LilBeaver Posted March 20, 2010 #28 Posted March 20, 2010 ... If doesn't feel better after todays ride I'll take it into the shop for a tune up Before you waste any money at a stealer [unless your shop is someone that you really do trust] you may want to make a new thread requesting a carb sync in your area; someone nearby you may have a tool to do it and may be willing to help. This will save you some cash AND make sure that the job is done correctly! By the way, make sure you look up the procedure on here to do it since the one in the service manual is incorrect.
Zfrebird4 Posted March 20, 2010 #29 Posted March 20, 2010 Frebird runs smooth and passes well in 5th at 55-65 mph. Nope doesn't set me back in the seat, but it also doesn't drop my gas gage $. JackZ nutting like fresh coffee after a morning ride! Jz
WHiP Posted March 20, 2010 #30 Posted March 20, 2010 Keith and Bob thanks for the chart. I read on this forum about how I should find the rev limiter to really understand how hard I should run. The first time I tried I got to about a 100 MPH (speedometer 100) in third gear. I thought that was wrong and I must have been in fourth. I tried again on a flat open stretch of I-10 East of San Antonio. In fourth gear the speedometer was reading 120MPH, the engine was wound up but no rev limiter, and I lost my nerve. The bike was handling fine but I've heard the DPS will take you to jail if your doing over a 100. From now on, I think I'll just trust your chart.
V7Goose Posted March 20, 2010 #31 Posted March 20, 2010 You should not be vibrating under 65 in 5th. As stated in the other posts, accel will be impacted at lower rpms, but it should run smooth. I spend a lot of time running backroads at 50mph in 5th as the copilot doesn't like the high rpm feel/sound. Smooth running at 50. Just as a reference, not a suggested regular practice, I can shift into 5th as low as 40mph and still run smooth. At that point however, as others have stated, there is no accel. Kinda like my old 6 cyl, 3 on the tree pickup from a "while" back... Good Luck. BobI'm not trying to get into a pissing contest over this point, but I find this VERY misleading for new owners. In my experience, anything but very mild acceleration when running less than 3,000 RPM will absolutely produce a lot of vibration and hammering as the engine lugs until the RPMs finally reach an acceptable level. The bike will run very smoothly at a sustained 40 MPH in 5th gear (and even better at 50), and you can even slowly accelerate from there without vibration, but if you try and twist the throttle too much, it will definitely vibrate until you finally get up to an appropriate speed for how much gas you are trying to give it. If somebody here thinks they have one that won't vibrate when they open the throttle below 65 in 5th gear, then I am very happy for them, but other owners should not expect that. Goose
earwig Posted March 21, 2010 Author #32 Posted March 21, 2010 thanks for all the input. I went for a 160 mile ride today, longest since I've owned the bike. I can run in 5th at 60, just maintaining my speed still get a lot of vibration, doesn't smooth out till 65. My BMW was a 4 cylinder as well so have a pretty good idea for that feel. I'm taking the carb suggestion, see if that helps.
V7Goose Posted March 21, 2010 #33 Posted March 21, 2010 One more suggestion for you - at a sustained easy speed on level ground, that bike should not vibrate as you describe, even if the carbs are out of sync. Engine vibration only comes on if the engine is trying to pull a load and one or more jugs are not working as hard as the others. I'm now wondering if your problem is an out-of-balance tire or defective tire? Often a tire out of balance will vibrate/bounce worse at increasing speeds, but not always; sometimes you can have a particular speed where it is worse and then have it smooth out again. You might want to check the tires out carefully. Hope you get it figured out, Goose
bamico Posted March 22, 2010 #34 Posted March 22, 2010 V7Goose raises a good elaborative point and he's quite right. When I stated smooth as low as 40-45mph, I meant only in the case of holding steady speed or very moderate accel (as he stated). Roll the throttle hard at 40 in 5th and the bike vibrates like crazy. I was simply trying to make the point that things should be fine below the reported 65mph. V7Goose, No worries on a pissing contest. You simply called out an elaboration/clarification. Have a great pm. Bob I'm not trying to get into a pissing contest over this point, but I find this VERY misleading for new owners. In my experience, anything but very mild acceleration when running less than 3,000 RPM will absolutely produce a lot of vibration and hammering as the engine lugs until the RPMs finally reach an acceptable level. The bike will run very smoothly at a sustained 40 MPH in 5th gear (and even better at 50), and you can even slowly accelerate from there without vibration, but if you try and twist the throttle too much, it will definitely vibrate until you finally get up to an appropriate speed for how much gas you are trying to give it. If somebody here thinks they have one that won't vibrate when they open the throttle below 65 in 5th gear, then I am very happy for them, but other owners should not expect that. Goose
BradT Posted March 23, 2010 #35 Posted March 23, 2010 This bike will run very smoothly in 5th all the way down to 45, PROVIDED: The carbs are in sync You do not try to accelerate faster than a '65 Datsun with 300K on the clock For anything other than very mild acceleration, you must have this engine over 3,000 RPM, which happens to be about an indicated 70 in 5th gear. Point number 2 is funny, and the rest of this is very true. Brad
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