501 starting problems

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Re: 501 starting problems

Post by EVguru »

The magnets coming loose is a known problem and it can destroy your stator in some cases if it happens whilst the engine is running.

Breaking the magnets loose and rebonding them is the safest plan. Dow Corning do an expoxy especially for the job.
Paul Compton
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morini_tom
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Re: 501 starting problems

Post by morini_tom »

Ok so I just re-read my notes from when I modified mine and it appears I mis-remembered slightly. The modification advances the idle ignition timing, not retards it.

I would say this could make starting even more prone to kickback. Has anyone with anon-electric start kokusan engine tried the mod who could confirm?

On the dart starting has never been an issue and I noticed no change in this regard when I modified my flywheel.

As said before though, the transformation to the rev hangup issue was a perfect fix.

As a quick test you could rotate the pickup mounting plate to see how it affects the idle ignition and hence kickstart behaviour withoith having to modify your flywheel. The mounting plate has a mark for 350 and 500. The 350 runs 5 degrees more advance than the 500 so set it to the 350 mark and see if your kickstart behaviour improves. Obviously don't try to ride the bike with it set like that or you'll also have 5 degrees too much advance at higher speeds, which could be damaging.

If that test does improve starting then trimming your flywheel is a good option as it will also improve the rev hangip.

If it makes kickback worse then at least you've not wasted a flywheel.

Don't forget that when you do change the ignition timing through flywheel mod or pickup plate movement you'll also need to readjust your carbs (drop the slides to counter the more advanced idle ignition and rebalance)

If you don't have it then remember the cagiva era engine manual which covers timing and pickup gap setting on the kokusan engines is available to download from the members area of the MRC website.

Tom
'It must be a .....'
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Re: 501 starting problems

Post by 'It must be a .....' »

EVguru wrote:Breaking the magnets loose and rebonding them is the safest plan. Dow Corning do an expoxy especially for the job.
Hi, could you please be more specific about the Dow Corning epoxy and a potential source of the product; I have spent time searching but nothing appropriate/definitive can be found.
Many thanks in anticipation.
MickeyMoto
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Re: 501 starting problems

Post by MickeyMoto »

So, the flywheel is still in tact. I have removed the link tube between the carbs and so a test. Started first kick! However only runs on one cylinder. Back to the drawing board. Now it only runs with the back choke. Scratch head. Hmm, rear carb loose on head. Fix that. Try again. Nope. More beard scratching. Must be running lean. Check mixture screws, and take another turn out. Now starts and runs on two not on choke. Get the balancers out, adjust and go for a ride. What a difference. Managed 10 miles. The jerking is still there (as is the jerk at the handlebars) although it is not nearly as bad. I never experienced the hanging revs, either. Powers away from 2,000 in top. Cruises at 100kmh with no stress. Next test is a longer run on the motorway. First, needs a wash!
MickeyMoto
Posts: 2415
Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: 501 starting problems

Post by MickeyMoto »

So, after my little trip last week, i was worried it was running weak on the main jet as it would not pull past 6k in top. The Excalibur would pull to 8k in top. Changed from 108 to 112 and pulls a lot better. Need a motorway run to confirm.
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