[Alex320]

I have a 1998 transalp 600, its one of those models whit a ecu not whit cdi's.
My transalp dose not rev past 3500 rpm and i cant reely figure out the problem.
When i bough the bike evrething was alright. The envine revved happily and had heeps of power.
One day i was doing a oil change and out of curiosity i took my exhaust of leaving only the headeers
I took a ride and there is wbere the problems began. At that time it only revved to around 5000rpm and after that it would fall on to its face.
After a while the problem got wort and worst to tbe point it wont go over 2000. So i started to investigate.
The air filter is clean and it seems there are no obstructions.
I dont have cdi's so i think that the spak is not the problem
The engine is healthy it has a lot of compresion
So the last thing i can think about are the carbs. I took them of and cleaned them. I did not foun any dirt but my diafragms where torn up. So i got new ones.
Now my engine can rev to 4000 cold and only 3500 warm.
When i rev it spits out a lot of black smoke, I think it gets to much gas and not enough of air.
What should i do next.
Sorry for my bad english, its not my first language.

 

[Martindebule]

Well Alex, I think you may have already diagnosed the problem. Carburettors are tricky things and it’s easy to get it all wrong if you’re not an expert. Try taking carbs off again and make sure all jets are really clean. Also some carbs have air jets that need to be kept clean. Did you put the pipes back on again ?
Have you tried removing the battery for 24 hours ? Don’t know about your bike but ECUs often have a ‘learning’ programme built in and removing the exhaust may have upset it and it needs re setting.
Im no expert on Transalps but have worked on lots of bikes n cars. Have you read through the Honda Manual ?

 

[Alex320]

I will open the carbs again, i think some of the air pasages are blocked and the slides dont work correctly. The last time i oppened them the jets were reelly clean.
I dont reely know what do you mean by pipes to put back. But if you mean the exhaust, its on, i had it off only for like 1 hour.
I will remove the battery for 24 h. I dont think i will hepl much becouse it is a pretty primitive ecu. Like it only drives the coils and thats it. Maybe it will help.
I have the honda owners manual, which it has some basic information, and the repair manual, which is pretty vast. I looked through them but I did not found anything helpful.
I hope its just the carbs whit a blocked pasage.
I have experience whit carbs and i dont reelly know how i messed up.

Thank you for your reply.

 

[Martindebule]

I will open the carbs again, i think some of the air pasages are blocked and the slides dont work correctly. The last time i oppened them the jets were reelly clean.
I dont reely know what do you mean by pipes to put back. But if you mean the exhaust, its on, i had it off only for like 1 hour.
I will remove the battery for 24 h. I dont think i will hepl much becouse it is a pretty primitive ecu. Like it only drives the coils and thats it. Maybe it will help.
I have the honda owners manual, which it has some basic information, and the repair manual, which is pretty vast. I looked through them but I did not found anything helpful.
I hope its just the carbs whit a blocked pasage.
I have experience whit carbs and i dont reelly know how i messed up.

Thank you for your reply.

Did you not balance them up ? If slides aren working well it won’t help. Could be a combination of things. When you found the damaged diaphragms did you think ‘aha that’s it’ and not looked so hard at the rest ? It’s something I’ve done, it’s all a learning curve. I’m sure you’ll get there

 

[Alex320]

I have took them off again and opened them up. I did the trick whit the ecu and the batery. I took the terminal off for 24 hr. It didnt hellped.
I took them apart and cleaned the real good(i reely insisted on them for like 2hr, they are shiny). I didnt find anything wrong whit them, the jets are stock and clean, all tbe ports are open, orings and gaskets are good, the butterflies i closing tight.
I dont get it.
I mounted them back up.
I gained a nother 1000 rpms in the rv range (now it pulls up to 4000) then it starts to blow black smoke.
I dont get it.
Why dose the fuel mixture gts so rich?
The jets are stock and they are in the correct cillinders.
Im starting to think about ignition problems.
But standing it revvs a lot like to 6000 and it seems to burn. It dose not missfire.
And im suspecting the ignition becouse it backfiers a lot when the engine is cold and even when it warms up i get a lot of pops and bangs.
I dont reely know what to do next i have to think abou it for a while,at least the bike is "rideable".
I reely think abou changing the ecu whit a stand alone and fuel injecring the bike.
I think about a speeduino.
Or a new set of carbs but they are expensive where i live.
Or maybe a diffrent kind of carburetors.
Thank you guys for the good sujestions!
I hope to find a solution.

 

[ds99]

look for a leak in the airbox?

 

[Alex320]

look for a leak in the airbox?

I dont think it could be a leak in the air box.
Becouse that woul make the bike run leaner.
Mine runs rich.

 

[Jackflash]

I had a similar problem with my '03 650. It turned out that the valves needed adjustment, they'd closed up in noticeably less than the standard 12,000km service interval.
A failed CDI feed to the non-tacho- drive cylinder on the Hyoo 250 I used to own also limited engine revs to about half.