Author Topic: A Can of Worms  (Read 6338 times)

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Offline T250K

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A Can of Worms
« on: January 27, 2009, 03:17:48 PM »
  ??? Anyone have any thoughts on the following please ?     My 1982 PE 250 twinshock was running like a dog when I bought it last year.    I've stripped the carby, and the jetting and all other bits and pieces were standard according to spec for a PE 250 X but in bad shape.    I've Replaced the needle which was bent,  checked out the nedle jet ( OK ), and reset the float level. 
 
It rides Much better now, but sounds and feels as though the timing is late.   Pulled the rotor off and according to  X  series specs the timing is actually a few degrees early.      The system is iffy ( rotate the backing plate until the hold down bolts are centred in the slots and nail it at that. )     

Are  X  specs OK for these very late twinshock PE's ?    On my bike the timing has been set with a score mark on the backing plate lining up with a mark on a ' spare ' support lug ( with no hold down bolt ) in the crankcase.   This setting is more advanced than if set by centering up the slots under the bolt heads.

Are there specs available anywhere which would give a figure for static timing, or maybe timing at a specified idle speed, which could be checked with a timing light ?

Is there any advantage in running a small variation from standard timing ?   Bike is used for what might be termed  Private Enduro.

The mixture is a fraction rich right thro the range, but is very close.  Fuel is Shell premium unleaded ( not a good idea according to recent Forum comments ), and Shell Advance 2S oil at 25 : 1,  ( recommended is 20 : 1 )  and ( just lately ) with 0.8% of Nulon octane enhancer. 

I reckon I can fine tune the mixture setting by running it closer to the recommended 20:1, but what % of extra oil ( less fuel ) is roughly equiv to a drop from 280 to 270 Main jet, and does Octane enhancer also have an effect on carby settings for correct mixture ?

Cheers,  :)       T250.     


 

Offline Noel

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Re: A Can of Worms
« Reply #1 on: January 27, 2009, 04:59:58 PM »
my first thought is that the CDI is not advancing,
can you check to see if timing changes as revs change,
cheers
Noel

Offline LWC82PE

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Re: A Can of Worms
« Reply #2 on: January 27, 2009, 05:52:37 PM »
do you have a 82 PE 250! you would be the only person besides my self who i know has one they are very rare. Could you send me some photos? do you still have the big metal tail light for it?

i have 2 1982 250 Z owners manual. From memoriy some specs are different to the X. main jet i think.

go to the PE forum and you will find a copy of the 82 250 Z manual

http://groups.yahoo.com/group/PEmotorcycles/

if you dont use 20 to 1 that will throw out the standard jetting specs in the book.

ok looking at it now for 1982 PE 250 Z

carb ID - 40621
main jet - 260
float height -10.7mm +/- 0.5
air screw - 1.5
throttle valve cuttaway - 2.5
jet needle - 6DH20-2
air jet - 2.5
pilot jet - #37.5
pilot outlet - 0.6
needle jet - Q-0
by-pass - 1.4


ignition timing - 13.5 deg +/- 2 deg BTDC at 6000 rpm

got more electrical specs if you need

this owners manual can also be found at http://pureenduro.free.fr/Div/documentation/PE%20250/manuel%20suzuki%20pe%20250%20Z.pdf

its all in there. i have september 81 issues and also an early 82 issue of the manual. im pretty sure specs in both are the same.

CDI's on these are pretty reliable. its the primary/pulser coils that pack up. specs for those coils are in the manual. i would be checking those aswell.


« Last Edit: January 27, 2009, 06:33:13 PM by LWC3077 »
Wanted - 1978 TS185 frame or frame&motor. Frame # TS1852-24007 up to TS1852-39022

Offline Marc.com

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Re: A Can of Worms
« Reply #3 on: January 27, 2009, 06:20:14 PM »
sounds like the carb was pretty shagged. The PE always seems pretty sensitive to air screw adjustment, have a fiiddle with that it may surprise you.
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Offline LWC82PE

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Re: A Can of Worms
« Reply #4 on: January 27, 2009, 06:31:05 PM »
also check the rubber seal on the choke plunger. these go hard and over time compress which leads to a poor seal which results in a slightly richer mixture all the time even though the choke is off :o this is very common on the Amal mark 2 cabies which are basically a  mikuni copy. i have to fix these all the time and what i do is either flip the rubber over if is not cracked or hard or punch out a new one from some fuel resistant rubber sheet like neoprene or some thin walled fuel line. fixes the problem everytime. many people do not think to check this.

