how the 08 faired for us with lots of deep snow

[turboal]

been a long time , the 08 was with a few issues but over all a good ride for many .
the right belt and the better approach to clutching for 09 should hopefully prov more satisfying . 08 responded best to an increased secondery pressure in all track lengths .
this seemed to be due to such a hard duro on the track rubber , leaving it very stiff on the tips and running a higher load factor in the clutches as the track speed increased .

engine durability for us in our long winter this year proved interesting and that doo needed to address the poor porformance out of the primary components as they were possabily the cause to what we saw in crank failure .
good number of cranks seemed to be what is called out of phase . meaning the pistons werent 180 degrees apart but on a good shaker . being one that shook real bad at idle in near new condition . found them to be 178 degrees apart .

not sure what the primary clutch component failure is due to . poor crank true and phase on some or poor balancing of the primary clutch , which is more likely . seeing as we arent seeing the balance clips in the primary since 07 when they changed it from the 06 and older versiion .

was totally happy with the secondery , just needed more spring end load pressure for there approach . pulled stock gearing once we did this .gained mega track speed in the deep stuff.

so we cross our fingers and see what they do with the 09

be nice if they could find a ton more fuel milage hahaha

 

[Snowbyrd]

Al, What do you think about the helix angle in the 09's?

 

[turboal]

not likeing what i am hearing they are considering , see what they actually show up with

 

[Tuesday]

Welcome back to the forum AL!

 

[live2beel]

Well I was the proud owner of one of the ones that shook like a jackhammer. But not anymore, drove me crazy.

 

[WhistlerCowboy]

Welcome back Al.

 

[winter brew]

My '07 shook more than most, finally lost a skirt at 1200 miles that took out the bottom end. New '08 engine is MUCH smoother. Could be why I was eating rollers and bushings too.

 

[gus bohne]

If you really found out of phase on oem sleds that as you say were 178ish, that would put the actual ingition timing either advanced or retarded also.

That would show as funky jetting, deto of unexpainable nature and or huge vibrations that will absolutly ruin a crank and clutch in very short order..

WOW, that might explain why the 5 xp 800's I dynoed last year were all 138 or less regardless of tuning,,, just plain DOGS !

On all of the snocross sleds I prep , we religiously true the cranks before they get fired for the first time. Typically they range from .002 to .007 out of true right from DOO..( on the 600's) 440's were NEVER like these junks.
Phasing has NOT been an issue on the 600, even last years fiasco with ring locators, ring back cuts and piston backcuts....

Dyno Jim was nice enough to post the test of the stock 600rs,, beg him to show you what the factory mod kit did..I dare you ,, beg him then be ready to laugh ,,,, and laugh you will....




Gus

 

[diamonddave]

Welcome back Al, how many d-shafts did ya see go down? Was also wondering if anybody had any experience running the 2.5 inch camo extreme track and if it would help a little in the clutch area.

How'd the bigbores hold up?

 

[turboal]

ya the whole season had a typical doo new model pattern to it . had we seen them delivered with the proper belt we would have had a lot less issues , throw in with it the belt tension locking device not working and you would have had a little less frustration all around .

drive shafts werent a major , one's zz here and there , more 07 cranks still out did the drive shafts failure but the 08 motor when they put them in the 07 pretty well fixed that end of the 07 problem .

both years are suffereing a major change in internal service life on the components in the primary . comparing it to the 06 and older primary and when we saw it need the same internals replaced has gone from 5000klm's to under 1000klm's with this new primary .
similiar primary on the 1000 and we dont see the same wear issue on it .

something is buzzing it apart and when we see the pimary wear this way you gotta know it isnt doing anything good to the internals of the motor .
typical failure on the internals is showing up on the center two main beatrings on the ones we have seen fail .
love the motor , hope they have a idea as to what and were .

the chassi is capable of flowing roughly 7mph more ground speed in the deep stuff than the older rev chassi . a lot better clearence in the tunnel on the 08 .

the stiff duro of the track that we hd last year had everything to do with the slower track speed we initally saw on the 08 versus the 07 .

once we squeezed the secondery harder we solved the track speed issue and a bunch of other issues at the same time .

actually we started the season expecting to see the 08 get bent , but after the season we can say it is one tough chassi .

oh just a tease here but there was fresh snow on mt revelstoke this am .
darn global warming

 

[Original Tetonice]

Al, same old same old once you address the historic issues that have plagued skidoo mountain sleds for years the XP like all Summit sleds work very, very well.

I hOTad a great time on my XP after 1900 plus miles and great compression in both jugs at seasons end.

32 degrees already here in the high country.


OT

 

[Dynamo^Joe]

My opinion the engine power and mismanagement has overcome the capacity of the wear components for this primary clutch.
The magnitude of the powerpulses, crankshaft phase in or out, contribute to premature bushing wear.

I believe the bushings need do be built with larger diameter but more importantly wider to reduce the damaging bending moment the clutch sees and causes sheave deflection.
...needs a tougher design primary tra primary.

 

[hatchers]

im done with Doo engines, the XP was by far the best sled ive owned....but the fuel curve on the 08 was a freakin rip off, hope the shops can recurve the 08 next year......all in all, the utilmate sled would be the M8 BD turbo in a XP chassis IMO....might have to doo just that

and talk of a decent doo helix is crazy.....never have, never will, buy the DJ helix and do your own weights and springs IMO, the doo 44/33 was still not enough for me as i really whated that nasty back shift that the DJ helix gives you

 

[turboal]

we saw it in the bike world when they tried to get big with an up right twin , they had to go to a v twin to loose the destructive vibrations and once they wen that way they were able to go real big on the bore .
once you are able to do that then you can slow down the rpm and get some longevity in the power department .
i like how cat approached the lay down motor in the m7 and m8 .
who has the longest lasting large displacment that lives very long inthe industery .4 strokes will win this and maybe the industery will see this as more important than what we are seeing for life in the 2 stroke motors of todays 800's