Re: Race Bike Build - Oct 12th/13th due date

Passive heat exchange is suitable for a head. Ill mount a pump/battery when its finished and compare the temps.

https://en.m.wikipedia.org/wiki/Thermosiphon

Re: Race Bike Build - Oct 12th/13th due date

Made some progress tonight.

Rigged radiator up, torqued air intake, took for a test run.

2nd set of jets was peppier. Still, both setups and the bike dies at wot.

1/8th throttle-turn 4 strokes with either idle jet.

PHBG 19

96 main

42 idle

60 starter

Doppler air intake box

Rejetted to

94 main

37 idle

55 starter

Doppler intake

Thoughts?

Re: Race Bike Build - Oct 12th/13th due date

Up jet the main.

Re: Race Bike Build - Oct 12th/13th due date

Today:

Starter 55

Idle 37

Main 98

Still dying at WOT and 1/2 throttle after 100 yards

Re: Race Bike Build - Oct 12th/13th due date

Mock up is solid. Have to retime and check for air leaks.

Need to upjet again..still dying with a 98 main. Fuel is clean and flowing.

20190802_190100.jpg

Re: Race Bike Build - Oct 12th/13th due date

Ill have shorter hose lengths on the finished bike. The radiator is held on by wire at the moment. Did 4-5 100 yard runs before dying. Temps at the head were high of 214

Re: Race Bike Build - Oct 12th/13th due date

Maybe its the float height? I have a clear phbg float bowl I use to set them up. I have had a number of carbs from all manufacturer's need the floats reset.

Re: Race Bike Build - Oct 12th/13th due date

Do i just bend the tab to set float height? It should be parallel to the mating surface, right?

Re: Race Bike Build - Oct 12th/13th due date

Checking needle height and float level tomorrow. Also putting a 45 idle in. My 37 seems too small

Re: Race Bike Build - Oct 12th/13th due date

Today:

Rejetted to a 104 main, 42 idle, 55 starter.

Moved the needle clip up one. Its a #9 needle.

Switched from NGK bh8 to bh7. Pulled plug was oily.

Temps hit 219. No water leak/steam.

Retiming this week. It backfired twice.

Removed the fuel filter and fuel quick disconnect to eliminate fuel delivery issues. Petcock is new and clean.

Re: Race Bike Build - Oct 12th/13th due date

Still having issues. Ready to ditch this carb.

Swapped floats and float needle. Down jetted. Retarded timing.

Still dying at any throttle position after about 150 yards.

Re: Race Bike Build - Oct 12th/13th due date

My money is on the cdi. Especially given the backfire.

Re: Race Bike Build - Oct 12th/13th due date

My advice would be:

1. Buy cheap non-titled 250-500cc 4t (ninja 250/300/500, yam R3) - or go miniGP with XR100 if there are local tracks doing that

2. Do a track day

3. Learn more in one track day than you’ll ever learn racing a moped

4. Apply new skills to moped racing

5. Win moped race

Andy has so many good points here - every single thing he has mentioned will help shave lap times. The biggest change I noticed in my lap times took me 7mo and counting to achieve - healthy clean diet, daily exercise and strength training, 60-80mi weekly cycling, and pure determination will take you faster than any top build - racing a motorcycle is 90% rider ability in most every case.

56E459AE-82BB-447E-8003-6C00BC0A7DC4.jpeg

Re: Race Bike Build - Oct 12th/13th due date

Why is it that every water cooled moped build has hoses half the length of the bike. Cut that shit down. Also Andy knows his shit so take is advice. Drop down bars and stretching those chicken legs out in every corner hoping to tap a knee on the payment wont win you races.

Re: Race Bike Build - Oct 12th/13th due date

Dirty30 Dillon /

I'm surprised no one else caught this, but your thermosiphon isn't going to work when your inlet and outlet are both on the top of the radiator. Thermosiphon relies on the rise of hot liquids/falling of cool liquids to function.

So you probably have no coolant flow.

Re: Race Bike Build - Oct 12th/13th due date

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> I'm surprised no one else caught this, but your thermosiphon isn't going

> to work when your inlet and outlet are both on the top of the radiator.

I don't think they are both on the top. previous closer-up photo had them opposed.

Re: Race Bike Build - Oct 12th/13th due date

Dirty30 Dillon /

> Dave & Bummerzz Wrote:

> -------------------------------------------------------

> > Dirty30 Dillon Wrote:

>

> > -------------------------------------------------------

>

> > I'm surprised no one else caught this, but your thermosiphon isn't

> going

>

> > to work when your inlet and outlet are both on the top of the

> radiator.

