VTR1000F Problem under 5000rpm, engine not even - choking

[wbonx]

Hello, this is my first post, I just bought a VTR1000F 1998 (60k km). The motorbike was stopped for 1 season (this is what the seller said), I got a good price because the bike seems to have huge carburation problems.
By the way, I love the bike and after 5K rpm the engine is incredible, a lot of fun ;)

This are the details:
At the minimum the engine is not even, stays on only because the minimum is quite high, but doesn't sound rounded.

Giving gas if the bike is cold it just dies. When the bike is warm and opening only a bit, the engine slowly reaches the 4500-5000 and then opens like a 2 stroke engine ;)
Instead opening the gas completely with the warm bike before 4.5000rpm the motorbike chokes and only very slowly and totally un even rises to 4.500 and then gets power.

I tried playing with the enricher (air choke) and I can see a slight change while driving and at the minimum, the feeling is that the motorbike rises slightly better opening only a bit the gas with the "air choke" on.

The motorbike is basically not usable.

The old owner showed me the bill from a mechanic doing a complete cleaning of the carburators 2 months ago (250euro) but the problem persists.
The motorbike is running with Termignoni exhaust and K&N filter. But the old owner had this parts on before the problem. He knows about bikes and I supposed disassembled and reassembled the bike 3-4 times to take care of small things.

It would be great if you guys have any idea of where I can start to debug the problem!!

I have a lot of experience with motorbikes engines and carburators.

Thanks!!!

[Wicky]

Greetings

Is the vacuum hose connected to the fuel tap correctly - to the back and side rather than pointing down.

K&N filter

While this is a relatively common & foolproof tuning mod on IL4s, on the VTR is takes time, effort using dynos and trial and error jetting to get it running smoothly. You could try a standard air filter.

If the bike has stood for a while the carbs could still be slightly gummed up and in need of a clean.

Make sure rest of the bike is serviced plugs etc. and choke cable is operating as it should and that the plastic retainer nuts where they connect to the carbs aren't broken.

[popkat]

Blocked pilot jets. many people don't clean the carbs properly and/or those small pilots can block again easily, buy some new ones and you should find it runs much better.

Also it's easy for the Choke on front carb to not be seated when putting them back on so the choke is constantly on.



.

[wbonx]

Blocked pilot jets. many people don't clean the carbs properly and/or those small pilots can block again easily, buy some new ones and you should find it runs much better.

Also it's easy for the Choke on front carb to not be seated when putting them back on so the choke is constantly on.

.

Hi Popkat, if the problem was the main jets the engine would be ok at the minimum I suppose. The carbs are suposed to be cleaned from a mechanic two months ago.

With the choke always on the bike would run ok at low rpm and would have problems on the high side since is there that need to be less rich, right?

@Wicky, thanks I will check the hose configuration and if the vacuum is leaky.
About the K&N .... I think it is on since years (that's what he said). Do you think is mandatory the DJ modification to needles and jets?

[VTRDark]

Welcome to the forum

With the choke always on the bike would run ok at low rpm and would have problems on the high side since is there that need to be less rich, right?

As you said the choke is in fact an enricher so you making it richer, it add fuel not air.

First off check the vacuum hose is connected to the right place on the petcock as wicky suggests. It goes to the side nipple not the one pointing down on the bottom. See read me for new members below for more info. And don't confuse your main jets with the pilot jets the are at opposite ends. If you have issues at low rev then it the pilot and fuel mixture. I would not take the work of someone apparently cleaning them. It would take much to remove the carbs, strip them down and gives things a blast through with some carb cleaner. You can see exactly what going on then and what's installed. Are we talking standard jetting here, how many slide holes are there? You could also try throwing a standard filter in and see how it behaves then.

I've not heard of a Termignoni exhaust on a VTR before. Is this the standard the header with end cans or has the exhaust been modified in some way.

[wbonx]

Ok, I may try with a standard filter. Or can I oil more the K&N ? Still have to check, I got the new bike today ;)

About the Termignoni, is the one in the picture, don't know if modified but the sound... is the most amazing thing on earth

Taking down the carbs is 3h of work, I would avoid it if I can. In my experience keeping the motorbike away for 1y shouldn't create carbs problems. I hope is the vacuum hose or the collectors or some other tubing in the wrong position.

[VTRDark]

Now that's a good looking VTR fastest colour too

is the one in the picture

Does this mean you only have the one can then and not two as a modified header to accommodate only the one end can will have an effect. Better for top end but not bottom end. Also how the other outlet in the header pipe has been cut and capped off.

[wbonx]

Hi, there are two can, I have still to check how they did the cut and past. But the pipes are on the motorbike since 8 years, smae for the K&D and no problems.

I took a picture under the tank, tried to disconnect the plug from the bottom but there was no change in carburation.

[wbonx]

This is the audio of the engine at the minimum:

https://mega.nz/#!hlBw2LZa!Hdw0jberTENb ... 9t8oQJzWks

[Wicky]

The thin vacuum pipe looks to be attached wrong - try looking round the back and reattaching...

[wbonx]

YES! Did it, saw a picture on the forum. ;)

Goes MUCH better.

Maybe the machanic did something else trying to compensate. If I open the gas at low rpm seems to be still out of carburation at low rpm, but I can ride it. Maybe it needs a bit to settle. This is a video:

https://mega.nz/#!wgh1TAJY!nKhD_FYxqdwt ... TueC8NseY4

[Wicky]

Goes MUCH better.

Now you've got PVILR out the way - which most of us have done at an early stage of VTR ownership the first time the tank is taken off. Hope your mechanic isn't charging you much :-)

I got a good price because the bike seems to have huge carburation problems.

As mentioned bung in a standard airfilter - but if the carburation has been monkeyed around with to try and 'improve' things with the combination of K&N and pipes then it will need some trial & error and logical thinking to get it running anything approaching normally.

Start with servicing the bike > Honda Factory Service manual is in the Workshop Knowledgebase section and it'll probaby need the carbs balanced as well.

[VTRDark]

Link works fine.

For mega links you either have to use chrome or if using firefox then you will also need the mega add on. For both, the link wont work directly so you have to copy and paste into a new tab.

Good to hear it was a simple fix. Get out and ride it now.

[VTRDark]

Here 's the 2nd link uploaded to workupload, a much better filehost and no risk of malware via Mega's downloader. Always download via browser with Mega.

http://workupload.com/file/J4XsyAq

You will have to disable adblockers otherwise you get emo girl. There's nothing unsafe it's only google ad's and site analytics. These can be bypassed using Ghostery and/or Privacy Badger. Adblock plus and edge is a no no as they will be seen. The popular adblockers get blocked any access unless you disable them.

I highly recommend privacy badger as an alterantive which is based on adblocker
https://www.eff.org/privacybadger

[wbonx]

Here 's the 2nd link uploaded to workupload, a much better filehost and no risk of malware via Mega's downloader. Always download via browser with Mega.

http://workupload.com/file/J4XsyAq

You will have to disable adblockers otherwise you get emo girl. There's nothing unsafe it's only google ad's and site analytics. These can be bypassed using Ghostery and/or Privacy Badger. Adblock plus and edge is a no no as they will be seen. The popular adblockers get blocked any access unless you disable them.

I highly recommend privacy badger as an alterantive which is based on adblocker
https://www.eff.org/privacybadger

Wow amazing... thanks a lot for reworking the link. This is really a nice community.

By watching the video, you get the feeling is fat or dry? (too much benz or air?)