust is really restrictive.  I've installed a Tecnigas Trek and am working on the jetting to get it right. It's quite a bit faster with the Tecnigas exhaust.

[chaz35]

Still getting too hot, so I raised needle to the 4th notch full up and changed main jet from 108 to 100.  I went with smaller main jet because I knew with needle full up would be too rich at idle.  I did some reading about how to tune Dellorto carb and still think I am on the right track.

Was a good test, because didn't run very well, but I realized 108 main jet was too rich and wasn't really helping to keep engine cool anyway.  With 100 main jet, ran a lot better top end, was rev'g to high 9000s pretty easy, maybe went over 10000 a couple of times.  100 main jet was too lean and still didn't really run any hotter, so verified to me needle controls mid range where engine is getting hot. 

Next, probably need to buy the next richer needle which I think may be W15.  Think starter jet 50, idle jet 38 are OK.  Maybe some benefit going to 2 cycle nozzle, but don't think so, not ready to try that until try next richer needle.  Only behaves badly at idle and progression with W6 needle full up, so easier to go to next richer needle than try smaller idle jet, change to 2 cycle nozzle, etc just to keep same needle.

I put it back where it was before, needle up to 3rd notch, changed main jet to 104 and went for long ride.  Very close to perfect, but still running hotter than I would like.  Would be great if would run well and stay under 380f, but maybe not possible?, hit 400f this time, but was hauling butt for sure.

I computed mileage and oil comsumption and got 48 mpg and 40.5 to 1 oil or 3.2 oz per gallon.  I have oil pump connected and add 2 oz oil with each fillup, usually approx 1.3 gallons of gas per fillup.  Cheers

[chaz35]

Ordered W17 needle, next richer one best I can tell.  Started with W16, then W6, next will try W17.  Did some more reading and after reading Dellorto manual 2X's and mopedarmy PHBG tuning guide 2 or 3X's I see some other possibilities, apparently Dellorto carbs can be bottomless holes for spending $'s for parts.  Not to worry, I am having fun and scooter is running great, just a little more tweaking, you know saying "you can spend 90% of your time and $'s for the last 10% of results".

If W17 needle doesn't do it, I also ordered 2 cycle 262AU nozzle and bushing to try.  Also ordered 264 nozzle to try, don't know what I am getting, didn't specify, but I have 262DL.  I am assuming there are only 2 bushings, AU for 2 cycle and AN for 4 cycle, but there are at least 5 different types of nozzles, such as AU, AN, BL, BM, and DL (which I have) available in various sizes from Dellortodirect.com.  A larger nozzle is the equivalent to using thinner needle, best I can tell.

May end up getting different slide.  Smaller cut-out is richer, larger cut-out is leaner 0 to 1/8 throttle.  Mine is too rich so maybe need slide with larger cut-out?  Also, order 4gr float which is one for 2 cycle.  Mine has "3g5" on it, so don't know what I have, but think maybe 5gr and is behaving like too heavy, which tends of create rich condition.

I am pretty confident will get carb running perfect.  Maybe some of the extra parts will come in handy when I put 19mm carb on Super9?  Cheers

http://www.mopedarmy.com/wiki/PHBG_tuning_made_easy._(a_step_by_step_guide)

and http://www.mopedarmy.com/wiki/How_To_Tune_PHBG_Carburetors

[mclark999]

Wondering if you could increase the cooling capacity at all with a scoop of some sort or better fan. 

I had thought of going big bore until I read about your temps.

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[paceneedsstides]

just got back from The Smoky Mountain Crawl after upjetting I ran god up there in the mountains and on The Tail of The Dragon. The nozzle/atomizer and bushing are designed for different style carbs and applications as AU/AN is 2T/4T the 2T atomizer has no holes for air to mix with the fuel where as the AN 4T has air holes that mix air with fuel before reaching the venturi. The AU bushing also has a c shaped lip to keep fuel and oil from shooting out of carb into the filter when letting off the throttle where as the AN bushing has no lip on it at all. I myself still haven't got the carb perfect but I was running cool up and down the Smokey Mountains all weekend. I've also been told by many 2T guys up there that the 21mm carb will not only give better power but slightly better MPG.