New guy with engine questions

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Laney
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New guy with engine questions

#1 Post by Laney » Mon Dec 12, 2016 4:58 pm

Hello all,

My dad has an Rd500 engined hybrid and over the last few days ive wired in the Zeeltronic and ironed out a few bugs so we could start it. Thanks to a thread i found on here we closed the pickup gap as it hadn't got a spark, so now it starts. However, from running it for 30 seconds or so the front cylinders sound normal and the expansion chambers warm up slowly, but the rear cylinders cough and spit out of the exhaust and the expansion chambers warm up very quickly.

Ive got the coils wired up correctly as per the zeel diagram, the carbs are brand new but are aftermarket ones, ive suggested dad checks the jet sizes in them, is it possible to get the coil leads mixed up from left to right? Or are both plug leads from one coil fired at the same time?

My only real 2 stroke knowledge is from an Rgv250 i own, and motorcross bikes, so im like a sponge for information! Thanks in advance,

Steve.

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pstamper
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Re: New guy with engine questions

#2 Post by pstamper » Mon Dec 12, 2016 8:18 pm

Plugs fire at same time. Does the Zeel let you change timing from front to back. Sounds like carbs. what are they?

Laney
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Re: New guy with engine questions

#3 Post by Laney » Tue Dec 13, 2016 5:19 am

I did connect my laptop to the zeel and don't recall seeing that function available to me. Ill have a look at the carbs tonight and put some more info up. Thanks.

Laney
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Re: New guy with engine questions

#4 Post by Laney » Tue Dec 13, 2016 6:49 pm

One thing i forgot to mention is that in the brief moments we have run the bike up, when the rear cylinders cough they spit a flame out of the silencers, almost as if it is firing at the wrong time?
Whilst that is happening, the front cylinders are running fine.

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phildu31
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Re: New guy with engine questions

#5 Post by phildu31 » Tue Dec 13, 2016 7:04 pm

Hi.
Check on Zeeltronic that you have same advance on front and rear cylinders, depending on your version you could have different values.
Did you check that front and rear crankshafts are well synchronized ?

Laney
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Re: New guy with engine questions

#6 Post by Laney » Wed Dec 14, 2016 10:42 am

Ok thanks, I will have a look at the zeel ignition files again. My dad built the engine back up and he is confident the static timing is correct, I have asked him to check it again to rule it out.!

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phildu31
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Re: New guy with engine questions

#7 Post by phildu31 » Wed Dec 14, 2016 12:13 pm

You can check the crankcases timing by removing the pipes.
Both rear left and front right ( respectively rear right and front left ) must be at TDC at the same time.

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Re: New guy with engine questions

#8 Post by MK » Wed Dec 14, 2016 3:44 pm

Here's my couple of eggs for your basket in the most likely order
- idle circuit issue on rear carbs. Float level, jet clogged, ....
- rear HT coil issue. Change front/rear coil and check if the issue is now on the lower ones. Especially check ground connection.
- cranks front/rear out of sync. Check that opposite pistons have the same TDC
- Offset between front/rear bank programmed. Check that with the ZeelProg software or the Handheld
Bye
Martin

Laney
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Re: New guy with engine questions

#9 Post by Laney » Thu Dec 15, 2016 5:13 am

Thanks for the continued input folks, hopefully we will get a few hours on it tonight and ill report back with results.
Steve.

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phildu31
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Re: New guy with engine questions

#10 Post by phildu31 » Thu Dec 15, 2016 9:32 am

Yes, please let us know how it is going.
For me, the fact that rear pipes warm up very quickly is more typical of an incorrect ignition advance.
But too lean is also possible.

Laney
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Re: New guy with engine questions

#11 Post by Laney » Sat Dec 17, 2016 1:08 pm

We have success! It turns out that dad had got the rear cylinders miss timed by a couple of teeth, good job its not a 4 stroke as we would of been replacing bent valves, but you live and learn. The only thing ive got to look into is the power valve motor doesn't cycle correctly when we put the ignition on. It just goes to full travel one way and stops.
Thanks for all the help folks.

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phildu31
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Re: New guy with engine questions

#12 Post by phildu31 » Sat Dec 17, 2016 1:48 pm

Good news !
That's what I thought.
For the power valves, do you use the Zeeltronic or the Yamaha command box ?

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Re: New guy with engine questions

#13 Post by MK » Sat Dec 17, 2016 3:15 pm

Could be a couple of things:
- faulty servo potentiometer (resistance does not change during moving, signal has spikes or interrupts)
- if stock controller: faulty controller (pretty common issue)
- miswired Zeel (either change left/right side of potentiometer or the two motor cables).
(The baseline is that the controller "sees" moving the servo in one direction and tries to "drive" it into position. If it's running away in one direction you invert either the input or output to make it react "in the other direction")
- test cycle not programmed (on the Ignitech you program that in the curve, the Zeel has the testfunction included, though not sure if it can be deactivated)
Bye
Martin

Laney
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Re: New guy with engine questions

#14 Post by Laney » Mon Dec 19, 2016 12:59 pm

Hello, its the Zeel controlling the power valves. I will have a better look at it tomorrow as i have a rare day off work!
Again thanks for your ideas.
Steve.

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phildu31
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Re: New guy with engine questions

#15 Post by phildu31 » Mon Dec 19, 2016 4:01 pm

Hi.
Yes, take a look at the Zeel.
Potentiometers have a high MTBF, you should be unlucky if it failed.
When all is ok, you should also check the oil pump synchronization.
More infos here : http://www.rzrd500.com/500phpBB3/viewtopic.php?t=14353

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