2001 XP restoration - 951 cylinder boring

[Wolverine]

Still working on my 2001 XP restoration (951 engine), went from D.O.A (sitting in the woods for 11 years) to running (poorly). After some work (see below), got ski to currently hit 50rpm at 5000 rpm. Yes, when new, she topped 64mph and around 7000rpm. So far I've rebuilt the carbs (mikuni), new solas prop, prop housing, wear ring, RAVE valve rebuilds, reed valves in great condition, checked carbon seal and shaft (look good), etc... Each of those updates gained me a few mph, rpm. The piston, rings and cylinder sleeves have scoring, etching and damage. I am having a machine shop hone (and or bore) the sleeves, they 'think' they might be able to go minimum .25mm. I 'read' you can slice .25mm on 951 without altering the RAVE blades. Is this correct? Since I have to widen the sleeves should I go minimum .25mm (with no RAVE blade altering) or would .50 or even 1mm provide me any benefit (speed gain)?

And, planning on removing the oil pump (mix gas/oil manually), and bypassing the RAVE valve solenoid using the 'drill hole in RAVE valve housing method'. Comments?
Lastly, looking for recommendations for the top end purchase (WST pistons or other)?

 

[mikidymac]

Only go to the next bore size to clean up the cylinders, no performance to be had going bigger.

No, keep the RAVE solenoid, do not go drilling holes.

Pro-X and WSM are fine rebuild parts.

 

[Wolverine]

Thank you Mikidymac... I was on the fence about the drilling the RAVEs. Are you aware of a video or Forum link that lays out how to test the pulse line from engine to solenoid?

 

[shamrock246]

I would keep the oil injection and just replace the line and bleed it.

 

[Grim]

Just my two cents, do only what is needed to get it running first, then make "aftermarket upgrades" when you know the engine is running well. If you change too any things you might not be able to chase down the problems as easily. Most people on the forum will tell you to leave the oil system in tact, it works great and is reliable, just make sure the hoses are in good shape. Your choice really. Honestly, I have looked at a lot of the aftermarket upgrades and haven't found any that are worth the time/money. Seems like they built these engines at their sweet spot and there isn't much more to get out of them...for the money.

My 98 GTX ltd was parked for several years too, these guys gave me a lot of good advise. One thing I did was replace all the hoses and verify all the check valve were working. I also replace all filters and anything with a seal/o-ring. Be leery of aftermarket parts, there are a few good ones out there but I would stick to OEM as much as possible. Good luck.

 

[Wolverine]

Thanks... I defer to the experts and will keep the oil pump Next question... I may be overthinking this, but I looked at the stamping on the elbow fitting on the head pipe, where the line runs to the water regulator. The shop manual (page 07-02-15) shows the stamp should read 16, mine reads 18? This is the original engine, any 2001 XP expert have a suggestion? Replace with 16 or the shop manual is incorrect?

 

[mikidymac]

Shop manuals were all over the place. Leave it there as I am sure nobody went to the trouble to swap it out.

 

[Wolverine]

Thanks again Mikidymac, I am probably overthinking some things but reading all the threads and watching videos on youtube, the information can get overwhelming/confusing.

 

[2strokeboy]

I doubt someone changed out the fitting but if it is wrong then that could cause performance issues

 

[etemplet]

I don't have a link but I found a page that told the inside diameter to the corresponding number on the fittings.