turbowrenchhead

Update: The stance of the bike is way better then the GT Thunder built one. I got to hit a few jumps on our spring ride in Big Bay MI. It never bottomed out and landed nice. I'm very happy with Richard at House of Horsepower.

I'm curious about the two different options that come with a +4 crank. What are the advantages or disadvantages between the short rod or the long rod? I will eventually drop a +4 into my motor but I would like to understand the options better.

You guys were right. The bottom end was terrible. After 30 mins of riding and the temps rose to 90 degrees it started bogging bad. I dropped the mains down to 440 and still bad. I pulled my jugs to make sure that the pistons were ok and they were. I had a .020 base in it and all I had on hand was a .030 base. I put that in and put 21cc domes and 420 mains and then it ran good after I got it rolling. I ran it like that the rest of the weekend. I pulled the plug and there was black and brown on the plug. Little rich but that was fine by me. The top end power was awesome. I pulled right to the top of 6th no problem. I was grabbing for 7th a few times but it wasn't there. I pulled 75mph on dirt. The last day I was running wide open on a wide dirt road and it popped bad. I shut it off and here I had run out of fuel in the on position. No good. After that I must of drove two miles at 5mph because it didn't want to come out of the low r's. It finally started coming on and I kept it above 30mph to get back to camp. Pulled a plug and there was grey on it. I was done for the weekend. It was almost over anyway. I'm now on the look out for a pair of virgin jugs to get professionally done. I want the bottom end back. If I can afford it I'll drop a +4 crank in it too.

Ended up with 460 jets. I hope it lasts the weekend

I'll has a set of stock cylinders professionally ported when I can afford it. Parts will run $1000 at minimum. Another $400~500 for dyno tuning. So yeah......oh how I wish I had unlimited funds.

I've done plenty of performance mods on customers cars atvs and snowmobiles. Just because I push the envelope on mine doesn't mean I don't know what I'm doing with other people's machines. Keep your comments to yourself please!

I didn't plan on spending $1800 this year and I really couldn't afford it but once I started I couldn't go back. I also started on the upgrades over a month ago. I was planning on having redline racing port a pair of cylinders this year. I bought a set of advertised 64.50mm cylinders that I was going to have professionally ported. The machinist measured them up and told me it would take a 66mm piston. So there was no way I was going to have that set ported. The seller wouldn't take them back either because I powder coated them. So I was stuck with the set. Money was really tight at that time so I did a DIY port job and planning on running them a season till I can get a decent set done. After the bad wash boards at the badlands I realized that my rear shock was no good. That cost me over $450 between the rebuild, another used shock and shipping. CDI $200 Coil $100 Ignition switch $40 Cylinders, decking, boring and weld, new studs $320 Pistons $190 Weld case $30 Gaskets, seals, o rings $80 Domes $120 V4's $200 New chain $100 Oil $20 Its easy to criticize when you have un-limited funds to spend on your toys. I have a limited budget and try to make the best of it. Its too late to do anything else with this build. I'm just going to have to try to jet it the best I can and cross my fingers. I picked up jets from 430 to 500 today. BTW the crank is the same.

Rings are fine. Ports were champhered

Yeah, stock carbs.

Doesn't bother me. I can still ride it just fine.

Bottom end feels just fine.

After $1800 in repairs this spring the bike is hauling ass! I was running 350 mains last year per dyno tuning and on the safe side of jetting. I'm did some wot runs tonight and I feels very strong. I put in 370's with this years new additions thinking thats all it would need. Upgrades: 66X54 Stock crank and pro lites DIY dune porting. intakes 6mm longer/1mm wider, exhaust 3mm wider/1.6mm raise port over last years pair. DIY case porting with roughed up trench surfaces. V4's 22.5 cc custom domes with a .048 squish 10mm band and 140 cranking psi. I ended up with the largest I had on hand, 420's. I'm starting to see brown in the color. Up to the 420's is was all grey plug chops. I even have my idle jet a 1/2 turn out on the richest setting. I was worried that I might have an air leak. So I put the leak tester back on it. Holds 7psi for 20 mins. I'm good! Now the next challenge, finding bigger jets locally. Too late to order them. I have to be ready by 5pm this Friday for the biggest ride of the year. This year even the DS650 will get left in the dust! Raptor 660's didn't pose a threat last year. For me to go up 7 sizes and still lean I must have made a significant increase in power. How much would you guys guess? I'm thinking I between 65 and 70hp

It was the original 87 shock that was rebuilt by gt thunder. They set it up with no preload on the spring. The one from richard has about 1/3 of the threads taken up for preload with a lighter spring

I don't have it.

Got my shock back today from Richard. I like the way the bike sits now. I have to wait for this weekend to get some trail riding in to see how it performs

I got my rear shock back from house of horse power. Now it sits nice! I threw my tank on and took it for a short spin. It feels good pulls hard

Use drill bits to sync the carbs. Slide a bit along the bottom of the runner and under your slide. Find a drill bit that fits under one slide. Take the bit and slide it under the other carbs slide and adjust your cable above the cap top sync your slides. Try squirting a small amount of starting fluid into the carbs and see if it will start. Then that will tell you if it's fuel or spark

I bolted the head back on and did another test. This time I used two pieces of solder through the spark plug hole and put them on opposite sides of the piston above the wrist pin. I though this was an easier way. I did several readings this way and I get .048-.050 depending on how much pressure I put on the caliper. Before I was measuring the solder perpendicular or across it with the caliper. This time I measured the middle of the solder parallel with it. I think that this would be more accurate then across it. I emailed David the info. I gave him tons of specs and info so the ball is now in his court. He has way more experience and I trust his judgment in cutting me a set of customs. I'm sure they will out perform off the shelf's.

My cracking compression went from 160 to 145 with the change the base. Now the online uccr calculator puts me at 12.9:1 with 155cc's of fluid I the chamber

I pulled the head off Saturday morning to measure the domes clearance and width for David. I got a .034 clearance and 22mm width. My deck height is .006 under. So not sure why I have a .055 squish. I'm mmeasuring above the wrist pin. There is no play in the rod bearings. Hmmmmm........

My cracking compression went from 160 to 145 with the change the base. Now the online uccr calculator puts me at 12.9:1 with 155cc's of fluid I the chamber

He's not cutting them till Tuesday morning. He wants me to do another squish test. It doesn't make sense how my squish went up by .010. I'm out of town till tonight.

What squish and band width should I go for?

Just not optimal

I got the bike running just now. Sounds nice! Now I have to wait for my rear shock and Noss's custom cut domes.