Engine fusion in steep slope.

Hi,

Is it common to have some small engine fusion when driving in steep slope?
If I hold the throttle constant I can feel small fusion, not massive, but some... if I give some more throttle is disappear, and if I goes back to constant throttle I coming back.

Engine: 81 750-4
Carbs: VM24

The engine running perfect in all other condition.

I was thinking these can be some weakness with the reservoir level or something?

It`s not a big problem, but always try to improve the bike

I've never heard of "engine fusion"; please describe. Also, at what rpm and what gear does this happen? Ed

I thing he considered load alternation. This is a sweet spot of driving condition you think your bike accelerate and brake a little
by its self. A slack or loosen chain drive or a weak rear wheel rubber damper could be the source.
A carb sync can also be a help to minimize or eliminate this.

Edit: constant jerking by lean fuel / air mixture

Michael

Don't know if this is the same. Years ago (my 74 900 was still fresh) There was a lake we used to visit. It had a long steep hill going down to the lake. A friend of mine had a 650 Yam he could not ride up the gravel hill. I got it to the top for him but in order to keep moving and motor running I would have at add a little throttle for immediate rear wheel spin. My 900 on the other hand would go right up with enough throttle to keep constant RPM's with speed like a slow walk.

At Hole in the Hills we had a steep dirt road going down to the ranch. 9% with two switchbacks. The Z1 climbed it very well at lower RPM's. Anymore and the tire would spin. Going down was a different matter. The rear tire would try to pass the front. 25 miles of logging roads to and from town. Bossie thought she was a dirt bike.:woohoo:
Steve

SWest wrote: At Hole in the Hills we had a steep dirt road going down to the ranch. 9% with two switchbacks. The Z1 climbed it very well at lower RPM's. Anymore and the tire would spin. Going down was a different matter. The rear tire would try to pass the front. 25 miles of logging roads to and from town. Bossie thought she was a dirt bike.:woohoo:
Steve

No wonder you love that b*t*h so much!

hehe it was google translate Maybe engine hesitation is a better English word?
It happens in old kind of RPM`s, I have driven on really steep hills and if I`m having the throttle constant it start to hesitation some, not huge drastic, but you can feel it in the forward "force going up and down", if I try to accelerate further the engine respond good, if I can try to keep the RPM steady on a higher RPM the same problem comes back.

I have only experienced these is really steep hills, not on slack hills.

I have used more time to "learn" the issue. I have driven on some long tours recently and the problem is not only with deep hills.
First I have never had the problem when driving downhill or on a flat road only when it`s going upwards.

If I`m running upwards a hill and have constant throttle the force from the engine can go up and down, not so much so the whole bike jerking back and forth, but you can feel it and if you give more throttle so the speed start accelerate it disappear.
I have a feeling it start only over 5k RPM. And then it happens I have between 1/3 and 1/2 of throttle on.

I`m quite sure it`s not the chain or the tires, because I can feel the engine is not stable/constant when it comes to force,
for me it looks like it jump over some ignition or something?

I have tried to move the gas tank level to reserve and PRI and also have had full tank, it has not solve the problem.

Thanking for you using your time to reading these.

From the description, sounds like a lean surge. At the throttle settings it's happening , I would think the needle needs to be moved up to richen up the mixture . Have you inspected the spark plugs? See what color they are. That will give you an indication of rich or lean mixture.

Thank you for feedback, sorry for slow replay, have been on Holiday. I will check the spark plugs these week and take some photos

I concur with the recommendation to raise the needle and see if that helps.

Thank you, I will test these later when I have time, problem is not big, so it not urgent for me, just to make it perfect I will take some photos and try the to raise the needle later when I have some time to take of the carbs.