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First, some history, then, some issues I hope this community can help me with.

I bought my vn750 in 2008, it´s a 1995 model. As this is not a common bike in Brazil, mechanics do not know much about it and tend to walk away from it. Mine had been mistreated for a while: carbs were dirty, the bike had been stalled outside in sun and rain, it wasn't starting very well. I bought it cheap and thought I could improve it´s performance over time.
The first year I rode it on and off. It always had difficulty starting up, no matter what I tried. When it ran, however, I really liked it, lots of power and kind of a no-nonsense robust bike. So I decided to invest a bit more.
I found a mech that said that he knew about it and could wrench on it. He took it apart and started working on it. Painted the engine, painted the wheels. Then stopped working on it. That is more than 3 years ago. All this time the bike stood there, dismantled.
Only recently did I discover a mechanic with a good workspace that seems to know how to deal with the bike. I brought it over to him, he´s putting it together. So far he´s checked the engine (says internally it´s in tiptop shape, only has 29k miles on it), mounted it in the frame, connnected the drive shaft, and is now starting on the supporting systems (cooling, electrical, brakes, etc.).
I doesn´t have to be beautiful for me, but I want the bike to be reliable and safe. If it proves to be so, I´ll invest in it over time and personalize it with my son, who has shown growing interest. He´s 16 and it would be a nice project to embrace together.
I have some questions that maybe you can help me with:
- The mechanic discovered that the ignition of the rear cilinder was one point off. Could that explain the difficulty in starting it up? What other consequences could it have for engine and riding behaviour?
- Here in Brazil, gas comes with 30 percent ethanol. What does this do to the bike? Would it be better to ride it on premium gas (avaliable, but a lot more expensive and higher octane)?
- I recall that the rear cilinder, on starting up, had white fumes coming out that disappeared after running for a while. What could this be?

I have said it before and I´ll say it again now: this is a great site and my learning curve has been steep here. Theoretically, I could finish the bike myself now, but for lack of workspace, tools and time I prefer it this way until it runs again. Then we´ll see where it goes.

Thank you all for your patience and all the best from Brazil.
 

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- The mechanic discovered that the ignition of the rear cilinder was one point off. Could that explain the difficulty in starting it up? What other consequences could it have for engine and riding behaviour?
I do not understand this. You wil have to explain it differently.

- Here in Brazil, gas comes with 30 percent ethanol. What does this do to the bike? Would it be better to ride it on premium gas (avaliable, but a lot more expensive and higher octane)?
E30 here in the states would be 92 octane and have 92% BTU. It would require 9% more gas volume. For me, to run right, this would require a jet change. Both pilot gas and air, with just a main gas jet. No shims.
- I recall that the rear cilinder, on starting up, had white fumes coming out that disappeared after running for a while. What could this be?
Probably steam.
 

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Discussion Starter #3
[I do not understand this. You wil have to explain it differently]

This is the jargon they use here. As I understand it, the ignition point (spark) did not totally coincide with max gas-air mixture compression.

[E30 here in the states would be 92 octane and have 92% BTU. It would require 9% more gas volume. For me, to run right, this would require a jet change. Both pilot gas and air, with just a main gas jet. No shims.]

What is the rationale behind this? Could you be more specific on which jets would be more appropriate?

Thanks man!
 

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ass hole extaordinaire
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if the timing is a tad off you may need to check the cam chain alignment

as far as the ethenol gas is concerned its not great for the bike but premium gas is worse see if you cant find ethanol free gas but if you cant just run regular pump gas

i have no clue what wmsonta is refering to when he says you need to rejet for ethanol gas but it seems that he believes that every time something is wrong with these bike you need to rejet

bike wont start = rejet :doh:
bike wont move when in gear = rejet :doh:
tires wearing uneven = rejet :doh:
blinker wont blink = rejet :doh:
 

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ass hole extaordinaire
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white smoke from one of the cylinders could also be a reed valve sticking open
 

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2014 KLR 650!
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Oi Wouter, eu creci en Campinas. Meu portuguese escrito nao e muito bom. Orivel sem spellcheck. Voce pode ajustar 'timing' um poco com o 'pickup coil mod'. Nao e problema andar com E30. O problema e quanto voce desha essa merda sintado para mais de cinco o sete semanas.

Did that make any sense? LOL.
 

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Crowley
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Outra pessoa que fala português também!

Não pode mover o momento de ignição. Movendo o pickup coil mais perto ao rotor faz um fração de diferença... Não bastante pra fazer um diferença ao ignição.

Eu tinhe ouvido que quando o cam gear salta um dente, o motor funciona mal.

Hope my português is up to par lol
 

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Discussion Starter #10
Oi Wouter, eu creci en Campinas. Meu portuguese escrito nao e muito bom. Orivel sem spellcheck. Voce pode ajustar 'timing' um poco com o 'pickup coil mod'. Nao e problema andar com E30. O problema e quanto voce desha essa merda sintado para mais de cinco o sete semanas.

Did that make any sense? LOL.
Thank you Goofyfoot. Your portuguese is perfectly understandable and more than sufficient to enable you to tour the beautiful semiarid mountainous regions here in the northeast. Google for 'Seridó Rio Grande do Norte' or 'Seridó Paraíba' and you'll see what I'm talking about.

What happens when you let it sit for 6 weeks?

Cheers, Wouter
 

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Discussion Starter #11
Outra pessoa que fala português também!

Não pode mover o momento de ignição. Movendo o pickup coil mais perto ao rotor faz um fração de diferença... Não bastante pra fazer um diferença ao ignição.

Eu tinhe ouvido que quando o cam gear salta um dente, o motor funciona mal.

Hope my português is up to par lol
Seu portugues está ótimo. Não queria mexer no pickup coil neste momento, quero ver a máquina andando primeiro. O dentinho do cam gear, pode ser. Acho que mexeu gente nessa moto que não entende dela.

Valeu Crowley, obrigado.
 

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2014 KLR 650!
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Look for the Grambo trick - CAM Chain tensioner. Voce talves precisa fazer MCCT.

Grambo - http://www.vn750.com/forum/showthread.php?t=1076

MCCT Conversion - I can't find it. I thought it was in the verses. Anyone know where that is?

E tambem quando voce nao unda no motor por mais de um mez, oh alcolico vira-se para o verniz nos Carburetor jets.
 

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..have a vulcan good day!
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enough !
 
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