
high end acceleration
- twofest5
- Posts: 25
- Joined: Tue Nov 12, 2013 11:55 am
- Location: Kelso, WA
- Motorcycle: 1977 GL1000 1984 1200 interstate 1989 gl1500
high end acceleration
Hello all. I'm looking for some help if anyone has any ideas. I swapped out the four carbs on Rose for a 34 PCT single carb and have adjusted it so that it starts easily runs great down the road and all seems great. This is my issue I cant seem to get over 90-95MPH. In 5th gear when I roll back on the throttle acceleration is slow. It doesn't jerk you back like the other gears. Rose is a 77 GL 1000 that I just crossed 90K with this weekend. Is this typical of 5th gear? could it be age? I have replaced the timing belts, new valve seals, and added a Dynatech electronic ignition. I'm not a speed demon but if I see someone stupid I would like to that I can get away from them. 

- robb
- Posts: 1060
- Joined: Mon Jul 19, 2010 7:46 pm
- Location: Lexington, North Carolina
- Motorcycle: 1989 Honda GL1500 Aspencade (sold)
2003 Honda Shadow VLX 600 Bagger
Re: high end acceleration
Sounds like a Solex. I suspect that just as it is with a V-twin, multiple carbs for top end but single has good torque. It's a trade off, single offers pulling power but bike needs more fuel than the one can supply. You have to decide if ride is better now than before and any speed over 80 mph is a waste on the highway.
Went through same experience with my 01 Vstar 1100 when two 38mm carbs were removed and replaced with a single 40mm. Larger jets will feed it but only to a certain limit. Later went to a S&S Super E and only after adding a Thunder Jet was it able to supply fuel needed for top end. On a Dyno bike went from 102 to 116 top end speed, roll-on from 60-80 was about 2 seconds. After all mods my 750 pound bike could do 0-80 mph in 5 seconds and that's the reason for one carb.
Went through same experience with my 01 Vstar 1100 when two 38mm carbs were removed and replaced with a single 40mm. Larger jets will feed it but only to a certain limit. Later went to a S&S Super E and only after adding a Thunder Jet was it able to supply fuel needed for top end. On a Dyno bike went from 102 to 116 top end speed, roll-on from 60-80 was about 2 seconds. After all mods my 750 pound bike could do 0-80 mph in 5 seconds and that's the reason for one carb.
- twofest5
- Posts: 25
- Joined: Tue Nov 12, 2013 11:55 am
- Location: Kelso, WA
- Motorcycle: 1977 GL1000 1984 1200 interstate 1989 gl1500
Re: high end acceleration
That makes sense. Thanks. I may get the rebuild kits for my original and put the old on and see the difference.