[Mark Grossman]

Purchased the clutch retro-fit kit, the needed tools, Loctite etc and put things together last night. While doing so, I spotted what happened and hopefully this can save someone some $’s down the line if they still have the original style clutch.

The drive gear that is bolted to the clutch drum was loose. The lockring was still against the nut but it loosened just enough to allow the clutch drum to spin on the gear. Granted, the pads were worn and everyone I kart with has had to replace the thing when the springs break, but still killed me to see I could’ve been up and running again by tightening that thing down.

The project was actually pretty fun and though I haven’t fired it up yet, optimistic everything will work just fine, and my new thinner wallet will save me some weight…….

 

Mark

 

[Mark Grossman]

decided to get things rolling and ordered the new clutch retro-fit kit. That was one expensive weekend….

[Mark Grossman]

it’s a wet clutch, so grease isn’t the issue. The pads are about 1mm thick which is the point where Rotax says to replace them. But of course they no longer sell those and have a new clutch kit for $650….. ouch.

[Mark Grossman]

So I did get out on Wednesday, and the kart seemed to run better with the alternate carb. Fired up on choke but didn’t idle nearly as high as my old carb did on choke, or other dd2’s at the track. Idle screw turned all the way up. Engine cleared out much better once warmed up and the mid-throttle hesitation not nearly as noticeable. On track performance did seem slightly better with a more pronounced boost around 7-8k. But it was quite chilly which will make any engine run a bit stronger. With half the radiator covered, never saw water temp over 125 per mychron readings, so thinking it was not warm enough. Going out again this Wednesday hopefully and will tinker some more. After 20+ solid laps, plug slightly wet and black/brown running 175 main, 1000′ altitude about 55 degrees out. Flat out runs wasn’t cutting out so maybe need to still go a bit leaner?

Maybe that new Tillotson carb will be the answer :)

 

Thanks,

Mark

[Mark Grossman]

Progress report:

My friend lent me a spare carb he had rolling around his toolbox. Took it apart and it’s setup exactly the same as the one I’ve been working on. All jets, venturi, float height etc are the same. Bolted it on and fired right up. Ran on choke o.k. for a minute and then went rich, so had to turn it off. Exactly the opposite of how my carb behaves. Only warmed up on stand, so hard to say how it’ll run on the track, but sounds fierce compared to before. Revs faster and around 7-8k screams, which is how it should behave from what I’ve read. and once temp got up, smoking pretty minimal.

Have a track day this week and we’ll see if things are better, but appears to be something funky with my carb. I’ve cleaned it a million times, sprayed cleaner through every hole and confirmed clear as could be. Assuming the borrowed carb runs as well as I hope, suppose I could start swapping bits one at a time to try and isolate the problem, but hoping my buddy will just sell me the one that works right.

Mark

 

[Mark Grossman]

Link didn’t work, curious to see what you’ve come up with.

[Mark Grossman]

certainly sounds like an air leak. If not the more accessible things, carb clamps, etc might want to do a pressure check. Could be bottom end leak or something else less obvious.

 

[Mark Grossman]

[quote quote=15488]The sensor 265560 is placed in the carter of the engine to mesure the crank revs , no oil there. Order part 431500.[/quote]

 

doink….I’ve been working on 4 strokes for too long…..  No oil to worry about there. Thanks for the detail. Will include that gasket in my next order and cross my fingers.

 

Mark

[Mark Grossman]

[quote quote=15388]He told me that the pick up has an original spacer, he has added the same one. ( 2 in total ). Hope this will work for you.[/quote]

 

Peter,

Certainly worth a try, and great info. I found one old thread somewhere that briefly mentioned the “sensor trick” but didn’t elaborate. Guessing I need to drain the oil to do this, and probably time for that anyways so will give this a shot.

Thanks for the help!

MG

[Mark Grossman]

[quote quote=15139]On the underside of the engine you have a sensor for your crankshaft rotation.
Take it out, put an O ring spacer to have the sensor farther away from the crank. I’m not running DD2 but a tuned Senoir, one day I was next to a professional team in the pitlane, running DD2 , they had the same problem. They changed carb, wirings,ignition coil etc etc. Madness. Until the moment a technician from another team came in and he told them to place the o ring spacer.
10 minutes later , problem solved. I hope this will work for you …. [/quote]

haven’t heard this one with my research, and will look into it. I did get the spare carbs from a friend and didn’t have a chance to try them. Got in some track time this week, and going leaner on the main helped, going richer hurt. Yet it still sounds better on choke. With the 178 the power was hitting maybe 8k and pulled strong, below that sounded like a loaded up old motorcycle.

Any idea what size o ring, or material?

Thanks,

Mark

[Mark Grossman]

The problem I have when I’m at the track is that I don’t want to tinker, just want to turn more laps. I don’t get out to the track often enough to be willing to spend the time and trouble-shoot, so I end up living with it . But I’m committed now as the kart is getting sorted out and this is the last issue…..actually once I get this figured out moving on to learning about the handling setup.

 

thanks for the words of wisdom,

 

Mark

 

[Mark Grossman]

I’ve read the jet-tech article maybe no less than 50 times, and it sits on my workbench. Thanks for such great info on both the jetting and PV setup. Definitely helped get me up to speed on what to look for.

when I bought the kart, it had a 190 main and was even worse, much worse and would barely run until I was screaming it. Yet keeping the choke on helped as it does now. Now that I’ve cleaned everything out no harm in trying to go up from the 182 a few sizes at a time and see if things go in the right direction.

Was supposed to have a track day today and was going to try a friends spare carb, but the track was closed for a private session…grrrr.

Ordered a new power valve, bellow, springs etc, Mikuni fuel pump and other bits to start replacing if the spare carb makes no difference. Though the kart is an ’08, it had barely an hour on it (per the mychron4) when I bought it last year. Prior owner wasn’t into it so it was essentially brand new. Everything is in perfect condition, fuel lines tight, Rotax oem battery, etc.  Maybe I should just replace it with a nice new ’13 kart……

Thanks,

 

Mark

 

[Mark Grossman]

Thanks Eric,lots to think about. Regarding fuel pump I have the round plastic one, oem. Looking at mikuni pumps but not sure which model…44-210, 211 etc?  Wouldn’t mind having that on hand.

For the battery, other than being charged, what else could be wrong?

And I will order another bellow for the power valve. Measures out to spec but can’t hurt to try another too.

A friend does have a spare carb, so that is probably the quickest test And eliminates many questions. Hope to get a track day and try that out.

At high Rpms the motor is strong and clean, so confident it’s nothing major. Having fun tearing into this and learning about the motor.

 

mark

[Mark Grossman]

the coupler slipped on a friend awhile back, so I did check that. Didn’t see any movement and fully engaged. Wish that was it, but will double check it while I’ve got everything apart. From what I’ve read about the old clutch, my days of using that were numbered anyways. Thanks for the tip.

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