89 Exciter Transformation!

[thefullmonte]

Comet lists the silver spring as correct for the Exciter. Granted you have some changes done in there. The silver is 85/190 rate of 84lbs/inch

Stay with the red for now. It is plenty aggressive for your application. Only change one thing at a time. Lighter weights would be a good start.

 

[Lasse]

So I got my new coil,
but the engine still won't rev past I'd say 5500 rpm,
even with the belt off !
I'm going to take a look at the stator tomorrow.

Since the engine does not rev over 5500 Rpm even with the drive belt off
the trouble at this point does not lie in the clutch system.

I'm not worried about gearing at this point because the belt is off...
I wonder if the problem could all be in my primary clutch...
I noticed it was "sticking" when I let off the throttle at 5500rpm,
and not releasing as quick as I would have thought.
Perhaps it's binding when it opens up, so it won't shift out all the way???
You'll see in the vid I post tonight,
I don't see the primary shifting all the way out, and when it re-opens it sticks !?

Yes, your Comet clutch can stick/binding.
( I have had this happen on 3 different Comet 108EXP )
...But since your engine does not reach top RPM even with the drivebelt off
this is not your main problem just now.

 

[stanage]

Since the engine does not rev over 5500 Rpm even with the drive belt off
the trouble at this point does not lie in the clutch system.

I guess that's comforting to know. I'll concentrate on the carbs and wiring instead. I get the feeling the needle jet may be clogged on the mag side, otherwise I'm going to clean up all the wiring coming out of the engine, and wrap them all individually.... i read somewhere if your wires are contaminated with oil, they will produce a badly running engine.

Also going to take some time to check the stator...

Question: My carbs each have 2 shim washers in the throttle slide, one is under the needle clip, the other is on top of the clip. My question is, should I be using them at all? Why wouldn't I simply rely on the position of the needle with the clips? Why use shims???

 

[Lasse]

Question:
My carbs each have 2 shim washers in the throttle slide,
one is under the needle clip, the other is on top of the clip.
1. My question is, should I be using them at all ?
2. Why wouldn't I simply rely on the position of the needle with the clips ?
3 . Why use shims ?

1. Yes.
2. You could do that,
...But the plastic shim has a little "shock absorbing" effect on the needle when it bounces
back and forth in the air/fuel stream inside the throttle venturi.
3. You can fine tune the needle position whit plastic shims.
1 shim is like moving your e-clip ½ step.

 

[Lasse]

Stanage....

I have some questions to rule out error sources:

1. Have you tried to shift the spark plug wires ?
...Put the PTO spark plug wire on the MAG cylinder and vise versa.
Does the trouble move over to the other cylinder ?

2. Faulty resistor inside the spark plug cap... ( 5000 Ohm )
( It produces spark on low revs but not or misses on high revs. )
Have you tried change your spark plug caps ?

3. Have you tried to put the MAG carburetor on the PTO cylinder
and vise versa ?
Does the trouble follow the carburettor ?

4. Do you have another exhaust system to try with ?
You could have a internal blockage in the exhaust system ( silencer/muffler )
due to a loose baffle or something like that.

 

[dsc577]

good advice,you will finally get this figured out,my exciter had similar issues,would only go 70 then start cutting out,yes it was the clutch(comet).this is not youre problem though,take the pipe apart,mine sat in ashed for 10 years and was a mouse hotel,seems to be carb problem,isnt that were this started?oh well,good luck!

 

[stanage]

Here is the video as promised.



At this point I'm running a 330main on the PTO side and a 350 on the MAG side. Needle clip is 2nd from bottom on both carbs.

I put brand new br9es plugs gapped at .024, and the PTO side runs on the rich side in my opinion, but the MAG side doesn't burn right at all. I cleaned that carb inside out again tonight, took the needle jet out and cleaned it with carb cleaner and compressed air. Cleaned out the choke plunger cavity as well as the entrance through the bell. Choke plunger cable is so-so but operates well, and doesn't hang.

PTO Side piston -
The MAG side piston looks brand new even though the machine has done atleast 300km on the new sleeves and pistons... Click for bigger pictures...




PTO on the left, MAG side on the right - what is wrong with the mag side?????

 

[stanage]

Update!

