So, on the lc hybrid have been dealing with the midrange throttle hickup at 5800 ish rpm. its was def carb related, and typically only on rollons. playing with it i determined it was a flow staling issue.
Now, it would pull thru under hard acceleration, and worked perfect everywhere else but it just was getting annoying. So, decided to get some slide inserts as discussed here:
http://www.2strokeworld.net/forum/index.php?topic=2046.0
In waiting for them, i just bought a new set of TM32s to experiment with and some P6 jet tubes from Chuck Q. while TMs arent my favorites, they are the most supported and DO work well.
also, they are short, from bellmouth to intake. like 5/8" shorter than the large vm34s i have. with the lc cyls and spacers and such driving the carbs back in the frame so much, filters are an issue.
I installed the carbs thursday, dialed in on Saturday. Yup, they work perfect.
luckily the cables and intakes and unis swapped right over.
250 mainjet, stock TM needle one clip lean (#2), 40 pilot 1 7/8 out.
starts 1st kick and just runs fantastic.
so, carbs:
(http://www.2strokeworld.net/wp-content/uploads/LC-HYBRID/tm32s-2020/20200618_202919.jpg)
plug chop pull off area:
(http://www.2strokeworld.net/wp-content/uploads/LC-HYBRID/tm32s-2020/20200620_195217.jpg)
(http://www.2strokeworld.net/wp-content/uploads/LC-HYBRID/tm32s-2020/20200620_195507-scaled.jpg)
this was a half throttle chop. I did a few more pulls at wot and was the same. In the tank bag was a jewelers loupe, and plenty of spare plugs as well. Chuck recommended leanest clip based on his 400 tuning, but it would hesitate and likes the 2nd better ON MY bike, (not nec yours).
since its an air-cooled 350 frame and I can not fit a carb extension to straighten the filters out, Im running angled unis but they are a bit smashed in there. theres just no room. (and im not going to cut the frame although its been suggested) I figured a y-boot would be ideal. But, 58mm bellmoutch carbs (both the VM34s and the TMs)
So, by chance, we just got a 3d systems 3-d printer at work on friday. and yes, it can print flexible durable rubber. (i'll be setting it up and using it wed) :cheerleader:
SO...
modeled this up last week & will print one. 2-2.5mm thick walls. this will fit both the vms and the tms. I do plan on experimenting with the vms and the ufos.
(http://www.2strokeworld.net/wp-content/uploads/LC-HYBRID/tm32s-2020/rdboot-5.jpg)
(http://www.2strokeworld.net/wp-content/uploads/LC-HYBRID/tm32s-2020/y-and-filter.jpg)
the boot from the filter to the carb bell mouth is about 4.2 inches of y and runner. :toot: filter is a large automotive cold air intake pleated filter. (3") . the y is modeled to allow the element to snap right onto the y itself. theres a nice graduated radius on the ID as well. That distance should take care of any reversion problems. from what i remember, 2-2.5: back from the bellmouth is enough, and the curve in the runner should abate it as well.
It should work pretty well. I hope. Maybe. :whistle: :umm:
VERY interested to see how the TMs compare to VMs with the inserts. :popcorn2:
That intake manifold is fancy. I would be making my own with silicone hose, clear caulk and maybe some duct tape!
I WAS GOING TO make one out of stainless tubing & tig it but the radius is so freaking tight i was having an issue finding tubing, and didnt want a pie cut tube. The smallest donut in that size was too big, that i could find at least.
Believe me I know how tight those filters are in there with flat slides...
Jetting is pretty close to my air cooled. :cheerleader:
Do you expect to change jetting with that air filter?
beats me. maybe. :umm: we'll see.
keep in mind, lc cyls aren't really different porting wise from aircooldes, stock to stock. so makes sense.
That is easily and by far the coolest thing I have seen today! Really impressive, Mark.
Sweet :metal: :metal:
So, my son, David Baldwin, will be doing some experimenting with adding UFOs and, X-Wings to the stock 28mm carbs on his RD350. He'll be making comparisons on the Dyno for documented results before and, after installing each new component. The only thing that is not stock are the expansion chambers and stator/CDI from Chuck. As I understand it, the carbs will be adjusted for proper (max) EGT.
:science: :popcorn2:
I will be waiting on the results too. Never heard of the wings till now. - https://www.boyesen.com/xwing-mx
ive read about those somewhat, even considered making the single blades, etc. as the reviews said on some of the other boards, if it was so great, and they have been around for so long, why weren't any of the factory teams using them? I mean it cant really hurt I guess. however, i firmly believe that the flatslides cure 90% of the problems, or the bandaid of a UFO does as well because it emulates a flatslide. I'll be very curious to see the results and hear feedback though. :vroom:
Similar devices have been around in the automotive world since at least the 1970's - I remember seeing ads. I think they were called the "Tornado". Agreed, if they work then why didn't auto manufacturers put them in their carbs?
i received the slide inserts just haven't had time to mess with them yet, but they are -very- well made, glad i went this way. will follow up soon. :twocents:
Quote from: Baldwin53 on June 26, 2020, 07:17:30 PM
So, my son, David Baldwin, will be doing some experimenting with adding UFOs and, X-Wings to the stock 28mm carbs on his RD350. He'll be making comparisons on the Dyno for documented results before and, after installing each new component. The only thing that is not stock are the expansion chambers and stator/CDI from Chuck. As I understand it, the carbs will be adjusted for proper (max) EGT.
That will be really interesting to see the results.
Just test and compare the results and only adjust jetting or timing if the motor needs it. BTW, max EGT is NOT what you are looking for. Peak efficiency is when torque is maximized at a particular RPM.
Drifting this subject a bit.
What are thoughts on enlarging the opening of the standard aftermarket rubber y-boot for the flatslides?
Would that be too restrictive?
I think I've got one opened enough, I just haven't fit it yet...
my opinion? bad idea. it fucks up the flow to the airjet openings in the bellmouth. Puts them in a turbulent zone.
I just put on 6" long unis in place of the 4's on the hybrid with the tm32s. it runs very strong with them. like 4 hour ride 2 weeks ago, saw 120 a few times maintained 80 most of the ride with lots of short power bursts on top of that. I may play w the 34s again in the spring though.
Thanks M for the explanation.