5 replies to this topic

[yellow_cad]

I believe the carb on my 72 OSSA is a Makuni (VM26) . Cleaned the carb completely and for the most part the bike runs pretty good with the exception of a sticking throttle and good idle some times not good other times. The throttle linkage isn't new but seems to work real well. Most of the time the linkage works freely and I can hear the slide shut but sometimes it gets stickty. Is it possible that my internal carb spring is too weak? Just in case it matters for some reason, I am not able to get the the adjusting screw that moves the slide to make much difference no matter where it is located. I seem to be setting the idle with the linkage fine adjust at the top of the carb and the fine adjust on the throttle linkage.

[Canada280i]

why are you not able to get at the adjuster on the carb? you should back off the throttle cable adjusters as this will only increase the issue as the slightest tensioning of the throttle will cause the revs to fluctuate

[lineaway]

Sounds like the pilot jet and/or circuit is plugged. Also check the needle and clip is not moving in the slide. Usually some sort of meatal clip is held down by the spring.

[BillyT]

yellow_cad, on 17 October 2011 - 10:16 PM, said:

I believe the carb on my 72 OSSA is a Makuni (VM26) . Cleaned the carb completely and for the most part the bike runs pretty good with the exception of a sticking throttle and good idle some times not good other times. The throttle linkage isn't new but seems to work real well. Most of the time the linkage works freely and I can hear the slide shut but sometimes it gets stickty. Is it possible that my internal carb spring is too weak? Just in case it matters for some reason, I am not able to get the the adjusting screw that moves the slide to make much difference no matter where it is located. I seem to be setting the idle with the linkage fine adjust at the top of the carb and the fine adjust on the throttle linkage.

Firstly it is a MIKuni, not a MAKuni.

Try this test disconnect the throttle cable from the throttle tube/grip. Pull the end of the throttle cable barrel in and out.

Does the slide still stick? If so your cable is kinked, damaged or at an extreme bend angle going down to the carb. Or it could be issues from the next test also. If it does not stick with the prior test, the two other options are. Is your throttle tube/grip sticking as you turn it with the throttle cable disconnected? If so remove it and check for burrs etc.

Your slide may be sticking. Take the carb off and check slide for and slide track on carb for nicks, scratches etc.

Edited by BillyT, 18 October 2011 - 01:17 AM.

[cookie]

Hi

Is there a fibre glass tank fitted to your bike?

I have had problems with two of my bikes with the slide sticking in the carb. This is due to ethenol added to modern petrol and the petrol has eaten the fibre glass tank causing very sticky carb internals. Check the inside of the fuel tank and the slidechamber on the carb, if it's sticky then I bet thats the problem.

The answer to this problem is to fit a metal gas tank and thoroughly clean your carb or drain the fuel from the tank and the carb at the end of every trial and let the tank dry out.

Hope this helps It did on my bikes

[yellow_cad]

cookie, on 21 November 2011 - 04:14 PM, said:

Hi

Is there a fibre glass tank fitted to your bike?

I have had problems with two of my bikes with the slide sticking in the carb. This is due to ethenol added to modern petrol and the petrol has eaten the fibre glass tank causing very sticky carb internals. Check the inside of the fuel tank and the slidechamber on the carb, if it's sticky then I bet thats the problem.

The answer to this problem is to fit a metal gas tank and thoroughly clean your carb or drain the fuel from the tank and the carb at the end of every trial and let the tank dry out.

Hope this helps It did on my bikes

Thanks, it was my tank dissolving a whole lot faster than I thought it could. I sloshed the tank with Caswell epoxy tank sealer. Now I am having issues getting it going but at least the tank is no longer the culprit.