Take a Look at These Plugs Please

[Broz]

What are you going to do for elevation and temp changes? Re-jet every time? Or are you going to do a vari-flow altitude compensator, dial-a-jets or something along those lines?

This Sled has the HAC.. High Altitude Compensation and I just calibrated the pod. As I shared in this thread. This was before milling the head to up the squeeze.

https://www.snowandmud.com/forum/f463/670-summit-high-altitude-compensator-hac-41125.html

Jeff

 

[drewski]

perfect!

 

[Broz]

Well she survived a mountain run over the weekend. We were as high as 7500 feet and the HAC did fine. It was still pulling good rpm and no fouled plugs. Sled runs really strong. We are still fighting an irratic idle issue with it. Some times it wants to pull down and idles really slow (under 1000) and sometimes dies. Can be a bit hard to start after warmed up good, then setting a while. Seems to always want a light throttle oening when hot, especially after a set of 10 or so minutes. We have played with pilot size, air screws in and out, float level etc. Seems to me the idles speed screws are in to far too. It wants a large air gap under the slide and that has me puzzled. Right now we are looking into belt alignment, deflection and some minor clutch tuning. I have a hunch the belt is a bit tight and pulls the idle down at times. This reminds me of racing, always looking for a bug..:d

Jeff

 

[0neoldfart]

Well she survived a mountain run over the weekend. We were as high as 7500 feet and the HAC did fine. It was still pulling good rpm and no fouled plugs. Sled runs really strong. We are still fighting an irratic idle issue with it. Some times it wants to pull down and idles really slow (under 1000) and sometimes dies. Can be a bit hard to start after warmed up good, then setting a while. Seems to always want a light throttle oening when hot, especially after a set of 10 or so minutes. We have played with pilot size, air screws in and out, float level etc. Seems to me the idles speed screws are in to far too. It wants a large air gap under the slide and that has me puzzled. Right now we are looking into belt alignment, deflection and some minor clutch tuning. I have a hunch the belt is a bit tight and pulls the idle down at times. This reminds me of racing, always looking for a bug..:d

Jeff

670's shake like a dog s**tting tacks - replace the viton tipped needle / seat assys with the heavier brass ones available through BRP or Mikuni. It will idle and start better. ( I don't recall the p/n, but pretty sure it was used on the older Mach 1's with 670 and twin pipes). The lighter viton needles "bounce" at idle, raising the float level in the carbs. Hope this helps you.

 

[Broz]

670's shake like a dog s**tting tacks - replace the viton tipped needle / seat assys with the heavier brass ones available through BRP or Mikuni. It will idle and start better. ( I don't recall the p/n, but pretty sure it was used on the older Mach 1's with 670 and twin pipes). The lighter viton needles "bounce" at idle, raising the float level in the carbs. Hope this helps you.

Great info, Thanks! We did a complete belt alignment and adjustment on the sled and it definatly helped. It appears the belt was a bit to tight and would get hot sitting and idling and drag the motor down. Last time out she ran like a top. But I will get a set of the brass needle / seats and have them ready to go if needed.

Thanks again for the nfo.

Jeff

 

[OVERKILL 19]

Did the plug chop today what do you guys think?

 

[Darrell262]

Last picture doesn't seem like it came through. I had a 98 Summit X, after putting a muffler on it, I squeeked it 2 times and the dealer told me to not run the 350-340 offset and run both at 350. I ended up just leaving stock muffler on it. Something to think about. As I am sure you know, these sleds don't like to be pointed downhill lol, Also a suggestion, I bought a engine brace to help keep alignment on the clutches during climbs.
What about running 1 jet size up extra for safety?