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Post by tsimi on Jul 2, 2020 22:45:52 GMT -5
Just a quick update.
I dropped the needle by raising it one notch. At first nothing changed until i realized that the choke was still ON. 😅
But then on the second try she cleared up. Smooth acceleration all the way up.
I looked at my last ride video from a year ago and i was wearing a jacket so i guess it must have been colder so the jetting was OK that time.
Now with 30+ i had to lean it out by simply dropping the needle. I just need to remember to raise it again when temps drop in autumn.
It's crazy how sensitive jetting has become with an open air filter in comparison to an airbox.
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Post by tsimi on Jul 2, 2020 22:51:39 GMT -5
You could also install a Venturi Divider to help smooth out the middle thottle range. But i would try needle position adjustments first. If the needle adjustments dont get rid of the symptoms, then i would add the venturi divider. Thx i'll definitely keep that in mind. |
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Post by tsimi on Jul 5, 2020 2:38:09 GMT -5
Just came back from a short ride. As mentioned already acceleration is nice and smooth now. A quick twist to the throttle and she lifts the front wheel with ease. Outside temp is 33 Celsius and she was running around 70-75 degrees Celsius depending on the speed. Before, with the previous needle setup, she was running around 55-60 degrees. I believe I could lower the main jet from 150 down to 148 or even a bit lower but I don't want to push it too much till she has a few more km on that cylinder. The brakes are scary as hell. At one point there was a red light which I saw a bit too late and I had to brake hard and she locked so hard that she started to slide and I couldn't stop her quick enough as I wanted to. So I gotta be careful and be more aware my surroundings at all times and react fast enough to avoid any collision with a car or other solid thing out there. One more thing I would like to add to the scoot is leg pegs that look like a handle bar across the floor. Something like birdman did on his scoot. Can someone tell me how you say that in correct English or does someone have a link to such item? |
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Post by aeroxbud on Jul 5, 2020 4:18:54 GMT -5
I don't have a link, but I think they are called highway pegs.
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Post by tsimi on Jul 19, 2020 4:33:45 GMT -5
Took her for another spin today. Raining season should be over at any time and summer (aka. hell) should start soon. Gave her a few time the good ol onion WOT! So powerful that she lifts the front wheel even at 80+ km/h when going WOT. Exciting and scary at the same time.
It was VERY hot today, 35 celsius (~95F).
I swapped the needle from JJK 2nd from top to JJH 2nd from top. I hoped that it will slightly richen up the middle and drop the cooling temps but it didn't go as hoped. The temps went even a bit higher up to 75-80 celsius.
On my last ride I had outside temp 33 -> scooter 70-75.
Today outside temp 35 -> scooter 70-80.
I still have a JJF needle to try which should be a bit more on the rich side. Just need to find that fine line between rich/lean and cool temps. Don't wanna go too rich though since the exhaust pipe has oil spray all over it. I know that cooling temps and carb tuning are related to a certain extend but outside temps and air speed that hits the radiator also matter. So I might have to add some cooling fans to the radiator to reduce temps.
Not really a summer scooter I guess.
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Post by 90GTVert on Jul 20, 2020 19:07:16 GMT -5
If your cooling problems come when you aren't moving or are moving slowly, a fan can make a big difference. I use a 4" SPAL puller fan and it really drops the temp if I'm stuck stopped. It really draws power too though. If it happens at speed, a fan or fans may not do much for you unless you have poor airflow through the radiators. Make sure of the obvious stuff like the coolant level is good, no air in the system, no power supply issues for the pump and so on. Not to to worry you, but a failing head gasket/seal can make them run hot. I can't say that I've ever jetted for coolant temp. That's usually reserved for CHT or EGT.
At least some good news is that it's not super hot. I would prefer to run my 2T cooler than what you are seeing as well, but 80C is just starting to get warmed up for most auto/moto applications.
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Post by Lucass2T on Jul 21, 2020 9:18:23 GMT -5
a failing head gasket/seal can make them run hot. Never knew this...  Is it because of hot exhaust gasses entering the cooling system or air getting trapped and making the circulating coolant less efficiënt? |
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Post by 90GTVert on Jul 21, 2020 10:27:19 GMT -5
It can burn off coolant if coolant is getting to the cylinder and then you'll run low on coolant eventually. You can get air and combustion gases in the system. This is what always happened with my 103cc. I had a bunch of pressure in my system all of the time. Like I'd remove the cap with the system cold and it would pop and release pressure and it would keep filling the reservoir with overflow when running (which may also result in coolant loss).
Tsimi has clear hoses, so he'd probably notice if it were leaking combustion gases into his coolant. It would likely start to get greyish in color. A bad leak into the cylinder will cause white smoke (steam) from the exhaust, but it could slowly burn it off and you'd likely never tell the difference in that and normal 2T smoking.
