jerks at low revs

[jzape2005]

Hello everyone .
I guess this issue has been discussed in this forum, but as not mastered the language well I expose my problem with my VTR, I apologize in advance for my English , , , ,
The G. P. weekend Motorland , Aragon , Spain , I went with my VTR to the races , during the trip the bike was perfect , but to get to the circuit generates the typical car jam , the engine temperature went up as usual, without actually a dangerous level , was launched the radiator fan and from that time the bike started to jerking at low rpm in first and second gear, the problem was solved to go by road back to normal and gave me more jerks , any ideas?
I have to say that this bike was stopped about a year , I 've done everything the maintenance since then , new air filter , spark plugs, oil, etc, except carburetion .
It is likely that the carbs are dirty ?
In normal use the bike is perfect , responds well to throttle , just do it with the engine warm and low revs , any help will be welcome. a greeting. Jzape2005

[koko]

Lower the gearing?

[bazza696]

It's a 1000 V twin, anything below 2500 revs will be jerky.

[ebenviljoen]

I had a similar problem with mine a while ago. I re-jetted the carbs, new filter etc. and found that when my bike was running warm, half way on the temp guage and just as the fan kicks in, my idle speed will drop 400rpm from 1400 to 1000. I confirmed it was running rich at that point by pulling the choke out as it completely stalls then. I turned my A/F screws a quarter turn in, and that solved it.

The idleing still drops a little when I am in town on a busy warm day, but is better than what it was. I couldn't say that mine was jerking when riding though.

When you are in town again, and it gets to that temp, try pulling your choke out slowly, and if it dies, then you are running rich probably.

As I understand it the engine runs richer the warmer it gets, hence why you use the choke when it is cold. This is only my understanding and I am sure someone will correct me if I am wrong

[VTRDark]

It's a combination of tuning and the fact that, like bazza say's, these bikes don't like running at such low revs. Especially when hot and in town traffic where it's all stop start stop start. The engine starts to choke up and sulk.

(:-})

[Diabolus]

I find high revs are needed for town work dont get out of second gear really. make plenty of noise, lets people in there boxes on wheels know your there so safer too.

[Duffy1964]

Bazza, I gave you a pm fella

[jzape2005]

Hello everyone and thank you for your answers,
I have taken several motorcycles, from 4 cylinder to three going for two, do not think that is very normal for the engine pulls almost stopped in a traffic light, the Japanese are good designers, or I think, I have reviewed the wiring, coils , plug connectors etc, if he was any loose, all right, as I said the filter and spark plug is new too, I looked at the book keeping vtr, there is a valve called torque, I have not found, could this be the reason for the Yanks?.
  This weekend if the wife and kids .... I may looketh happens to bicilindrico. , Greetings and bursts all, jzape2005

[Wicky]

Have you checked the cush drive for the rear sprocket? and cleaning carbs after a year stored up sounds a good idea. Remember to balance them after refitting.

[AMCQ46]

this sounds like the heat is effecting the fueling, and some suggestions would be

1) check the Throttle Position Sensor and set as close to 500 Ohms
2) Idle mixture is too lean or too rich - first check the air filter and remove carbs and clean out jets, then adjust 1/4 turn in or out
3) petrol tank or carb vents are blocked and vapour locked with the heat - inspect all pipes incase trapped
4) carb balance

outside options could be the coils or HT leads breaking down in teh heat. it is possible to unscrew the plug cap off the HT lead and cut 10mm off and screw back on.

[leevtr]

What air filter is fitted ?

[VTRDark]

1) check the Throttle Position Sensor and set as close to 500 Ohms

Finally I'm glad you mentioned that Al as that was my first thoughts, but I did not want to mention the TPS and start the whole discussion off again whether it should be adjusted or left as is, and whether it makes a difference or not.

When I first got my bike I had the same issues with riding in London traffic. Took the carbs off, fitted the vacuum hoses for carb balance, cleaned and checked the jetting was all as standard. Put them back on and balanced the carbs but the low seed jerkiness was still there. I then took the carbs back off adjusted the TPS to 500, put the carbs back on and re-balnced the carbs again, it solved the issue. The balance before and after the TPS adjustment is important as this has a direct effect on the butterfly which controls the TPS so affects the reading.

Quote from Factory Pro
(The people that make the jet kits amongst other bits)

Also - as with ALL VTR1000's - the TPS must be checked and set to 500 +/- 10 ohms - or low speed cruise smoothness is impossible to attain.
They have been seen as much as 900 ohms as delivered.

http://www.factorypro.com/prod_pages/prodh77.html

And it's true.

jzape2005 here's some links and direction for you to save you searching. Pay particular attention to the links at the bottom of the following.
http://www.vtr1000.org/phpBB3/viewtopic ... 14#p238578

You may want to have a read through the rest of the posts in that thread too. You will find the carb standard jetting setup at the following.
http://www.vtr1000.org/phpBB3/viewtopic ... 14#p238565

2) Idle mixture is too lean or too rich - first check the air filter and remove carbs and clean out jets, then adjust 1/4 turn in or out

This mixture (A/F) is also important along with the TPS adjutsment. The stock (base) settings for the mixture (fuel screws) will get you close, but if you want spot on then use the following guide.
http://www.vtr1000.org/phpBB3/viewtopic ... 14#p238528

What AMQ has suggested there is spot on and will sort this issue out for you.

(:-})

[leevtr]

Sorry fellas, but unless every storm I've ridden, has had the tps set to 500, that theory is rubbish. I've ridden 40,000 miles on 3 firestorms, not one have I set up the tps, and never had these symptoms.I even rode my current one at low revs ( 1800 rpm ) with the tps in mind the other day and it was smooth. Not pullung strong, but no sign of any jerkiness whatsoever.

[leevtr]

Not looking for a row by the way, but the statement that ALL VTRs must have the tps set obviously doest apply to the 3 I've had.

Then again I've not had ccts fail or r/rec go on me ( although been in belgium when my mates battery cooked, what an effing pain !! )

[VTRDark]

No row's here mate but this is exactly why I didn't want to say anything and let people work it out for themselves. I suppose the fact that the TPS is set out of the factory for best emissions and not best performance tuning helps as well does it. Hence the reason that every TPS is set to a different reading. No two bikes will be exactly the same out the factory.

I think I will take factory pro's word for it after their years of performance tuning and extensive testing on an eddy current dyno. It also says to adjust to 500 Ohms in the Honda workshop manual. And like I say it worked for me. Yes there are some people out there that say it doesn't do anything for them and yes there are some people that say it has improved things. Some with standard engines and some with highly modified. But it is simple to put back to as it was previously if one makes a note of what it is set at to begin with so worth a try. Along with proper tuning it helps.

Tuning alone did not solve it for me but helped, so I then adjusted the TPS which did. This proved to me that the TPS does indeed have an effect. I made no other changes between tuning and adjusting the TPS.

Anyway I didn't think you would be seen crawling along in heavy traffic.

(:-})