I have just completed a cosmetic resto of a 76, 350 Sherpa which has been stood for 20+ years. Mechanically it sounds OK. Now that I have fired her up, I have 2 issues:

There is a significant change in engine speed with no corresponding throttle movement. The motor will rev and then slow almost to a stall. with no throttle input. It also seems to take a long time to spool down when revved.

Secondly there is a large "flat spot " on the first 1/8 throttle or so.

I have just replaced plug, points and condenser and thoroughly cleaned the Bing 84 carb out to get her fired up. The air screw is at 1.1/2 turns out.

Something else which is odd, If I lean the bike over to the left or right, the engine speeds up

I have new crank seals but have not yet put them in, pure laziness I guess !

Any suggestions gratefully accepted.

Edited November 22, 201411 yr by 1973tr6

Try putting those crank seals in for starters buddy

Vic, Good to hear from you again, this description is a lean condition,loose slide maybe;

with air breather hose loose & bike running hold pressure on the slide & see if things

calm down.

Larry

had similar problem with a 350 i had once turned out it was the breather pipe on the bing carg was to long i cut it back and bingo sorted the problem. also i was told to lay the bike on it's side this worked before i cut the breather pip back i use to lay it on it's side every i started it. as boghopper says be good start to put the new crank seals in if it's been stood 20 plus years they will be rock hard.

Yup, have done the ignition side seals, only took 30 minutes..... Had a battle with the clutch pins until I realised that by turning the clutch basket so that the pin I wanted out was at BDC, push the spring and hey presto, they fell out.

Other than having 3 hands or the special tool, what is the best way to get them back in again ?

I have to go out and get a puller tomorrow, the flywheel won't move :-(

ibhbul, bondy, will work on the carb once the crank seals are done.

Edited November 23, 201411 yr by 1973tr6

After what I've been through with my bike I would say its a carb issue,not sure what carb you got fitted but the a also used to accelerate when you leaned them over it was a float issue cheers andy

Float was my first thought but the seals are getting replaced first. I am going to try things one at a time and the try the bike between each step, then I'll know what the answer is..... I am off to have a meaningful discussion with the flywheel, see if we can reach an agreement about it coming off the shaft !

The best way to get the springs and pins back in the clutch is with a tool. If you don't want to shell out for one, you could always make one. I took this route, but tbh I could have earned enough to buy several in the time it took me to make it.

I also would replace crank seals first, also check the slide of the Bing, i'm told that top riders used to replace the slide every 3 races.

clutch spring compressor:

http://www.trialscentral.com/forums/gallery/image/2481-bultaco-clutch-spring-compressor-001/

Vic, the drive wheel is just stuck, careful not to lose key.

As to the clutch pins if you don't have a nice puller like Guy has,

lay her down and make a small oil spot on the floor (trans breather),

good friend with long nose pliers and you with same, not fun!!!

Good luck

Larry

PS did we put a condenser under the tank as we discussed?

Edited November 23, 201411 yr by lbhbul

OK, with the help of a puller the flywheel came off, replaced the seals and o rings, reassembled and got the pins in with my daughter's help.

Fired up right away and better, but not right. Would only run with the choke part way on. and still a flat spot. Tried pressing on the slide - no difference - I decided to take a closer look at the carb and found the pilot jet clogged and impossible to remove....... yes I tried pretty much everything including drilling the jet out............. shouldn't have done that !!!!!!

so........... I am now in the market for a replacement carb.

Good grief , good old Bings!

PM me as I can maybe help with the problem.

Larry