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Post by benji on Jul 21, 2020 12:15:25 GMT -5
a failing head gasket/seal can make them run hot. Never knew this... Is it because of hot exhaust gasses entering the cooling system or air getting trapped and making the circulating coolant less efficiënt? if I remember correctly, pressurized water has a higher boiling temperature and therefore cools better. |
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Post by tsimi on Jul 21, 2020 19:32:37 GMT -5
90GTVertI saw temps rising when doing those short WOT runs. The good thing is the temps are steady and not rising or going beyond max. 80C. My area is a lot stop and go driving which usually won't let me rev out the motor too much unless i go crazy with it. When cruising i see temps around 70C average during this hot time. One year ago when i drove her the last time it was autumn/winter and ambient temps where way cooler and i was seeing 55-60 C The Roost manual says the following Track race: 50-60C Drag race: 35-60C Those temps are pretty vague though. I mean at what ambient temps where they taken? There is a big difference between driving somewhere at 10C ambient temp or the Utah desert. If they say that you have to keep those temps no matter what ambient temp then that will take some tinkering. I will try to source some fans and see if i can put them on a separate battery with a ON/OFF switch to run them only when really needed.
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Post by 90GTVert on Jul 21, 2020 21:29:46 GMT -5
They probably don't care what the ambient temp is. That's just where they'd like it to be by any means necessary. Without seeing any additional text, I'd guess they want you to keep it cool for best performance. I've quoted cool temps like that many times and many people tell me they're too cold, but I think it runs harder. Nice to see some documentation from a manufacturer that agrees too. It could be that they really don't want high temps for tolerances/wear.
If temps are rising during WOT runs, fans may not do much. Normal airflow should cover it at speed. Maybe try to make sure you are getting good flow through them. Looks pretty open from what I recall, but doesn't hurt to give it a critical look with air movement in mind.
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Post by Lucass2T on Jul 22, 2020 4:48:09 GMT -5
Also the area behind the coolers need to be open for the hot air to escape, kinda no brainer.
You got that part covered better.
Maybe try making some sort of air ducts from the front to the coolers + a fan?
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Post by pitobread on Jul 22, 2020 15:48:47 GMT -5
You want air to go from high pressure to low pressure.
If you give a path of least resistance between the frontal area and the rads the air will choose the least resistance every time. Duct and 2 sided foam tape and seal your rads so all the air passing goes thru and not around. You will see temps decrease significantly
Story time.
My buddy had a TE72 Toyota Corolla with a 4AGTE (GZE converted bottom end) as a drift car, he often complained after hot lapping it drifting coolant temps would climb to an uncomfortable level as the car is sideways and air flow thru the rad is not as good with a sideways car.
One morning before an event I went out to the garage and took a cardboard box and cut it up and used packing and duct tape to seal the rad to the front rad support and sealed all the holes in the rad support as well.
It worked so well, temps dropped and that cardboard stayed on there in some variant till he swapped in an SR and did a V mount.
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Post by tsimi on Aug 4, 2020 23:12:51 GMT -5
Drove her to work yesterday which is a total distance of 16km. Lots of traffic and was mostly driving at 1/8 to 1/4 throttle. Gave her the onion when ever i could on short straights. Max speed was 114kph (70mph) at 13720rpms and she was far from done and didn't even break a sweat to get there. She did well and got me to work and back without much trouble. Outside temp was around 36C (97F) Temps stayed usually between 70-82C (158-179F). She did go up to 86-88C when i was at WOT for a bit longer than the usual short bursts. So i eased off the throttle just to be safe. The main issue at the moment for me as a driver are the hot radiators that act like damn heaters around my shins. And the loud engine sound. For short test drives around my block it is bearable but if you drive for a longer time period in traffic the sound can get annoying. And i wear a helmet which dampens the sound so i can't imagine the people around how annoyed they must be. When i arrived at home and removed my helmet i had a ringing in my ears. That loud she is. I tell you this scoot is not a good summer scoot. How is it for you 90GTVert? You got a similar radiator setup. Does it feel hot too around the lower legs? Next step is to get some better wind channel towards the rads so the temps can drop a few degrees. I will try to come up with something see if it works. |
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Post by Lucass2T on Aug 5, 2020 5:28:40 GMT -5
Myself I am always riding with ear plugs.
I had the same problem with the axis. It has a tapered intake (for higher air velocity) hose + huge air filter but that acts like a megaphone.
Thats why i fabricated an intake silencer which made a huge difference in sound volume and made riding it way more comfortable.
Most of the noise is coming from the intake you know.
Another thing you can do is wrapping the exhaust with heat wrap (about 20cm after the flange up to the tail pipe).
It muffles that typical pingy 2t pipe sound.
And maybe make some shrouds to guide away the hot air?
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