These 36mm carbies are easy to get, i got a box full of them. you can also buy them brand new

you will also have tuning problems with a worn slide/body. im yet to really see this as a problem on most Mikunis i have seen (unless they have done a lot of work) as they had dis-similar mating surfaces unlike the old british Amals that have alloy slide on alloy body, they are so crap, i lost track of how mnay of those ive binned. the thing we used to do is ge them resleeved. the place fits a SS sleeve over the slide so there is more of a 'bearing surface' it fixes the slop but due to a poor sealing top cap and no cable boots, water/moisture gets into the carby and a chemical reaction occurs with the alloy and the SS slide and the bodies distorts and the slide seize etc and you gotta get in there with wet and try and sand the carby. No thanks. After seeing what these re-sleeve jobs are doing now and with the availability of new fresh Amals we no longer recommened re-sleeves and just sell the customer a whole brand new carby.These 36mm carbies are easy to get, i got a box full of them. you can also buy them brand new
« Last Edit: January 27, 2009, 09:13:35 PM by LWC3077 »
Wanted - 1978 TS185 frame or frame&motor. Frame # TS1852-24007 up to TS1852-39022

Offline Marc.com

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Re: A Can of Worms
« Reply #5 on: January 27, 2009, 08:49:19 PM »
I would still be looking at the carb, if it looks worn bin it and get a better one, Bit suspicious as to why the needle would be bent. Jetting only needs to be a clip position out sometimes and it is like night and day.
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squirtmoto

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Re: A Can of Worms
« Reply #6 on: January 27, 2009, 09:12:59 PM »
Another thing to look for on any PE ignition is the flywheel magnets
These are very fragile and cracks can be hard to detect. Any cracks in the magnets will alter your timing

Offline LWC82PE

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Re: A Can of Worms
« Reply #7 on: January 27, 2009, 09:16:43 PM »
yeah thats pretty common as well, but ive picked up many used flywheels that have been ok still. its more of an issue with weak magnets from wreckers/ebay sellers who remove the flywheels and just let them sit like that not on the bike, without the stator fitted inside or with out keepers. ive discussed re-magnetizing these with someone i know and he reckons he can do it.
Wanted - 1978 TS185 frame or frame&motor. Frame # TS1852-24007 up to TS1852-39022

Offline Lozza

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Re: A Can of Worms
« Reply #8 on: January 27, 2009, 09:46:43 PM »
The plug knows all as does a timing light. Check/ replace plug cap, the choke plunger would be something that would be very easy to over look.  The Nulon booster is making little difference except to Mr Nulon and Super Cheaps bottom line, try 2-5% Acetone from a fibreglass place. Will make no difference to jetting at all.An over advanced ignition will be better down low and ping it's head off up top a to retarded ignition will be a slug down low and a rocket on the pipe.
Has the cylinder recently been rebored to a larger size?
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Offline T250K

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Re: A Can of Worms
« Reply #9 on: January 28, 2009, 04:02:49 PM »
All good info there, thanks Guys.    Now that I have a figure for the timing I'll check everything and see what's what.    Reckon the jetting is pretty close but will now go straight to 20:1 fuel, and work it out from there.

Yes, Leith, the compliance plate shows 8/1982 so great to think I might have picked up a rare one.  Wasn't the PE 175 monoshock by 1982 , were there no full floater 250's in '82 ?     Thanks for the lead to  Z  specs.    As you said, all carby stuff exactly the same as an  X  except for the main jet.     I've got new 270 and 260 so will try those if the fuel mix doesn't do the trick.      My bike has been worked over unfortunately.  It's in good shape, but all electrics removed ( got them in a bag ), and it has aftermarket plastics.  Also a later engine, No.  207880.    Most of the original one ( ? ) No.  206660  in pieces with the bike.   Am pretty sure the tailight was a small rectangular plastic job but will check and let you know, and will organise some photos over the weekend.

