Track Bike - Plan B

[Off Road]

After pulling the carbs from the bike, I carefully removed the float bowls to check the gas.
Both float bows were only about 1/2 full.
The fuel levels were about 6 to 8 mm low.

[L.B]

I wonder if the vent hoses are to blame?If they longer they have a scavenging effect on the fuel in the bowl no?
Id replace with a dual outlet pingle & be done with it.If not vents it must be the fuel lines?
Have you got a gopro........?
Id also bolt that motor back together & just cane the absolute krist out of it now....

[Hooligan]

I saw some interesting data tonight. I dropped the mains on my LC from 220 to 210 and left everything else exactly as it had been. This is with stock pipes and airbox.

At mid throttle running at a constant 7000 rpm I swear the EGT's were lower at approx 1325 when they had previously been around 1350+. At WFO and 9000 rpm the max temp I saw was 1404 when previously I had seen 1400 max temp.

One thing I noticed is that the cylinders change temp differential depending on the rpm range. In the mid range, the left cylinder was hotter then as the revs increased, the right cylinder became hotter. At max temp the cylinders were within 5 deg of each other. Normally they are within 20 to 50 deg of each other.

All the above was done at 8:30 at night on a slightly cool evening, which by past experience has resulted in elevated temps due to denser air. I would almost say that dropping a main jet size has had no effect on EGTs to it potentially has resulted in slightly lower EGTs.


While everything was apart for the rejetting I discovered one of the fuel lines was badly kinked from being slightly too long. Seeing Steve's issues this gave me a bad turn. However it hasn't seemed to cause any issues for me. I replaced it regardless.

[T.RexRacing]

I'm running stock carbs, and the stock fuel tank petcock.
I don't think I have an issue with the petcock screen, because the fuel lines were full of gas.
I'll definitely check the vents on the carb bowls.

It's not the amount but the speed of flow I'm concerned with. That and the bowl vents. I am curious in addition to float level has the fuel level been verified? I'm sure it's a supply issue of some type. Check gas cap venting?

I'd remove the fuel lines at the carbs,use a suitable receptacle and vacuum pump on the petcock to verify flow.

[seahorse]

+ 1 on the gas cap, its gota vent. No vent = fuel at the start of the ride until it reaches a point where a vaccum is created and it will stop flowing, which sounds like what happened to you on the ride.
Do you have a vac line? is it in good condition?. As you know a crack in a vac line should in theory limit or stop fuel flow.
Worth going over the carbs again I guess, I know you already have, but worth a check/clean when they are off. I recently retrieved an eye lash from just under a needle/and seat, only noticed it when I pulled up at the servo and fuel was pissing out my right carb.
That fuel level should stop right at the gasket line with the clear line check. ( as you well know)
The tabs on the float arms generaly end up level or just slightly lower.
PS, sad news on a rebuild, I feel for you mate.

[kpke]

Mr. Off Road, sorry to see you are continuing to have troubles.

I can't offer much help to you unfortunately, but since you like math, perhaps this will help???


Since the fuel tank would go on and come off 1000 times on my 500, I put these 90° quick disconnect fittings but was concerned about fuel flow.






A reply from wolfgangh went like this


kpke wrote:
Sunday, 8/17/14
I decided to go ahead and use the quick disconnects for the fuel lines under the tank. There was no feed back regarding a previous post I made questioning fuel flow thru these things. A friend of mine seems to think they will flow plenty of fuel. But I still have some doubts since they used large 3/8 lines from the factory and these will reduce that down some. We shall see.

This is wolfgangh's reply:
I usually do the following math to get a ballpark figure, using expected max. peak fuel consumption. My calculation is in ltrs/100km as we do in most part of Europe, you can modify this to mpg of course:

Assumed max. consumption is 20l/100km at a speed of 200km/h.
Within 1 hour, you would drive 200km = 20l * 2, so you would burn 40l of fuel.
Your fuel lines need to flow a min. of 40l/hour.

So put a fuel line into an empty bottle and measure the amount of fuel you get within a minute. If it is min. 40/60 = 0,67l, you should be safe. If it is 1l per minute, you can feel even better.




Maybe try this to check the fuel flow out of your tank.

I hope this helps.

Ken

[silverstrom]

This is all too familiar. Maybe the 5th time is a charm

[Off Road]

So, I have a "new" theory.

Vapor lock on the fuel tank. Fuel stops flowing into the carbs. Engine runs out of gas. Engine runs lean. Engine seizes.

I disassembled my gas cap to make sure that it was venting correctly.
In the vent system, there is a small piece of sponge like material.
Mine was old, and hard, and crusty, and very difficult to blow through.
I removed it and reassembled the cap. It's definitely venting now.



My To-Do list is getting smaller.
Add coolant to the Rad.
Install the gas tank, seat, and side panels.
Ride it like I stole it.





This time around, I changed the needle clip from the 5th groove, to the 4th groove, because it was too rich in the mid-range.

I hear that the 5th Engine Rebuild is the lucky one, so I've got $10 that says the engine's going to run fine, for at least 2000 km.
Anybody else want to join in the fun and take a guess at how long it will last this time.
Closest to the actual mileage takes it all.

[seahorse]

Cant wait to see her back on the road, ps I like that paint scheme, and the LC Dash, that's different, but does the job.

[2smoke]

Please tell me you have pressure tested for air leaks this time??????
Especially the reed block and manifold area for the RH carb.

[Hooligan]

Cant wait to see her back on the road, ps I like that paint scheme, and the LC Dash, that's different, but does the job.

That's not an LC dash. It is the dash that bike came with from the factory. The '83 RZ used many parts that were similar to or interchangeable with the earlier LC. Hence the reason it was named the "LC2"

[seahorse]

That is an LC dash and I wont hear any other description from anybody, even if I get a call from the boss at Yamaha, it will still be an LC dash in my mind..
But cheers for that interesting bit of info Hooligan, we never got the RZ with LC dash in Australia. I love the LC guage.
Surely the LC dashed RZ has to be a bit of a novelty, I don't recall seeing a production RZ with a factory LC guage ever.
But I love it.
And so we don't get off track I love that paint scheme, its my new favourite.
Probably because my brother came home on a new one in Aus in I think it was 85, " with the Bikini and bean guage".
He was trying to out do my 82LC. If I could go back in time.

[Hooligan]

Its not exactly the same as an LC dash. IIRC the LC doesn't have the red ticks and the redline is lower. I'd have to go look at mine.

[Off Road]

The instrument housing is off of an LC.
The tach is an electronic unit from an 86+ RZ350, and it's mounting bolts are offset, which is why it sits crooked.
The Speedo is from an RZ500.

[2smoke]

Cant wait to see her back on the road, ps I like that paint scheme, and the LC Dash, that's different, but does the job.

That's not an LC dash. It is the dash that bike came with from the factory. The '83 RZ used many parts that were similar to or interchangeable with the earlier LC. Hence the reason it was named the "LC2"

Nope.
It is an LC dash and the 83/84 Canadian bikes came with the same dash as the us bike but metric.


And the speedo is not from an RZ500, its from a FZ750!
The 500 has a white needle with a red stripe like the rz350.