| Author | Message | ||
     Onahog |
Hey...Does anyone no about Thunderstorm heads bending valves ? I have a 1996 S2t with thunderstorm heads, 10-1 HD pistons and Screamin eagle bolt in cams..I bought this unit with 2 bent exhaust valves and a piston that is chipped out by the intake vavle pocket...Not sure what happened..Over rev?? set at 6250 rpm Headquaters ign...Missed shift and float? To tight clearances?...Any ideas or previous similar mishaps? You can reach me at hankb@mts.net I also listed on ebay a stock S2 seat and Carbon Fibre aircleaner if anyone needs one and I am looking for a Corbin Gun fighter and lady....TTYL.......hankb.....Onahog.. | ||
| Bluzm2 |
You better have Thunderstorm pistons to match the heads. Not sure if the HD's are the correct ones. You better check the pushrods too. They might be bent. Brad | ||
| Rick_a |
That's strange. 6250 is a really low rev limit. 6800 is pretty safe for a stock top end with bolt-ins. It would take a lot more than that to float some valves. I'm sure it was higher! For anything to bend valves is rare. The pistons/cylinders suffer most at high revs if the valve train is set up properly. It should be using Thunderstorm Buell pistons that have a 15 degree dome. If not it'll merely suffer from having low compression. Which cams are actually used? I had a guy who "bolted-in" a set of Screaming Eagle 536 cams 'cause someone else told him it was ok even after I gave him comprehensive instructions of what needed checking. The result was very similar. I've heard of that happening often with Andrews N6's, too. | ||
| Swampy |
Rev limiters only work on the way UP! | ||
| Onahog |
Thx 4 the replies.. Yes, the unit has the HD pistons with the domes..# 22671-98ya....It has a head quarters Ign # 21835 set at 6250rpm...Head #s 16826-98Y,16835-98YA......It bent 2 pushrods as well.. Im not sure which S/E cams it has, as all they have on them is a 5 digit # on each one, plus 1,2,3,4..Anyway of telling them otherwise? I ordered new buell piston kits, # 22677-98y, which gives me the same piston complete, and I think Im going to use some play dough and check all the clearances, I just havent figured out how to get the lifters pumped right up with out startin it..Ya think many hand turns would fill em? Any views would be helpfull...Hankb.. | ||
| Firemanjim |
Must have broken a cam or something similar so engine kept turning over but valves did not,voila,bent valves and pistons with funny marks on them. | ||
| Rick_a |
That's a good point. Check the pinion gear and woodruff key. Torque it to 70ft-lbs not the 30 in the manual...and use red locktite. | ||
| Onahog |
Hmmmmmmm Will do... Gotta try find out what cams these are...Listed in new topic..HELP...LOl | ||
| Buelldyno_guy |
Im going to use some play dough and check all the clearances, May I suggest using the play dough or clay to hold a few small 1/2 inch pieces of solder. Check dome to head in two places and each valve to piston. You want the piston to smash the solder so you can measure it. Of course if it hits so hard without the solder then You do have a problem. S/E 536 cams should work well with stock Thunder Storm and stock valve train. Now having said that if someone mixed and matched the parts during the build without checking the clearance that's the problem. Hope this helps. ... Terry | ||
| Hurricaneleah |
I agree with Rick/fireman and would definitely check your pinion. This happened on my X1 road racer. Also check your cam bushing for discoloration or to make sure they aren't spun in the cases. In my case, the oil pump failed, which caused the cams to lock up in the bushings, which caused the pinion to sheer/spin, which caused the valves to hit the pistons and bend everything. Typically #2 cam will be the first one to lock up. This is a worst case scenario of course! While your in the motor, I would suggest upgrading the oil pump drive pinion gear with the 2007 XB Bronze pinion. Cheap insurance. The 1996 S2 came with what was essentially a sportster camshaft (hence the low rpm limit), and consequently sportster valve springs. Even the thunderstorm heads used the stock sportster spring. I would say you are on borrowed time if your running a SE or andrews grind with the stock springs. I would upgrade those to the recomended SE springs while your replacing valves. This could be the cause of the failure as well if you have a weak or broken spring. There are two coils per spring so you have to inspect both to see if they are broken...the inner ones are tough to see. Good luck! It will be worth it...S2's are cool bikes. | ||
| Fiery_xb |
Hey Wes, How's it going?!!!! | ||
| Hurricaneleah |
Pretty good Nancy! Have just about recovered from Daytuna and everything is back in one piece again...Do you have your drag racer ready to go yet? Union grove opens for business next weekend! BRING IT!!!!!!!!! | ||
| Rick_a |
That is incorrect. 536's require springs and usually require stock pistons to be fly-cut for valve clearance on the exhaust side, at a minimum. Up to .500 lift bolt-ins are no problem, except for those with high TDC lifts. XB springs can handle such lift, but even then they are designed for a cam with "gentle" valvetrain dynamics and are I'll suited to steeply ramped profiles. Like I said before, one poor fellow I know took similar advice and pretty much destroyed his new cams and top end. '99-up M2's had a setup with stock sporty cams and Thunderstorm heads. Most magazine testers seemed to like that combination best. I prefer the N9's. They're a nice compromise IMHO. This is probably the best, most condensed source for such set up tips that I've come across, and some of the best folks to deal with. http://www.nrhsperformance.com/tech.shtml | ||
| Onahog |
NRHSPerf....Great site...Im studyin it... Thx Guys...I will let ya no my results...Hankb | ||
| Onahog |
NRHSperf site Has awsume engine info... Im doin the clay check on valve to pistons.. |
