Archived Posts

[Admin]

Hi to everyone,
My name is Dave and I'm new to this forum and find the info very informative. I'd say it's the next best thing to actually talking to the original engineers. Anyway, here's my question. I want to try and reseal my GT380's crank. I've seen the site or link that shows Kick Start's T500's drawing and pixs of his crank splitting tool

(http://www.ozebook.com/compendium/t500_files/crank.htm)

but I cant make out most of his spec's etc, it's too fuzzy. I'm sure his originals are ok and I PM'ed him but he hasnt replied. Has anyone resealed a 380 using his splitter tool and could you share your experience etc? I have an extra motor so I guess I could try to do it first to see how successful it would be.
Looking forward to any and all suggestions.

[Admin]

Hi Guys
Took the T500 out for a spin at the week-end. went about 20 miles when suddenly, bike stops running on left cylinder. I pull over, pull the plug and check spark - nice chocolate brown colur and seems to spark okay. Didnt have my flipping tool set for once, so i put the plug back in and kick it over - fires on both again. Off I go for another mile trying to get home - same thing happens again - twice more.
Didnt have time to check it over as it was late.
Where do I start? Whats likely to be the problem? Its got new points and fuel runs down fine when I disconnect the line and stick it on prime.
Give me a few things to check out lads. By the way, anyone know how I can check the coil in situ? Bike has resistance caps.
Thanks
Mark

[Admin]

Could be a bad plug or a bad coil. When a bad coil gets hot it quits firing. Then when you let it cool down some it will fire again till it gets hot, then quits. Sounds like a bad coil.

[Admin]

Zook-e
That kind of confirms something I read way back. I'm sure I saw something about testing the coil? Anyone have any info?
Thanks
Mark

[Admin]

Testing a coil is easy. Use an ohm meter and read the resistance across the primary (the positive input to ground). Coils will read something like 5 ohms. I don't know what a T500 coil reads, but something like that. Compare them. Then check the secondary by using the ohm meter again reading from the plug cap to ground. It should be in the 5-10K ohm range. Maybe a bit more if a resistor cap is used.

Now, the problem with this is that your failure doesn't seem to happen when you want it to.....so the easiest thing to do is to swap the coils and try to move the problem.


Lane

[Admin]

probably on the same as lane..swap the lead on the plugs left to right etc.if still goes on the same pot then the coils are ok. then fit a new plug.when you run your bike and it cut out on the left etc did you start her up after a couple of minuts and firing on both pot if so then its possible that the float height is set wrong.plugs shouldn't be choco- brown but greyish brown....

[Admin]

Thanks guys will try and look at her this week-end. Sad to say that lately my thoughts have been turning to selling her. I've only ridden the bike a dozen times this year what with other commitments, minor maintenance work etc.

Its not a cash thing - I wrote that off ages ago - I guess to own one of these old babies is to accept tweaking and teasing it regularly.

What started me thinking is that my mate just brought a dependable (and boring IOM) BMW enduro bike. He just presses 'start' and off he goes grinning into the sunset, I'm always taking it easy, listening for trouble and cleaning my bugger's chrome. Yeah okay you could say his bike has no 'character' and mine draws a crowd even amongst veteran bikers, but week-ends like the last one sure take the edge off of it.

Right, I've had a rant, I'm off for a drink to drown my sorrows.
Mark

[Admin]

Yeah, I hear that!

The solution, of course, is to own two or more bikes!

I have a 2006 'Busa that is my dependable ride - but it tends to get me in trouble! I haven't bothered modding it, just pipes, Power Commander and a TRE unit - I mean what can you do to a bike like that? 160bhp is way too much for me to begin with and I'm not a good enough rider to over-tax that level of chassis componentry!

Then I have my 1982 GSX750SZ Katana, with an 813cc big bore kit, braced frame/forks, new fork internals, Yosh pipe, stage III carburetion (with pods), etc. That's for when I'm feeling aggressive, it's fast, but it's not fast like the 'Busa so I can't get in TOO much trouble! It SHOULD be dependable too, unfortunately, I built it myself so I'm still tracking down a few problems!

For example, I just learned that coils do not ground too well through powdercoating - it took me a while to track down that problem... Does it have spark? Well let's see, remove plug GROUND it to head and voici! It sparks, well, can't be spark then... Haha! It runs great now though.

