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xj598 Woe..


xj598
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Ok so here we are as promised in teh 'Introduce yourself' section..

I had the XJ598 running up the road in the last couple weeks for the first time following a basket-case rebuild and was pretty chuffed. but now it simply will not start. I rebuilt the top end with new rings set valve shims etc.. before instaling the motor so I'm reasonably comfortable with those mechanics. I also have the correct TCI for the Radian pick-ups and I'm getting a spark. When  I initially tried the motor with XJ600 (BS32) carbs  it wouldn't start for love, money or Bradex easy start. I then fitted the 550s BS28s though and all went well - for a while and as said I even manged some forward motion... I have since also tried starting  it from my auxliary tank but zippo. Ideally I need some FZ600/Radian BS30 carbs, but I'm struggling to see why it now won't start on the BS28s (which have been well cleaned BTW). It does start on a few breaths of Bradex so I'm sure it's a fuelling issues. I will likely pull the carbs again to check levels,jets etc.. again but if anyone has another suggestion I'll gladly hear it... Cheers J

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Have you tried it with the tank fuel filler open? Sometimes it can be blocked especially as it's been sitting around for a while. Otherwise have you got an external fuel bottle to try to start it without the tank attached, you can then see what's happening at the carbs. Just a couple of thoughts on your problem, your right if it starts or fires with Bradex then it has to be fuel related.

Edited by slice
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check for cracks in the inlet manifolds too, it might be letting air in somewhere.

 

do you have  a compressoin checker?

when I did my xj motor, I inadvertantly skipped a tooth on the exhaust, it started but would rev over 5 k. luckily no damage was done.

I would double check timing and everything to get a base line, then have another look at those carbs as mikunis have some real small holes and needs a ultrasonic bath to get rid of detrious.

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Thanks for the replies..

Compression tested ok after I had reassembled - only one pot which had suffered water damage was down to about 135.

Anyway went back to it tonight to check float levels ( a bit low but not too bad) then I drained the carbs fully ( and noticed some slight debris) and swapped back to my aux tank. Now it starts (!)  a bit rough mind you but at least I'm back to where I was. Last year I tried some electrolysis on the tank which worked but probably not well enough.  I'll get some brick acid at the weekend and give it a go with that I think..

Cheers

J

J

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Would suggest you don't use Brick acid (Hydrochloric acid) to clean your tank, have you tried this? http://www.doityourself.com/stry/5-tips-for-cleaning-motorcycle-fuel-tanks

It takes a bit longer to do but is better than chucking the stuff your thinking of in. Just a suggestion mind it's your bike after all.

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Have you tried it with the tank fuel filler open? Sometimes it can be blocked especially as it's been sitting around for a while. Otherwise have you got an external fuel bottle to try to start it without the tank attached, you can then see what's happening at the carbs. Just a couple of thoughts on your problem, your right if it starts or fires with Bradex then it has to be fuel related.

Yes, I did the nuts and bolts in the tank thing before the electrolysis (the bike was in bits  for 14 years before Imade my foolish ebay bid - the power of nostalgia !). In fact I've opted for phosphoric acid which is a widely used rust treatment/converter so we'll see how that goes. The stuff I ordered is 85% concentrated but I read 10% is still Ok for this purpose so I'll be diluting with distilled water I think.

Cheers

J

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Oh OK that should work, good luck.

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Phosphoric acid and water, that's basically what Jenolite is, also makes a good flux when soldering if you have nothing else.

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