>

> I don't think they are both on the top. previous closer-up photo had

> them opposed.

I couldn't see another photo of the radiator, I see the head has been oriented correctly, but I am pretty sure the radiator is meant to be oriented horizontally, not vertically.

Re: Race Bike Build - Oct 12th/13th due date

Bike as it sits is a mock up. Return hose is significantly cooler as it sits. Hoses will be cut down, will have a pressure release valve, and will have a temp gauge.

I dont want to invest in real track days or a real bike. This is for fun, im not trying to add another hobby. My "winning" goals are for shits and giggles. No one cares if you win.

Replaced ht coil too. Will do cdi and check back in.

Re: Race Bike Build - Oct 12th/13th due date

Dirty30 Dillon /

> Dickie Thompson Wrote:

> -------------------------------------------------------

> Return hose is significantly cooler as it sits.

This is normal, your head is moving the hot coolant into the upper exit. I'm saying that the coolant isn't being forced to move through the fins of your radiator, in a hot-to-cold fashion, which is where the real effects of thermosiphon are gained.

Re: Race Bike Build - Oct 12th/13th due date

Good point. Right now temps are fine, when everything is swapped over to the other roller the hoses will be shortened, radiator horizon etc.

Is straight water ok to run? Or should i put an additive in

Re: Race Bike Build - Oct 12th/13th due date

Maybe some R134a . LOL

JK . ;)

Re: Race Bike Build - Oct 12th/13th due date

I was thinking of just cramming some freeze pops in the hoses before the race.

Thats why they are that length.

Re: Race Bike Build - Oct 12th/13th due date

Ha . That might just work . And , the die would let you know about any leaks . :)(edited)

Re: Race Bike Build - Oct 12th/13th due date

Put a 94 main in today. No 4 stroking but still dies after about 200 yards. Bogs out.

Re: Race Bike Build - Oct 12th/13th due date

Dirty30 Dillon /

When you measure temps, are you talking water temps or head temps?

Re: Race Bike Build - Oct 12th/13th due date

Head temps. Water temp gauge isnt installed yet. Doing that tonight on the hot line.

Re: Race Bike Build - Oct 12th/13th due date

Not chiming in with my 0 knowledge of racing but......

Is that the CDI/ht Coil box that comes with the treats CDI? Or the 2041. I have had terrible experiences with those CDIs. If you are sure you have 0 air leaks I would swap the HT coil and see what that does then swap the CDI box or swap out the coil/ht combo(depending on the setup)....what is your timing set at? You said the plug looks oily. I wonder if you could be loading up the pipe and cylinder and causing it to bog out.

Re: Race Bike Build - Oct 12th/13th due date

> Baron Von Hamilton Wrote:

> -------------------------------------------------------

> Not chiming in with my 0 knowledge of racing but......

>

> Is that the CDI/ht Coil box that comes with the treats CDI? Or the

> 2041. I have had terrible experiences with those CDIs. If you are

> sure you have 0 air leaks I would swap the HT coil and see what that

> does then swap the CDI box or swap out the coil/ht combo(depending on

> the setup)....what is your timing set at? You said the plug looks oily.

> I wonder if you could be loading up the pipe and cylinder and causing it

> to bog out.

Replaced the ht coil. I forget timing degree. Retarded it pretty well.

Black oil in the silencer too.

Replacing phbg with a tm24 this week to see where it sits.

Re: Race Bike Build - Oct 12th/13th due date

> Dickie Thompson Wrote:

> -------------------------------------------------------

> No one cares if you win.

My fault thought this was a race bike thread

Re: Race Bike Build - Oct 12th/13th due date

> river 2strokes Wrote:

> -------------------------------------------------------

> My advice would be:

>

> 1. Buy cheap non-titled 250-500cc 4t (ninja 250/300/500, yam R3) - or go

> miniGP with XR100 if there are local tracks doing that

>

> 2. Do a track day

>

> 3. Learn more in one track day than you’ll ever learn racing a moped

>

> 4. Apply new skills to moped racing

>

> 5. Win moped race

Just based on body position alone in the mopedgp photos, I've kinda assumed that anyone who had any other Moto racing experience would sweep mopedgp even on a "non competitive" bike but I haven't been to one of their events so maybe not.

Seems like a good strategy though. I feel like I could whip my variant around a kart track kinda quick.

Mars has the right idea with his kx65 derbi thing. If he knew how to ride it I bet he would win everything all the time.

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