So, this morning I spoke with 2 snowmobile/dirt bike mecanics, and they both told me this sounds like a crank seal problem. Therefore I have decided, since I finish at noon today, I'm going home, ripping the engine out and replacing the MAG side seal. I figure its a 3 hour, 13 step process!?

1) Drain the coolant
2) Disconnect the carbs and pulse tubing
3) remove the exhaust manifold and pipe
4) disconnect the oil pump tubing and oil tank
5) Disconnect the magneto wiring
6) Loosen engine mounts
7) Pull engine out?!
remove the water pump/magneto housing cover
9) remove the magneto
10) Flip engine and split the base
11) replace crank seal
12) clean, and yamabond the case surfaces
13) put it all back together!?

How long do I wait for the yamabond to harden? 24 hours?

Am I missing something else???

 

[stanage]

Captain, our seal is blown!

yep, its def. the seal... its nasty looking, and there was all kinds of debris and there is a trace of spooge on the bottom right hand side that leaks down...

Im going through the whole entire engine now. Water pump, oil pump, etc...

Magnets were all rusty, and full of crud, and everything else was pretty dirty...

Magneto before:

Magneto After:

Mag seal:

Engine casing before:

After:

 

[prankster]

Damn stanage! Glad to see u worked it out Now i´m really looking forward to see the beast in action.I´m also following your clutch work with big interest. Next year i´ll start playing with my clutches

 

[stanage]

It's gonna scream for sure! Now if I could just get the primary clutch off, I could split the case and change the seals. I'm having quite a bit of difficulty removing it. I replaced the water pump seals, and the gaskets for the water pump and oil pump and ordered a new water pump belt. I don't trust the one that's in there. I also cleaned every single piece that came off so the engine shines now!

 

[dsc577]

i used a grade 8 bolt and a good tapered punch,came right off,read you can also wrap the bolt with teflon tape and fill the clutch with water,tighten bolt and it comes off

 

[stanage]

i used a grade 8 bolt and a good tapered punch,came right off,read you can also wrap the bolt with teflon tape and fill the clutch with water,tighten bolt and it comes off

Did you have to heat up the shaft first? I tried the method of filling the hole with 80weight oil, and then I teflon taped a grade 10 3/4-16 bolt (I have a comet), and although some oil oozed out the sides I couldn't get enough pressure to pop it... now I think the first inch of threads is stripped, so I may have to re-tap the bore to the next size up... This is pissin me off... I'll see if I have a tapered punch that fits and is solid....

 

[dsc577]

no, but i did tighten it and rap on it with a hammer,mine was a comet to,i thought the threads were 5/8-11? i see they make em in3/4-16,16mm-1.5,9/16-18

 

[stanage]

I wonder if i put the bolt I have in, with water in there, and put it outside for the night? Will the freezing effect pop it off? Or just expand it and bust it up? Food for thought I guess...

 

[dsc577]

mine is 3/4 16,my cheap puller,can see model # also

 

[stanage]

OK, I have about the same length bolt, but I can't see the length of the punch. What length are you using? It looks like 7 1/2? Im going to pick one up tmrw, at the sametime as I pick up a tap to bore the sleeve over to the next thread size up, which I believe is M20 x 1.5 Then I'll get a bolt for that, and the punch, and this time I'll heat the clutch up a bit before I give it to er.

 

[dsc577]

1/2 square by 6 in.

 

[prankster]

Just be careful when u use heat, i burned my seal when i tried to get my previous comet loose... And heat didn´t work either, i had to kill it totally and grind to get it out I tried everything...used clutchpuller with oil and coilseal but cutting was the only way for mine.

 

[Lasse]

I tried the method of filling the hole with 80weight oil,
and then I teflon taped a grade 10 3/4-16 bolt,
and although some oil oozed out the sides I couldn't get enough pressure to pop it...
Now I think the first inch of threads is stripped,
so I may have to re-tap the bore to the next size up!

It is of great importance that you use a bolt with the right thread and thread pitch.
Otherwise you will destroy the threads inside the clutch itself and you will never get it off !!

I wonder if put water in there,
and put it outside for the night ?
Will the freezing effect pop it off ?

Yes, This is a very gentle and effective method that works very well if you have a bolt with the correct thread.