Af18 zx50 corsa running extremely hot.

[mantrans]

hi, I have a zx50 that I had been doing the finishing touches on tuning then added the Corsa pipe and it is dangerously hot all of a sudden, creeps around 330-350 on my vapor but when I hit cruising speeds of 40mph or more it sits on 400 degrees sometimes a little more. I can leave my house and drive a 1 to 2 miles down the road and already be at the 350-400 range, making Wot tuning pulls is almost usless as it goes to north of 450 degrees, the most I have seen was 499. This has only happened a couple times after I do something I think will help and it doesnt.

70cc corsa
MHR full cirlce crank
Case, intake ported to match
Polini race pipe
Stage 6 intake
Polini 24mm pwk carb
currently using a BR9 plug
124 MJ,50 pilot oil is 32:1 although I tried 44:1 last night and was just as bad.
started on vp110, currently switching between vp116 and q16( oxy fuel) I jet differently for both, I experiment quite a bit and enjoy trying fuels I think will suit it.
A little more info, I was running a 128 MJ on the PG longpipe, maybe could have gotten away witha 126 but the corsa pipe seems to like it smaller.

Here it is, I do not have a fan shroud, the factory one came no where close to fitting and I tried doing some modifications last minuet and took it beyond the point of no return, now having a pipe that isnt in the way it may have worked. The shroud is expensive and would no tbe in before a big ride I am in. I am not saying I wont run one.

On to the questions.
Is that odd to come to that temp so quickly even without a shroud?
I did a compression and leak down test and it was tight
could it be stemming from something else? I did cut the crap out of my seat and and made a giant straight shot opening to the motor and directed the air in also pieces to draw air through the fins. Thanks for the help, I know I talk alot!

[mantrans]

check compression and squish, report back with the numbers. we have seen some oddball deck height differences in these honda blocks. Your comp is either too high, or you have an air leak. Your super fat jetting suggests an air leak.

I run the same setup at sea level and its a 108 main on the same carb. I've never heard of anyone running bigger than a 110 on a 24/corsa

Just did a compression and leak down test, compression was at 125 and the leak down test held air the whole time, had my compressor at 90psi and the tester at 90psi and it didnt move, it is in working condition because I had done one before about a month ago on the same setup and I thought the exhaust had a small leak and the gauge bled down to 87psi, used better gasket ( from scooter swap shop) and it read higher.

As far as squish I will know when my upgrades studs from you guys come in as the cylinder will be off. Im leaving it one right now because I am maching up my fan and engine shroud I just built. The gasket I am using is the metal one supplied with the kit, then just the o ringed head.

I can go down on jetting, I had a 110 in there and it barely ran but it ended up being another stupid issue that is fixed now. I am hoping to have the temp figured out by friday night and get some good tuning in saturday. In the midst of all these issues the thing runs freakin hard without a hiccup, pulls hard the whole time from 10mph to 70mph.

[bonesv]

check compression and squish, report back with the numbers. we have seen some oddball deck height differences in these honda blocks. Your comp is either too high, or you have an air leak. Your super fat jetting suggests an air leak.

I run the same setup at sea level and its a 108 main on the same carb. I've never heard of anyone running bigger than a 110 on a 24/corsa

Just did a compression and leak down test, compression was at 125 and the leak down test held air the whole time, had my compressor at 90psi and the tester at 90psi and it didnt move, it is in working condition because I had done one before about a month ago on the same setup and I thought the exhaust had a small leak and the gauge bled down to 87psi, used better gasket ( from scooter swap shop) and it read higher.

As far as squish I will know when my upgrades studs from you guys come in as the cylinder will be off. Im leaving it one right now because I am maching up my fan and engine shroud I just built. The gasket I am using is the metal one supplied with the kit, then just the o ringed head.

I can go down on jetting, I had a 110 in there and it barely ran but it ended up being another stupid issue that is fixed now. I am hoping to have the temp figured out by friday night and get some good tuning in saturday. In the midst of all these issues the thing runs freakin hard without a hiccup, pulls hard the whole time from 10mph to 70mph.

Wow! That's a good seal on that!!! The other thing you can test is the crankcase leak-down test to see if there are any leaks that could manipulate the fuel mixture to a lean condition, which could really cause some damage. Only use a small amount of air pressure with this test though-6 to 7 lbs is suffice. Use a smaller gauge for that like a 0-30 lb.

[1man8scoots]

Ya I don't think you made it a mile even. You guys were up ahead of me but not far and I saw your tail light go dim and you turned into 7 helleven

[bonesv]

So,......just what is a zx50 anyways? I saw it's an af18 motor w/mods but I have not heard of the zx50 unless it's an Asian market model..........Dio??? Got any pics?