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Flat 349

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Hi All


I have a 1984 349. the one with the grey frame. Running a Mikuni from Inmotion and Electrex ignition, crank seals replaced.


I bought the bike as a very original low useage barn find, then did the above during recommissioning.


Had a few issues last year with it being very flat....not revving out smoothly...or at all really :-(


Eventually resolved it, new inlet manifold and also re-installed the ignition with some washers to space it out slightly (other stuff on here about that)


I know you shouldn't change 2 things but I was getting desperate as the problem didn't show up on the road or greenlaning, just in sections.


Anyway did a trial and all was good, revving out cleanly.


Put bike away and used my Beta for a while.


Want to use the Mont in a few weeks time in a bit bigger (for me!) trial so used it in a local event......and the problem had returned!


It was a mostly nadgery trial so not really a problem, starts first or second kick and beautifully smooth off the bottom, but no snap or revs really beyond 2,500 ish.


I really want to use the Mont in the next trial but I will need a few revs and third gear on the climbs, any ideas what may have happened??

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would it be a pain to see how it goes with origanal points set up , what colour is plug ie it doesnt just need to go up to a larger main jet ,, also is exhaust free flowing and not clogged , and air filter aint over oiled ?

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When it reaches the rev limit of 2500, does it die, 4 stroke, 8 stroke or misfire unevenly? Does throttle position make any difference to its upper rev limit?

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Ta for the replies chaps, I think i may have had a bit of  "senior" moment!


But in answer it sort of 4 strokes, sounds flat and will not rev.


The weird thing is between sections it will build up revs OK, which is why it seems fine on the road.




I forgot that the last time I rode when it was working great it was pinging a bit between sections, as well as the other bits I had dropped the needle one notch.


When I got back I moved it back to where it was as I was convinced the manifold and ignition were the problem.


Would needle position cause this?  Kicking myself as I could have tweaked that at the trial easily but had forgotten I had done it :-(

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The first thing I'd suspect is the ignition. A mate of mine has had one of those and it's been back to them four times to sort out and it still won't run properly or anything like. The bike is now back on points and running as it should. I know of someone else who has had nothing but bother with one as well on his 349.


First thing I'd do if it was mine is put the points back on without touching anything else. If the problem persists put the original carb back on with the points and take it from there.

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Ta for the reply's all, it was needle height!


Trial on Saturday, was a bit of a risk as it has probably the biggest hills I ride each year but it flew....mostly with me still on it!


Totally messed up the first hill in second, after that all good in third!


Amazed that one notch made such a difference.....maybe the Mikuni is a bit sensitive


Someone else also recommend moving back to points, totally understand from a fault finding point of view...thankfully I must have a good one!


2 kick starting after not being used for a month or more, 1 kick otherwise.


High compression and old knees....I need all the help I can get!

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