starts in only one cylinder

[ddcristi]

Hello all,

I haven't been around for quite a while, but I'm back now..

I have a small problem with my RD04 and I have no idea how to solve it. What happens? Whenever I try to start the bike, when it's cold, it only starts in onw cylinder. The second one only starts after a few minutes. I've had this problem since I got the bike... But I thought it was a problem of old spark plugs and air filter... So I've changed the spark plugs with a set of brand new ones, I've changed the air filter.. And I still have the problem. The carburetors are also clean.

After whe bike warms up, everything is OK.. If I stop it and start it again, works perfectly.. The problem appears only when the engine is cold.

Thanks, DDC

[Simon]

fuel pump?

[ddcristi]

fuel pump?

I have no idea... But if it were the fuel pump... wouldn't I have problems on BOTH cylinders? And both when the engine is cold and warm?

[Lord Stig]

Sounds like what I had onmy RD07a - I think I've cured it but not sure.

If it does this every time it would be worth checking to see if you have sparks. If you don't I would think the problem is more likely to be with the ICU, because the RD04 has a coil for each plug - it's unlikely to prevent the engine firing if only one plug fails. Same with the plugs themselves. The LT wiring to each coil is likewise unlikely to be the cause because you have two sets for for each cylinder.

If you don't, two other possibles would be the classic sticking choke problem, which coats the plug so badly that they won't spark until the bike gets warm. Seems to affect the front more than the rear cylinder, but that might be just the bad luck I've had. The second possibility is low compression on the front - most likely either valves or rings. If there is not enough compression you don't get the bang. As friction warms the working parts they expand and seal properly, or at least better.

My guess is that it'll be the choke or ICU...

[Vegeta]

Hello from Greece, this is my first post in this forum. I had the same problem with my @ RD07. It turned out to be the choke spring in one of the carburettors. It was broken and it functioned as it was always on for one cylinder. Check also the choke cable as it splits at some point. It could be cut somewhere.

[Simon]

I have no idea... But if it were the fuel pump... wouldn't I have problems on BOTH cylinders? And both when the engine is cold and warm?

No, mine wouldnt start very well and only on one and then when i did get it go it was only on one. Changed the fuel pump and its fine again. I would reackon that yours is not a fuel pump issue though.

[djadams]

Yep, check sparks first. Could well be a coil problem.

Unlikely to be fuelling I'd've thought, but if sparks are ok, then could be a problem with the choke on that cylinder. Seems unlikely mind.

[ddcristi]

Thanks for all the replies... All I have to do now is to get some spare time to check all these things... Maybe this week-end..

Thanks again, DDC