Hello everybody
I am a first time user of the forum and this is my first experience with a trials bike. I have however a long experience with bikes in general.
I have not seen any other item on the forum, so I hope someone can help me a little further.
This bike is from a friend of mine. He asked me to look at it and I can use it so now and then when it runs again.
The bike was always running very well and nothing has been changed to the bike, apart from what I describe below.
When I got the bike it had not been used for over a year and it wouldn't start.
Obviously the carburetor was all gummed up, so I cleaned it.
When I put it all back together the problem started.
The bike starts well, but reacts badly at the throttle. Slow response and does not run high. (I think this is called 4 stroking)
Lots of smoke and the ends of the overflow tubes are wet with gasoline. They however do not "flow"
The spark plug is wet, but I have not run it for long.
My conclusion is that the mixture is (way) too rich.
See below for the details and for what I did and tried. (the obvious float height, float valve and cold start system)
Nothing has however made any change to the problem so far, not even dropping the needle 2 notches.
I now plan to change the needle and jet, the float with the valve and the plunger of the cold start.
These all however seem to be in good working condition, so I am a little lost and do not expect this will solve the problem.
I therefore would like to hear if anyone on this forum has ideas on what else to try or look for.
The bike is a Montesa 314 R
The carb a Dellorto phbh 26 SD
clip on 3rd groove from top
jets:
Needle X6
needle jet BN 264
main jet 97
cold start jet 60
iddle jet 60
float bowls white, connected, 9,5 gram type 9010.1
float valve 200
airscrew 3/4 out
Sparkplug BPR5ES (also tried without resistor)
Can anybody confirm this is all correct?
Carburettor body and jets cleaned with ultrasonic
all seals replaced with new.
Float height is 24 mm, welding line is parallel to carb body.
Float weight is 10 gram on my scale, but it only measures in full grams, so could be anywhere between 9,5 and 10,5 grams
Floats are opaque, but I cannot see any gasoline inside. No sound when I shake.
The float valve seems to close well when I blow on the gasoline tube. The rubber tip looks ok.
Cold start plunger seats firmely on the jet when closed.
New sparkplug and old spark plug, both same bad result.
The needle has small wear marks.
I dropped the needle by moving the clip to the upper groove (2 notches up) and the engine still seems to run way to rich. (4-stroking)
I hope anybody has a suggestion.