Revs hang when changing gear

[Ade81]

Hi all,

I'm a newbie to bike forums as I've usually managed to get things sorted with a Haynes manual and the help of some friends/family so please let me know if I'm missing anything as this is my first ever post

I've always had bikes from the age of 14 and am fairly competent with a spanner. I've had two strokes, big inline fours and a big single previously. Currently got a 954 blade that I've had from new and recently picked up a 97 storm as a winter project.

Always fancied a big twin so I thought 'why not?'. It was running badly (or barely) when I bought it and the tank was rusty as an anchor on the inside, possibly due to it being left outside. So, got the cosmetics sorted out, por15'd the tank, un seized the seized bits and am now working on the running. I'd always managed to avoid setting carbs and thought that it was about time I learned. In hindsight maybe carbs this big we're not a good starting point but it's a bit late to wimp out now.

I've managed to get it running to a rideable standard thanks to a lot of reading and some very knowledgeable posts on here. It had been dynojetted by a previous owner and was running 190 dyno main jets, 48 pilots, needles on 4th clip and the fuel screws done up tight! It has a standard air box and filter with scorpion cans.
It currently has 170 front 175 rear mains, 48 pilots, needle on second clip, fuel screws one turn out and two of the three lift holes blocked up.

Like I said its not too bad, pretty rough in traffic under 2500 rpm but I'd guess this to be normal for one of these? It also seems to hang at 4000 rpm when changing gear which seems to suggest its lean there? When I took the plugs out to check after a run they're black and sooty as you like which would suggest it's rich?? It pulls smoothly through the whole range and seems to have plenty of power. Any help would be greatly appreciated.

[Ade81]

Oh and I've done the TPS mod too

[lloydie]

Set the mixtures to 1.75 out front and 2 out rear ,
Needles to 3rd from blunt end and 180f 185r mains ,
That should give you a good base setting to work from as it should run good (it's how mine is currently set)

[Pete.L]

Also check the choke plungers and cable to make sure the choke is fully closed


Sent from my iPhone using Tapatalk

[lloydie]

Also check the choke plungers and cable to make sure the choke is fully closed


Sent from my iPhone using Tapatalk

Good point

[Ade81]

Ok thanks guys, will try that and update the progress

[VTRDark]

Welcome to the forum Ade Your doing well so far as you have your profile pic up Lots of links in the read me for new members below. Please take a read through them.

Careful with them choke plungers if you decide to remove the cables for lubing up as the plastic nut on the carb end snap very easily. It's best to remove the carbs first before undoing these.

That will be dynojet mains Lloydie mentioned there. It's best to not mix and match keihin and dynojet together. I wonder if there is dynojet springs along with them needles

In hindsight maybe carbs this big we're not a good starting point

Harder to tune but easier to work on

Like I said its not too bad, pretty rough in traffic under 2500 rpm but I'd guess this to be normal for one of these?

They can be smoothed out. The TPS will help but it's also down to your pilot circuit/mixture. Also make sure you do a carb balance. Before and after setting the TPS. Adjusting the carb balance/syncing the screw affects the position of the TPS.

Have you had the carbs apart and given them a thorough clean out considering the state of the tank and the bike has been sitting a while. Don't forget to remove the fuel mixture screws and give that passageway a good blast through with an airline and/or carb cleaning spray, and dont loose the little springs, washer and rubber O ring that sits on the mixture screws. You may have to pick the O ring out before blasting through.

Some useful links at the bottom of the following post.
http://www.vtr1000.org/phpBB3/viewtopic ... 14#p238578

(:-})

[Ade81]

Thanks Carl, took me half an hour to get that pic to fit will be sure to read the new members stuff

I get what you mean about those plastic nuts on the choke plungers, one was broken off in there when I got the bike, eBay to the rescue.

The carbs looked pretty clean when I had them stripped down and have had new float needles and mixture screws. Admittedly I didn't blast the passageway when I changed them so will definitely do that while I've got them off.

[Ade81]

Hi all,

Finally got round to having another look at the bike, tried lloydies setup and was no better on mine really. So I decided to fit the 45 pilots I had with the 160 and 165 dyno jets I had to make it as lean as I could.

Improved it loads, really smooth low down, only now it stutters a bit accelerating from about 3000 rpm. I'm thinking I've leaned it off too much so will raise the needles next time it's apart and see what happens!

Also I've noticed if I stop somewhere after being out for a bit it doesn't like to get going again and runs like sh1t for a couple of miles, thought it was the stand switch at first by the symptoms but pretty sure now that it's not. On the whole it's improving

[darkember]

I presume you have thoroughly checked all your vacuum pipes as any fault with these will also cause poor running conditions

[Ade81]

I'm pretty sure they're all ok but as I said I need to get it apart again anyway so I'll double check that.
Thanks for the tip.