98-700 w/ slp twins

[Thunder101]

looking for some feed back, I have a 98 700 with 220cyl raised ex ports 40 mm flats, v force w matched carb boots, goes good = to my buds F7 but
i was expecting to pull more rpm but 79-8050 was it ? are the pipes holding
it back?

 

[mtn junkie]

looking for some feed back, I have a 98 700 with 220cyl raised ex ports 40 mm flats, v force w matched carb boots, goes good = to my buds F7 but
i was expecting to pull more rpm but 79-8050 was it ? are the pipes holding
it back?

I would say spin it at 8300 I had one back in 97 and if memory is right I turned it at 8300 to 8400 with slp twins I would start fine tuneing by first make sure the jetting is right then start with lighter weights in primary clutch it shouldnt take much go half gram increments. I think I had 56 gram lighting weights in mine. and if that doesnt work check timeing under aload good luck

 

[jgd]

I ran a similiar '98 700 w/220's, 40mm mics, SLP heads, SLP Twins, etc. Those SLP twin pipes make their power between 8,000 - 8,200 RPM. If you spin it over 8,200 RPM you will be losing power. Also, if you're using the stock tach, you can't really trust it's accuracy. :beer;

 

[olymon]

how old is your primary spring? You could get a new one with the same starting spring rate and another 20 lbs. or so higher finish rate. Cheaper than getting a set of weights.

 

[sled_guy]

I ran a similiar '98 700 w/220's, 40mm mics, SLP heads, SLP Twins, etc. Those SLP twin pipes make their power between 8,000 - 8,200 RPM. If you spin it over 8,200 RPM you will be losing power. Also, if you're using the stock tach, you can't really trust it's accuracy. :beer;

I just pulled out my notes from my '98. Carl's Cycle porting, SLP canister style twin pipes, Himark Head, Keihin carbs. Jack's porting setup called for 8400rpm and that's where I ran mine and it pulled like a sun of a gun. As jgd said, don't trust the stock tach.

What altitude are you running at?

sled_guy

 

[Hillboy]

sled guy and I had the same set up what pipes are you running that is the key and are the carbs bored by who my 39 bored were 42.5

 

[jgd]

Maybe I misunderstood the post. The 220 jugs had the more aggressive porting and were found on the 97 and some 98 700's, I thought that was what Thunder101 was talking about, my mistake. However if the porting is stock 220, then the SLP pipes are designed to run between 8,000 and 8,200 RPM. If your porting is "enhanced" (like the Carl's job) then I would defer to sled_guy. I'd rather be riding :beer;

I just pulled out my notes from my '98. Carl's Cycle porting, SLP canister style twin pipes, Himark Head, Keihin carbs. Jack's porting setup called for 8400rpm and that's where I ran mine and it pulled like a sun of a gun. As jgd said, don't trust the stock tach.

What altitude are you running at?

sled_guy

 

[Thunder101]

Ive raised the exaust ports 2mm I would have to find my notes,,,,,this was my first go at porting a 2stroke. so I never took the notes like I do now. I was just looking for some info on how I should go at this.
I put this together a couple years ago and it went good but I have two other sled that I ride and work on so this one has sat for a while now. I was thinking of cutting 1" inch out of the header pipes. or less ?? I could not even start with the math for pipes but I do know that will effect were the power comes in.
I will look for my notes tonite.
my thinking is that I added 10* of exaust duration and that should have moved the power peek up rpm so Im thinking the pipes might be holding it back. ? tuned for lower rpm then my porting is ?