My GT, I actually plan on making that my commuter, though I really should have built a 380 to take advantage of the under 400 insurance bracket. Oh well, the 'Busa and the Kat put too much pressure on my wrists and hands for commuting, and since my GT was my first ever bike I can't just NOT restore it! Maybe I should have kept my last restoration project, a 1982 GS750TZ... OR maybe buy that GS650G at the shop right now, adjusting chains does kinda suck!

Oops, threadjack, got kinda carried away there...

[Admin]

if its any consolation mark,I've had my ol 'T' 2 years on the road since restoring her and all I have clocked up is about 2,000 miles in that time.don't worry to much the engine is a tuff old boot.rarely that I have problems now.used to have problems alot so much that I wanted to rid of her.but that is only because of lack of knowledge. once you've learnt how these thing runs so what was a headache becomes I know what it is......you can still buy the electronic kits from boyer branson .the only thing missing is the screen plate which I can make for you if you wish.in the old days we were always fetteling with theses bikes nothing has change these bikes can take a hammering just make sure she warmed up 1 st.I learn't that these bikes don't like being fussy pussying what I mean riding slow all the time best now and again give her a good thrashing.I've notice with my bike if I've riden slow for quite awhile some thing doesn't quite feel right but once I've open her up she start to feel right. maybe it just me who knows.the most importance thing on these is your CARBS if these are not set right she will not run great.you do know of cause that the jets in each carbs are different...eg quote from leaflet...the needle jet in right carb is p4 and the left is p5,the idle speed 1200/1500rpm.many atimes I've felt like selling but only because she doesn't get used much as I would have like. my missus won't let me sell it after all the work I've put into her beside she's paid for..you'll only regret it if you do sell her she say's. she is right! sure I have another bike which is capable of going hell of alot more speed and stop on a six pence and just press the buttonto start .but I still get the buzz off the ol girl.different bike all together to be truthfull the ol girl is rough,vibs,need 1/2 mile to stop etc etc but she over 30 years old not a patch on modern bikes but modern bikes don't have the character as these old bangers and requires a little different skills eg my bike turn into a sharp corner easyand at speed but the ol girl you can't take the same corner as you would with a modern bike. well I think I've rattle on enough here..enjoy

[Admin]

John
Thanks for the tips and pep talk - I needed a little encouragement.
Will get out and check that coil. I guess after putting in so many hours restoring her, it would be like losing a limb..
Cheers
Mark

[Admin]

Okay. Where I last left off we were thinking that the loose oil pump adjustment probably caused a loss of compression in all three cylinders, eventually causing the engine not to run. I didn't confirm the false compression readings due to a bad gauge.

Here's the measurements

Ring Gap____Min to Max Bore Diff____Piston diameter
L=0.029"____0.0011"____2.755"
C=0.025"____0.0004"____2.753"
R=0.027"____0.0006"____2.754"
spec=0.027____0.0018"____Max


Remember, I also have a leaky left outer seal. The left piston has the most blow by and the most wear. It's within spec for cylinder wear, but the rings and the left seal must be replaced, at a minimum. I might replace the piston, but the accuracy of the digital caliper is a little low.

The wear on the left cylinder makes sense now, since it was probably running leaner due to the leaky outer left seal. So, if one can find a positive with the leaky oil pump, it forced me to look harder at the condition of the engine, which was going to eventually get into trouble with the left cylinder, and probably only really caused excessive ring wear.

Here's what I'm planning. Perform a more accurate measurement on the pistions. Replace the rings and the left outer seal, without splitting the cases, if possible. Maybe replace the pistons, if they're worn.

Anyone have some good accurate measurements on the std bore pistons, or is the one point the manual specs sufficient to determine piston wear?

Anyone have experience with the procedure to replace a outer crank seal without splitting the cases?:!:

Thanks,
Ron

[Admin]

Mark Haase has done it on an RD. Pull the seal like a KAW outer seal. To install the new one, you'll have to cut off the lip. It may or may not hold. It's a toss-up, but doesn't cost much to try it. I'd do a pressure test before running it to be sure it'll hold.


Lane

[Admin]

hmmm, might be interesting to try. The first thing I'd have to do is remove part 26. Is that pressed on? Is there a way to get that off?

http://www.3cyl.com/~mraxl/gt/manuals/p ... piston.htm

[Admin]

Can the gear indicator switch leak if the inner seal isn't right? I've put in new seal (inner and outer o-ring), and I still get a little oil dribble. Any ideas?????

[Admin]

The older swiches were plastic, and sometimes if you overtighten them, they'll still leak.

The newer ones were metal, but if the outer o-ring seal isn't placed precisely, it can leak, Also, don't overtighted.

I've had those boogers drive me crazy, too.