Highway stalling / won't pull redline at full throttle

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Re: Highway stalling / won't pull redline at full throttle

Postby Barbie & Skipper » Thu Jan 03, 2019 11:28 am

Well, it appears that Barbie is mostly sorted now.

When I pulled the carbs this time, I bolted the air cleaner base on the carbs to check the butterfly openings. The rear carb was not opening all the way, even though the carbs sync'd okay on the manometer. I had to go to the adjustment limit to get the rear carb to open fully.

The rear slide was returning quicker than the front slide, so I put Syl-Glide in the ring when the piston diaphragm seats on the carb. Also on the topside edge around the diaphragm. I was careful to keep it out of the vacuum port.

As the carb jet kit had not arrived, I didn't shim the needle.

After bolting everything back together, Barbie now pulls strong through redline. The mid-range bog is gone. At worst, there is still an almost imperceptible hesitation, but it is not every time, so I'm not sure if it's there, or is just my imagination.
Barbie - 89 VTR250 - 6k+, back on the road.
Skipper - 90 VTR250 - 36k+, painted black & white, "ran when parked", upcoming project.
Parts bike - 90 VTR250 - 20k+, "maintained" by idiots, but mostly complete, no title.
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Re: Highway stalling / won't pull redline at full throttle

Postby Murdo1 » Thu Jan 03, 2019 3:02 pm

Good work. Now that you have both carbs opening fully together, has this effected your syncing or idle?
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Re: Highway stalling / won't pull redline at full throttle

Postby Barbie & Skipper » Thu Jan 03, 2019 3:22 pm

Murdo1 wrote:Good work. Now that you have both carbs opening fully together, has this effected your syncing or idle?


I knew I was forgetting something in my report. :oops:

The exhaust temps match fairly closely, but I haven't put the manometer back on the bike.

The bike was idling at about 3k rpm with the idle mixtures @ factory of 2 1/8 out. I had to turn them in almost all the way to get the idle down to 1500. It sort of freaked me out, so I monitored header temps pretty closely. Since nothing was out of line, I quit worrying. Exhaust temps vary, but mostly stay in the 300-330F range at idle now.

I actually idle mixture'd it down below 1500, and used the throttle stop to bring it back to 1500.

It bugs me to be that far out of nominal specs, but it's nice to have the bike run well, and stay at proper temps.
Barbie - 89 VTR250 - 6k+, back on the road.
Skipper - 90 VTR250 - 36k+, painted black & white, "ran when parked", upcoming project.
Parts bike - 90 VTR250 - 20k+, "maintained" by idiots, but mostly complete, no title.
Barbie & Skipper
 
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Joined: Fri Nov 16, 2018 5:12 pm

Re: Highway stalling / won't pull redline at full throttle

Postby squirrelman » Thu Jan 03, 2019 7:40 pm

good work, now you can enjoy the awsome-ish feeling of 250cc power ! :roll:

it's OK to slightly bend the link tab the adjusting screw sits on if you're careful. ;) but it's impossible to synch carbs if airbox base isn't bolted up and cross-screw isn't tight. i've seen VTR carbs with way too much slop in the holes and pins on the front/back linkage to get a really accurate synch at idle.
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Re: Highway stalling / won't pull redline at full throttle

Postby Barbie & Skipper » Fri Jan 04, 2019 12:37 pm

squirrelman wrote:good work, now you can enjoy the awsome-ish feeling of 250cc power ! :roll:

it's OK to slightly bend the link tab the adjusting screw sits on if you're careful. ;) but it's impossible to synch carbs if airbox base isn't bolted up and cross-screw isn't tight. i've seen VTR carbs with way too much slop in the holes and pins on the front/back linkage to get a really accurate synch at idle.


LOL I do enjoy the "awesome-ish power" of the VTR 250. It reminded me of the time I picked up a used set of replacement forks for my GL1100 project bike, and the guy asked if it was my first GoldWing. I said "yes", and he told me that I would love the power of the GoldWing. I didn't have the heart to tell him that my daily ride was a Concours 14 (156hp). :)

As it turned out, he was right. I loved the GL1100. Still do. It's been parked now for about 5 years, and will be my next project.

The great thing about the VTR's is that they are fast enough to keep up with and/or outrun most traffic, but not so fast that you get into trouble accidentally. Quiet and unobtrusive, they don't attract unwanted attention. And the mirrors stay smooth, so you don't get surprised from behind. Awesome-ish power, indeed.
Barbie - 89 VTR250 - 6k+, back on the road.
Skipper - 90 VTR250 - 36k+, painted black & white, "ran when parked", upcoming project.
Parts bike - 90 VTR250 - 20k+, "maintained" by idiots, but mostly complete, no title.
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Re: Highway stalling / won't pull redline at full throttle

Postby squirrelman » Fri Jan 04, 2019 9:30 pm

"The great thing about the VTR's is that they are fast enough to keep up with and/or outrun most traffic, but not so fast that you get into trouble accidentally. Quiet and unobtrusive, they don't attract unwanted attention. And the mirrors stay smooth, so you don't get surprised from behind. Awesome-ish power, indeed."


exactly why i prefer riding a smaller bike around town, either a Hawk or VTR, not something bigger like my '97 VFR ! :o unobtrusive, small, quiet, and capable. ;) unlike a VFR, i know the reasonable power of VTR won't get me into much trouble. :lol:

comix-vfr 12-5-16 004.JPG


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042_42 vtrclumsbstb.JPG
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