670 clutching

[prairieguy]

wow i feel like a little kid learning to talk lol this is my first ski-doo project and i've never played with ski-doo clutching so forgive me for all the questions this year.

i'm running a 98 670 non ho in a 01 500 summit chassi (s2000) 136 stock track
just finished putting new top end in, went once over
i'm going to regear it to 23/43 13 wide (500 was only 11 wide)
running 500 secondary which is a RER clutch with a 50 deg helix maroon spring
now my question i can't get top rpm so i pulled my primary apart to find out
that i have hollow pins and 299 ramps stock ramps are 286 for the 670's why would there be 299 ramps in there? like what would you want to run them for? so my question is what ramps should i put in the sled? i don't really know what each different ramp will do.

also what are you guys running for jetting? the sled has 40mm carbs and no DPM the manual calls for 290/310 with 60 pilots i'm around 3000 ft. i'm running a short boot with no oil pump set up with a 50:1 pre mixture i know i have to jet up for bigger pistons but should i be running a stronger mixture because i was running 350's and my egt's where reading hot. is that because with a oil pump my mixture is stronger than what i'm premixing? i also can't get the engine to idle @ 1700rmp but i'm running 45 pilots if i put bigger pilots in will that help the idle issue?

i bought this engine and clutch from a friend and he had it all messed up(he had the 670 in a ski-doo mod with a 164 track and said it wasn't enough for him) so i'm trying to turn everything to stock and see how it runs in my summit chassi and then work up from there.

i'm only 19, going to college and trying to work on amy sled on the weekend when i can get home and money is kinda tight or i would be driving a new sled (i love working on sleds so this is why i'm doing this convertion)

if anyone has some info that will help me please feel free
thanks
joe lukan

 

[NoSecondChances]

45 pilots seem small to me.

EGT's could be showing really rich fuel burning in the pipe. Don't tune by your EGT's, use plugs and piston wash to set your jetting and then use your EGT # as a reference point (i.e. if plugs look good and wash looks good but EGT's are only reading 1100, use 1100 as your reference point for a good tune). This was a Summit motor right? Go to 286 or 287 Ramps IMO. I have a book of info at home on this sled, I can look it up for you.

You can go to www.StBoni.com and look up your yr and model for the specs too.

If you are on a budget, play it safe and keep it rich and tune conservatively. Better to foul a plug than not have a sled to ride... I'll PM you later with some more info. Good luck!

 

[winter brew]

I always liked the 294 ramps on the 670's. 200/320, 294's. as much weight as it will pull under a load. Shallow out that helix a bit if you can and consider gearing down a little.

 

[$nowMeansBroke]

Another college kid on a tight budget here
Mine is a '93 Mach 1 670 engine in a '97 Summit 670 chassis that I put a 144x2 track under. I don't remember for sure what the gearing is now though.

Here is what was recommended to me for clutching from a few different people.

Primary:

286 ramps
160/290 spring---Purple/Blue
Lightweight Adj. Pins ( 12 to 13 grams)

Secondary:

Straight 47 helix
Beige spring @ B-6

 

[prairieguy]

does any one know the differences between the 286 ramp and a 294 ramp is one heavier than the other?

also i ordered a summit 670 primary spring from ski-doo and they gave me a black tal spring the one that was in the sled was shorter and black with two different colors. does anyone know what they might be?

thanks for the help everyone