The carby is very good except for the needle.   Don't know what the Hell happened there.  Looked like molegrip marks just below the bottom groove, a couple of flats below that, and seriously bent.  Some people can ruin an anvil just by looking at it I guess, but it could have been a lot worse when I see what some of you Guys find in Bikes you've bought.   The choke seal was good but I had to re set the float level, previously way low.   Had tried one up and one down for needle position but book standard is best by a country mile.    Started at 1 1/2 turns for the idle mixture but have had to settle for a touch over 1 1/4 to clean up the whole bottom end, thanks Noel it makes a huge diference.

Lozza, I'll try a mix with acetone.  Am not sure the PE actually needs anything but had been running Nulon in my KTM which pings just once in awhile coming OFF a hard run, so had added an Irish drop to the PE just to be sure to be sure  :D.      Is there anything to watch out for, using acetone in plastic or glass tanks ?        Cheers,   T250.

Offline Marc.com

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Re: A Can of Worms
« Reply #10 on: January 28, 2009, 04:18:43 PM »
  Wasn't the PE 175 monoshock by 1982 , were there no full floater 250's in '82 ?     

Suzuki's failure to build a Floater 250 and 400..... what the hell were they thinking not building the PE 200/250/465 floater.

Nothing good happened at Hamamatsu after that until the RMX turned up, which was offered as only a 250. Imagine if there had been a hard core RMX 125/200/250/500 ..... I mean they put the 500 motor into a bloody quad. Who makes these decisions ?????.
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Offline cloggy

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Re: A Can of Worms
« Reply #11 on: January 29, 2009, 08:00:44 AM »
I think it was to do with a previous world recession/high yen. Crooks in the UK told me the prices virtually doubled and the stuff stopped shifting. They've still got loads of spares

Offline Marc.com

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Re: A Can of Worms
« Reply #12 on: January 29, 2009, 10:20:15 AM »
Yep i think we can expect a few years of bold new graphics and not too many new models this time round as well.

Really most of the current bike Husaberg notwithstanding are the same old soggy biscuits with not too many bold leap forwards.
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Offline Noel

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Re: A Can of Worms
« Reply #13 on: January 29, 2009, 11:55:03 AM »
just had another thought,
how clean is your exhaust system,and silencer
maybe needs a burn out,
cheers

Offline T250K

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Re: A Can of Worms
« Reply #14 on: January 30, 2009, 02:10:48 PM »
 Yair, thanks Noel, am hoping to get back onto it on Sunday so will check it out.    Cheers,   

Offline LWC82PE

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Re: A Can of Worms
« Reply #15 on: January 30, 2009, 06:58:38 PM »
T250K, there were no full floater PE 250 or 400's the only full floaters were the 175 82-84. tail light should have originally looked very similar to a TS 185ER one, but depending on the origin of your particular bike it may have still only had the X model rubber light. i think they stepped up ADR requirements in 82 and thats why they had the large metal body tail light.

if you still have the metal reinforcement plate under the rear fender, that will mean it had the big light fitted as this support was to help carry the extra load of the heavier light. if you send me some photos sometime i will point out a few other things to you and see how it compares to my Z.
Wanted - 1978 TS185 frame or frame&motor. Frame # TS1852-24007 up to TS1852-39022

Offline T250K

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Re: A Can of Worms
« Reply #16 on: January 30, 2009, 08:14:37 PM »
  :) No worries Leith.   I'm hoping to get back onto the PE on Sunday but Work has stopped play so will see how it pans out.    My bike has a new aftermarket rear fender, no reinforcing plate, will check in the box of spare bits from the previous owner and see if it's in there.    Photos will turn up eventually.     Cheers,