Hi, everyone. I have a quick question about how to best ride the bike. Up until now I've been riding only at low rpms (under 6k mostly). at highway speeds I've been getting some pretty consistent fuel starvation especially going up hill. A friend of mine suggested I should try using the whole power band so I've been riding the last couple of days trying to keep the rpms between 6 and 10k as much as possible. I have to admit that I haven't done much work at 9 or 10k but I'll get there. this has meant mostly riding in 1st and 2nd gear around the city and on the highways 4th or 5th and down shifting up hills.

well the fuel starvation hasn't been a problem but I have a couple of questions for you all about riding this way. is it harder on the bike? I'm afraid I'm causing more wear and tear. I may be paranoid but I think the engine is developing a knocking sound. it was there before but seems louder now. is that possibly because of the rpms? it has 13,000 miles on it. maybe time for a valve adjustment? plus when I back of the throttle at these rpms the exhaust pops pretty good. I used to think that was a big problem but this same friend said don't even think about it. the backfires are just part of the package. is that accurate? anyways, let me know what you all think about this. maybe share how you ride if you like. thanks.

it is fun to ride up there. woohoo!

Well if you get fuel starvation at 6K, what makes you think that you wont get it at 10K

What symptoms are you showing for fuel starvation?

Are you at 6K then goto WOT(Wide Open Throttle) and it bogs on you?

More RPMS=More Wear

yeah thats about right. if I'm in high gear and around 6 or 7k and open the throttle (especially if I'm going up hill) the engine stalls. I have to wait until the carbs fill before I can go again. also I always put it on prime before I hit the highway.

I figured more rpms equals more wear but the bike doesn't red line until 11k so is it ok to ride consistently in the mid to high range?

where do you keep the rpms?

It does stand to reason that fuel starvation should be independent of rpms (wot is wot right?) but that hasn't seemed to be the case.

What I suspect is that you do not have fuel starvation but a lean/rich spot at around 6K.

Does it get worse or better with temperature changes outside?
What happens if you put the choke on while you are at like 6K and then gun it?

the bike runs better in general when its warmer. thats an interesting theory, the question I have then is why wouldn't I be able to start the bike right away after the stall if its not fuel starved?

If I have a spot thats too lean/or rich, how do I tell which? I should run some cleaner through to make sure one of the jets isn't clogged or dirty. or could it be the the wrong size?

do you know which of the jets controls power at that range?

I've never put the choke on while I ride, only while I'm warming it up. I'll give it a try.

Yeah if you have to pull over and wait then its probably fuel starvation, but you can also do the ol-WOT throttle run and then pull the plugs to see how they look.

I am not sure about the newer carbs, but I think the 6K area is the transition period between the mids and main. Either way if you are getting fuel starvation check your vacuum hose to the petcock

What kind of speeds are you carrying at 6-7 grand in high gear.  At 70 mph I'm at roughly 5200 RPM and going up hill I don't NEED to shift though i often doo.  Around town I'm running between 3750 and 4000 rpms and try not to go below that cause the bike is way out of its power.  If you choke it and she takes off, you're lean and the choke is cutting back some of the air.  If it dies, rich because theres too much fuel already and choking makes it worse.

At 13000 miles has your bike seen a tune up?  If not I'd say go through the basic maintainance items, spark plugs, filter, ect.  See what happens after that.

at 70 mph I'm at or above 6k and thats usually when the stall happens. down shifting has really helped. I'll look at the vacuum line but I run on prime so it shouldn't matter right? I'll also try choking it. I haven't been in to look at the spark plugs to see if its showing lean or rich. I'll have to do that too. I still wonder if anyone else rides it consistently in the mid to high rpm range and if riding it that way will cause any damage.

I run the race bike at 10.5K for 1.5 miles per lap for 8 laps per race. 


I will have to tear it down in a bit but you know thats how it goes. THese bikes are tough, and will be okay, but it does shorten there life.

Have you checked the undertank petcock and ensure that the knotch is perfectly up and down because it is really sensative to misalignmnet and will cut flow.

10.5k eh? that sounds like fun. I want to get into racing but I'm still really new to riding so not yet. I did spend a little time over the weekend up against the red line but I haven't been there much.

I'll check the tank petcock. I've not once but twice forgotten to turn it to 'on' before re bolting it to the frame so I won't rule that out...

just driving around the city i guess it isn't really necessary to be at 8k. sure is fun though. on the highway I'll be down shifting up hills and not riding in high gear the whole time.

The first thing that I'd check is the tank mounted petcock. They are very picky about being in the exact right spot (it isn't up against the stop) and it's hard to see what you're doing under the tank.

Second, if you're starting to run the bike hard you should check out the valves soon.

As far as the RPM, the bike is tough and can take some flogging, but more RPM is more wear and when you're just cruising, there's no need to keep the RPM up really high. Sometimes it's necesarry or preferable for the obvious reasons to keep the RPM up but when there's no reason to it's just kind of pointless.

Quote from: dchrist on May 13, 2007, 10:11:59 AM
it has 13,000 miles on it. maybe time for a valve adjustment?

Well you should check valves every 4k Miles so, yes it is time.
About rpms, I ride in the city up to 6k normaly and higher only if i need to get away from cars quickly.
Holding the revs high with no throttle is no point. You should use at least half throttle when you are accelerating normaly. And past 7k with half throttle things start moving Really try using more throttle. Ride 5k in lower gears and wack it open, you might be surprised .

For a well working motorcycle back popping does not appear.

About the engine damage : The moment you start the engine, you start damaging it. Or it is called wearing. You wont get any instant damage by riding in high rpms, just the engine will wear quicker, especialy if the oil used is low quality.

Riding high in rpms has one advantage though, you can get lots of power in little time should you need it, and you don't have to down shift.